checkCol.asm

EXTRN BALL_X:WORD
EXTRN BALL_Y:WORD
EXTRN BALL1_X:WORD
EXTRN BALL1_Y:WORD
EXTRN BALL2_X:WORD
EXTRN BALL2_Y:WORD
EXTRN PADDLE1_X:WORD
EXTRN BALL_VELOCITY_X:WORD
EXTRN BALL_VELOCITY_Y:WORD
EXTRN PADDLE_X:WORD
EXTRN drawPaddle:FAR
EXTRN clearTile:FAR
EXTRN TIME:BYTE
EXTRN POWERUPSARR:BYTE
EXTRN PADDLE_WIDTH:WORD
EXTRN GAME_OVER_FLAG:WORD
EXTRN GAME_OVER_FLAG2:WORD

PUBLIC checkCollision
PUBLIC checkCollision2

.MODEL SMALL
.STACK 100h

.386

.DATA
    SCREEN_WIDTH  EQU 160
    SCREEN_HEIGHT EQU 200
    BALL_SIZE     EQU 5
    PADDLE_Y      EQU 180
    PADDLE_HEIGHT EQU 10
    TILE_WIDTH  equ 20
    TILE_HEIGHT equ 10
    BALL_VELOCITY_MAG EQU 1
    COLLISION_X dw ?
    COLLISION_Y dw ?
    COLLISION_X_FLAG db ?
    COLLISION_Y_FLAG db ?
    POWERUP_FLAG DB 0
    SEED DD 5970917
	MULTIPLIER EQU 22695477	
	INCREMENT EQU 1
	MODULUS EQU 2147483647
    rest_position_X equ 80
    rest_position_Y equ 150

.CODE
getPixelColor PROC FAR
    MOV AX, 0

    MOV AH, 0Dh
    INT 10h
    MOV AH, 0

    CMP AX,44
    JE setPowerUp

    CMP AX,140
    JE setPowerUp

    CMP AX,92
    JE setPowerUp

    ret

setPowerUp:
    MOV POWERUP_FLAG,1
    RET
getPixelColor ENDP

getPixelColor2 PROC FAR
    MOV AX, 0

    MOV AH, 0Dh
    INT 10h
    MOV AH, 0

    RET
getPixelColor2 ENDP

LCG PROC FAR
	PUSHA
	MOV EAX, SEED
	MOV EBX, MULTIPLIER
	MUL EBX
	ADD EAX, INCREMENT
	MOV SEED, EAX
	MOV EDX, 0
	MOV EBX,MODULUS
	DIV EBX
	MOV SEED, EDX
	MOV EAX, EDX
	POPA
	RET
LCG ENDP

checkPowerup PROC FAR
    CMP POWERUP_FLAG, 1
    JNE ExitCheckPowerup

    MOV ECX, 5
    MOV SI, 0
resetPowerups:
    MOV POWERUPSARR[SI], 0
    INC SI
    LOOP resetPowerups

    MOV AH, 00h
	INT 1Ah
    MOV EAX, CX
    SHL EAX, 16
    MOV AX, DX
    MOV SEED, EAX
    CALL LCG

    MOV EAX, SEED
    MOV EDX, 0
    MOV ECX, 3
    DIV ECX

    MOV SI, DX
    MOV POWERUPSARR[SI], 127

ExitCheckPowerup:
    RET
checkPowerup ENDP

checkPaddleCollision PROC FAR
    MOV AX, BALL1_Y
    ADD AX, BALL_SIZE
    CMP AX, PADDLE_Y
    JL  endCheckPaddle

    MOV AX, PADDLE_Y
    ADD AX, PADDLE_HEIGHT
    CMP AX, BALL1_Y
    JL  endCheckPaddle

checkPaddleX:
    MOV AX, BALL1_X
    ADD AX,BALL_SIZE
    CMP AX, PADDLE1_X
    JLE  endCheckPaddle

    MOV AX, PADDLE1_X
    ADD AX, PADDLE_WIDTH
    CMP AX, BALL1_X
    JLE  endCheckPaddle
    
    MOV AX, PADDLE_WIDTH
    SHR AX,1
    MOV AH,0
    SUB AL,7
    MOV DX,AX

    MOV AX, BALL1_X
    ADD AX, BALL_SIZE / 2
    MOV BX, PADDLE1_X
    ADD BX,7
    CMP AX,BX
    JL farLeft
    ADD BX,DX
    CMP AX,BX
    JL nearLeft
    ADD BX,DX
    CMP AX,BX
    JL nearRight
    JMP farRight
    JMP endCheckPaddle
    RET

nearLeft:
    MOV BALL_VELOCITY_X, -BALL_VELOCITY_MAG
    MOV BALL_VELOCITY_Y, -BALL_VELOCITY_MAG*2
    JMP endCheckPaddle
farLeft:
    MOV AX,BALL1_Y
    CMP AX,PADDLE_Y
    JGE collideFromSide
    
    MOV BALL_VELOCITY_X, -BALL_VELOCITY_MAG*2
    MOV BALL_VELOCITY_Y, -BALL_VELOCITY_MAG
    JMP endCheckPaddle
nearRight:
    MOV BALL_VELOCITY_X, BALL_VELOCITY_MAG
    MOV BALL_VELOCITY_Y, -BALL_VELOCITY_MAG*2
    JMP endCheckPaddle

farRight:
    MOV AX,BALL1_Y
    CMP AX,PADDLE_Y
    JGE collideFromSide

    MOV BALL_VELOCITY_X, BALL_VELOCITY_MAG*2
    MOV BALL_VELOCITY_Y, -BALL_VELOCITY_MAG
    JMP endCheckPaddle

collideFromSide:
    NEG BALL_VELOCITY_X

endCheckPaddle:
    CALL drawPaddle
    RET
checkPaddleCollision ENDP

checkCollision PROC FAR
    MOV POWERUP_FLAG, 0
    MOV AX, BALL1_X
    MOV BX, BALL1_Y
    MOV COLLISION_X_FLAG, 0
    MOV COLLISION_Y_FLAG, 0

; Check left boundary
LeftBoundary:
    CMP AX, 1
    JG  RightBoundary
    NEG BALL_VELOCITY_X
    JMP EndCheck

; Check right boundary
RightBoundary:
    CMP AX, SCREEN_WIDTH - BALL_SIZE -1
    JL  TopBoundary
    NEG BALL_VELOCITY_X
    JMP EndCheck

; Check top boundary
TopBoundary:
    MOV BX, BALL1_Y
    CMP BX, 12
    JG  BottomBoundary
    NEG BALL_VELOCITY_Y
    JMP EndCheck

; Will be removed later for game over
; Check bottom boundary
BottomBoundary:
    CMP BX, PADDLE_Y + 2
    JL  skipBottomBoundary
    MOV AX, rest_position_X
    MOV BALL_X, AX
    MOV AX,rest_position_Y
    MOV BALL_Y, AX
    MOV BALL_VELOCITY_X, 2
	MOV BALL_VELOCITY_Y, -1
    SUB GAME_OVER_FLAG, 7
    JMP EndCheck

skipBottomBoundary:
    CMP BX, 100
    JL TopEdgeColor
    CALL checkPaddleCollision
    JMP EndCheck

; Check the color of the pixel at the top and bottom edges of the ball
TopEdgeColor:
    MOV CX, BALL1_X
    MOV DX, BALL1_Y
    DEC DX
    DEC DX
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromTop

    MOV CX, BALL1_X
    MOV DX, BALL1_Y
    DEC DX
    DEC DX
    ADD CX, BALL_SIZE - 1
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromTop 

BottomEdgeColor:
    MOV CX, BALL1_X
    MOV DX, BALL1_Y
    ADD DX, BALL_SIZE
    INC DX
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromBottom

    MOV CX, BALL1_X
    MOV DX, BALL1_Y
    ADD DX, BALL_SIZE
    INC DX
    ADD CX, BALL_SIZE - 1
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromBottom

; Check the color of the pixel at the left and right edges of the ball
LeftEdgeColor:
    MOV CX, BALL1_X
    DEC CX
    DEC CX
    MOV DX, BALL1_Y
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromLeft

    MOV CX, BALL1_X
    DEC CX
    DEC CX
    MOV DX, BALL1_Y
    ADD DX, BALL_SIZE - 1
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromLeft

RightEdgeColor:
    MOV CX, BALL1_X
    ADD CX, BALL_SIZE
    INC CX
    MOV DX, BALL1_Y
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromRight

    MOV CX, BALL1_X
    ADD CX, BALL_SIZE
    INC CX
    MOV DX, BALL1_Y
    ADD DX, BALL_SIZE - 1
    CALL getPixelColor
    CMP AX, 0
    JNE BallCollidedFromRight

    JMP EndCheck

; Clear the tile above the ball
BallCollidedFromTop:
    CMP COLLISION_Y_FLAG, 1
    JE skipNegYTop
    NEG BALL_VELOCITY_Y
    MOV COLLISION_Y_FLAG,1
    skipNegYTop:
    MOV COLLISION_X,CX
    MOV COLLISION_Y,DX

    MOV AX, COLLISION_X
    MOV CX, TILE_WIDTH
    DIV CL
    MOV AH, 0
    MOV DX, AX

    MOV AX, COLLISION_Y
    MOV CX, TILE_HEIGHT
    DIV CL
    MOV AH, 0
    MOV AH, AL
    MOV AL, DL

    CALL clearTile

    JMP TopEdgeColor

; Clear the tile below the ball
BallCollidedFromBottom:
    CMP COLLISION_Y_FLAG, 1
    JE skipNegYBottom
    NEG BALL_VELOCITY_Y
    MOV COLLISION_Y_FLAG,1
    
    skipNegYBottom:
    MOV COLLISION_X,CX
    MOV COLLISION_Y,DX

    MOV AX, COLLISION_X
    MOV CX, TILE_WIDTH
    DIV CL
    MOV AH, 0
    MOV DX, AX

    MOV AX, COLLISION_Y
    MOV CX, TILE_HEIGHT
    DIV CL
    MOV AH, 0
    MOV AH, AL
    MOV AL, DL

    CALL clearTile

    JMP BottomEdgeColor

; Clear the tile to the left of the ball
BallCollidedFromLeft:
    
    CMP COLLISION_X_FLAG, 1
    JE skipNegXLeft
    NEG BALL_VELOCITY_X
    MOV COLLISION_X_FLAG,1
    
    skipNegXLeft:
    MOV COLLISION_X,CX
    MOV COLLISION_Y,DX

    MOV AX, COLLISION_X
    MOV CX, TILE_WIDTH
    DIV CL
    MOV AH, 0
    MOV DX, AX

    MOV AX, COLLISION_Y
    MOV CX, TILE_HEIGHT
    DIV CL
    MOV AH, 0
    MOV AH, AL
    MOV AL, DL

    CALL clearTile

    JMP LeftEdgeColor

; Clear the tile to the right of the ball
BallCollidedFromRight:
        
    CMP COLLISION_X_FLAG, 1
    JE skipNegXRight
    NEG BALL_VELOCITY_X
    MOV COLLISION_X_FLAG,1
    
    skipNegXRight:

    MOV COLLISION_X,CX
    MOV COLLISION_Y,DX

    MOV AX, COLLISION_X
    MOV CX, TILE_WIDTH
    DIV CL
    MOV AH, 0
    MOV DX, AX

    MOV AX, COLLISION_Y
    MOV CX, TILE_HEIGHT
    DIV CL
    MOV AH, 0
    MOV AH, AL
    MOV AL, DL

    CALL clearTile

    JMP BottomEdgeColor

EndCheck:
    CALL checkPowerup
    RET
checkCollision ENDP

checkCollision2 PROC FAR
    MOV AX, BALL2_X
    MOV BX, BALL2_Y

BottomBoundary2:
    cmp BX, PADDLE_Y + 2
    JL  skipBottomBoundary2

    SUB GAME_OVER_FLAG2, 7
    JMP EndCheck2

skipBottomBoundary2:

; Check the color of the pixel at the top and bottom edges of the ball
TopEdgeColor2:
    MOV CX, BALL2_X
    MOV DX, BALL2_Y
    DEC DX
    DEC DX
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

    MOV CX, BALL2_X
    MOV DX, BALL2_Y
    DEC DX
    DEC DX
    ADD CX, BALL_SIZE - 1
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

BottomEdgeColor2:
    MOV CX, BALL2_X
    MOV DX, BALL2_Y
    ADD DX, BALL_SIZE
    INC DX
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

    MOV CX, BALL2_X
    MOV DX, BALL2_Y
    ADD DX, BALL_SIZE
    INC DX
    ADD CX, BALL_SIZE - 1
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

; Check the color of the pixel at the left and right edges of the ball
LeftEdgeColor2:
    MOV CX, BALL2_X
    DEC CX
    DEC CX
    MOV DX, BALL2_Y
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

    MOV CX, BALL2_X
    DEC CX
    DEC CX
    MOV DX, BALL2_Y
    ADD DX, BALL_SIZE - 1
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

RightEdgeColor2:
    MOV CX, BALL2_X
    ADD CX, BALL_SIZE
    INC CX
    MOV DX, BALL2_Y
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

    MOV CX, BALL2_X
    ADD CX, BALL_SIZE
    INC CX
    MOV DX, BALL2_Y
    ADD DX, BALL_SIZE - 1
    CALL getPixelColor2
    CMP AX, 0
    JNE BallCollided

    JMP EndCheck2

; Clear the tile above the ball
BallCollided:
    MOV COLLISION_X,CX
    MOV COLLISION_Y,DX

    MOV AX, COLLISION_X
    MOV CX, TILE_WIDTH
    DIV CL
    MOV AH, 0
    MOV DX, AX

    MOV AX, COLLISION_Y
    MOV CX, TILE_HEIGHT
    DIV CL
    MOV AH, 0
    MOV AH, AL
    MOV AL, DL

    CALL clearTile

    JMP TopEdgeColor2

; Clear the tile below the ball

EndCheck2:
    RET
checkCollision2 ENDP

END