Computer game theory


This project is a study on making the game Spy Of Sky and a coherent animated movie. Spy Of Sky is a top-down scrolling shooter game, where the main purpose is not to get discovered.

The main problem of the project is to make the enemy air planes of the game more intelligent and how realistic behaviour could make the game more fun and challenging. Artificial intelligence is the main research area and the focus of artificial intelligence is beneath the branch, that is called, autonomous agents.

The animated movie is an introductional cut-scene, which includes a small narrative and introduces some of the key game play elements of Spy Of Sky.

Testing Spy Of Sky has showed that people find it very much like some of the old arcade games, like 1945, wings of fury among others. Research of those games has given some nice ideas to implement in

Spy Of Sky contain four mission, before the final, where the president of Gatrukistan must be assassinated.

The Artificial intelligence of the enemy are build on theory of the book AI: A Modern Approach by Stuart Russell and Peter Norvig, two of the leading in this field. The enemys of the game will be autonomous agents called simple reflex agent, that uses state driven design to choose between their behaviours. The agents are FSM, finite state machines, which is a procedure to define each behaviour of each state and the transitions from state to state.

Their behaviour is based on the behaviours of what would be expected from a real pilot under these circumstances. 

The movie of the game, which is made in Maya 6,0  a 3D software, is  limited animation and will be described from a narrative point of view as well. The construction and testing of the movie, the changes from idea to editing will also be described throughout this report.


In this report I am working with Artificial Intelligence (AI ) at autonomous agents. I will apply AI on autonomous agents in the game, Spy Of Sky, to make the air-battles in the game more realistic and challenging.

Furthermore the development of Spy Of Sky and a coherent animated video, will be described in details.

The research area is the branch on AI that is called autonomous agents, which previously has be researched in AI: A Modern Approach by Stuart Russell and Peter Norvig, ISBN: 0131038052

Besides that research about limited animation and computer games principles.

Problem statement:  

Can I sophisticate the A.I of the enemy airplanes in a traditional arcade scrolling game, a thereby make the air battles more challenging and realistic.

Sub problem and questions

How would a human pilot of an enemy airplane or helicopter react and behave under these circumstances.

Through this project I will research on how human behaviour can be transmitted into autonomous agents.

How do I make a game play that is based on not getting discovered and how can I illustrated that with an intro cut scene.

What is the definition of animation and how does it relate to my project and the history of animation.


Due to the limited amount of time and resources I have chosen not to focus on following things during this project:

Political/ethical aspects.

Marketing/promotional aspects.

Economic considerations.



Background Research

The main research area of my project is AI at autonomous agents, which is a pretty large area. But I will focus on the areas related to my project.

I will look at some taxonomies of AI at autonomous agents and some design principles for autonomous agents.

Further more I will research about related games and limited animation.

Game research

Related games

Because of the many good comments about Spy Of Sky being an arcade look alike game, I have researched on some of the old games, that was popular and what made the so popular

Games Research:

Based on articles[1], reviews[2]&[3] and own experience by playing.

  • 1945

1945 is a classic top-down arcade shooter. The fast paced game features a variety of enemies and pick-ups, plus many new weapons.

  • 1942

Very much like 1945 but look different.      

Early 1942                               Later 1942               1942 Bozz

  • R-type

R-type is very much like 1945 except that it takes place in the future and the scrolling is side wards instead of top-down.

“You are the last pilot on Earth, and you must fly the untested R-90 against the Evil Bydo. Great game features like three unique Force pods with their varied weapons;Round Force, Shadow Force, and Cyclone Force. Excellent level design with outstanding special effects make for a great arcade experience. Blast your way through amazing levels filled with hordes of enemy inhabitants, and insanely huge bosses!”[4]

So end of level bosses are also a major difference between R-type and 1945.

  • Xenon 1 og 2

Xenon is a top-down scrolling space shooter game. There are rows of enemies twists around in unpredictable patterns like small worms. Between each level the player has the opportunity to upgrade the ship. There are many types of power-ups and end of level monsters.


xenon2                                                              xenon 1

  • Agony

Agony was one of most popular side scrolling shooter for the amiga platform. The sound and the graphics was very intense. The game play was rather boring and the game wasn’t that replay able. But the one thing that made it interesting was the struggle to get weapon upgrades. The upgrade function had many levels and was pretty cool.

Off course many other games can be mentioned in this forum, e.g. asteroids, space invaders and so on, but to those games above had some similar trait with Spy Of Sky and had some unique elements of individuality.

  • Wing of fury

“Wings of Fury takes place in exactly 1944, during the Pacific theatre, where you get to take control of a F6F Hellcat, a small but very versatile fighter plane. Your mission is to aid a temporarily stranded aircraft carrier by bombing nearby islands, shooting down enemy aircraft, sinking enemy ships, and generally being a pain in the Japanese butt.

Generally Wings of Fury is a very satifying experience with many minor but nice details, such as the F6F Hellcat slowing being lifted up from the belly of the carrier, and just dipping slightly towards the water as it lifts off from the end of the runway, and then seconds after automatically pulling up the wheels and hook. Flying more than around 50 meters above water level will shift the viewpoint from close up view to a macro view. In this perspective you have a better view of the overall picture when dropping bombs, but in order to strafe you’ll have to get closer to the ground. This will of course leave you more vunerable to the enemy’s AA fire. Getting hit results in oil leakage, and you’ll eventually have to return to your carrier for repairs, fuel refill, and getting fresh supplies of nasty things to drop on the Japanese.”[5]

Conclusion on research:

I will try to take some of the best aspects from some of the old popular games. Two main things stroke me during this research, which was the wide spectrum of equipment, that was obtainable and the end-of-level-monsters also called the “bosses”.

The idea with the equipment, was very good and easy to merge into the universe of Spy Of Sky. The bosses was quite different. Many of the games with bosses where saveable games, where it might take the player half an hour and 50 attempts to achieve the skills to beat the boss. Besides that, the boss is about being good to steer and shoot, and Spy Of Sky in about not getting discovered.

I some way I have a boss, but the boss is the additional mission at the end of each level. So the bosses in Spy Of Sky is:

Level 1: Running crossfire at the border

Level 2: Running crossfire at the border, advanced

Level 3: Plant the bomb

Level 4: Assassinate the president of Gatrukistan

What is AI

AI Depot is a website dedicated to the field of AI. Its aim is to provide a focus point for the community, with regular features, recent news and useful resources.

They has this definition of AI[6]:

“Artificial Intelligence is a branch of Science which deals with helping machines find solutions to complex problems in a more human-like fashion. This generally involves borrowing characteristics from human intelligence, and applying them as algorithms in a computer friendly way. A more or less flexible or efficient approach can be taken depending on the requirements established, which influences how artificial the intelligent behaviour appears.

AI is generally associated with Computer Science, but it has many important links with other fields such as Maths, Psychology, Cognition, Biology and Philosophy, among many others. Our ability to combine knowledge from all these fields will ultimately benefit our progress in the quest of creating an intelligent artificial being. “

As you can read, this research area is pretty big. Thoughout this report I will focus on AI at autonomous agents in relation to computer games. According to Wooldridge and Jennings[7] an autonomous agent is that includes topics like sensing, models of emotion, motivation, personality, and action selection and planning.

AI can be divided into these cells to get an overview of the purpose of AI[8]:



Figure 1, AI overview

AI for autonomous agents

In the following abstract I will talk about how AI can be applied to agents. An autonomous agent is an agent that exercies control over its own actions[9].

When talking about AI for autonomous agents there are 4 kinds of agent types[10]:

  • Simple reflex agents
  • Model-based reflex agents
  • Goal based agents
  • Utility agents

Simple reflex agents are the most simple of those. They percepts the state of the environment and based on the condition of the environment, they perfom a action, the so called condition-action rule.

This could for example be a automatic vacuum cleaner. [11]

“If status = dirt then return suck

Else if = location A = return go right”

Else if = location B = return go left

Model-based reflex agents percepts the state if the environment. But it also considers how the world evolves and what actions it does. Based on those circumstances it also performs a condition action rule.

This could be the ghost of pacman[12],

It checks the world if pacman is near. If it is near it chases it. If the pacman is near and has eaten a cheese if will try to evade. Besides that is has some of the features from simple reflex agents, it uses to move around the maze.

Model-based reflex agents are often state driven. Like the example with ghosts of Pacman where it is showed how it is state driven.

If this state then return this action.

Else return this action

Model-based reflex agents are normally more complex than this example, and can have an infinite number of states.

Goal based agents percepts the state if the environment. Consider how the world evolves and what actions it does. But besides that it “thinks” about how the world evolves, if a action is performed.

This form of agent is pretty sophisticated and is used in many modern action games like Fifa soccer[13]. Goal based agents has states but is driven by a BDI. BDI means Belief, desire and interest. The belief is referring to the perception of the world. The desire is referring to the goal of the agent. And the interest refers to the actions it does.

Utility agents is the same as goal based agents, but has a build in function, that is a kind of success criteria. How happy will I be if do this action, it asks itselves. One can say that it has the ability to make forwarded thinking.

Utility agents are used in more advanced games and is the used by the cutting edge developers.

The cutting egde and the future of AI.

[14] “Chris Butcher the developer of the A.I. for halo1 and 2 stated few thing that made his A.I. into one the most sophisticated on the marked.

  • The character uses its AI “senses” to perceive the world — to detect what’s going on around it.
  • The AI takes the raw information that it gets based on its perception and interprets the data.
  • The AI turns that interpreted data into more processed information
  • The AI makes decisions about what its actions should be based on that information.
  • Then the AI figures out how it can best perform those actions to achieve the desired result based on the physical state of the world around it.

Because the characters are forced to perceive the world around them, they are, in many ways, limited like the player by their senses — in their overall awareness of what is going on around them. This limitation creates more lifelike behaviour for the AI characters, as they can be surprised, make mistakes and decisions based on their perceptions of what’s going on around them.”

So the development of AI in games has come pretty far. To test how humanlike an AI is, Turings test is used. Alan Turing (1950) made a test that should test if a machine could think and behave intelligently[15].

The test is having a human interrogator and a human and an AI system to answer on the other side.

