mirror of
https://github.com/blondie7575/GSCats.git
synced 2024-11-22 06:31:48 +00:00
299 lines
4.6 KiB
ArmAsm
299 lines
4.6 KiB
ArmAsm
;
|
|
; terrain
|
|
;
|
|
; Created by Quinn Dunki on 7/29/17
|
|
;
|
|
|
|
|
|
TERRAINWIDTH = 640 ; In pixels
|
|
MAXTERRAINHEIGHT = 100 ; In pixels
|
|
COMPILEDTERRAINROW = TERRAINWIDTH/4+3 ; In words, +2 to make room for clipping jump at end of row
|
|
VISIBLETERRAINWIDTH = TERRAINWIDTH/4 ; In words- width minus jump return padding
|
|
VISIBLETERRAINWINDOW = 80 ; In words
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; renderTerrain
|
|
;
|
|
; No stack operations permitted here!
|
|
;
|
|
; Current implementation: X cycles per row
|
|
; Trashes all registers
|
|
;
|
|
renderTerrain:
|
|
FASTGRAPHICS
|
|
ldy #MAXTERRAINHEIGHT
|
|
lda #$9cff ; 4 Point stack to end of VRAM
|
|
tcs ; 2
|
|
|
|
sec
|
|
lda #compiledTerrainEnd-VISIBLETERRAINWINDOW-3
|
|
sbc mapScrollPos
|
|
sta PARAML0
|
|
|
|
renderTerrainLoop:
|
|
lda #$0000 ; Background
|
|
ldx #$1111 ; Foreground
|
|
jmp (PARAML0)
|
|
|
|
renderRowComplete:
|
|
lda PARAML0
|
|
sec
|
|
sbc #COMPILEDTERRAINROW
|
|
sta PARAML0
|
|
dey
|
|
bne renderTerrainLoop
|
|
|
|
SLOWGRAPHICS
|
|
rts
|
|
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; clipTerrain
|
|
;
|
|
;
|
|
clipTerrain:
|
|
SAVE_AXY
|
|
|
|
sec
|
|
lda #COMPILEDTERRAINROW*MAXTERRAINHEIGHT-3
|
|
sbc mapScrollPos
|
|
tay
|
|
ldx #MAXTERRAINHEIGHT
|
|
|
|
clipTerrainLoop:
|
|
clc ; Compute buffer to for saved data
|
|
txa
|
|
asl
|
|
asl
|
|
adc #clippedTerrainData-4
|
|
sta PARAML0
|
|
|
|
lda compiledTerrain,y
|
|
sta (PARAML0) ; Preserve data we're overwriting
|
|
inc PARAML0
|
|
inc PARAML0
|
|
|
|
and #$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 #MAXTERRAINHEIGHT-1
|
|
lda #compiledTerrain
|
|
sta PARAML0
|
|
|
|
compileTerrainLoop:
|
|
sty PARAML1
|
|
jsr compileTerrainRow
|
|
dey
|
|
bmi compileTerrainDone
|
|
|
|
clc
|
|
lda #COMPILEDTERRAINROW
|
|
adc PARAML0
|
|
sta PARAML0
|
|
|
|
bra compileTerrainLoop
|
|
|
|
compileTerrainDone:
|
|
RESTORE_AY
|
|
rts
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; compileTerrainRow
|
|
;
|
|
; PARAML0 = Start of compiled row data
|
|
; PARAML1 = Row index
|
|
;
|
|
compileTerrainRow:
|
|
SAVE_AXY
|
|
ldy #0
|
|
ldx #0
|
|
|
|
compileTerrainColumnLoop:
|
|
stz compileTerrainOpcode
|
|
|
|
; Right half
|
|
lda terrainData,x
|
|
cmp PARAML1
|
|
bcc compileTerrainColumnBGRight
|
|
beq compileTerrainColumnBGRight
|
|
lda #$00da
|
|
compileTerrainColumnLeft:
|
|
sta compileTerrainOpcode
|
|
inx
|
|
inx
|
|
lda terrainData,x
|
|
cmp PARAML1
|
|
bcc compileTerrainColumnBGLeft
|
|
beq compileTerrainColumnBGLeft
|
|
lda compileTerrainOpcode
|
|
ora #$da00
|
|
|
|
compileTerrainColumnStore:
|
|
sta (PARAML0),y
|
|
inx
|
|
inx
|
|
iny
|
|
iny
|
|
cpy #VISIBLETERRAINWIDTH
|
|
bne compileTerrainColumnLoop
|
|
|
|
RESTORE_AXY
|
|
rts
|
|
|
|
compileTerrainColumnBGRight:
|
|
lda #$0048
|
|
bra compileTerrainColumnLeft
|
|
|
|
compileTerrainColumnBGLeft:
|
|
lda compileTerrainOpcode
|
|
ora #$4800
|
|
bra compileTerrainColumnStore
|
|
|
|
compileTerrainOpcode:
|
|
.word 0
|
|
|
|
|
|
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; 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
|
|
inx
|
|
inx
|
|
|
|
txa
|
|
and #$03ff
|
|
tax
|
|
|
|
cpy #TERRAINWIDTH/2
|
|
bne generateTerrainLoop
|
|
|
|
rts
|
|
|
|
|
|
; Terrain data, stored as height values 4 pixels wide
|
|
|
|
terrainData:
|
|
; .word 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
|
|
; .word 20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39
|
|
; .word 40,39,38,37,36,35,34,33,32,31,30,29,28,27,26,25,24,23,22,21
|
|
; .word 20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,80
|
|
; .word 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
|
|
; .word 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
|
|
; .word 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
|
|
; .word 1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,0,0,80
|
|
|
|
.repeat TERRAINWIDTH/4 ; VISIBLETERRAINWIDTH
|
|
.word 0
|
|
.endrepeat
|
|
|
|
compiledTerrain:
|
|
.repeat COMPILEDTERRAINROW * MAXTERRAINHEIGHT
|
|
.byte 0
|
|
.endrepeat
|
|
compiledTerrainEnd:
|
|
|
|
clippedTerrainData:
|
|
.repeat MAXTERRAINHEIGHT
|
|
.byte 0,0,0,0 ; xx,jmp,addr
|
|
.endrepeat
|
|
|