Mostly working PPU integration with GTE rendering pipeline
This commit is contained in:
Lucas Scharenbroich
parent
64f7106143
commit
d3a7eecc6e
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@ -37,6 +37,9 @@ Tmp3 equ 246
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Tmp4 equ 248
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Tmp5 equ 250
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FTblPtr equ 224
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FTblTmp equ 228
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phk
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plb
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sta MyUserId ; GS/OS passes the memory manager user ID for the application into the program
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@ -1080,6 +1083,6 @@ nmiTask
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ds \,$00 ; pad to the next page boundary
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PPU_MEM
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CHR_ROM put chr2.s ; 8K of CHR-ROM at PPU memory $0000 - $2000
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PPU_NT ds $2000 ; Nametable memory from $2000 - $3000, $3F00 - $3F14 is palette RAM
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PPU_OAM ds 256 ; 256 bytes of separate OAM RAM
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PPU_NT ds $2000 ; Nametable memory from $2000 - $3000, $3F00 - $3F14 is palette RAM
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PPU_OAM ds 256 ; 256 bytes of separate OAM RAM
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458
demos/smb/ppu.s
458
demos/smb/ppu.s
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@ -2,6 +2,29 @@
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;
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; Any read/write to the PPU registers in the ROM is intercepted and passed here.
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const8 mac
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db ]1,]1,]1,]1,]1,]1,]1,]1
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<<<
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const32 mac
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const8 ]1
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const8 ]1+1
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const8 ]1+2
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const8 ]1+3
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<<<
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rep8 mac
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db ]1
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db ]1
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db ]1
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db ]1
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db ]1
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db ]1
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db ]1
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db ]1
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<<<
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mx %11
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dw $a5a5 ; marker to find in memory
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ppuaddr ds 2 ; 16-bit ppu address
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@ -495,34 +518,409 @@ PPUDMA_WRITE ENT
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y_offset equ 16
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x_offset equ 16
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drawOAMSprites
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:tmp equ 238
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; Scan the OAM memory and copy the values of the sprites that need to be drawn. There are two reasons to do this
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;
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; 1. Freeze the OAM memory at this instanct so that the NES ISR can keep running without changing values
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; 2. We have to scan this list twice -- once to build up the shadow list and once to actually render the sprites
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OAM_COPY ds 256
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spriteCount ds 0
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db 0 ; Pad in case we can to access using 16-bit instructions
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; 248 is reserved for the blitter
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mx %00
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scanOAMSprites
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sep #$30
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ldx #4 ; Always skip sprite 0
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ldy #0
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:loop
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lda PPU_OAM,x ; Y-coordinate
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cmp #200+y_offset-9
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bcs :skip
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lda PPU_OAM+1,x ; $FC is an empty tile, don't draw it
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cmp #$FC
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beq :skip
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lda PPU_OAM+3,x ; If X-coordinate is off the edge skip it, too.
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cmp #241
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bcs :skip
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rep #$20
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lda PPU_OAM,x
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sta OAM_COPY,y
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lda PPU_OAM+2,x
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sta OAM_COPY+2,y
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sep #$20
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iny
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iny
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iny
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iny
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:skip
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inx
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inx
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inx
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inx
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bne :loop
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sty spriteCount ; Count * 4
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rep #$30
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rts
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; Screen is 200 lines tall. It's worth it be exact when building the list because one extra
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; draw + shadow sequence takes at least 1,000 cycles.