                      Figure 2, Turings test – The setup for Alan Turing’s test of AI

So far no AI had been able to trick a human interrogator, but the AI is get closer and closer, so maybe in the future it will happen.

In the future we will see even more sophisticated AI. If Moore’s law[16] sustains the AI has pretty good possibilities for the future. Ray Kurzweil stated this[17] for future 2029 of AI, where the AI go beyond the human intelligence:

AI would be able to translate voices in real time, and would be used a lot in telephones.

AI would be able to play instruments a well a humans.

AI would be implemented in human brains.

AI is will have a consciousness.

Small computers would make AI able to be implemented in everything and everywhere.

It would be common to date AI-personalities.

Some researchers claims that Ray Kurzweil is overreacting, but the fact is, that his earlier predictions, where right and his predictions for 2009, which were made in 2001 is already about to become true. 

If we look at the recent knowledge in AI, it is not unthinkable that AI, might change the theory of computer games. In my opinion the difference between computer controlled characters and player controlled characters will be blurred. When first an AI has passed the Alan Turing test, the theory will change drastically.

Richard Bartle, MUSE Ltd, Colchester, Essex, United Kingdom. Wrote this article[18] about player types in MUDs, that categorizes players into four categories based on their purpose of playing. The socializer of the graph below will be reconsidered. The player term used at left would change name an be called character, because one can distinguish between computers and humans. Especially not if all communication is non-speaked.

Interest graph




animation research

In this abstract I will write about animation as concept, my own idea and how I relate my opinion of what animation is to my animation in the game.

As I started brainstorming on the idea of animation, I found out that I would like to make an intro animation for my game. Trailers and in-game animations where irrelevant, but a nice introductional cut-scene, could also be interesting to work with.

As the work progressed I found out that I wanted to make a intro scene, that told the story of the game and that could introduce some game play elements. Besides that I would make a level introduction, where an officer tells about the level.

What is animation

As working with animation, my opinion on the concept animation has turn far from my starting point. My first thought was that is was movement over time, a very physical way of looking at it, but soon found out that it was more than that.

Following are some public definitions of animation:

  • “Animation is the process by which we see still pictures MOVE. Each picture is shot on film one at a time and is shown at the rate of 24 pictures per second making the pictures appear to move”. [19]
  • “Animation is the art of bringing something to life”. [20]
  • “A simulation of movement created by displaying a series of pictures, or frames. Note the difference between animation and video. Whereas video takes continuous motion and breaks it up into discrete frames, animation starts with independent pictures and puts them together to form the illusion of continuous motion”.  [21]
  • “Animation is the simulation of movement through a series of pictures that have objects in slightly different positions” [22]

To see animation in a bigger perspective one need to know what animation is good for.

What is animation good for:

Nielsen (1995) stated [23]

  • Indicating movement
  • Illustrating change over time
  • Visualizing three-dimensional objects
  • Attracting attention

The two most important of those if you want to find a definition of animation are the two first. So animation is indicating movement and are illustrating change over time.

My definition of animation

Trying to define what animation is, I thought it would be a idea to divide it into a mathematical, a humanistic and a general approach.

A mathematical explanation including the laws of physics. 

Mathematical explanation:  An object changing position an over time.

The physical definition of velocity is;  Changing of position over time.

Critique: two pictures showing the same object at two different positions is according to this definition an animation, but it would be bad animation, that is more a comic stripe.

A humanistic explanation including a philosophical perspective.

Humanistic explanation: bringing a dead object into life.

Critique: very philosophic, but doesn’t say that much. What is life? And is it really alive?

My own definition on animation

General explanation:  Animation is the simulation of movement through a series of pictures that have objects in different positions over time.

Critique: This definition includes the mathematical  and humanistic approach and is short and precise. It doesn’t say anything about what kind of movement it is or how fast it is, so it is still open for interpretations.

Interpretations can good because, movement, pictures and different positions are difficult to define and are very different in different types of animations.

Movement covers both a robot arm making the same movement over and over again and e.g. a horse running, which is more anima[24] movement. Movement covers abstract as well as obscure movements and don’t care if the movements is lifelike or dis-lifelike.

Norman Mclaren stated that it is not the pictures that makes the animation, but the in betweens/ difference. His opinion I find very true and is in my definition covered by the words, “through a series of pictures”. The single pictures are depending on each other.

The word, simulation, is very expressive as the movement is not taking place from a real/physical point of view. Then there is a grey zone, which is a flock of birds, that is flying around and suddenly in the flock is looks like the face of a famous person shows up and is blinking with his eye. This is not a physical pictures that you can take home, but its definitely real and again only a simulation.

The word pictures covers both the physical ones and those generated on the retina in the eye. This is important thus old animation techniques like shadow theatres, is not digital or drawn, but animation in real time.

How does this definition relate to my animation

Animation is the simulation of movement through a series of pictures that have objects in different positions over time.

Looking at my own animated movie in relation to my definition of animation, some interesting questions pops up.

Limited animation includes among other things still pictures, where symbolism or sound carries the story through. According to my own definition this is not animation because there is not movement over time. Thinking about that, I must state that I don’t think still pictures is animation, but I see it as a part of an animation, so the word limited, covers it pretty good.

The rest of the movie has either particles or polygons (objects) that changes position over time and thereby creates simulation of movement.

When one tries to define something, there is always aspects that are more covered than others. The purpose of definitions is a short cut to understand a bigger area of knowledge. I think that the only way to define animation is learning by doing or in other words, experience. By this I also states that there is no wrong definition of animation only different opinions.

Research animation

In this paragraph I will research and discuss the use of limited animation.

 Wikipedia says:

“Limited animation is a process of making animated cartoons that does not follow a “realistic” approach. The short cartoons and feature films of Walt Disney from the 1930s and 1940s are widely acclaimed for depicting animated simulations of reality, with exquisite detail in every frame. However, this style of animation is very time-consuming and expensive. “Limited” animation creates an image that uses abstract art, symbolism, and limited movement to create the same effect, but at a much lower production cost. This style of animation depends more upon “suspension of disbelief[25]” to tell a story; the story exists more in the viewer’s imagination. It also encourages the animators to indulge in artistic styles that are not necessarily bound to the limits of the real world. The result is a new artistic style that could not have developed if animation was solely devoted to producing simulations of reality. Without limited animation, such ground-breaking films as Yellow SubmarineChuck Jones‘ The Dot and the LineJames L. Brooks‘ The Critic, and many others could never have been produced.

The process of limited animation also allows for animation cells to be duplicated, resulting in a lower number of separate frames per second. While the standard rate of film projection is 24 frames per second (and video projection, including VCR and DVD displays, are as much as 30 frames per second), cartoons produced through limited animation may have as few as 12, 8 or even 6 frames per second. The reduced number of frames causes the halting, “jerky” motion seen in lower budgeted TV cartoons, as opposed to the smoother flow of animation seen in most feature films and high-quality TV animation.

Limited animation was originally founded as an artistic device, though it was soon used widely as a cost-cutting measure rather than an aesthetic method. The UPA studio made the first serious effort to abandon the ultra-realistic approach perfected by Disney. Their first effort at non-realistic animation, Gerald McBoing Boing, won an Oscar, and it provided the impetus for limited animation to be accepted at the major Hollywood cartoon studios, including Warner Brothers and MGM. However, the real attraction of limited animation was the reduction in costs: because limited animation does not place a great emphasis on detail, it is much less expensive to produce. The 1950s saw all of the major cartoon studios change their style to limited animation, to the point where painstaking detail in animation occurred only rarely.

Limited animation techniques were used during the 1960s and 1970s to produce a great number of inexpensive, poor quality TV cartoons. Such TV series as Clutch Cargo are infamous for being produced on ultra low budgets, with camera tricks used in place of actual animation. Despite the poor quality of the animation, the TV cartoon studios Hanna-Barbera and filmation thrived during this period. Japanese animation, anime, is also known to use lots of limited animation, especially in TV series.

The cost-cutting techniques used to mass-produce cartoons on a low budget included:

  • cells and sequences of cells were re-used over and over again — animators only had to draw a character walking one time.
  • only portions of a character, such as the mouth or an arm, would be animated on top of a static cell.
  • the visual elements were made subsidiary to audio elements, so that verbal humour and voice talent became more important factors for success.

Animated cartoons which made good use of limited animation included Gerald McBoing BoingMister MagooThe Rocky and Bullwinkle Show, and South Park.

In recent years, nostalgia for the 1970s, combined with technologies such as Macromedia Flash, have led to a revival of the genre of limited animation.”  Following quotation is borrowed from

Some other common features used with limited animation is flattened perspective/dead background, abstract backgrounds, strong primary colours, which all share the low production cost which is typical for limited animation.

One of the latest limited animation success, South Park, where made in Macromedia Flash and has a characteristic limited animation, which where to be seen on the halting movement and lack of movement. It made a huge success because of the lines, with humour and bad language.

 “And compared to the massive $5 million­ to $6 million­per-episode budgets of hit sitcoms like Frasier and Friends, animated half-hours are cheap to produce–running only about $2 million an episode.” Written By Alan Waldman (From the May 2000 issue of “Written By”)

Other well known limited animations[26], where Superman 1966, filmation and again Super friends in 1973. Flintstones, mighty mouse[27], beavis and butt-head and the Simpson’s[28].

Limited animation vs. full animation, a discussion on the movie

From a production cost point of view the my movie is definitely limited animation, but from a narrative point of view the story is more concretely told and does not depend on the eye of the beholder as much as in traditional animation. Besides that I have try to simulate the animations of the movie as they are in reality, which is no a limited characteristic[29].

The frame rate of the movie is 25 frames pr. Second (pal), where less is more common in limited animation, especially in hand draw animation, where movement is very heavy in production cost. But the official requirement, of Aalborg University, for the hand in movie, demanded 25 frames pr. Second.

This is according to my opinion only when talking of non-3d computer animations as my movie is. The production time is not getting longer, because the computer calculates the in betweens. Also the depth is as simple as the non-depth, when animating in Maya.

The repetition of animated scenes I use is also common for limited animation.

Other things common for limited animation dead background, which is also present in my movie.

