GSCats/terrain.s

573 lines
8.8 KiB
ArmAsm

;
; terrain
;
; Created by Quinn Dunki on 7/29/17
;
.if 0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; renderTerrain
;
; No stack operations permitted here!
;
; Trashes all registers
;
renderTerrain:
FASTGRAPHICS
lda #0
sta SCRATCHL2 ; Row counter
lda #$5f1f ; 4 Point stack to end of VRAM
tcs ; 2
sec
lda #compiledTerrainEnd-VISIBLETERRAINWINDOW-3
sbc mapScrollPos
sta PARAML0
renderTerrainLoop:
; Note that DP register is normally $0000, so that is used as the BG/BG case
lda #$0011 ; BG/FG
ldx #$1111 ; FG/FG
ldy #$1100 ; FG/BG
jmp (PARAML0)
renderRowComplete:
lda PARAML0
sec
sbc #COMPILEDTERRAINROW
sta PARAML0
tsc
clc
adc #320
tcs
lda SCRATCHL2
inc
cmp #MAXTERRAINHEIGHT
beq renderTerrainDone
sta SCRATCHL2
bra renderTerrainLoop
renderTerrainDone:
SLOWGRAPHICS
rts
.endif
.if 0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; renderTerrainFillMode:
;
; Trashes all registers
;
renderTerrainFillMode:
jsr renderTerrainSpans
rts
SAVE_AXY
ldy #0
ldx #200-MAXTERRAINHEIGHT
renderTerrainFillModeLoop:
jsr enableFillMode
sty PARAML1
jsr renderTerrainRowFillMode
inx
iny
cpy #MAXTERRAINHEIGHT
bmi renderTerrainFillModeLoop
renderTerrainFillModeDone:
RESTORE_AXY
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; renderTerrainRowFillMode:
;
; PARAML1 = Row index (top relative)
;
; Trashes PARAML1
;
renderTerrainRowFillMode:
SAVE_AXY
lda PARAML1
asl
tay
ldx vramYOffset,y
stz renderTerrainRowFillCurrent
sec
lda #MAXTERRAINHEIGHT
sbc PARAML1
sta PARAML1
ldy leftScreenEdge
sty renderTerrainRowFillColumn
renderTerrainRowFillModeColumnLoop:
tya
asl
tay
lda terrainData,y
cmp PARAML1
bmi renderTerrainRowFillModeBlack
lda renderTerrainRowFillCurrent
cmp #$10
beq renderTerrainRowFillModeColumnLoopNext
lda #$10
sta renderTerrainRowFillCurrent
sta VRAM+(200-MAXTERRAINHEIGHT)*160,x
renderTerrainRowFillModeColumnLoopNext:
inx
inc renderTerrainRowFillColumn
ldy renderTerrainRowFillColumn
cpy rightScreenEdge
bne renderTerrainRowFillModeColumnLoop
renderTerrainRowFillModeDone:
RESTORE_AXY
rts
renderTerrainRowFillModeBlack:
lda renderTerrainRowFillCurrent
cmp #$70
beq renderTerrainRowFillModeColumnLoopNext
lda #$70
sta renderTerrainRowFillCurrent
sta VRAM+(200-MAXTERRAINHEIGHT)*160,x
bra renderTerrainRowFillModeColumnLoopNext
renderTerrainRowFillCurrent:
.word 0
renderTerrainRowFillColumn:
.word 0
.endif
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; craterTerrain
;
; PARAML0 = X pos of center in pixels from logical left terrain edge
; PARAML1 = Y pos of center in pixels from bottom terrain edge
; Y = Radius of circle, in pixels
;
; Trashes SCRATCHL
craterTerrain:
SAVE_AX
lda #TERRAINWIDTH ; Convert X pos to terrain-right byte count
sec
sbc PARAML0
sty SCRATCHL ; Center width in bytes