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shadowBitmap ds 32 ; Provide enough space for the full ppu range (240 lines) + 16 since the y coordinate can be off-screen
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; A representation of the list as [top, bot) pairs
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shadowListCount dw 0 ; Pad for 16-bit comparisons
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shadowListTop ds 64
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shadowListBot ds 64
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mx %00
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buildShadowBitmap
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; zero out the bitmap (16-bit writes)
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]n equ 0
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lup 15
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stz shadowBitmap+]n
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]n = ]n+2
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--^
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; Run through the list of visible sprites and ORA in the bits that represent them
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sep #$30
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ldx #0
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cpx spriteCount
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beq :exit
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:loop
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phx
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; ldy PPU_OAM,x
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ldy OAM_COPY,x
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iny ; This is the y-coordinate of the top of the sprite
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ldx y2idx,y ; Get the index into the shadowBitmap array for this y coordinate
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lda y2low,y ; Get the bit pattern for the first byte
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ora shadowBitmap,x
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sta shadowBitmap,x
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lda y2high,y ; Get the bit pattern for the second byte
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ora shadowBitmap+1,x
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sta shadowBitmap+1,x
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plx
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inx
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inx
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inx
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inx
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cpx spriteCount
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bcc :loop
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:exit
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rep #$30
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rts
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y2idx const32 $00
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const32 $04
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const32 $08
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const32 $0C ; 128 bytes
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const32 $10
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const32 $14
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const32 $18
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const32 $1C
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; Repeating pattern of 8 consecutive 1 bits
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y2low rep8 $FF,$7F,$3F,$1F,$0F,$07,$03,$01
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rep8 $FF,$7F,$3F,$1F,$0F,$07,$03,$01
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rep8 $FF,$7F,$3F,$1F,$0F,$07,$03,$01
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rep8 $FF,$7F,$3F,$1F,$0F,$07,$03,$01
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y2high rep8 $00,$80,$C0,$E0,$F0,$F8,$FC,$FE
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rep8 $00,$80,$C0,$E0,$F0,$F8,$FC,$FE
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rep8 $00,$80,$C0,$E0,$F0,$F8,$FC,$FE
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rep8 $00,$80,$C0,$E0,$F0,$F8,$FC,$FE
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; 25 entries to multiple steps in the shadow bitmap to scanlines
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mul8 db $00,$08,$10,$18,$20,$28,$30,$38
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db $40,$48,$50,$58,$60,$68,$70,$78
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db $80,$88,$90,$98,$A0,$A8,$B0,$B8
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db $C0,$C8,$D0,$D8,$E0,$E8,$F0,$F8
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; Given a bit pattern, create a LUT that count to the first set bit (MSB -> LSB), e.g. $0F = 4, $3F = 2
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offset db 0,7,6,6,5,5,5,5,4,4,4,4,4,4,4,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3 ; 0, 1, 2, 4, 8, 16
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db 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2 ; 32
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db 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
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db 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
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db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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; Scan the bitmap list and call BltRange on the ranges
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mx %00
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drawShadowList
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ldx #0
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cpx shadowListCount
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beq :exit
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:loop
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phx
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lda shadowListBot,x
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and #$00FF
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tay
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cpy #201
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bcc *+4
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brk $cc
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lda shadowListTop,x
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and #$00FF
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tax
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cpx #200
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bcc *+4
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brk $dd
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lda #0 ; Invoke the BltRange function
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jsl LngJmp
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plx
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inx
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cpx shadowListCount
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bcc :loop
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:exit
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rts
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; Altername between BltRange and PEISlam to expose the screen
