Contra Wars: Game Input and Logic

Setup

• Variables read:
  • MyOffset
  • bkey
  • gkey
  • rkey
  • players
  • MyNum
  • StartPosArray
• Variables updated:
  • players
  • MyPosition
• Calls:
  • none
• Description:
  • Initializes player when game begins

firebullet

• Variables read:
  • players
  • MyPosition
• Variables updated:
  • players
• Calls:
  • UPDATESHOTSEND
  • startbullet
• Description:
  • Allocates a bullet in a player's bullet array if there's space available

KbdInstall

• Variables read:
  • none
• Variables updated:
  • OldKbdV
• Calls:
  • none
• Description:
  • Installs a keyboard interrup that checks if any of the above keys have been hit or released and sets or resets the appropriate variable if so.

KbdUninstall

• Variables read:
  • OldKbdV
• Variables updated:
  • none
• Calls:
  • none
• Description:
  • Uninstalls our keyboard interrupt and replaces the old one.

MouseInstall

• Variables read:
  • none
• Variables updated:
  • MouseHeight
  • MouseLength
  • LeftButton
  • RightButton
• Calls:
  • none
• Description:
  • Installs our mouse interrupt that sets and resets the above variables when the appropriate actions are taken.

MouseUninstall

• Variables read:
  • none
• Variables updated:
  • none
• Calls:
  • none
• Description:
  • Uninstalls our mouse interrupt and sets the old one back into place.

WaitForInput

• Variables read:
  • Maincounter
  • vertical
• Variables updated:
  • vertical
• Calls:
  • none
• Description:
  • Waits for input until the beginning of the next vertical retrace

movebullet

• Variables read:
  • players
  • bulletarray
• Variables updated:
  • players
• Calls:
  • none
• Description:
  • Moves the bullet in the appropriate direction using bulletarray to look up it's velocity and terminates the bullet after a certain count

CollisionDet

• Variables read:
  • MyPosition
  • TileCanMove
  • Collision
  • LeftButton
  • RightButton
  • MyOffset
  • UPKEY
  • DOWNKEY
  • LEFTKEY
  • RIGHTKEY
  • NewDir
  • boxes
  • MyxOffset
  • MyyOffset
  • MyxSize
  • MyySize
  • BulletCount
  • wkey
  • HisxSize
  • HisySize
  • WalkCount
  • Players
• Variables updated:
  • MyPosition
  • collision
  • NewDir
  • BulletCount
  • players
  • MyxSize
  • MyySize
  • HisxSize
  • HisySize
• Calls:
  • WAVPLAY
  • firebullet
  • CheckTileMove
• Description:
  • Checks for collisions between the player and other objects in the game and updates the appropriate variables.

startbullet

• Variables read:
  • Players
  • StartBulArray
• Variables updated:
  • players
• Calls:
  • none
• Description:
  • Determines the initial position of the bullet using startbularray

Structures:

PointType struc
          x dw   ? ; x-position 
          y dw   ? ; y-position
PointType ends
PlayerType struc
          Team      db   ? ; team number the player belongs to
          Firing    db   ? ; a bool as to whether the person is firing
          Walk      db   ? ; a status as to current walk state
          GamePos   dw   2 dup(?) ; the player's position in game
                                  ;coordinates
          Dir       db   ? ; direction player is facing
          Bullets   db   MAX_BULLETS*6 dup(0) ; the bullets fired by the player
          Dead      db   ? ; bool as to whether player is dead
PlayerType ends
BulletType struc
       pos     dw  2  dup(0) ; the bullet's current location on the screen
       dir     db  0         ; the direction of the bullet, 1-32
       count dw 0            ; determines range of bullet
       status  db  ?         ; the status of the bullet
BulletType ends

Variables:

Players PlayerType NUM_PLAYERS dup (<>) ; holds the stats for all 
                                        ; players in the game 
tile_map db MAP_WIDTH*MAP_HEIGHT dup (0)    ; holds the map tile indices
MyPosition  PointType <>                    ; the player's current position
MyDirection db ?                            ; the player's current orientation 
Maincounter dw ?                            ; keeps track of time
LEFTKEY  db ?                               ; set when left arrow
key is hit
RIGHTKEY db ?                               ; set when right arrow key is hit
UPKEY    db ?                               ; set when up arrow key is hit
DOWNKEY  db ?                               ; set when down arrow key is hit
KEY   db ?                                  ; set when left arrow key is hit
qkey  db ?                                  ; set when left arrow key is hit
esckey  db ?
wkey db 0                                   ; set when left arrow key is hit
LeftButton  db ?                            ; set when left button is hit
RightButton db ?                            ; set when right button is hit
MyOffset dw 0                               ; position in players

MyxOffset db 0                              ; used to hold top left offset
MyyOffset db 0                              ; of current bounding box

NewDir db 0                                 ; New direction the player is trying to turn in

MyxSize dw 0                                ; Size of current bounding  box
MyySize dw 0                                ; ditto

HisxSize dw 0                               ; Size of current bounding box
HisySize dw 0                               ; for another player
Bulletcount db 0                            ; used to enter delay after one bullet is fired before the next can be
BulletCount2 db 0                           ; 
WalkCount db 0                              ; used to delay walking animation
rkey db 0                                   ; signals r key pressed
gkey db 0                                   ; signals g key pressed
ckey db 0                                   ; signals c key pressed
bkey db 0                                   ; signals b key pressed
HelloSpew dw 0                              ; used to send periodic Hello messages

Constants:
NUM_WALK_STATES                      ; number of animation states
NUM_PLAYERS equ 18                   ; the maximum number of players
MAX_BULLETS equ 6                    ; the maximum number of bullets a
                                         ; player can fire
NUM_TEAMS   equ 3                    ; the number of teams allowed in
                                         ; the game
TRUE  EQU 1                          ; for boolean logic
FALSE EQU 0
MAP_WIDTH  equ 50                    ; number of tiles in the
                                         ; x-direction in world map
MAP_HEIGHT equ 32                    ; number of tiles in the
                                         ; y-direction in world map
WALK_STATE_STILL equ 0               ; state when standing still
WALK_STATE_LEFT  equ 1               ; state when walking on left foot 
WALK_STATE_RIGHT equ2                ; state when walking on right
foot
SIZEPLAYERSTRUCT equ 58
SIZEBULLETSTRUCT equ 8
BULLET_WAIT equ 20                   ; delay after which a player can fire a bullet again
BULLET_RANGE equ 40                  ; count at which bullet disappears
WALK_TIME equ 23                     ; determines time before next animation

MACROS:
DOSEXIT                    ; macro from macros.inc
CheckCol                   ; checks for collisions given the sizes and
                               ; offsets in game coordinates of two bounding boxes
MapLookUp                  ; given game coordinates, figures out tile
                               ; coordinates