My movie contains many frames per. second and movement in depth which is not limited animation principles.

When talking of limited animation some of the traditional rules can not be transmitted into 3D computer production, because the reduction of production time is to be find in other procedures of the production. These are still images, dead backgrounds, no hair or cloth, limited light effects, particle systems, cut aways of heavy animated objects, among others.

So my conclusion is that my animation is limited animation even though is has some of the old fashion elements of full animation.

The project


Related projects

Even thought the scientific level is much higher following project are related to mine:

Excalibur by the AI-center

“Our goal is to develop a generic architecture for autonomously operating agents, like computer-guided characters/mobiles/items, within a complex computer-game environment. These agents must be able to find the right actions to pursue their given goals and adapt their behaviour to new environments or opponents. But not only the actions of the individual agent have to be intelligent, agents should also be able to communicate and perform coordinated group actions. “


“Gamebots is a project started at the University of Southern California’s Information Sciences Institute that seeks to turn the game Unreal Tournament into a domain for research in artificial intelligence.

The core of our project is a modification to Unreal Tournament that allows characters in the game to be controlled via network sockets connected to other programs. The game feeds sensory information for the character over the network connection. Based on this information, the client program can decide what actions the character should take and issues commands back over the network to the game to have the character move, shoot, talk, etc.”

Most other research institutions are working on AI in general. The field of AI is still pretty small compared to other research areas, which made it difficult for me to find good similar project, made by either students or professionals.

The game

Design document

The purpose of this design document is to express the vision for the game. It uses, The anatomy of a design document, by Tim Ryan 1999, as inspiration. In this paragraph I will focus on the first level of the game.

Game concept:

Spy of sky is an arcade top-down scrolling shooter game for the PC combined with spy photography, where the main theme is not to get discovered. The game is seen from above and includes shooting enemy airplanes, taking difficult photos of military locations and in the meanwhile avoiding chimneys, radar stations, anti-aircraft-missiles and scaring the farmers cows. The player must combine ingenuity with creativity to make enough pieces of intelligence before the border is reached, to enter next level. The game is developed in game maker language.


Buying the license to game maker is an exceptional opportunity to make an interesting game. The game is inspired from the game 1945, see related games page 6


You are a pilot working for your government. You are sent in the field in a simple tourist airplane, to take photos of foreign territory. Your main job is to take spy photos of military bases, factories that might contain WOMD, hangar ships, troops and so on. The photos are difficult to take, thus the angel of the shot is your control parameter.

To make it even harder, the are several objects that tries to stop your quest. There are chimneys, jets, Anti-aircraft-missiles, Helicopters, balloons, military defence planes (MDP) , and local farmers, that don’t want to be interrupted in their local peace.

The Helicopters, Jets and the MDP are the flying enemies. The are very hardcore and will hunt you until one of you die.

Your plane has a condition bar i.e. the plane don’t crash because it is getting hit by a bullet.

If you have taken enough picture before you reach the border, you succeed the level. Your government have bribed local farmers, and your have to make a landing in the cornfield before you must run in the crossfire from the military of the border.

Then you are sent to new areas to take new pictures. There are 4 missions. For further description see page 49, the narrative of the game.

For each mission the player get different honour medals and gets his or her airplane upgraded with new stuff.

While on a mission it also possible to collect new equipment, that falls of enemy airplanes that have been shot down.

In this game you must be able to be sneaky, take precise photos, avoid suddenly obstacles, shoot down enemy airplanes and make accurate landings.

Key features:

  • Intelligent enemies : enemies are programmed to make the game harder for you. They will definitely join you for a nice air battle.
  • Advanced photo taking: The photo scenario are very sophisticated and when a photo is taken, it is immediately generated and shown, so you can see the precision of your shot as a photo.
  • Story: the story of the game is nothing like any other game. Most game are about killing and slaughtering, Spy Of Sky is about not getting discovered.
  • Cool equipment: Depending on the mission and your wishes, different equipment can help you. Before each mission your government have given you 100.000 equipment money to optional upgrades for your airplane.


Halo – Makes the plane resistible of some shots.

Multishot – Makes the cannon of the plane shot 3-doubled spread shot.

Heathsentitive camera – Secret photo locations are revealed.

Field glasses – Increases the vision range.

Avoid radarstations – A stealth function make the plane undiscoverable.

Missiles – 2 build in heath seeking missiles is yours to use.

Jet engine – makes you plane faster.

Auto landing system – that make the landing automatically.

Turistsign – Makes the pilot harder to discover for patrolling helicopters.


Top-down scrolling arcade shooter combined with photography simulation. It is an alternative modern war game, where pieces of intelligence are the key to victory. In real warfare you don’t just go around shoot people, but have to be more careful and avoid getting discovered. That’s why Spy Of Sky is more realistic than other war games even though the game is taking place in a caricatured universe.


The game isexecutable on a PC with windows on it.

Concept art:

Cover with screen dumps from the intro.

On the backside of the cover there is several screen dumps from the intro, the start screen, the equipment room and the game.

The cut-scene intro is showing some of the most exciting game play elements and works a backstory of the story.

The functional specification

  • Game mechanics

The gameplay can be divided into smaller tasks:

Shoot enemy aircraft:

There are three kinds of enemy aircraft;  Helicopters, Jets and  MDP.

Helicopters are observing the airspace and will regularly enter the airspace around you. Their behaviour is described more in detail under AI see page 34.

The  MDP, is usually entering the airspace if they are being informed about you. Scaring cows, will cause the MDP to arrive. Also radar stations can contact the MDP. The MDP’s behaviour is described more in details under AI, see page 34.

The MDP has a condition bar, so you can see how far you are from killing it.

The Jet is not implemented in the prototype, but for further details, see page 34

Take pictures of military units

There are several buildings and likewise locations on the ground. Units that obviously are of military character like, a column of tanks or a hangar ship will give x point depending on the precision of the picture. At the bottom of the screen there is a photo bar that needs to be full, before the border is reached, to enter next level.

There are also secret military objects, that also needed to be photographered. They looks like ordinary house, farms or evens mountains. The first times those locations are present they will be marked with coloured lighting outline, that indicates that it is a photo goal. The following times they green outline will be hidden and it is up to the user to remember it.

There are also hidden radar stations that will contact the MDP if you take pictures of them. The hidden radar stations are displayed as secret military objects, but are a little different. The first time they are revealed they will be outlined with a red border.


Chimneys, balloons, radar stations, anti-aircraft-missiles, scaring the cows and driving radar trucks.

This is the result of a collision with these objects.

Chimney are very obviously not good to fly into. The plane looses much condition in its condition bar.

Balloons will frequently enter the screen. They can be avoided by diving the plane. They are obviously not good to fly into. The plane looses much condition in its condition bar and the balloon explodes with a big bang.

Radar stations sends out radar waves that are circular and displayed as green, developing waves. If you are crossing a radar wave and alarm will sound and the MDP will arrive in a short time.

Some of the photography-goals are military bases that are in possession of anti-aircraft-missiles. Avoid those, they will cause a great amount of damage.

If you are being nearer to a farm, please check that the there is no cows in the fold.

If you fly directly over a herd of cows they will run away scared and the farmer will come running and scream at you. He will contact the MDP, and the MDP will come in short period of time.


There are several types of equipment that will help you, and you can choose up to 3 equipments among those:

Halo: provides you with an armour, that prevents damage from 4 bullets.

Multi shot: sends out 3 bullets at the time in a fan.

Heath sensitive camera: secret photo locations are revealed.

Field glasses: longer line of sight.

Avoid radar stations: makes the plane immune to radar waves.

Missiles: shoot a heat sensible missile 2 times.

Jet engine, makes you fly faster.

Auto landing system, that makes the landing automatically.

      Tourist sign: Helicopters has to be closer than else to detect you.

When your photo bar is full, you are ready to go home. Sporadically runways will show up, and the level is then completed when landing is succeeded. The landing process is to press the F-key as fast as possible, when entering the runway and if the pressing is fast enough the plane will stop before the end of the runway or else take a great amount of damage.

Core game play




Skill demanding

Game flow

The first level is described here and are as followed:


The player starts in the equipment room, where he chooses the stealth/avoid radar equipment. The he select done and the game starts. The players is starting with taking some nice and easy photos, before farms, military bases and helicopters shows up later on. The player know from his earlier experience with Spy Of Sky, that some photo targets is more difficult than other and the score is much higher if he make a photos of those.

Then a helicopter is entering. The player know that he has missed some photo targets and that he has to compensate by taking some chances. So the player flies towards the helicopter and into a small passage between a chimney and a military base, knowing that the smallest shake on his hand will cause the base to shot, the helicopter to fire shot and the MDP to arrive. But he makes it and a valuable photo from the centre of the military base is added.


The player know that if he just focuses on not getting discovered and thereby not getting delayed by the MDP, he should just take some low risk photos and the mission would be accomplished before the border is reached.

But shortly after a split second of lack of attention. The photo shot end inside the of the a helicopters detecting area. The helicopter evades and the MDP is entering the screen. The player panics for a short while and crashes into a balloon. The plane condition is threatening low and the air battle against the MDP is getting really exciting. But the skilled gamer shoot fastly the MDP in best and lucky manner.

            The player is now only having short time left before the border is reached. He takes a couple                     of photos and lands on a runway right after.


Helicopters, MDP, main plane, radar stations, driving radar trucks, Jets.

Gameplay elements






Radar stations

Main plane

Military units



Military bases

Driving radar trucks

Secret photo locations.


User interface

The HUD in the bottom of the screen is showing following:

  • A message box show information about the game. E.g. don’t scare the cows or press the D bottom rapidly to make a landing.
  • Photo bar: Indicated if you have taking enough photos.
  • Condition bar: The condition bar is showing the “health” of the plane.
  • Border bar: Shows how much time there is left, before the border must be reached, else you run out of fuel.
  • At right the right side of the screen a discoveredness bar is placed, which indicated how close you are from being discovered. (not implemented in the prototype)

Game Physics and Statistics:

The main plane is able to be up or down in order to avoid object. When turning the plane side wards the plane heels over.

The main plane can collide with bullets, MDP, Helicopters, balloons, Jets, chimneys and missiles.

The game physics don’t change depending on the statistics of the main plane i.e. the plane down get slower because it has taken damage.



Get a Medal and enter next level    
Crossfire at the border  
Game Over  
The game  
Start screen  
Figure 4, Flowchart  


Early prototype screen dump

mock up of the office room and

the “in game”                                                        Sand sprites solutions

Functional Requirements in equipment room:

Here I will make a detailed walk through the functionality of the equipment room. When the cursor is over a thumb picture, the picture is enlarged above. When clicking on the thumbs the price is subtracted from the buying money. The chosen equipment is showed and listed in the big square at the right side of the screen.

The player can unpick all the chosen equipments and when he is done, the done bottom can be clicked.

A plane with the chosen equipment is rotating in the big square to the right.

Art and video

Nice cover with different screen dumps


The intro sequence

The level intro sequence


Overall Goals:

Colours: dusty, military

Mood: exciting, dangerously

Style: The sprites used in the game should either be snapshots from Scenes build up in Maya or real pictures manipulated to fit in size.

  • Sound and music

The sound scape used while the startscreen is on, should be a war/military inspirated sound. In the equipment room the music should be intense and thrilling, to symbolize the excitement of the upcoming mission. A Stressing music environment, where alert sounds and planesounds should create panic.

SoundFX in the prototype:

Speaked messages to guide the player

Enginesound for both the mainplane, the MDP, the Jet and the helicopter.

Shooting sounds and explosion sounds.

Mooh or the sound of a running cow.

Photographing and alert sound.

Sounds of officer speaking.

Sound of crashing mainplane and running out of fuel.

Success sound when accomplishing a level.

Sad mooded song, when game over.

Short time left, hymn

Cutscenes are describes under the paragraph the animation, the script. see page 55

List of used sprites and pictures of the special effects ( 1. level only):

Environmental sprites:



Rocks / cliffs


Vegetation ( trees and bushes

Hills and mountains

Interactive sprites on the ground:

Factory with chimney




  • Cows running
  • Jellying farmer

Radar base:

  • Radar waves
  • Rotating dish

3 different military bases, some with camouflage

  • Anti air craft missiles
  • Soldiers running


  • Walking
  • shooting

Interactive sprites in the air:




  • Heeling
  • Landing
  • Crashing
  • Rotating airscrew
  • Moving up and down


Flock of Birds


  • smoking
  • blinking


Airplane missiles

Gun bullets

Antiaircraft missiles

All the choose able equipment

Different explosions

Sprites for other thing:

Level succeed

Game over

Real pictures of the photoshots

Loading screen, where the controls are showed.

Technical specification

This is just a short description of the tech-spec.

Platform and OS: Spy Of Sky works on a PC and is executable in windows.

Requirements: 600 MHz, 100 Mb Hard drive, Graphic card on directX level. 128 mb ram.

External Code: The game is developed in game maker language, which is much like pseudo-code. There are several function that are predeveloped, and are easy to call.

Code Objects: Even thought game maker language in not object oriented, but event oriented, you still have to look at it from an object oriented way.

Each object, runs it own events. In order to keep it so simple as possible, I have tried to make it so each object are only controlling its own behaviour. Off course the autonomous agents, are affected by the surrounding object, but the affection is controlled by the A.I. of the agent. Some object are controlled by other, which likely will be called controller objects.

Control Loop:  The environment in the game is controlled by the objects, which are set to reproduce it selves within a given timeframe. E.g. the radar are set to enter the screen every 300 frames, which is 10 sec.

In this way the game developer saves time building up the entire level, but can anyway still influence the frequency an position of the instances.

AI in the game

In this abstract I will tell about the AI developed for Spy Of Sky

If have decided to implement two agents in the prototype, the MDP and the helicopter.

They will be Model-based reflex agents and will be implemented with a state driven design.

Finite state machines

Finite state machines are from a game perspective a model of a device with a finite number of states. It can only be in one state at the time and based on input either transit to another state or perform an action. Each state represents a specific behaviour, that are based on common sense of what a real pilot would do under these circumstances.

The purpose of FSM is to divide the behaviour of an object into states, and determine how the object change from one state to another.


                                         Figure 5, FS-diagram for MDP

State transition table for MDP

Current stateConditionState transition
Attackingweaker than enemyHit’n run strategy
AttackingWeak conditionkamikazi
Hit’n run strategyWeak conditionkamikazi
Hit’n run strategyStronger than enemyattacking

Behaviour definitions:

  • MPD (Military defence plane)

The main goal of the MDP is to destroy the main plane. The condition-action rules are applied based on this behaviour.

Description of the three states:

Attacking behaviour: Fly around semi- randomly changing directions and shoots bullets towards the main plane.  It will try to stay right above the main plane to make as many bullets hit as possible.

Shooting frequency: 1 bullet/ 19 step

Shooting range: middle

Bullet speed: middle

Bullets pr. Shot: 1

Avoid objects: yes

Hit’n run behaviour: Flies faster here than in attacking mode. Will attempt to change side of the screen to avoid as many bullets a possible.

Shooting frequency: 1 bullet/ 32 step

Shooting range: middel

Bullet speed: middel

Bullets pr. Shot: 1

Avoid objects: yes

Kamikazi: When the health of the MDP is low, is will try a kamikazi hit on you. It will fly towards you an don’t avoid any objects. Here the speed faster that in hit’n run mode.

Shooting frequency: 1 bullet/ 13 step

Shooting range: middle

Bullet speed: middle

Bullets pr. Shot: 1

Avoid objects: no

The MDP are entering the screen at the top. It primarily stays in the top half of the screen.

It send bullets backward in the direction of the main plane.

If it is being hit by a bullet is will move side wards to avoid the potential upcoming bullets in a row.

It don’t change height and stays at the same height as air balloons.

The MDP can take 12 shots before it crashes.

FSM: Helicopters

                  Figure 6, FS-diagram for helicopter

State transition table for Helicopter

Current stateConditionState Transition
ObservingBeing shot atCall for help
ObservingSees photographing or explosionsCall for help 
ObservingNon of above within 10 seconds.Leaving 
  • Helicopters

The main goal of the helicopter is to discover if the main plane is a spy plane or a hostile plane.

Description of the three states:

Observing: It stays primarily in the top side of the screen, but tries to stay over factories. It stands still in the air, when checking a given area. It flies rather slow.

It stays on screen for 10 seconds. It checks a given radius for any photographing or explosions. The checking radius is the line of sight for the helicopter

It’s checking radius looks like below and the radius is 145 pixels:

The grey area

Is the primary

patrolling area.                             Helicopter


                               This means it can check all parts of the screen.

Call for help: If the helicopter sees any photographing, explosions or are being shot at, it will try to escape and call for help(MDP).

It will try leave the screen zig zaging to avoid bullets.

It shoots missiles towards the main plane.

Shooting frequency: 1 bullet/ 15 steps

Shooting range: high

Bullet speed: middle

Bullets pr. Shot: 1

Plane speed: high

Leaving: It will fly away be exiting the screen at the left side, if there is no threats for 10 seconds. Plane speed rather slow.

The Helicopters are entering the screen frequently. They will appear in the top of the screen and will decelerate as they enter.

Helicopters is patrolling at a height similar to the air balloons. The pilot is looking for potential hostile intruders, so he don’t look out for air balloon. If he crashes into one of them the helicopter will explode.

It is possible to shot down a helicopter before is leaves the screen, but it takes some skills and luck.

The helicopter is very fragile, which mean that is can only take 3 shots before it crashes.

  • Jets ( the Jets is not realised in the prototype and is therefore not written in details)

The Jets only enter when the player is caught by a radar. They comes up from one of the bottom corners of the screen.

They are circling randomly around the screen are avoiding all ground object.

They send missiles at the main plane frequently. They are very tenable which means that they can take 18 bullets before they crash. The Jets don’t avoids bullets, but moves very fast compared to the main plane.

If the main plane collides with it, the main plane receives a great amount of damage.

The avoiding system

The avoiding system is based on influence mapping (not realised in the prototype). Influence mapping works with a world map, where all potential threats are considered and given a threat value. The world map represents the entire screen, which is divided into smaller frames.

The main things that the MDP’s and the helicopter’s should avoid is the air balloons, the bullets and the main plane.

The threats are given some danger values, dependant on how close you are to it.

Balloons: 10 – 7- 3 -1 (circular)

Main plane: 10 – 7 – 4 – 3 (circular)

Bullets: 5 – 4 – 3 – 2 – 1 (vertical line upwards)

Influence map, world map of Spy Of Sky

333+13+31+3333+3+5 bullet
7Balloon 107+13+31+7Balloon 1073+1+3+5 bullet
333+13+31+3+33+33+33+3+5 bullet
0MDP003477+5      bullet
0000347Main plane 10

In this example the MDP would choose the way mark with the red arrows, which is the most low risk way if the danger values are summed.

Description of the MDP in gamemaker:

The MDP is entering at the top of the screen. There is three states that the MDP could be in. Attacking, hitnrun and kamikazi.

The attacking state is set to true a the MDP is generated.

The switch between the states is dependant on the health value of the MDP and the Health value of the main plane and is measured in the end step event

On the step event the behaviour of the states is defined.

  • The attacking behaviour is made by letting the MDP fly towards a point right above the main plane, avoiding all instances, to make the flight more unpredictable.
  • The hitnrun behaviour is made by letting the MDO fly from the right side of the screen to a point of the left side of the screen and when that point is reached, the MDP goes back to a point in the left side and so on. At the same time is will avoid all instances.
  • The kamikazi behaviour is made by letting the MDP fly towards the coordinates of the main plane and don’t avoid any objects.

The bullet frequency is in the end step event, given dependant on the current state. If the MDP is colliding with a bullet, it will step to the right to avoid upcoming bullets.

To avoid the MDP to exit the screen, some barrier detectors has been made on the begin step, to overrule other actions. If the plane is trying to exit to the right, it will be asked to go left and so on.

Description of the helicopter in gamemaker:

The helicopters are entering the screen above.

There are 3 states.

The patrolling state is initial and is on the creation event set to 10 seconds.