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exposeShadowList
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:last equ Tmp0
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:top equ Tmp1
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:bottom equ Tmp2
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ldx #0
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stx :last
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cpx shadowListCount
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beq :exit
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:loop
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phx
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lda shadowListTop,x
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and #$00FF
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sta :top
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cmp #200
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bcc *+4
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brk $44
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lda shadowListBot,x
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and #$00FF
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sta :bottom
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cmp #201
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bcc *+4
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brk $66
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cmp :top
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bcs *+4
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brk $55
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ldx :last
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ldy :top
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lda #0
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jsl LngJmp ; Draw the background up to this range
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ldx :top
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ldy :bottom
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sty :last ; This is where we ended
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lda #1
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jsl LngJmp ; Expose the already-drawn sprites
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plx
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inx
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cpx shadowListCount
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bcc :loop
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:exit
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ldx :last ; Expose the final part
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ldy #200
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lda #0
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jsl LngJmp
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rts
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; This routine needs to adjust the y-coordinates based of the offset of the GTE playfield within
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; the PPU RAM
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shadowBitmapToList
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:top equ Tmp0
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:bottom equ Tmp2
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sep #$30
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ldx #2 ; Start at he third row (y_offset = 16) walk the bitmap for 25 bytes (200 lines of height)
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lda #0
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sta shadowListCount ; zero out the shadow list count
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; This loop is called when we are not tracking a sprite range
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:zero_loop
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ldy shadowBitmap,x
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beq :zero_next
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lda mul8-2,x ; This is the scanline we're on (offset by the starting byte)
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clc
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adc offset,y ; This is the first line defined by the bit pattern
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sta :top
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bra :one_next
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:zero_next
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inx
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cpx #28 ; End at byte 27
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bcc :zero_loop
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bra :exit ; ended while not tracking a sprite, so exit the function
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:one_loop
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lda shadowBitmap,x ; if the next byte is all sprite, just continue
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eor #$FF
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beq :one_next
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tay ; Use the inverted bitfield in order to re-use the same lookup table
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lda mul8-2,x
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clc
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adc offset,y
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ldy shadowListCount
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sta shadowListBot,y
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lda :top
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sta shadowListTop,y
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iny
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sty shadowListCount
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bra :zero_next
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:one_next
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inx
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cpx #28
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bcc :one_loop
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; If we end while tracking a sprite, add to the list as the last item
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ldx shadowListCount
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lda :top
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sta shadowListTop,x
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lda #200
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sta shadowListBot,x
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inx
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stx shadowListCount
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:exit
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rep #$30
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lda shadowListCount
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cmp #64
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bcc *+4
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brk $13
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rts
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; Helper to bounce into the function in the FTblPtr. See IIgs TN #90
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LngJmp
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sty FTblTmp
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asl
