Project 7: Advanced Computer Graphics: Artificial Intelligence Behind the Graphics

• Save the pieces of the  project so you can later demonstrate each one

• Make a directory ~/video/project7 in your home directory

• In game design, the algorithms underlying intelligent behavior are referred to as AI, or Artificial Intelligence. The aiDumbBiped01.wdl script  provides basic animation of models, enabling characters other than the player to move about in a game.
  
• Copy one of the levels from a previous project to the project7 directory, and use it for the current project.
•  Then, place a player model  and add the behavior script plBiped01.wdl by right-clicking the model. 
  
• Add a third-person camera.
  
• Build and run the game to check for errors.
• Next, add a second model to the level, such as hero.mdl and place the new model directly in front of the player, away from any walls, and facing away, as illustrated below.

• Add the AI script "Dumb AI Bipeds(01)" aiDumbBiped01.wdl to the game
  
• Add the behavior aiDumbBiped01 to the opponent
  
• Then, build and run the game.
• When the game first runs, the new character should run away from the player.  However, the player will probably stop after hitting the first obstruction (due to some script bugs? in current version)
<>
• Make a new copy of the aiDumbBiped.mdl (from the template_6/code subdirectory of 3D GameStudio), and place the copy in the directory of the game. 
  
• Rename the copy aiDumbtw.wdl, and avoid using a long file name since this may cause errors in the game. 
  
• Open the new aiDumbtw.wdl script file in SED, and edit as described in Chapter 8, including lines as below:
  

• Further down in the file,
  

• Near the bottom of the aiDumbtw.wdl file, rename the action AiDumbtw.
• In the newer versions of  3D GameStudio, new templates must be placed in the template_6/code subdirectory of 3D GameStudio.  Since this directory cannot be written to by students,  we must work around the problem.  First, use File::ProjectManager to add a 3rd person camera, Biped Player, and Dumb AI Bipeds scripts to your game, then recompile.  To include the new action in your game, copy the entire contents of aiDumbtw.wdl to the end of your main game script (game7.wdl).  In WED, make sure that File::Prefernce::Advanced::Reload is set to Prompt so that WED will reload the script when edited in SED.   After editing and saving the main game script, your new action "AiDumbtw" should be available to be added to entites in your game.

  In addition, it might be necessary to add three "define statements" to the code, since it seems that these are somehow ignored even though these statements should have be loaded from BipedPhy01.wdl. As below, the define statements should be added just ahead of the corresponding code that was given above.

  define _max_ang_force_pan__003,SKILL6;
  aiDumbBiped01_ang_force_vec.pan = my._max_ang_force_pan__003;
  define _max_force_x__003,SKILL3;
  aiDumbBiped01_force_vec.x = my._max_force_x__003;
  define _max_force_y__003,SKILL4;
  aiDumbBiped01_force_vec.y = my._max_force_y__003;

• Open the behavior customization window and set values as suggested in the book
• Hopefully the opponent will reun around the level, and slide along walls
• Once the game is running properly, experiment with different settings for the AI model.

• Even more erratic behavior can be created with some randomization. 
  
• As described in Chapter 8, add code  
  

• Rebuild and run the program. 
  
• The model should exhibit fairly random behavior. 
  
• Experiment with other randomizations
  

• Add a Spider model as an opponent (download from Conitec http://au.conitec.net/ models )
  
• Add the "Simple FPS AIs(01)" script
• Change to a first-person camera
  
• Add the AIFPS01_Guard behavior to the spider
• Rebuild and run the game
• When running the program, "Parameter Unknown" errors may occur in some wdl scripts at run-time.  This may occur if the sequence of include files is incorrect or if an include file is missing altogether.  In some versions of GameStudio, the "unknown parameter FXA_Exp1_Flash" error is caused because fxa01.wdl was not included before weaponfx00.wdl.  This should have been automatically included when "Simple FPS AIs(01)" was added.  It will be necessary to manually add the include statement to your game's main wdl script file as illustrated below:

• You should have spiders chasing   the player as below (after walking near the spiders)
  

• The random movements of the preceding section may be fine for some games, but often it is desirable to have characters follow defined paths.
• Add a path for one of the spiders to follow as shown below

Figure 3.  Path added for path-following spider.

• Add the path number ot the propertirs of the AIFPS01_Guard behavior of the spider.  Remove any other opponents from the game.
  
• Rebuild and run the game.
• 
  

Copyright © 2005- 2007  by Thomas Paul Weldon