AI for Games CM0328D

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AI for GamesCM-0328D
Video Games and Real Time AI
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Video Game Early History

• 1958 Willy Higinbotham invents a tennis-like
  game on an oscilloscope
• 1961 Steve Russell creates Spacewar on a PDP-1
• 1968 Ralph Baer patents a TV video tennis game
• 1971 Nutting release a video game cabinet (for
  Spacewar). It bombs.
• 1972 Atari formed and Pong released test
  units get flooded with quarters
• 1977 Atari releases VCS home video console
• 1978 Nintendo releases computer Othello, Atari
  releases football (using a trackball), Midway
  imports Taitos Space Invaders

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Video Game Genres

• Abstract, Adaptation, Adventure, Artificial Life,
  Board Games, Capturing, Card Games, Catching,
  Chase, Collecting, Combat, Demo, Diagnostic,
  Dodging, Driving, Educational, Escape, Fighting,
  Flying, Gambling, Interactive Movie, Management
  Simulation, Maze, Obstacle Course,
  Pencil-and-Paper Games, Pinball, Platform,
  Programming Games, Puzzle, Quiz, Racing,
  Role-Playing, Rhythm and Dance, Shoot Em Up,
  Simulation, Sports, Strategy, Table-Top Games,
  Target, Text Adventure, Training Simulation, and
  Utility

The Medium of the Video Game (Mark J. P. Wolf)
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Video Game AI

• Mostly a mix of
• Scripting (e.g. shooting games)
• Rule-based systems
• Pathfinding
• Finite state machines (with/without a stack)
• Simple planning
• Environmental Triggers

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Rule-based AI

• Build a flowchart for a simple plant-eating
  organism
• Then build a flowchart for a meat-eating organism
  that would beat your plant-eater
• Then build a flowchart for a plant eating
  organism that would be successful against your
  meat-eating organism

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Pathfinding
Start
Finish
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A search (1)

• 1) Add the starting square to the open list.
• 2) Repeat the following
• a) Look for the lowest F cost square on the open
  list. We refer to this as the current square.
• b) Switch it to the closed list.
• c) For each of the 8 squares adjacent to this
  current square
• If it is not walk able or if it is on the closed
  list, ignore it. Otherwise do the following.
  
• If it isn't on the open list, add it to the open
  list. Make the current square the parent of this
  square. Record the F, G, and H costs of the
  square.
• If it is on the open list already, check to see
  if this path to that square is better, using G
  cost as the measure. A lower G cost means that
  this is a better path. If so, change the parent
  of the square to the current square, and
  recalculate the G and F scores of the square. If
  you are keeping your open list sorted by F score,
  you may need to resort the list to account for
  the change.

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A search (2)

• d) Stop when you
• Add the target square to the open list, in which
  case the path has been found, or
• Fail to find the target square, and the open list
  is empty. In this case, there is no path.
• 3) Save the path. Working backwards from the
  target square, go from each square to its parent
  square until you reach the starting square. That
  is your path.

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Pathfinding Step 2
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Pathfinding Step 3

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Pathfinding Step 4


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Pathfinding Step 14



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Getting back the path




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Finite State Machines
Switch up
ON
OFF
Switch down
And so much more