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asl
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tay
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iny
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lda [FTblPtr],y
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pha
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dey
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lda [FTblPtr],y
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dec
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phb
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php
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sta 1,s
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ldy FTblTmp ; Restore the y register
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rtl
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; Callback entrypoint from the GTE renderer
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drawOAMSprites
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phb
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phd
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phk
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plb
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pha
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lda DPSave
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tcd
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; Save the pointer to the function table
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sty FTblPtr
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stx FTblPtr+2
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pla
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; Check what phase we're in
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;
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; Phase 1: A = 0
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; Phase 2: A = 1
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cmp #0
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bne :phase2
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; This is phase 1. We will build the sprite list and draw the background in the areas covered by
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; sprites. This phase draws the sprites, too
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ldal nmiCount
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pha
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; We need to "freeze" the OAM values, otherwise they can change between when we build the rendering pipeline
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sei
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jsr scanOAMSprites ; Filter out any sprites that don't need to be drawn
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pla
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cmpl nmiCount
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beq *+4
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brk $1F ; Should not have serviced the VBL interrupt here....
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cli
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jsr buildShadowBitmap ; Run though and quickly create a bitmap of lines with sprites
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jsr shadowBitmapToList ; Can the bitmap and create (top, bottom) pairs of ranges
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jsr drawShadowList ; Draw the background lines that have sprite on them
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jsr drawSprites ; Draw the sprites on top of the lines they occupy
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bra :exit
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; In Phase 2 we scan the shadow list and alternately blit the background in empty areas and
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; PEI slam the sprite regions
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:phase2
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jsr exposeShadowList ; Show everything on the SHR screen
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; Return form the callback
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:exit
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pld
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plb
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rtl
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drawSprites
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:tmp equ Tmp0
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sep #$30 ; 8-bit cpu
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ldx #4 ; Ok to always skip sprite 0
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:oam_loop
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lda PPU_OAM+3,x ; remove this test once we can clip sprites
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cmp #241
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bcs :hidden
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; Run through the copy of the OAM memory
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lda PPU_OAM+1,x ; $FC is an empty tile, don't draw it
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cmp #$FC
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beq :hidden
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ldx #0
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cpx spriteCount
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bne oam_loop
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rep #$30
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rts
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lda PPU_OAM,x ; Y-coordinate
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cmp #200+y_offset-9
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bcs :hidden
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mx %11
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oam_loop
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phx ; Save x
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phx
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lda OAM_COPY,x ; Y-coordinate
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inc ; Compensate for PPU delayed scanline
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rep #$30
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and #$00FF
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asl
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@ -539,26 +937,26 @@ drawOAMSprites
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adc #$2000-{y_offset*160}+x_offset
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sta :tmp
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lda PPU_OAM+3,x
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lda OAM_COPY+3,x
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lsr
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and #$007F
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clc
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adc :tmp
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tay
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lda PPU_OAM+2,x
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lda OAM_COPY+2,x
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pha
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bit #$0040 ; horizontal flip
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bne :hflip
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lda PPU_OAM,x ; Load the tile index into the high byte (x256)
