Stacken/c64-livecoding
6
0
Fork 0
Code Issues 1 Pull requests Projects Releases Packages Wiki Activity Actions

more pritty circle bugs

Browse source
This commit is contained in:
hugova 2025-06-26 22:38:11 +02:00
parent 8b955a5007
commit d691d692b9
1 changed files with 13 additions and 23 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
wip-hugo/routines/circle/circle.s
View file

@ -4,15 +4,14 @@
.include "circle.inc"
;; We use the algorithm jerkos method
;; https://schwarzers.com/algorithms/
LDY Y_pos
LDX X_pos
;; X_pos = X_pos + r (hack, should fix later ( xpos == ypos is not always true))
CLC
LDA X_pos
ADC radius
STA X_pos
;; t1 = radius >> 4
LDA radius
LSR
@ -22,39 +21,30 @@
STA t1
while_x_bigger_then_y:
STY Y_pos
STX X_pos
STA temp
jsr pixel_draw
LDY Y_pos
LDX X_pos
LDA temp
INY ; y++
INC Y_pos ; y++
;;t1 += y
CLC
LDA t1
STY temp
ADC temp
ADC Y_pos
STA t1
;; t2 = t1 - x
SEC
STX temp
SBC temp
LDA t2
SBC X_pos
STA t2
;; if t2 < 0 then skip to endif
CMP #$00
BMI endif
if:
DEX; x--
DEC X_pos ; x--
STA t1 ; t1 = t2
endif:
;; repeat if X > Y
STX temp
TYA
CMP temp
LDA X_pos
CMP Y_pos
JMP while_x_bigger_then_y
BEQ while_x_bigger_then_y
;BNE while_x_bigger_then_y
.endproc