If the patrolling time has run out, the helicopter will change state to leaving, where it will leave the screen.

On the step event the AI detects if there is a collision with a photoshot or an explosion within the fixed radius.

If there is a detection the helicopter changes state to, where it starts shooting and is exiting the screen.

If it is being shot at, is stated true as well.

The exiting is pretty simple, it says, that if is true and the helicopter is outside the room, then destroy it.

Testing the game

In this paragraph I will clarify the user tests I made during the development process.

The first test was at the midterm presentation, where about 25 students of the medialogy line at Aalborg university, where gathered to see and hear about the game, watching with critical eyes.

Here are the comments from the student and their answers to a questionnaire that was made for the event.

The questions were divided into the story of the game and the graphical style of it.

The game

  User test               Good things                                                          Bad things

The graphical  style

  User test                           Good things                                              Bad things

Evaluation on the game and the graphical style:

What seems a repeating issue discussing Spy Of Sky is the arcade style. Many comments regarding that has been put in, both under good things and bad things. That told me, that I was making a really retro, arcade, shooter from the 80’ies. Depending on the eyes that is looking, that is either a good thing or a bad thing, but no games can satisfy everyone.

I decided to keep the arcade style and make some more improvements.

Is the game funny or serious?, is the style fantasy or realistic? Two question, that is pretty similar, were giving me a hard time. I decided to keep the style cartoonish and caricaturic and thereby discard all previous sprites based on realistic pictures.

The game was at that point a realistic war game, but my interest was to make it funny and that shined through the serious. Why can a serious game not be funny I asked my self? I decided to keep the serious style, but to make a funny approach to it.

To test the game, before making the final changes I had 10 students, of the medialogy line from Aalborg University, in for testing it.

The main purpose was to test whether it was to hard or too difficult. The test was build up like this.

Tekstfelt: When playing the game five times

Level of difficulty from 1-5 ( 1 is toughest ) 

Any improvements:

The best part of the game :

Replay-ability from 1-5 (5 is most replay-able)

Free comments :

When playing the game once

Level of difficulty from 1-5 ( 1 is toughest ):

Any improvements:

The best part of the game:

Free comments:

During the game I observed their behaviour on screen, their difficulties and so on.

The result of the test is as followed:

When playing the game once

Level of difficulty from 1-5 ( 1 is toughest ):  2,1,2,1,1,3,2,2,2,2

Any improvements: It should be easier to take pictures, Show chosen equipment. I want to shoot things so they explode. What is the control keys ?

The best part of the game: old school with new improvements, fun, old-school game, Amiga.

When I was detected by the enemy, it felt like being in a desperate situation, fighting for my life

Free comments: What is the meaning with the air balloon, Looking forward to see the next level. I want to blow up stuff and kill people.

When playing the game five times

Level of difficulty from 1-5 ( 1 is toughest ) 2,2,1,2,3,3,3,2,2,2

Any improvements:  Easier to take photos, 2 player function, It’s too hard taking pictures

I did not know what to take pictures of apart from the military bases

The best part of the game :old school with new improvements, it’s challenging. Classic arcade style. Cool that the level is different each time (random).

Replay-ability from 1-5 (5 is most replay-able) 4,3(good in small doses), 3,5,4,4,3,4,3,3

Free comments : difficult to understand CG-voice, It was easier to complete with stealth.

It is the kind of game that you can play when you have nothing to do, meant in a good way, I would be nice to have clear information from the start of what to take photos of. It’s very entertaining.

The purpose of letting the test persons try the game five times, is to test how fast they develop skill for Spy Of Sky.

The total average level of difficulty did rise from 18 to 32, after the five test games, which indicated that there is a felling of progress in the development of the skills.

Unfortunately there was a common opinion on, that the “photo taking” was too difficult, but well it’s what it is all about, so maybe five game of practice is not enough.

This is a statistic of the average “photo taking” percent in the five games, rounded up:

1 game: 16,6 % of the needed photos for completing 28,0 %         ————- | | ————— 31,7 %         ————- | | ————— 25,0 %         ————- | | ————— 36,8 %         ————- | | —————

Actually one of the participants manage to complete level one, but his health was very critical.

Sum up on the comments, observations, good and bad:

Observations: What is the controllers some test persons asked. Some player though that each object was only photo-shoot-able once. Some players didn’t knew it was bad to take pictures near the helicopter. Some players didn’t knew that the skulls was photo targets. There was some misunderstanding about what was fly-under-able and fly-over-able. Many players didn’t knew that it was no good to fly over farm.

Good: It’s very entertaining, cool that the level is different each time (random), It is the kind of game that you can play when you have nothing to do, meant in a good way. Old school with new improvements, it’s challenging. Classic arcade style. It was easier to complete with stealth.

Bad: There is no prices on the equipment, difficult to understand CG-voice. I would be nice to have clear information from the start of what to take photos of. It should be easier to take photos, a 2 player function would be nice, It’s too hard taking pictures. I did not know what to take pictures of apart from the military bases. What is the control keys? What is the meaning with the air balloon? Looking forward to see the next level. I want to blow up stuff and kill people. It should be easier to take pictures. Show chosen equipment. I want to shoot things so they explode.

The conclusion of the test is as followed:

The test results is in this paragraph only evaluated on negative feedback.

Obviously some things need to be changed. There is definitely a need for information about the controls, the photo targets, and the things that should avoided.

The level of difficulty seems a little too hard regarding the photo taking and the amount of photos needed for completing the game.

The equipment room needed some information.

Changes in the games based on the test:

The equipment room don’t need much change. The prototype don’t contains the right box, where all information about picked equipment is placed. But prices should be added to the enlarged picture, when shopping new equipment.

The solution of the missing information is a pop-up screen before the game starts with a tip-of-the-day, where all needed information is placed.

To make the difficulty more easy, the amount of photos needed to complete the level is reduced by 20 %. The difficulty of the photo taking process remains unchanged as it is the primary skill needed the entire game If the photo taking becomes more easy, the player might find it to easy, when being more practiced.

Description of the prototype

Due to limitation on time and resources I have chosen to implement the primary parts of the first level. Here is a list of the following things, that is not implemented in the prototype.

  • The crossfire at the border is not made. Here is a rough draft to visualise the idea.
  • The influence map is replaced with, a build-in avoiding-system, in Gamemaker.
  • The Jets, the flock of birds, the yelling farmer and the hospitals are not implemented.
  • When a picture is taken, the precision of the shot is shown in a little frame at the bottom, that feature is not implemented.
  • A high score is not implemented
  • The feature with picking up equipment from enemy airplane that has been shot down is not implemented
  • There is not implemented the rotating air plane showing the equipment in the equipment room.
  • The radar truck, the hidden radars and the secret photo target are not implemented
  • The green outline is substituted with a skull.
  • All the informations in the information box is not implemented.
  • Some spites is replaced with realistic photos.
  • The detection bar a right is not implemented.
  • The landing feature where the player should press F. Right now the plane should just be over the runway.
  • The high score is not implemented.

Game struggle and choices

In this paragraph I will discuss the struggle of the game and the choices the player has to make.

First I will sum up on the choices the player has to make during the game. The first choice the player has to make it to choose equipment.

According to article[30],  decisions can be divided into different levels. The figure below shows different types of decisions and their consequences. Minor or inconsequent decisions should be avoided.

         Figure 7, decision scale

The first decision the player has to make in Spy Of Sky is to choose equipment, which according to the figure above would be a necessary decision because the consequence of the decision has a delayed impact. The equipment decision could also be called a informed or long term decision.

If we then look a the next choices of Spy Of Sky, the rest of them are “in game”. Those decisions would either be important or critical decision dependant on the condition of the main plane.

To understand the choices “in game” we need to look at the struggle of the game.

When playing Spy Of Sky it is necessary to differentiate between beginners and experienced player that have played the game many times before.

Half of each level in Spy Of Sky works like a tutorial to next level, which means that  if you are a master of level one you are not sure to pass level two the first time you try it, because new struggle types are introduced. Each level introduces new forms of struggles, which could be e.g. driving radar cars, hitter photo goal, changes in range and frequency of bullets or missiles and so on.

To complete Spy Of Sky the player have to accomplish all four levels straight up, without getting killed. There are no saving possibility. This will off course mean that a player who has completed the game, have played level one, many times.

A first time player will find level one very hard the first couple of times and an experienced player knows it so well that he or she can pass the level with no problems.

The conclusion is that the choices of the game changes dependant on the experience of the player. An experienced player would be able to see that he or she has missed some phototargets and he or she has to compensate by taking more risky and valuable photos to catch up before the border is reached, a so called upside/downside decision. The experienced player would also know his or her favourite equipment based on previous success.

Spy Of Sky is designed as open as possible to consider as many different player types as possible.

Richard Bartle, MUSE Ltd, Colchester, Essex, United Kingdom. Wrote this article[31] about player types in MUDs, that categorizes players into four categories based on their purpose of playing. This map can after my opinion be used on any games to consider the interests of a game.

Interest Graph




















The graph shows 4 axis and the player types in between. The killers in Spy Of Sky is only looking for Air battles and are focusing more on that than anything else. They will therefore try to make the MDP arrive.

The explorers has also been considered. They will try to explore the world of Gatrukistan to find short cuts, new photo objects, errors or the most valuable photo shots. They are not as considered as killers but, they will still have fun.

Achievers are trying to get highest score, the best rank, the best level and so on. In Spy Of Sky they will probably trying to get as far as possible to complete the game or go for the high score. They will also try to complete the levels in as short time as possible.

The socializers are the only of those four that are not considered, but their function are mostly working in MUD, where they can meet other people over the internet.

To get back to the choices and the struggle, non stop action will get boring over time, which is why each level is separated and of course because the missions of each level is different. The level introduction and the chance to choose new equipment is a nice breath of fresh air before a new level starts.

This mean the decision line over time looks like this: A very common dot-line-dot structure.

                                     |-   ———-   –   ———-   –   ———-   –   ———-|

Spy Of Sky and the narrative

When talking about narratives in games you first need to consider if a game can be a narrative. In this paragraph I will discuss the aspects of narratives in Spy Of Sky.