sbc SCRATCHL
and #$fffe ; Force even
clc
adc #terrainData
sta PARAML0
lda circleTable,y ; Look up circle data
sta SCRATCHL
tya ; Iterate over diameter
asl
tay
craterTerrainLoop:
dey
dey
bmi craterTerrainDone
tya
clc
adc PARAML0 ; Clip to terrain edges
cmp #terrainData
bmi craterTerrainDone
cmp #terrainDataEnd
bpl craterTerrainLoop
lda (SCRATCHL),y ; Fetch circle Y value
clc
adc PARAML1 ; Convert to terrain-space
bmi craterTerrainZero
sta SCRATCHL2
lda (PARAML0),y
cmp SCRATCHL2
bmi craterTerrainLoop
lda SCRATCHL2 ; Circle value is lower, so use that
sta (PARAML0),y
bra craterTerrainLoop
craterTerrainZero: ; Circle went negative so clip to 0
lda #0
sta (PARAML0),y
bra craterTerrainLoop
craterTerrainDone:
lda #1
sta terrainDirty
RESTORE_AX
rts
.if 0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; clipTerrain
;
;
clipTerrain:
SAVE_AXY
sec
lda #COMPILEDTERRAINROW*MAXTERRAINHEIGHT-3
sbc mapScrollPos
tay
ldx #MAXTERRAINHEIGHT
clipTerrainLoop:
clc ; Compute buffer to for saved data
txa
asl
asl
adc #clippedTerrainData-4
sta PARAML0
lda compiledTerrain,y
sta (PARAML0) ; Preserve data we're overwriting
inc PARAML0
inc PARAML0
and #$ff00
ora #$004c ; jmp in low byte
sta compiledTerrain,y
iny
lda compiledTerrain,y
sta (PARAML0) ; Preserve data we're overwriting
lda #renderRowComplete
sta compiledTerrain,y
tya
sec
sbc #COMPILEDTERRAINROW+1
tay
dex
bne clipTerrainLoop
RESTORE_AXY
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; unclipTerrain
;
;
unclipTerrain:
SAVE_AXY
sec
lda #COMPILEDTERRAINROW*MAXTERRAINHEIGHT-3
sbc mapScrollPos
tay
ldx #MAXTERRAINHEIGHT
unclipTerrainLoop:
clc ; Compute buffer that saved data is in
txa
asl
asl
adc #clippedTerrainData-4
sta PARAML0
lda (PARAML0)
sta compiledTerrain,y
inc PARAML0
inc PARAML0
iny
lda (PARAML0)
sta compiledTerrain,y
tya
sec
sbc #COMPILEDTERRAINROW+1
tay
dex
bne unclipTerrainLoop
RESTORE_AXY
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; compileTerrain
;
;
;
compileTerrain:
SAVE_AY
ldy #0
lda #compiledTerrain
sta PARAML0
compileTerrainLoop:
sty PARAML1
jsr compileTerrainRow
iny
cpy #MAXTERRAINHEIGHT
beq compileTerrainDone
clc
lda #COMPILEDTERRAINROW
adc PARAML0
sta PARAML0
bra compileTerrainLoop
compileTerrainDone:
;jsr compileTerrainSpans
RESTORE_AY
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; compileTerrainRow
;
; PARAML0 = Start of compiled row data
; PARAML1 = Row index
;
; Note: DA = PHX = FG/FG
; 48 = PHA = FG/BG
; 5A = PHY = BG/FG
; 0B = PHD = BG/BG
compileTerrainRow:
SAVE_AXY
ldy #0
ldx #0
compileTerrainColumnLoop:
stz compileTerrainOpcode
; Check column 0
lda terrainData,x
cmp PARAML1
bcc compileTerrainColumn0BG
beq compileTerrainColumn0BG
; Column 0 is FG, so check column 1
inx
inx
lda terrainData,x
cmp PARAML1
bcc compileTerrainColumn1BG
