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fix monogfx.disc() inaccurracy

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Irmen de Jong
2025-10-05 23:03:53 +02:00
parent 44741a8e32
commit 9aff280d10
4 changed files with 14 additions and 101 deletions
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36
examples/test.p8
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@@ -1,42 +1,16 @@
%import graphics
%import monogfx
main {
sub start() {
graphics.enable_bitmap_mode()
monogfx.lores()
uword radius
for radius in 1 to 10 {
graphics.circle(30*radius, 100, lsb(radius))
graphics.disc(30*radius, 130, lsb(radius))
mydisc(30*radius, 160, lsb(radius))
monogfx.circle(30*radius, 100, lsb(radius), true)
monogfx.disc(30*radius, 130, lsb(radius), true)
monogfx.safe_disc(30*radius, 160, lsb(radius), true)
}
repeat {}
}
sub mydisc(uword xcenter, ubyte ycenter, ubyte radius) {
; Warning: NO BOUNDS CHECKS. Make sure circle fits in the screen.
; Midpoint algorithm.
if radius==0
return
ubyte @zp ploty
ubyte @zp yy = 0
word @zp decisionOver2 = (1 as word)-radius
while radius>=yy {
graphics.horizontal_line(xcenter-radius, ycenter+yy, radius*2+1)
graphics.horizontal_line(xcenter-radius, ycenter-yy, radius*2+1)
graphics.horizontal_line(xcenter-yy, ycenter+radius, yy*2+1)
graphics.horizontal_line(xcenter-yy, ycenter-radius, yy*2+1)
yy++
if decisionOver2>=0 {
radius--
decisionOver2 -= radius*$0002
}
decisionOver2 += yy*$0002
decisionOver2++
}
}
}