sprites.asm -- Commodore 64 Sprite Multiplexer

sprites.asm

.importonce

//***************************************************************************
//	VIC II
//	BANK 0: $0000 - $3FFF
//	BANK 1:	$4000 - $7FFF
//	BANK 2:	$8000 - $BFFF
//	BANK 3: $C000 - $FFFF
//***************************************************************************


//***************************************************************************
//	To calculate the sprite location use:
//	LOCATION = (BANK * 16384) + (SPRITE POINTER VALUE * 64)
//	Where BANK = 0 - 3 and SPRITE POINTER VALUE = 0 - 255.
//	SPRITE POINTER VALUE: 0: 0 * 64 = 0  (beginning of current VIC bank)
//						  1: 1 * 64 = 64 (beginning of current VIC bank + 64)
//***************************************************************************
.function fnSprite_ORA_Value(sprite) {
	.if(sprite == 0) .return %00000001
	.if(sprite == 1) .return %00000010
	.if(sprite == 2) .return %00000100
	.if(sprite == 3) .return %00001000
	.if(sprite == 4) .return %00010000
	.if(sprite == 5) .return %00100000
	.if(sprite == 6) .return %01000000
	.if(sprite == 7) .return %10000000
}

.function fnSprite_AND_Value(sprite) {
	.if(sprite == 0) .return %11111110
	.if(sprite == 1) .return %11111101
	.if(sprite == 2) .return %11111011
	.if(sprite == 3) .return %11110111
	.if(sprite == 4) .return %11101111
	.if(sprite == 5) .return %11011111
	.if(sprite == 6) .return %10111111
	.if(sprite == 7) .return %01111111
}

.macro SetSpritePointer(sprite, value) {

	.var addr = SCR_BUFFER + [[1024 - 8] + sprite]

	.print "SetSpritePointer"
	.print "		SCR_BUFFER = " + fnPrintMemoryAddress(SCR_BUFFER)
	.print "		DBL_BUFFER = " + fnPrintMemoryAddress(DBL_BUFFER)
	.print "		SCR_BUFFER + [[1024 - 8] + sprite] = " 
		+ fnPrintMemoryAddress(addr)

	lda #value
	sta addr
}


.macro EnableAllSprites() {
	.print "EnableAllSprites"
	lda #$FF
	sta $D015
}

.macro DisableAllSprites() {
	.print "DisableAllSprites"
	lda #$00
	sta $D015
}

.macro EnableSprite(sprite) {

	.print "EnableSprite " + sprite

	lda $D015
	ora #fnSprite_ORA_Value(sprite)
	sta $D015
}

.macro DisableSprite(sprite) {
	.print "DisableSprite " + sprite
	lda $D015
	and #fnSprite_AND_Value(sprite)
	sta $D015
}

.macro EnableSpriteMultiColor(sprite) {

	.print "EnableSpriteMultiColor " + sprite

	lda $D01C
	ora #fnSprite_ORA_Value(sprite)
	sta $D01C	
}

.macro EnableAllSpritesMultiColor() {
	.print "EnableAllSpritesMultiColor"
	lda #$FF
	sta $D01C
}

.macro SetSpriteColor(sprite, color) {
	.print "SetSpriteColor"
	.print "	Sprite: " + sprite
	.print "	Color:	" + fnPrintColorName(color)

	lda #color
	.if(sprite == 0) sta $D027
	.if(sprite == 1) sta $D028
	.if(sprite == 2) sta $D029
	.if(sprite == 3) sta $D02A
	.if(sprite == 4) sta $D02B
	.if(sprite == 5) sta $D02C
	.if(sprite == 6) sta $D02D
	.if(sprite == 7) sta $D02E	
}

.macro SetAllSpritesColor(color) {
	.print "SetAllSpritesColor"
	.print "	Color:	" + fnPrintColorName(color)

	lda #color
	sta $D027
	sta $D028
	sta $D029
	sta $D02A
	sta $D02B
	sta $D02C
	sta $D02D
	sta $D02E
}

