Apple-2gs-SW/iigs-game-engine
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Add support for sprite priority

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This commit is contained in:
Lucas Scharenbroich 2023-05-22 13:55:56 -05:00
parent d402d60a4e
commit 56b66033a7
2 changed files with 143 additions and 1 deletions
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2
demos/smb/ppu.s
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@ -1025,7 +1025,7 @@ oam_loop
:noflip
pla
asl
and #$0106 ; Set the vflip bit and palette select bits
and #$0146 ; Set the vflip bit, priority, and palette select bits
drawTilePatch
jsl $000000 ; Draw the tile on the graphics screen

142
src/SpriteRender.s
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@ -195,11 +195,19 @@ pal_select dw $3333,$6666,$9999,$CCCC
_DrawTileToScreen
:palette equ 248
phb
pea $0101
plb
plb
bit #$0040
beq :no_prio
bit #$0100
jeq _DrawPriorityToScreen
jmp _DrawPriorityToScreenV
:no_prio
bit #$0100
jne _DrawTileToScreenV
@ -231,6 +239,73 @@ _DrawTileToScreen
plb
rtl ; special exit
_DrawPriorityToScreen
:palette equ 248
:p_tmp equ 144
phx
and #$0006
tax
ldal pal_select,x
sta :palette
plx
clc
]line equ 0
lup 8
ldal tiledata+{]line*4}+2,x
adc :palette
eor: {]line*SHR_LINE_WIDTH}+2,y
sta :p_tmp
; Convert the screen data to a mask. Zero in screen = zero in mask, else $F
lda: {]line*SHR_LINE_WIDTH}+2,y
bit #$F000
beq *+5
ora #$F000
bit #$0F00
beq *+5
ora #$0F00
bit #$00F0
beq *+5
ora #$00F0
bit #$000F
beq *+5
ora #$000F
eor #$FFFF
and :p_tmp
andl tiledata+{]line*4}+32+2,x
eor: {]line*SHR_LINE_WIDTH}+2,y
sta: {]line*SHR_LINE_WIDTH}+2,y
ldal tiledata+{]line*4},x
adc :palette
eor: {]line*SHR_LINE_WIDTH},y
sta :p_tmp
lda: {]line*SHR_LINE_WIDTH},y
bit #$F000
beq *+5
ora #$F000
bit #$0F00
beq *+5
ora #$0F00
bit #$00F0
beq *+5
ora #$00F0
bit #$000F
beq *+5
ora #$000F
eor #$FFFF
and :p_tmp
andl tiledata+{]line*4}+32,x
eor: {]line*SHR_LINE_WIDTH},y
sta: {]line*SHR_LINE_WIDTH},y
]line equ ]line+1
--^
plb
rtl ; special exit
_DrawTileToScreenV
:palette equ 248
phx
@ -261,6 +336,73 @@ _DrawTileToScreenV
plb
rtl ; special exit
_DrawPriorityToScreenV
:palette equ 248
:p_tmp equ 144
phx
and #$0006
tax
ldal pal_select,x
sta :palette
plx
clc
]line equ 0
lup 8
ldal tiledata+{{7-]line}*4}+2,x
adc :palette
eor: {]line*SHR_LINE_WIDTH}+2,y
sta :p_tmp
; Convert the screen data to a mask
lda: {]line*SHR_LINE_WIDTH}+2,y
bit #$F000
beq *+5
ora #$F000
bit #$0F00
beq *+5
ora #$0F00
bit #$00F0
beq *+5
ora #$00F0
bit #$000F
beq *+5
ora #$000F
eor #$FFFF
and :p_tmp
andl tiledata+{{7-]line}*4}+32+2,x
eor: {]line*SHR_LINE_WIDTH}+2,y
sta: {]line*SHR_LINE_WIDTH}+2,y
ldal tiledata+{{7-]line}*4},x
adc :palette
eor: {]line*SHR_LINE_WIDTH},y
sta :p_tmp
lda: {]line*SHR_LINE_WIDTH},y
bit #$F000
beq *+5
ora #$F000
bit #$0F00
beq *+5
ora #$0F00
bit #$00F0
beq *+5
ora #$00F0
bit #$000F
beq *+5
ora #$000F
eor #$FFFF
and :p_tmp
andl tiledata+{{7-]line}*4}+32,x
eor: {]line*SHR_LINE_WIDTH},y
sta: {]line*SHR_LINE_WIDTH},y
]line equ ]line+1
--^
plb
rtl ; special exit
; Draw a sprite directly to the graphics screen. If sprite is clipped at all, do not draw.
;
; X = sprite record index