dos33fsprogs/graphics/gr/plasma/plasma.s
2021-01-09 13:19:52 -05:00

169 lines
2.2 KiB
ArmAsm

; do a (hopefully fast) plasma
; 151 -- original
; 137 -- optimize generation
; 136 -- align lookup table so we can index it easier
; 130 -- optimize indexing of lookup
; 126 -- run loops backaward
; 124 -- notice X already 0 before plot
; 131 -- use GBASCALC. much faster, but 7 bytes larger
; 129 -- run loop backwards
; 128 -- set color ourselves
; 127 -- overlap color lookup with sine table
.include "zp.inc"
.include "hardware.inc"
CTEMP = $FC
SAVEOFF = $FD
SAVEX = $FE
SAVEY = $FF
;================================
; Clear screen and setup graphics
;================================
jsr SETGR
lda #0
sta DISP_PAGE
lda #4
sta DRAW_PAGE
;col = ( 8.0 + (sintable[xx&0xf])
; + 8.0 + (sintable[yy&0xf])
; ) / 2;
create_lookup:
ldy #15
create_yloop:
ldx #15
create_xloop:
clc
lda #15
adc sinetable,X
adc sinetable,Y
lsr
lookup_smc:
sta lookup ; always starts at $d00
inc lookup_smc+1
dex
bpl create_xloop
dey
bpl create_yloop
create_lookup_done:
forever_loop:
cycle_colors:
; cycle colors
ldx #0
cycle_loop:
inc lookup,X
inx
bne cycle_loop
plot_frame:
; plot frame
ldx #39 ; YY=0
plot_yloop:
ldy #39 ; XX = 0
txa
lsr
php
jsr GBASCALC ; point GBASL/H to address in A
; after, A trashed, C is clear
plp
lda #$0f ; setup mask
bcc plot_mask
adc #$e0
plot_mask:
sta MASK
plot_xloop:
stx SAVEX ; SAVE YY
tya ; get x&0xf
and #$f
sta CTEMP
txa ; get (y&0xf)<<4
asl
asl
asl
asl
ora CTEMP ; get (y*15)+x
tax
plot_lookup:
; sta plot_lookup_smc+1
plot_lookup_smc:
lda lookup,X ; load lookup, (y*16)+x
; lda lookup ; load lookup, (y*16)+x
and #$f
lsr
tax
lda colorlookup,X
sta COLOR
jsr PLOT1 ; plot at GBASL,Y (x co-ord in Y)
ldx SAVEX ; restore YY
dey
bpl plot_xloop
dex
bpl plot_yloop
bmi forever_loop
; iny
; cpy #40
; bne plot_xloop
; inx
; cpx #40
; bne plot_yloop
; beq forever_loop
colorlookup:
bw_color_lookup:
.byte $55,$22,$66,$77,$ff,$77,$55 ; ,$00 shared w sin table
sinetable:
.byte $00,$03,$05,$07,$08,$07,$05,$03
.byte $00,$FD,$FB,$F9,$F8,$F9,$FB,$FD
;colorlookup:
;.byte $00,$00,$05,$05,$07,$07,$0f,$0f
;.byte $07,$07,$06,$06,$02,$02,$05,$05
;.byte $00,$55,$77,$ff,$77,$66,$22,$55
.org $d00
;.align $100
lookup: