ARTIFICIAL INTELLIGENCE IN GAMING

Presented by: Vivek M Bhasi

Under the guidance of Mr Pramod Pavithran

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ITS HARD WORK!!!

• 8192 processors

• 2.8 TB of memory in the blue gene l supercomputer

• 22 million neurons

• 11 billion synapses

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SIMULATION OF HUMAN BEHAVIOUR…IMPOSSIBLE???

• Simulation of actual human behaviour would be extremely difficult if not impossible

• Quite often the games give a perception of reality

• ie: Games appear to have characters who are much more “intelligent” than they

actually are…

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SO HOW DO THEY DO IT THEN???

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STATE MACHINES

• Sometimes non-player characters make decisions using state machines

• Each non-player character would have a certain number of states which it will go to

when certain criteria are met.

• An example can be cited from old FPSs

• As the intelligence of the characters increases the decision trees associated with

their actions become more complex

• The core behaviour of the NPCs are defined only by a few states. The remaining

states are for rare circumstatnces.

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DISADVANTAGES OF STATE MACHINES

• State machines are inherently predictable to a certain degree

• There is a limit up to which the number of states can be increased

• Defining the transitions between the states is a difficult task

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THE PLANNING SYSTEM

• Allows various characters on-screen to act uniquely

• A planning system makes a gaming character work out what it has to do in order to

fulfil an objective.

• In order to achieve a goal, the computer looks at the situation in which it wants to be,

and then work backwards from it to calculate the best way of achieving the desired

result.

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WORKING BACKWARDS…..AN EXAMPLE

• In an FPS the objective of the AI bots is to make sure the target is dead.

• But since the objective hasn’t been accomplished yet, the preconditions are analysed

in a backtracking fashion

• This process continues till the basic precondition is reached .

• Then the AI starts satisfying each condition starting from the base case till the final

objective is met.

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ALL TERRAIN

• Now that we have characters that seem intelligent , how do we make them know

where they are?

• The AI characters can’t see the game world as it would take a huge amount of

processing power

• The characters need some sort of guide to give them an idea of where they can go

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• This often takes the form of a navigation grid that shows obstacles and the shape of

the terrain, but developers often also use a navigation mesh (usually called a

navmesh) that’s local to the current 3D scene.

• A navmesh is basically a low-resolution 3D mesh that sits on top of a 3D scene and

shows an AI character the areas to which it can move, as well as featuring tags and

hints to the AI that have been placed by the designer

• “The designer will place this invisible mesh any place he wants the AI character to

potentially move to".

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NAVMESH IN ACTION

• Animators create a variety of animations

that the game designers can use

according to the terrain

• These animations are used by the

designers to make the characters

traverse certain areas.

• Navmeshes provide a method for NPCs

to find paths and also offers extra

spatial information

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NAVIGATING THROUGH VOLUME

• Navigating through the entirety of the space available to the NPCs makes the gaming

experience more realistic

• To address this issue something called“segments” are used.

• Segments are a series of points and links, which may or may not be on or attached to

the navmesh.

• The AI is free to create paths using these segments just as it would on a normal

navmesh

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• The planning system is used to combine different segments, thus creating paths in

space where the characters can move in.

• The probable destinations of the moving characters are calculated in order to avoid

collisions

• Highly complicated programming involved

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DESTRUCTIBLE ENVIRONMENTS

• Adds to the realistic experience of a

gamer

• Gamers can cause damage to the

environment and thereby affect the

gameplay

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HOW IT WORKS

• The NPCs keep checking their environments every 0.5 to 1 sec and respond to the

changes using the planning system

• Changes can be identified by using Navmeshes

• ie: Whenever rigid bodies are removed from the environment , their corresponding

outlines are identified in the navmesh and the characters are made to respond

accordingly.

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AI IN GAMES- WHERE NEXT?

• The general mindset of gamers are changing…

• AI acceleration is being welcomed more than ever

• Advancements ?......After the state machines and the planning system , the next step

is Online learning ie: Online chatbots such as Jabberwacky learn as a result of

constant online input.(strategies , playing styles etc)

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CONCLUSION

• Simulating actual human behaviour is very difficult and so games use various forms

of trickery to give an impression of intelligent behaviour

• The ultimate aim of AI is to improve the gaming experience and give a realistic feel

to the game

• Various methods including state machines, planning systems ,online learning etc are

used to run and improve the AI.

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THANK YOU

QUESTIONS???

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