To start out this paragraph I will start with a description of the story and the plot.

Spy Of Sky, the story:

Truman Bube is working for his government. He is sent to Gatrukistan in a simple tourist airplane. His main job is to take spy photos of different locations.

He know that he has to take enough photos before he reach the border and have to make a landing in the cornfield before you must run in the crossfire from the military of the border.

Then he is sent to new areas to take new pictures. All together 4 missions to honour his country.

Spy Of Sky, the plot:

A pilot is flying around taking pictures of military bases, then he flies over a farm just to scare the cow in the fold. The farm is angry and informs a military defence plane about him.

The pilot is flying over the farm again and is laughing turning his head backwards. Then the military defence plane shows up and shots the plane, so it explodes. The look laughing to the skies.

Then Truman Bube is in an office, where and officer says hello. The officer tells Truman about a the upcoming mission that he is about to accomplish. Here is the text version of the speak from the military man:

“ Hello Truman Bube

Hello sir !

The government are having troubles with gatrukistan because they are considered a threat for national security. It has been informed that they possesses a big amount of weapons of mass destruction and are working on new forms of chemical warfare.

You are assigned to go undercover to gatrukistan on a photography mission to make pieces of intelligence. You will be using a simple tourist plain to avoid to much attention.

Hopefully you can do better than our former agent, that failed his mission.

Unfortunately the situation is critical, which means if you miss in action we are not able to help you.

We have bribed some local farmers, that will help you with disposal runways when you are ready to go home.

We will transport your plain in a airplane-carrier to the border of gatrukistan.

Watch out:

  • Helicopter’s are patrolling in the area and will call for the local military if they discover that you are not a tourist.
  • The local farmers likes the peace and will not tolerate if you scare their cows.

The government has supported us with a lot of money to equip you with the latest technology.

You are free to choose which equipment that will help you.

Well, what do you say ?

I will try my best to honor my country sir !

Dismissed !  “

Truman accepts the mission and accesses the equipment-room, where he must choose the equipment that fits him.

The mission begins and it is now up to the player to accomplish it. If the player don’t make it a picture of his gravespot is showed and the game starts over.

If the player make it, Truman gets an honour medal and returns to the office with the officer. Truman is congratulated and told about the second mission, where he must take pictures of the infrastructure.

The scenario restarts if he make it and third and firth level are like this:

3rd: Truman has to take photos of military bases that shoots back. The level is getting harder and harder before he reaches the centre of the military of Gatrukistan. Here Truman has to plant a bomb in the power line centre, that will make the military of Gatrukistan in-operational.

4th: The government is about to invade Gatrukistan to destroy the threat of terror actions. Truman’s mission is to fly towards the Palace where the president of Gatrukistan rule his dictatorius empire. The palace is located on an island and Truman has to fly there over the sea, where hangar ships and other boats are shooting at him, before he must sneak inside the palace, avoiding the guards to assassinate the president, to weaken the management of Gatrukistan.

As you can read the hole story is build up, upon the theme, not to get discovered.

Then Truman has to return to his plane, before the guards finds out about it.

Then Truman returns to the office where the President of his of country is celebrating the extermination of nuclear weapons and is tributing Truman Bube for his admirable effort.

Discussion on the narrative

The cut scenes in Spy Of Sky is in a very common way, which is to make an introduction of the game and to tell the back story[32].

Translation of a story from book or a movie can be done in many ways, but the story of Spy Of Sky is a short story written only for this game purpose.

To talk about a narrative can be difficult because time works different in games than in traditional movies. The story is controlled by the player in the game session. The relationship between the viewer and the movie are different between the player and the game.

According to my opinion a good translation between different mediums, is a translation where the mood and the experience of the story is kept. A great example of this is Bjergkøbing Grand prix[33], which in a narrative manner kept the sweet story and the visuals, translating it from movie to game.

Some people might claim that everything can be described in a narrative manner. But I don’t think it makes it into a narrative. Its more like, that the narrator is making it into a narrative. Otherwise games like Tetris or Pacman would have a narrative, which I think would be a over interpretation. But again it is up to the player of a game to determine if he or she think that there is a narrative. For me a game like Grand theft auto is non-narrative, even though is has a linear distinct storyline based on missions that the player has to accomplish. Each mission is introduced with a cut scene, that in my case just is interrupting the action and are a necessary evil to create more challenging actions. One can say, that I make my own story, but it is fictive and created on a imaginary level. 

In spite of that I still think Spy Of Sky has a very clear narrative. The predetermined story line, is linear, there are no possibilities for the player to choose out branches of the story or a free mission. This story line has to be followed, just like in games like Half life 1 and Half life 2[34]. It is build on quest structure and has a protagonist, that the player controlles. Besides of the intromovie the narrative part is used for telling the player what to do and works as small rewards. In Spy Of Sky you know who you are, who you controlles, which I think gives a stronger impact from a narrative point of view.

Another thing that supports that Spy Of Sky is a narrative is that dramatic structures and the actant model can be applied to the plot of the story.

On the other side the interaction is ruin the narrative, but from a non-interactive point of view, it is definitely a story. A thing one can do is observe the body position of the player[35]. The leaned back position is often used, when non-interactive parts of the game is showed, like in a cinema. When a part of the game is interactive the player changes body position to a lean forward position, which separates them from the cinemagoer. This could be a thing that indicates this big aspects that makes movies and games different from narrative point of view.

Narrative translations between mediums is a matter of interpretations. But in my opinion translations between mediums is only possible if the narrative is changed. The premises of the story change, so naturally the story has to change to adapt the new environment.

A little help to make the story even more clear, could be to show some text before the movie starts, that says: 2 months ago. This could enhance the sense of backstory, and that the pilot is not the same character that is controlled by the player.

“Animation offers a medium of story telling and visual entertainment which can bring pleasure and information to people of all ages everywhere in the world.”


American motion-picture producer, pioneer of animated cartoon films. 1901-1966

The animation

The Script

The story

You see a pilot take some spy photos. Then he flies over a military base and takes some more pictures and the base shots at him with missiles, but he barely avoids them.

Then he flies over a farm where he scares the cows which results in that the farmer comes out and jells. The farmer sends smoke signals which are seen by a local military airplane, that takes off. The pilot looks back laughing. The pilot flies over the farm again and looks back and laughs again.

Then he turn his head around and is being shot down by the bullets of the local military airplane. The main plane explodes and the farmer laughs revengefully.


The main character is the pilot.


The Enemy is the farmer and the military defence airplane (MDP)  is the helper.

Other characters:

The cow and the farmer.

The shadow/contrast:

When looking at the movie as a part of the game the contrast to the pilot is the player, that is told later on that he or she hopefully can do better or the history will retell is selves. The player is thereby told that he or she should behave exact opposite.


The locations is the airspace over Gatrukistan a fictive low-tech land. It is a bright and semi-cloudy day. The ground is dusty. The farmer has two houses and a fold, where his cow grasses. The military base consists of two anti-aircraft guns and some huts.


Functional: The main plain, the MDP, the fork, the missiles, the anti aircraft guns.

Dead props: Sky, ground, fold, farm houses, the military huts, the tower and the barrels.

Nice to have Vs. need to have:

The animation is limited animation, which is why all nice to haves has been cut away. Here are some examples of nice to haves:

Men operating the anti air guns, hair, pilot-glasses, full cow shot, more nature elements, trees, brushes, hills, mountains and so on. The slamming door scene could had been fully animated. More cows and more time spending on the shades.


An undercover pilot is foolhardy and carelessly flying around taking spy photos and making fun with the local citizens. But he forgot one thing, Nemesis !


An undercover pilot flies around and takes spy photos of military installations. Then he flies down over a farm and scared the cows. He laughs and laughs but the farmer sends out smoke signals which are seen by an local military airplanethat takes off to help the farmer. The local military airplanesurprises the pilot, and he is being shot down. So the farmer gets his revenge.

The storyboard of the animation:

The Storyboard can be find in the annex from no. two – nine.


Fade from black

Scene 1:  The main plane is showed

Establishing shot – medium long shot

Scene 2:   The pilot is looking to the sides looking for something and sees something

Medium close shot

Scene 3:   Some photos are taken of a military base

pilot cam

Scene 4:   The pilot is looking to the sides looking for something and sees something

Medium close shot

Scene 5:   Some photos are taken of a military base, while being shot at.

Pilot cam

Scene 6:   The main plane barely avoid the two missiles from the military base

Long shot

Scene 7    The pilot looks back and laughs.

Medium close shot

Fade to black

Scene 8:   The farm is shown

Establishing shot – giant perspective – long shot

Scene 9:   The cows of the farm is shown

Medium shot

Scene 10:.The pilot is looking to the sides looking for something and sees something

Medium close shot

Scene 11:.The plain flies closely over the farm

Long shot

Scene 12: The cows is scared and runs

American shot

Scene 13:.The farmer yell at the plane.

Medium close shot

Scene 14: The pilot looks back and laughs.

Medium close shot

Scene 15: The farmer goes inside and slams the door

Giant perspective – medium long shot

Scene 16: The farmer sends smoke signals from his chimney

medium long shot

Scene 17: The MDP sees the smoke signals in the horizon and takes off.

Long shot

Scene 18: The MDP is shown flying, to show that is gets closer.

Long shot

Scene 19: The plain flies closely over the farm

Long shot

Scene 20: The cows is scared and runs

American shot

Scene 21: The farmer yell at the plane.

Medium shot

Scene 22: The pilot looks back and laughs.

Medium close shot

Scene 23: The M.P. shows up and shots the mainplane

Long shot

Scene 24: The mainplain explodes.

Long shot

Scene 25: The farmer look revengefully laughing to the sky

Medium shot.

Fade to black

The actant model

The actant model is a model that show the foundation of the structure in a narrative. It is invented by Algirdas-Julien Greimas (1917-92)

Model 9, A.J Greimas´ model  

The subject of my story is the pilot of the main plane. The subject is often the main character.

The object is the thing that he must solve, which is his photography mission. He is working for the government, which means, that the government is both the sender and the receiver.

There is no one to help him, but himself. The opponent is the military of the Gatrukistan, but also his foolhardy actions.

This mean that the actant model looks like this is my case:

Him self/ the military  
The pilot of the main plane  
No one/ him self  
Photo mission  
Model 10, A.J Greimas´ model modified  

the lower axe is also called the axe of conflict. This is where the main problem of the story is. The story is introducing the game and show some gameplay elements. The main struggle in the game is avoiding getting discovered by the military. The conflict of the story can therefore easily be transmitted into the game, where foolhardiness is not a success criteria.

In the level intro an officer show a picture of the pilot in the story and says that hopefully you can do better that our former pilot, which again corresponds to the bad foolhardy personality which is no god in Spy Of Sky.

The movie is made on dramatic structure:

Model 11, dramatic structure

The main plane end the character is introduced in the beginning. The conflict is elaborating and escalating and the character reaches the point of no return, when he scares the cow of the farmer.

Then comes the climax or the solutions of the problem where the pilot is being shot down. Then the story ends and the intensity of excitement, which is the y-axis, is fading off.

Some uses a twist around the point of the climax, but in my case it has the classic structure.

Character sheets:

The main character and the farm, was created from a picture made up in my head. The main character needed no special look, but had to be able to express some of the needed emotions.

The military base was inspired from the game commandos:

The cow was inspired from this pictures and the focus was on the cute, sad and cartoonish look:

The main plane was inspired from this picture, which is a 3D model:

The farmer was made from picture in my head inspired from a memory game I played when I was 10 years old. I found the game and the picture in my basement and had afterwards scanned it. I think it look pretty accurate except of the shades and the beard.

How the animation was done

When talking about animation, there are many different types. The one used in the movie is CGI, computer generated images, made in 3D with the program Maya 6.0[36].

The animation is called limited animation. Limited animation is animation, where many scene and shot are reused. There might also occur shots with no animation. Besides that, the environment is very simple and don’t change perspective. Limited animation is mostly seen in non 3d-CG animations.

Besides that the legs of the cow is not modelled or animated, because of the use of an American shot.

First the idea was written down. Then I made a draft for the storyboard. Look at annex no.1

Then I started finding pictures of planes, military bases and cows and spotted those characteristics that I wanted to use. To save some time and to visualize my thoughts I started modelling some of the character in Maya.

The storyboard was remade with some corrections and bigger drawing, transitions, sounds, mise-en-Scène and camera movement was added.

Then the story was ready for the first test. I found some students that didn’t knew about the story and tested the story by placing the pictures of the storyboard in a slideshow, with homemade sounds.

The conclusion of the test was that the introduction of the story was difficult to understand, especially that the pilot actually was taking photos. The critique was used to optimise the flow and the plot.

Then the animatic, which can be found on the enclosed CD, had to stand a bigger test. The midterm presentation, where about 25 student of the medialogy education from Aalborg University, where watching with critical eyes.

Here are the comments from the student and their answers to a questionnaire that was made for the event.

The questions were divided into the story of the animation and the graphical style of it.

  User test                                  Good things                                          Bad things

The story:         The homemade sound was pretty funny.  

                          Great sounds.

User test                             Good things                                              Bad things

The graphical        It is good that it is not too realistic             The office scene is boring


                             Funny, cartoonish, caricature, 80’ies       Keep the style more old school.

                                                                                                Use the same colours more

After evaluating on the questionnaire I realised that there were some problems.

The story

More focusing and some close up shots on the pilot in the beginning could solve the identification problem. Then the protagonist and antagonist would be more clear. Furthermore I skipped an introductional close up clip of the farmer and replaced it with a establishing shot of the farm.

The problem with too many repeated scenes was a tougher one. Two scenes were deleted, but I had to jump some low bridges in the process in the knowledge of that I was doing it all by my self. Limited animation was a way to tell this story, that is a big workload.

Then some student suggested that a speaker could make a short introduction of the pilot and his mission. hoped the deleted scenes and close up shot on the pilot was assisting to make the story more simple. Besides that, some things are better unsaid, an old phrase says, which is why I think it would ruin the atmosphere.

The sound of the animatic was homemade. The cow was speaked as “mooh” , the shooting as “bang bang” and so on. Those scenery sound was made only for testing purpose, but was working pretty good, because they was funny and fit in the graphical style. Some of them was rather exaggerated, so I skip some and kept the best.

The last thing was the misinterpretations of the smoke signals. Some thought that the MDP was seeing a fire, some thought it was to create a nice atmosphere or to make, but no one understood the message. My belief was that it would work, when the final scenes was made in Maya and edited together.

Looking back that was a mistake. A telephone call from the farmer to the pilot of the MDP would had been another solution. A great idea that would take some time to model and animate, but would be very easy to interpret was to lead the farmer send a carrier pigeon that should fly to the pilot of the MDP, with a letter that told the situation and then the farmer took off. It could look like this:

The graphical style

The graphical style was judged on the drawings and the screen dumps of the so far Maya work.

There was many good comment on it and some word that described the style. Funny, cartoonish, caricature, 80’ies. The funny, cartoonish and the caricature was those I felt was already in my mind and I decided to keep the style as it was.

I ignored the comments to make it 80’ies and to make more old school. The comments are quite wide and it wasn’t was I was aiming for.

The office scene was shown by a screen dump. Some student thought it was boring. Well it is an alternative to make a letter a write the information on that. Cut scenes are after my opinion always boring, but to make it less boring I changed the camera position, added some picture on the projector, shortened it and off course the animation of the gesticulation of the officer could help also.

Then the scenes and the animation was made in Maya and the editing step of the process could begin.


The editing was made in, Final Cut Pro, a high end editing software.

The first thing I did was to add all the sound. To make more coherence between the scenes, continuity was used.

 The line of movement was kept and fade to blacks were used to make a jump in time and space.

To make the idea with the smoke signals work, montage was used to make more sense.

During the editing phase the “mooh” of the cow was deleted because it was not good.

Due to the fact that the movie is limited animation, jump cutting has been used to shorten production time.

The rendering

The rendering was made with Maya’s own render software. The animation clips was saved as targa images in production quality and was afterwards gathered in video mach[37], where they where saved as mpeg-video clips in pal format. The aspect ratio is 1,33 near to the one on TV.

The animation techniques

The animation with the hands and the picture where the door is slammed was made by making the movements over and over again in front of a mirror, to make sure that it looked good and to get at sense of the timing.

During research on the animation about air planes I found some movie clips of real air planes. The study of those showed me that a plane taking off, would slow down in speed when the wheels let go of the ground, because of the some force from the forward direction was moved to the upwards direction.

When the MDP is taking off in the movie, I have tried to copy that, to make it more realistic.


Left before right, is not used in the shooting plane scene, to make misdirection. But the explosion is not obeying the 180 degree rule.

About the Maya work


The modelling part of the process was definitely one of the most time consuming parts. The cow,

the farmer, the house, the fold, the faces, the arms of the officer and many more objects was build

up from scratch.


The main technique to manipulating the polygons was translating, rotating and scaling.

Many of the odd polygons was created by subtracting one or more polygons from each other.

The roof of the house in the farm was originally a rectangle cube, but by cutting it into half’s it got

the right shape.

Before Boolean difference                       After Boolean difference

The subtracting function is called Boolean-difference and is only possible with simple polygons.

The subtracted object can afterwards be moves, scaled and rotated, which make the Boolean difference change in real time. This little trick is used to animate the mouth of the farmer.

The faces, the body of the farmer and the arms and finger of the officer is made with smooth proxy.

First a cube is created, then a smooth proxy function is performed on it. The exponential level is set to two, which result in that the cube becomes round like a ball. The smooth proxy is good to create organic like objects, like faces and body parts.

Then the body mass is ready to be modelled. The object is turned from object mode into face. In face mode it is possible to select a single or more face and manipulate them. As shown on the picture below a cube is manipulated this way. The upside face has been translated upwards and is scaled up. This result in that the cube is now looking more like a head shape. The cube around the head is the smooth proxy box, which is the one that is manipulated.

Smooth proxy and face manipulation

As shown on the picture above the next step in the modelling process is to extrude faces.

On the picture the head from the previous picture is used. The downside face has been extruded with the face extrude tool and scaled up, and now the head shaped polygon has change into a nice bell.

In this way the original cube can be turned into a more complex object.

The smooth proxy box around the object which is used to manipulate the object can be split into smaller polygons, which is useful, when creating a mouth. The split polygon tool can divide faces of an object into half’s. On the picture below, one side of the bell has been split into half’s and the upper one has been extruded. Now the bell has turned into a door handle.

Split polygon tool and face extrude.                       Vertex translation

Another control parameter when manipulating the smooth proxy box is the vertex. They are the “corners” of the box. On the right picture above the result of the manipulating vertex is shown. At the bend of the handle the two vertex are selected and translated up and inwards. Now the handle look like the tongue of a creature.


Making the animations, was a tough part of the process. Estimating the duration of a small movement like changing hand position while talking, is a duration of milliseconds. So much of the animation about estimation and verifying. When animating multipolygonal compiled objects, like the plane, a smart thing to do, is to group them together.

Afterward smaller sections can be grouped and make an animation in the animation, like the cannon in the scene called “MDPonitsway”.

Another smart thing to do, when working with a main character is to set driven keys.

Driven keys is a numeric value with a name, that is added to channel box of the driven object.

I have used driven keys to animate the hands. For each finger a bend is animated. Maximum bend has been given the value 15 and overstretching the finger has been given the value of –3. Besides that a common grasp for all 5 fingers has been set and a spread, to make further things possible.

To the right in the picture above the driven keys for each finger, spread and grab is placed in the channel box.


The basic thing of animation is keyframing. Keyframing is setting up positions that object in the scene are placed at on a given moment. I Maya the user works with a timeline, where all the keyframes are placed on. On the picture above there are some red lines on the timeline. At right the ringfinger is marked with black. The red line represent the keyframes for ringfinger.

Looking at a scene like “flying over the farm” the plane is placed outside the screen on frame one. Then a keyframe is keyed. Then the cursor of the timeline is moved to the endframe of the scene. The plane is now moved all the way to the other side of the farm and outside the screen again. And a new keyframe is placed. Playing the movie now will show the plane moving from a position to b position within the time between the two keyframes.