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lda OAM_COPY,x ; Load the tile index into the high byte (x256)
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and #$FF00
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lsr ; multiple by 128
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tax
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bra :noflip
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:hflip
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lda PPU_OAM,x ; Load the tile index into the high byte (x256)
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lda OAM_COPY,x ; Load the tile index into the high byte (x256)
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and #$FF00
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lsr ; multiple by 128
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adc #64 ; horizontal flip
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@ -567,22 +965,20 @@ drawOAMSprites
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:noflip
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pla
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asl
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; and #$0080 ; Set the vflip bit
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and #$0106 ; Set the vflip bit and palette select bits
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drawTilePatch
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jsl $000000 ; Draw the tile on the graphics screen
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sep #$30
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plx
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plx ; Restore the counter
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inx
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inx
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inx
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inx
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cpx spriteCount
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bcc oam_loop
|
||||
|
||||
:hidden
|
||||
inx
|
||||
inx
|
||||
inx
|
||||
inx
|
||||
bne :oam_loop
|
||||
rep #$30
|
||||
rts
|
||||
|
||||
plp
|
||||
plb
|
||||
rtl
|
||||
46
src/Render.s
46
src/Render.s
|
|
@ -153,6 +153,11 @@ _DoOverlay
|
|||
:disp jsl $000000
|
||||
rts
|
||||
|
||||
; Callback structure with pointers to internal rendering functions
|
||||
ExtFuncBlock
|
||||
adrl BltRange
|
||||
adrl PEISlam
|
||||
|
||||
; Special NES renderer that externalizes the sprite rendering in order to exceed the internal limit of 16 sprites
|
||||
_RenderNES
|
||||
jsr _ApplyBG0YPos
|
||||
|
|
@ -172,7 +177,6 @@ _RenderNES
|
|||
:no_tile
|
||||
|
||||
jsr _ApplyTiles ; This function actually draws the new tiles into the code field
|
||||
; jsr _ApplyBG0XPos ; Patch the code field instructions with exit BRA opcode
|
||||
|
||||
stz tmp1 ; virt_line_x2
|
||||
lda #16*2
|
||||
|
|
@ -194,22 +198,45 @@ _RenderNES
|
|||
lda tmp4
|
||||
stal nesBottomOffset
|
||||
|
||||
ldx #0 ; Blit the full virtual buffer to the screen
|
||||
ldy ScreenHeight
|
||||
jsr _BltRange
|
||||
; This is a tricky part. The NES does not keep sprites sorted, so we need an alternative way to figure out
|
||||
; which lines to shadow and which ones not to. Our compromise is to build a bitmap of lines that the sprite
|
||||
; occupy and then scan through that quickly.
|
||||
;
|
||||
; This is handled by the callback in two phases. We pass pointers to the internal function the callback needs
|
||||
; access to. If there is no function defined, do nothing
|
||||
|
||||
lda ExtSpriteRenderer
|
||||
ora ExtSpriteRenderer+2
|
||||
beq :no_sprite
|
||||
beq :no_render
|
||||
|
||||
lda ExtSpriteRenderer
|
||||
stal :patch+1
|
||||
stal :patch1+1
|
||||
stal :patch2+1
|
||||
lda ExtSpriteRenderer+1
|
||||
stal :patch+2
|
||||
:patch jsl $000000
|
||||
stal :patch1+2
|
||||
stal :patch2+2
|
||||
|
||||
:no_sprite
|
||||
; Start the two-phase rendering process. First turn off shading and invoke the callback to
|
||||
; draw sprite regions
|
||||
|
||||
jsr _ShadowOff
|
||||
|
||||
lda #0 ; Signal we're in phase 1 (shadowing off)
|
||||
ldx #^ExtFuncBlock
|
||||
ldy #ExtFuncBlock
|
||||
:patch1 jsl $000000
|
||||
|
||||
; Now perform the second phase which renders the whole screen and exposes the sprites that were
|
||||
; drawins in the first phase
|
||||
|
||||
jsr _ShadowOn
|
||||
|
||||
lda #1 ; Signal we're in phase 2 (shadowing on)
|
||||
ldx #^ExtFuncBlock
|
||||
ldy #ExtFuncBlock
|
||||
:patch2 jsl $000000
|
||||
|
||||
:no_render
|
||||
stz tmp1 ; :virt_line_x2
|
||||
lda #16*2
|
||||
sta tmp2 ; :lines_left_x2
|
||||
|
|
@ -402,7 +429,6 @@ _DrawFinalPass
|
|||
ldy _Sprites+SPRITE_CLIP_TOP,x ; PEI Slam to the top of the overlay (:bottom is greater than this value)
|
||||
ldx :cursor
|
||||
sty :cursor
|
||||
; brk $44
|
||||
jsr _PEISlam
|
||||
lda 3,s ; Retrieve the sprite index
|
||||
tax
|
||||
|
|
|
|||
|
|
@ -144,6 +144,7 @@ zpToUse = userId+4
|
|||
lda zpToUse,s ; Get the direct page address
|
||||
phd ; Save the current direct page
|
||||
tcd ; Set to our working direct page space
|
||||
stal tool_direct_page ; Stash a copy in memory
|
||||
|
||||
txa
|
||||
and #$00FF ; Get just the tool number
|
||||
|
|
|
|||
|
|
@ -85,6 +85,7 @@ _BltRange
|
|||
lda BlitterDP ; Set the direct page to the blitter data
|
||||
tcd
|
||||
|
||||
php ; save the current processor flags
|
||||
sei ; disable interrupts
|
||||
_R0W1
|
||||
tsc ; save the stack pointer
|
||||
|
|
@ -95,7 +96,7 @@ blt_entry jml $000000 ; Jump into the blitter code $XX/YY00
|
|||
blt_return _R0W0
|
||||
stk_save lda #0000 ; load the stack
|
||||
tcs
|
||||
cli ; re-enable interrupts
|
||||
plp ; re-enable interrupts (maybe, if interrupts disabled when we are called, they are not re-endabled)
|
||||
pld ; restore the direct page
|
||||
|
||||
sep #$20
|
||||
|
|
@ -106,3 +107,16 @@ stk_save lda #0000 ; load the stack
|
|||
|
||||
plb ; restore the bank
|
||||
rts
|
||||
|
||||
; External entry point. Can be called directly from another bank
|
||||
BltRange
|
||||
phd
|
||||
phb
|
||||
|
||||
ldal tool_direct_page
|
||||
tcd
|
||||
jsr _SetDataBank ; only affects accumulator
|
||||
jsr _BltRange
|
||||
plb
|
||||
pld
|
||||
rtl
|
||||
|
|
@ -14,17 +14,19 @@
|
|||
; Y = last line (exclusive), valid range >X up to 200
|
||||
_PEISlam
|
||||
cpx #200
|
||||
bcc *+3
|
||||
rts
|
||||
bcc *+4
|
||||
brk $14
|
||||
; rts
|
||||
cpy #201
|
||||
bcc *+3
|
||||
rts
|
||||
bcc *+4
|
||||
brk $15
|
||||
; rts
|
||||
|
||||
txa
|
||||
tya ; x must be less than y
|
||||
stal :screen_width_1
|
||||
tya
|
||||
txa
|
||||
cmpl :screen_width_1
|
||||
bcs *+3
|
||||
bcc *+3
|
||||
rts
|
||||
|
||||
|
||||
|
|
@ -74,6 +76,10 @@ _PEISlam
|
|||
adcl :screen_width_1
|
||||
tcs
|
||||
|
||||
cmp #$9D00
|
||||
bcc *+4
|
||||
brk $85 ; Kill if stack it out of range
|
||||
|
||||
dey ; decrement the total counter, if zero then we're done
|
||||
beq :exit
|
||||
|
||||
|
|
@ -115,3 +121,21 @@ _PEISlam
|
|||
|
||||
:stk_save ds 2
|
||||
:screen_width_1 ds 2
|
||||
|
||||
; A stashed memory location just in case we need it. This is filled in the GTEStartUp()
|
||||
tool_direct_page ds 2
|
||||
|
||||
; External entry point. Can be called directly from another bank
|
||||
PEISlam
|
||||
phd
|
||||
phb
|
||||
|
||||
ldal tool_direct_page
|
||||
tcd
|
||||
jsr _SetDataBank ; only affects accumulator
|
||||
jsr _PEISlam
|
||||
plb
|
||||
pld
|
||||
rtl
|
||||
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue