dos33fsprogs/graphics/gr/plasma/plasma_bot.s
2023-10-29 18:01:18 -04:00

221 lines
3.7 KiB
ArmAsm

; do a (hopefully fast) plasma type demo
; 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
; 119 -- forgot to comment out unused
; 121 -- make it use full screen (40x48)
; 149 -- add page flipping
; 144 -- optimize a bit
; 141 -- smc DRAW_PAGE
; 144 -- for bot, backwards jump
; 142 -- from qkumba, remove php/plp
; 141 -- from qkumba, remove SAVEX
; goal=135
.include "zp.inc"
.include "hardware.inc"
CTEMP = $FC
;SAVEOFF = $FD
;SAVEX = $FE
;SAVEY = $FF
;================================
; Clear screen and setup graphics
;================================
plasma:
jsr SETGR ; set lo-res 40x40 mode
bit FULLGR ; make it 40x48
; color = ( 8.0 + 8*sin(x) + 8.0 + 8*sin(y) )/2
; becomes
; color = ( 16 + (sintable[xx&0xf]) + (sintable[yy&0xf])) / 2;
; we only create a 16x16 texture, which we pattern across 40x48 screen
create_lookup:
ldy #15
create_yloop:
ldx #15
create_xloop:
clc
lda #15 ; 8+8 (but 15 works better)
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
; X and Y both $FF
create_lookup_done:
forever_loop:
cycle_colors:
; cycle colors
; can't do palette rotate on Apple II so faking it here
; just incrementing every entry in texture by 1
; X if $FF when arriving here
; ldx #0
inx ; make X 0
cycle_loop:
inc lookup,X
inx
bne cycle_loop
; set/flip pages
; we want to flip pages and then draw to the offscreen one
flip_pages:
; ldx #0 ; x already 0
lda draw_page_smc+1 ; DRAW_PAGE
beq done_page
inx
done_page:
ldy PAGE1,X ; set display page to PAGE1 or PAGE2
eor #$4 ; flip draw page between $400/$800
sta draw_page_smc+1 ; DRAW_PAGE
; plot current frame
; scan whole 40x48 screen and plot each point based on
; lookup table colors
plot_frame:
ldx #47 ; YY=47 (count backwards)
plot_yloop:
txa ; get (y&0xf)<<4
pha ; save YY / SAVEX
asl
asl
asl
asl
sta CTEMP ; save for later
txa ; get Y in accumulator
lsr ; call actually wants Ycoord/2
ldy #$0f ; setup mask for odd/even line
bcc plot_mask
ldy #$f0
plot_mask:
sty MASK
jsr GBASCALC ; point GBASL/H to address in (A is ycoord/2)
; after, A is GBASL, C is clear
lda GBASH ; adjust to be PAGE1/PAGE2 ($400 or $800)
draw_page_smc:
adc #0
sta GBASH
;==========
ldy #39 ; XX = 39 (countdown)
plot_xloop:
; stx SAVEX ; SAVE YY
tya ; get x&0xf
and #$f
ora CTEMP ; combine with val from earlier
; get ((y&0xf)*16)+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 ; we actually only have 8 colors
tax
lda colorlookup,X ; lookup color
sta COLOR ; each nibble should be same
jsr PLOT1 ; plot at GBASL,Y (x co-ord goes in Y)
; ldx SAVEX ; restore YY
dey
bpl plot_xloop
pla
tax
dex
bpl plot_yloop
bmi forever_loop
colorlookup:
bw_color_lookup:
; blue
;.byte $55,$22,$66,$77,$ff,$77,$55 ; ,$00 shared w sin table
; pink
.byte $55,$11,$33,$bb,$ff,$bb,$55
; this is actually 8*sin(x)
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
; want this to be at 3f5
; Length is 141 so start at $3f4 -
; 1013 - 141 + 3 = 875 = $36B
jmp plasma
; make lookup happen at page boundary
.org $d00
lookup: