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kfest: rasterbar works!

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This commit is contained in:
Vince Weaver 2018-07-20 23:18:56 -04:00
parent 0d547eff4b
commit 1cfb2422e4
1 changed files with 52 additions and 13 deletions
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65
kfest2018/raster.s
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@ -4,6 +4,7 @@
; Zero Page
FRAMEBUFFER = $00 ; $00 - $0F
YPOS = $10
YPOS_SIN = $11
DRAW_PAGE = $EE
CURRENT_OFFSET = $EF
OFFSET_GOVERNOR = $F0
@ -383,15 +384,15 @@ loop2:
; we have 4518-6 = 4512 to work with
rasterbars:
; delay 1618 (4512, -2661 draw_rasterbars
; - 147 clear - 86 set_rasterbar
; delay 1611 (4512, -2661 draw_rasterbars
; - 147 clear - 93 set_rasterbar
; Try X=8 Y=35 cycles=1611
; Try X=3 Y=77 cycles=1618
ldy #77 ; 2
ldy #35 ; 2
loop3:
ldx #3 ; 2
ldx #8 ; 2
loop4:
dex ; 2
bne loop4 ; 2nt/3
@ -415,15 +416,18 @@ clear_fb_loop:
;==================
; Set Rasterbar
;==================
; 16 + 52 + 18 = 86
; 16 + 52 + 18 = 86 +7 = 93
lda YPOS ; 3
and #$fc ; 2
lsr ; 2
ldx YPOS ; get YPOS ; 3
lda sine_table,X ; 4+
sta YPOS_SIN ; 3
and #$fc ; mask off bottom 2 bits ; 2
lsr ; X = (YPOS / 4)*2 skip odd ; 2
tax ; 2
lda YPOS ; 3
and #$3 ; 2
lda YPOS_SIN; get bottom 2 bits 0..3 ; 3
and #$3 ; use to decide which pattern to use ; 2
cmp #$0 ; 2
@ -534,7 +538,7 @@ done_draw_rasterbar:
ldx YPOS ; 3
inx ; 2
cpx #24 ; 2
cpx #32 ; 2
;===========
; 7
beq raster_bottom
@ -747,3 +751,38 @@ gr_offsets:
.word $450,$4d0,$550,$5d0,$650,$6d0,$750,$7d0
sine_table:
.byte 12 ; 12.000000 0
.byte 14 ; 14.145992 1
.byte 16 ; 16.209514 2
.byte 18 ; 18.111268 3
.byte 20 ; 19.778169 4
.byte 21 ; 21.146161 5
.byte 22 ; 22.162671 6
.byte 23 ; 22.788636 7
.byte 23 ; 23.000000 8
.byte 23 ; 22.788641 9
.byte 22 ; 22.162682 10
.byte 21 ; 21.146177 11
.byte 20 ; 19.778190 12
.byte 18 ; 18.111292 13
.byte 16 ; 16.209541 14
.byte 14 ; 14.146020 15
.byte 12 ; 12.000029 16
.byte 10 ; 9.854037 17
.byte 8 ; 7.790513 18
.byte 6 ; 5.888756 19
.byte 4 ; 4.221851 20
.byte 3 ; 2.853856 21
.byte 2 ; 1.837341 22
.byte 1 ; 1.211370 23
.byte 1 ; 1.000000 24
.byte 1 ; 1.211353 25
.byte 2 ; 1.837307 26
.byte 3 ; 2.853807 27
.byte 4 ; 4.221789 28
.byte 6 ; 5.888683 29
.byte 8 ; 7.790432 30
.byte 10 ; 9.853951 31