Artificial Intelligence Routines

The artificial intelligence routines handle both the AI computer-controlled units and the human player's movement, as well as hit detection. These routines are also the basic data manipulation for the game

• UnitUpdate -- is is the primary movement function for the game. The unit's data, stored in arrays, is modified and updated corresponding to each individual unit's actions, be it movement, if it fired, if it was hit, and if it is not even there at all. The graphics, sound, and networking routines take it from there.

  ; ----------------------------------------------
  ; UnitUpdate
  ;
  ; Inputs: UnitArray -- An Array containg the infor of all the units on the screen
  ; DS is assumed to be equal to CSEG
  ;
  ; Outputs: UnitArray -- Updated position variables
  ;
  ; Input/Output: Nothing.
  ;
  ; Purpose: The Artificial Intelligence for the computer controlled units
  ;
  ; Written by: Matthew Curry
  ; -----------------------------------------------

• BulletUpdate -- this function handles the movement and creation of everyone's favorite projectile. It is a subfunction of UnitUpdate.

  ; ----------------------------------------------
  ; BulletUpdate
  ;
  ; Inputs: BulletArray
  ;
  ; Outputs: BulletArray
  ;
  ; Input/Output: Nothing.
  ;
  ; Purpose: Moves the bullets into their new locations
  ;
  ; Written by: Matthew Curry
  ; -----------------------------------------------

• CollisionDetect -- this function is a subfunction for the UnitUpdate function. It will determine if hits are made… be it from bullets hitting you, or someone else, or things colliding with each other.

  ; ----------------------------------------------
  ; CollisionDetect
  ;
  ; Inputs: BulletArray & UnitArray
  ;
  ; Outputs: Updated inputs
  ;
  ; Input/Output: Nothing.
  ;
  ; Purpose: boundary detection, to determine when things
  ; die and aren't required on screen anymore.
  ;
  ; Written by: Matthew Curry
  ; -----------------------------------------------

• addNewEnemy -- This function adds a new enemy to the screen

  ; ----------------------------------------------
  ; addNewEnemy
  ;
  ; Inputs: Image of type of enemy to be encountered & UnitArray
  ;
  ; Outputs: UnitArray is updated with it's stats
  ;
  ; Input/Output: Nothing.
  ;
  ; Purpose: to create new enemies to fight
  ;
  ; Written by: Matthew Curry
  ; -----------------------------------------------

• Collision -- This function detects of a collision occurs between an enemy and a player. If a collision occurs, the enemy and the players status bytes are both set to DYING.

  ; ----------------------------------------------
  ; Collision
  ;
  ; Inputs: position of player and position of enemy units
  ;
  ; Outputs: Destruction if there is a collision
  ;
  ; Input/Output: Nothing. ;
  ; Purpose: This method uses a simple but not very efficient circle
  ; (deltaX^2 + deltaY^2 = RADIUS^2) to detect collisions. As such, each
  ; unit must be approximated by a circular radius
  ;
  ; Written by: Nathan Hamstra
  ; -----------------------------------------------

Artificial Intelligence Structures

The artificial intelligence structures will be described below.

• Unit -- This is the structure that will be used for every unit in the game, either a human controlled player or a computerized enemy.

  Unit STRUC   IDUnit db ? ;bit 7=1 if nonplayer    status db 10b ;ACTIVE,        ; INACTIVE -- All units start here        ; DEAD,        ; JUSTFIRED    path db 00000001b        ;To be determined - possibly straight, zigzag; plus        ; different values for the ground units (2nd level)        ; Bit 0=1 if unit heads straight across screen        ; Bit 1=1 if unit zig-zags        ; Bit 2=1 if unit is on player avoidance course        ; Bit 3=1 if unit is on player pursuit course        ; Bit 4-7 indicate player independent direction    FireRate db ? ;in time interrupts between shots.    MovementRate db ? ;in 32nds of a pixel, timer interrupts=32 times/sec    RowPosition dw ? ;the VGA screen row pos., in pixels    ColumnPosition dw ? ;the VGA screen column pos., in pixels    Image db ? ;unit's picture    timeOfFire dw ? ;ime when unit last fired, unused so far Unit ENDS

• Bullet -- This is the structure that we will be using as the bullet type.

  Bullet struct ;structure for storing the projectiles   bstatus db 1 ; 1=bullet inactive, 0=bullet active   direction db ? ; 1 if right, 0 if left   positionr dw ? ;Bullet position, row and column   positionc dw ? Bullet ends

Artificial Intelligence Constants

These are all of the constants used for the Artifical Intelligence Routines

• ACTIVE EQU 1
• INACTIVE EQU 2
• DYING EQU 4
• JUSTFIRED EQU 8
• max_Enemy EQU 5
• max_Player EQU 2
• max_Object EQU 7
• max_Bullet EQU 40
• sizeOf_Unit EQU 12
• sizeOf_Bullet EQU 6
• STRAIGHT EQU 1
• ZIGZAG EQU 2
• AVOID EQU 4
• PURSUIT EQU 8
• UP EQU 16
• DOWN EQU 32
• FORWARD EQU 64
• BACK EQU 128
• RADIUS EQU 12