beq compileTerrainColumn1BG
; Columns 0 and 1 are FG/FG, so PHX
lda #$00da
compileTerrainColumn2:
sta compileTerrainOpcode ; Cache results so far
; Check column 2
inx
inx
lda terrainData,x
cmp PARAML1
bcc compileTerrainColumn2BG
beq compileTerrainColumn2BG
; Column 2 is FG, so check column 3
inx
inx
lda terrainData,x
cmp PARAML1
bcc compileTerrainColumn3BG
beq compileTerrainColumn3BG
; Columns 2 and 3 are FG/FG, so PHX
lda compileTerrainOpcode
ora #$da00
compileTerrainColumnStore:
sta (PARAML0),y
inx
inx
iny
iny
cpy #VISIBLETERRAINWIDTH
bne compileTerrainColumnLoop
RESTORE_AXY
rts
compileTerrainColumn0BG:
; Column 0 is BG, so check column 1
inx
inx
lda terrainData,x
cmp PARAML1
bcc compileTerrainColumn01BG
beq compileTerrainColumn01BG
; Columns 0 and 1 are BG/FG, so PHA
lda #$0048
bra compileTerrainColumn2
compileTerrainColumn01BG:
; Columns 0 and 1 are BG/BG, so PHD
lda #$000b
bra compileTerrainColumn2
compileTerrainColumn1BG:
; Columns 0 and 1 are FG/BG, so PHY
lda #$005a
bra compileTerrainColumn2
compileTerrainColumn2BG:
; Column 2 is BG, so check column 3
inx
inx
lda terrainData,x
cmp PARAML1
bcc compileTerrainColumn23BG
beq compileTerrainColumn23BG
; Columns 2 and 3 are BG/FG, so PHA
lda compileTerrainOpcode
ora #$4800
bra compileTerrainColumnStore
compileTerrainColumn23BG:
; Columns 2 and 3 are BG, so PHD
lda compileTerrainOpcode
ora #$0b00
bra compileTerrainColumnStore
compileTerrainColumn3BG:
; Columns 2 and 3 are FG/BG, so PHY
lda compileTerrainOpcode
ora #$5a00
bra compileTerrainColumnStore
compileTerrainOpcode:
.word 0
.endif
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; prepareRowRendering:
;
; Set SCBs to match rendering mode of each terrain line
;
; Trashes SCRATCHL, SCRATCHL2
;
prepareRowRendering:
SAVE_AXY
ldx #199
stz SCRATCHL2
prepareRowRenderingLoop:
lda #0
PLAYERPTR_Y
sec
lda playerData+GO_POSY,y
sbc #GAMEOBJECTHEIGHT
cmp SCRATCHL2
bcc prepareRowRenderingCompileMode
beq prepareRowRenderingCompileMode
jsr enableFillMode
bra prepareRowRenderingLoopNext
prepareRowRenderingCompileMode:
jsr disableFillMode
prepareRowRenderingLoopNext:
inc SCRATCHL2
dex
cpx #200-MAXTERRAINHEIGHT
bne prepareRowRenderingLoop
RESTORE_AXY
rts
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; generateTerrain
;
; Trashes everything
;
generateTerrain:
ldy #0
ldx #0
lda #terrainData
sta SCRATCHL
generateTerrainLoop:
lda sineTable,x
lsr
lsr
clc
adc #30
sta (SCRATCHL),y
iny
iny
inx
inx
inx
inx
txa
and #$03ff
tax
cpy #TERRAINWIDTH
bne generateTerrainLoop
; lda #1 ; Debug values
; sta terrainData
; lda #2
; sta compiledTerrain-4
rts
.if 0
compiledTerrain:
.repeat COMPILEDTERRAINROW * MAXTERRAINHEIGHT
.byte 0
.endrepeat
compiledTerrainEnd:
clippedTerrainData:
.repeat MAXTERRAINHEIGHT
.byte 0,0,0,0 ; xx,jmp,addr
.endrepeat
.endif