To make the plane dive, the frame where the dive starts and end must be keyed too. Between those frame another keyframe is placed after putting the plane in the lowest position of the dive. This will look like shown below. In the case shown there is put multiple keyframing on the dive to make the animation more smooth. In this case the plane is also rotated to make the dive look caricaturic.

Keyframing the animation of the a diving plane

Rigging the arms of the officer:

The arm of the officer where made of joints and bones. The start joint is the shoulder, then the elbow, wrist and fingers. Each of the joint are either parent or child in their relationship. The elbow is the child of the shoulder and the wrist is the child of the elbow and the shoulder. The shoulder is therefore the parent of all the other joints.

To make them rotate the right way, so the movement became realistic, the local axis where rotated to fit in.

Skinning the arms of the officer

The skinning was made with a tool called smooth binding. The arm was modelled and was then smooth binded with the bones and joints. To fit in size, the joints where scaled so they fit the inside of the arm.

Then the polygons of the arm, followed the movement of the bones.

Building up the scenes:

To support caricature design of the my style I chose to make the ground more spherical to illustrate the sense of horizon. The same camera angel and light, where reused to make it indifferent, from scene to scene.


To make the objects have right surface, different textures where used. UV mapping is a tool, where a simple image is project onto an object. This  is used to make sand, sky, roof of farm, cow, pictures on the screen in office among others. Here are some of the pictures, used texturing objects.


Lights in the scene is very important to make the models look good and realistic. In my case where the same scene is used to make different shots, it is important to keep the light settings, so the environment don’t change.

In all the scene a ambient backlight was used to create the sense of daylight. Then some keylights where added to make it look more like sunshine and to put focus on objects.

The last scene with the laughing farmer a sidelight where used to create a dramatic effect of the exploded main plane.


In most of the scenes the perspective where used as a steady camera. Taking photos of the military base scene, where made with an animated camera to illustrate the view of the flying pilot, a so called dolly cam.

In the office scene their where some zoom effect, to make the focus change to the canvas.


The Graphic and sounds

Following things are borrowed:


The music are borrowed from the game Pacific Heroes

Some sound effect are also used from that game, which where cut out and manipulated.

Other sound effect like the running cow and the diving plane in the movie was borrowed from CD I had, with 1001 sound effects.


Tank red

Tank green




Background image in equipment room

Air balloon

All the equipment thumbs

The game over picture

The medal, when the level is completed


The helicopter

The gunfire

The start screen

The control screen and the credits screen background image

Following sources has been used: Gamemaker resource pack 1+2, google image search, Pacific Heroes and

The rest of the sprites in the game, it either made pixel by pixel or build up in Maya. Some of the elements of the movie, the main plane, the farm, the military base and the MDP was taken directly from the Maya environment the movie was shot in.

Other sound was recorded mouth to microphone. The CG voice by the officer in the office, was made in Talkany, a free text to speak converter, which can be downloaded here:

Future work

In this paragraph I will discuss possibilities of future work.

Regarding the intro movie, the scene with the smoke signals conceived as confusing and is misinterpreted. To make the story more clear, the scene could be replaced with a sequence, where the farmer is writing a letter, puts it on a carrier pigeon and sends it away. It could look like this:

The movie should be enhanced from limited animation to full animation.

To optimise the game play and the experience of Spy Of Sky, following things should be corrected:

  • More informative sound effect could be added. The precision of a photo shot could be graduated into, average photo, nice photo, super photo and perfect photo, which would be speaked like perfect photo is in the prototype.
  • The condition bar, the border line bar could flash to illustrate that the situation is critical and it could be supported with a bass beat.
  • The reverb and the white noise of the speaked sounds in the game could be adjusted to make them sound like a voice over a radio system.
  • The game would have a more dynamic and modern look if it was made in 3D or at least an isometric view.
  • The AI could be changed to goal based agents, with BDI models.
  • To make the game have a more dynamic look, shadows of the airplane, chimneys and air balloons would enhance the spatial effect.

The sounds

The melody of the, game-over-screen, is in minor, to make a sad mood.

The melody of the equipment room is loaded with a bass rhythm to indicated the thrill of the upcoming mission.

The frequency of the, main-plane-sound, could be heightened when heeling to the sides, to make the sound scape and the control more intuitive.

The soundscore at the start screen has a typical war sound. The light drum rhythm makes it very military.

Reverb and some white noise of the speaked sounds in the game could be adjusted to make them sound like a voice over a radio system.



The results

Philosophical perspective

In this paragraph I will reflect on AI. As written earlier there is this common known taxonomy of AI and Autonomous Agents made by Stuart Russell and Peter Norvig.

That taxonomy is made from a programming point of view and I will in the following try to make a taxonomy that has a more humanistic approach.

Predefined behaviour agents

Refers to a behaviour that is planned, where no input influence the behaviour of the agent.

Environment-dependant behaviour agents

Has a predefined behaviour but the actions are dependant on aspects from the environment

Reflective behaviour agents

Is similar to Environment-dependant behaviour agents, but reflects on inputs and actions to perform a, as optimal, behaviour as possible.

Self developing behaviour agents

Is similar to Reflective behaviour agents, but has the ability to develop new input interpretations and new actions.

The stippled line illustrates the thin line there is between this and human behaviour.

Human behaviour agents

This agent type is no yet developed. No AI has yet passed the Turing’s test. But theoretically it is possible to copy the human behaviour.

Another taxonomy is Stan Franklin and Art Graesser’s[38] that in a very detailed way divides agents into 11 types of agents. According to my opinion is the purpose of  a taxonomy to make overview and 11 types is too many to do that. Their approach is from my point of view the functionality of the agent and the utility.


Spy Of Sky is a top-down scrolling arcade shooter for the PC, where it is about not getting discovered, more than shooting down enemy airplanes.

Building up the AI started with some research about autonomous agents. I decided to implement two agents in the prototype, the MDP and the helicopter.

The agents are model-based reflex agents with a state driven design. Their state are defines via FSM, finite state machines, a tool to define the states and the transition between them.

In traditional arcade shooter, the agents are simple reflex agents, that perform simple task. To make the game more challenging and realistic I have defined a behaviour set(FSM), for each state of the agent of Spy Of Sky.

Their behaviour set is based on common sense of what a real pilot would do under these circumstances, to make the AI and the experience more human and thereby more realistic and challenging.

The animation made for this game is an introductional clip, where game play elements are introduced. The main purpose of the game, not to get discovered, are also revealed in the film. To underline the, not to get discovered, the officer in the office that introduced the level, tells the player that hopefully he or she can do better than the former pilot that missed in action.

The narrative of Spy Of Sky is build upon that back story, and it has a narrative that can be applied on a dramatic structure.

The animation is limited animation, which is an animation type, with following characteristics:

Dead backgrounds

Reused scene

Reused movements

Cuts that reduces movement in the scene

Speak is a strong key element

Still images

Few in-betweens

Low frame rate

No movement in depths

Many of these rules are in my opinion related to non-3D-CG animations, where they are very time consuming and thereby heavy in production cost. To reduce the heavy productions costs, is one of the main reasons to make limited animation.

My movies are 3D animation and I consider it limited, because many rules where used to make the production time shorter. There are e.g. still images, reused scenes, dead backgrounds, cuts that reduces movement in the scene.

My definition of animation is: Animation is the simulation of movement through a series of pictures that have objects in different positions over time.

This definition includes the mathematical  and humanistic approach and is short and precise. It doesn’t say anything about what kind of movement it is or how fast it is, so it is still open for interpretations.

Looking at my definition compared to limited animation, my definition do not cover still images, which is seen in limited animation. But I my opinion still images is not animation, probably the reason why it is called limited animation.

Apart from that my animation covers the rest of my movies.

When one tries to define something, there is always aspects that are more covered than others. The purpose of definitions is a short cut to understand a bigger area of knowledge. I think that the only way to define animation is learning by doing or in other words, experience. By this I also states that there is no wrong definition of animation only different opinions.

Literature list



Naturlig og kunstig intelligens, Niels Ole Bernsen & Ib Ulbæk, 87-17-05927-5

Ånden i Maskinen, Ray Kurzweil, 87-90959-15-9

AI a modern approach, steward & Russell

Annex no. 1

Looking to the sides  
Main plane establishing shot  
Annex no. 2  
The main character is looking to the sides and sees something  
Looking to the sides  
Taking photos  
The main character is looking to the sides and sees something  
Looking to the sides  
Taking photos  
Annex no. 3  
The main character is looking to the sides and sees something  
Being shot at  
Annex no. 4  
The main character is looking back while laughing.  
Flying over the farm  
Looking to the sides  
Annex no. 5  
The main character is looking to the sides and sees something  
Slamming door  
Annex no. 6  
The farmer goes inside and slams the door  
The main character is looking back while laughing  
Smoke signals  
Flying over the farm  
Annex no. 7  
Annex no. 8  
The main character is looking back while laughing  
Happy farmer  

[1]   press vertical at the menu at left






[7] Wooldridge, M., and Jennings, N. R. 1995
Intelligent Agents: Theory and Practice.
The Knowledge Engineering Review 10(2): 115-152

[8] Russell and Norvig,  AI a modern approach, chapter 1.01

[9] The third international workshop on agent theories, architectures, and languages, springer-verlag, 1996

[10] Russel and Norvig, AI a modern approach chapter 2.4


[12] Classical arcade game

[13] Popular soccergame with the website



[16] Gordon Moore predicted in 1965 that the size of the computational power doubled for each 24 month.

[17] Ånden i maskinen, Ray Kurzweil, 87-90959-15-9







[24] means soul in Latin

[25] Suspension of disbelief is a willingness of a reader or viewer to suspend his or her critical faculties to the extent of ignoring minor inconsistencies so as to enjoy a work of fiction.





[30] Improving player choices by Tracy Fullerton, Christopher Swain and Steven Hoffman 2004


[32] Games telling stories – a brief note on games and narratives – by Jesper Juul



[35] Games telling stories – a brief note on games and narratives – by Jesper juul


[37] Rendering software for movies.