.macro SetSpriteMultiColor0(color) {

	.print "SetSpriteMultiColor0 " + fnPrintColorName(color)
	
	lda #color
	sta $D025
}

.macro SetSpriteMultiColor1(color) {

	.print "SetSpriteMultiColor1 " + fnPrintColorName(color)

	lda #color
	sta $D026
}

.macro SetSpriteX(sprite, xpos) {

	.print "SetSpriteX"
	.print "	Sprite: " + sprite
	.print "	XPos:	" + xpos

	lda #xpos
	.if(sprite == 0) sta $D000
	.if(sprite == 1) sta $D002
	.if(sprite == 2) sta $D004
	.if(sprite == 3) sta $D006
	.if(sprite == 4) sta $D008
	.if(sprite == 5) sta $D00A
	.if(sprite == 6) sta $D00C
	.if(sprite == 7) sta $D00E
}

.macro SetSpriteY(sprite, ypos) {

	.print "SetSpriteY"
	.print "	Sprite: " + sprite
	.print "	YPos:	" + ypos

	lda #ypos
	.if(sprite == 0) sta $D001
	.if(sprite == 1) sta $D003
	.if(sprite == 2) sta $D005
	.if(sprite == 3) sta $D007
	.if(sprite == 4) sta $D009
	.if(sprite == 5) sta $D00B
	.if(sprite == 6) sta $D00D
	.if(sprite == 7) sta $D00F
}


.macro DrawSprites() {
	.print "DrawSprites: " + fnPrintMemoryAddress(*)

!drawstart:
	ldx #$00
	ldy #$00
!loop:
	lda SORTSPRX, y
	sta $D000, x

	lda SORTSPRY, y
	sta $D001, x

	inx
	inx
	iny

	cpy #$08
	bne !loop-

	clc
	adc #$18
	sta $D012
	lda #<!drawstart+
	sta $FFFE
	lda #>!drawstart+
	sta $FFFF
	jmp !exit+

!drawstart:
	ldx #$00
	ldy #$08
!loop:
	lda SORTSPRX, y
	sta $D000, x

	lda SORTSPRY, y
	sta $D001, x

	inx
	inx
	iny

	cpy #$10
	bne !loop-

	clc
	adc #$18 
	sta $D012
	lda #<!drawstart+
	sta $FFFE
	lda #>!drawstart+
	sta $FFFF
	jmp !exit+

!drawstart:
	ldx #$00
	ldy #$10
!loop:
	lda SORTSPRX, y
	sta $D000, x

	lda SORTSPRY, y
	sta $D001, x

	inx
	inx
	iny

	cpy #$18
	bne !loop-

	clc
	adc #$04
	sta $D012
	lda #<SortSprites
	sta $FFFE
	lda #>SortSprites
	sta $FFFF
!exit:

}


//*****************************************************************************
//	Map virtual sprites to physical ones
//*****************************************************************************
.macro MapSprites() {


}


.macro MoveSprites() {
	.print "MoveSprites: " + fnPrintMemoryAddress(*)

	ldx #$00
	ldy #$00
!loop:
	lda #$01
	adc SPRY, y
	// sta SPRY, y

	iny
	cmp #num_sprites
	bne !loop-
}

//*****************************************************************************
//	Sort the sprite arrays
//*****************************************************************************
.macro SortSprites() {

	ldx #$00
!loop:
	ldy SORTORDER + 1, x
	lda SPRY, y	
	ldy SORTORDER, x
	cmp	SPRY, y
	bcs !dontswap+
!swap:
	lda SORTORDER + 1, x
	sta SORTORDER, x
	tya							//	Y still has previous value
	sta SORTORDER + 1, x		//	This can be sped up with ZP
!dontswap:
	inx
	cpx #num_sprites - 1
	bne !loop-

!donesorting:
	//	Now that the SORTORDER index is sorted,
	//	copy the sorted indexes to the SORT tables
	ldx #$00
!loop:
	ldy SORTORDER, x

	lda SPRY, y
	sta SORTSPRY, x

	lda SPRX, y
	sta SORTSPRX, x

	lda SPRC, y
	sta SORTSPRC, x

	lda SPRF, y
	sta SORTSPRF, x

	inx
	cpx #num_sprites 
	bne !loop-
}