Which are the various AI(Artificial Intelligence) Techniques used in Games?

AI(Artificial Intelligence): Techniques used to emulate the human thought process in a computer.

Types of Game AI:
Generally, the following 3 types of AI is being used in most of the games:

1. Roaming AI
2. Behavioral AI
3. Strategic AI

1- Roaming AI: It models the movement of game objects. i.e. the decisions made by game objects that determine how they roam around in a virtual game world.

Basically, roaming AI is used whenever a computer controlled object must make a decision to alter its current path, either to achieve the desired result in the game or simply to conform to a particular movement patternn.Types of roaming AI:
· chasing
· evading
· patterned roaming

• Chasing: It is a type of roaming AI in which a game object tracks and goes after another game object or objects. This approach is used in many shoot-em-up games where an alien or enemy chases after player’s ship or car or bike or the player himself. It is implemented by altering the alien’s velocity or position based on the current position of the player’s ship.
  
• Evading: It is the logical counterpart to chasing. it is another type of roaming AI in which a game object tries to get away from another object or objects.
  
• Patterned roaming: It is a type of roaming AI that uses a predefined set of movements for a game object. Patterns can include circles,figure eights, zigzags, or even more complex movements.
  

2- Behavioral AI: This type of gaming AI uses a mixture of all three roaming AI algorithms to give game objects specific behaviors.. eg. if you want the alien or enemy to chase sometimes, evade other times, follow a pattern some other times, and may be even act randomly every once in a while. behavioral AI can also be used to alter the difficulty of the game. eg. You would like to favor a chasing algorithm more than random or patterned movement to make the aliens or enemies more aggressive in the higher levels of a game.

3- Strategic AI: Any AI designed to play a game with a fixed set of well defined rules is known as strategic AI. eg. a computer controlled chess player would use strategic AI to determine each move based on trying to improve the chances of winning the game.
Strategic AI tend to vary more based on the nature of the game because it is so tightly linked to the rules of the game.