I was bored, so I decided to code 2 circle algorithms:
lua code:
function draw_circle_b(xc,yc,r)
local x = 0
local y = r
local p = 3 - 2 * r
if not r then return end
while y >= x do
draw_quad(xc-x, yc-y, 1, 1)
draw_quad(xc-y, yc-x, 1, 1)
draw_quad(xc+y, yc-x, 1, 1)
draw_quad(xc+x, yc-y, 1, 1)
draw_quad(xc-x, yc+y, 1, 1)
draw_quad(xc-y, yc+x, 1, 1)
draw_quad(xc+y, yc+x, 1, 1)
draw_quad(xc+x, yc+y, 1, 1)
if p < 0 then
x=x+1
p=p+(4*x+6)
else
x=x+1
y=y-1
p=p+(4*(x-y)+10)
end
end
end
function draw_circle_n(xc,yc,r)
draw_disk(xc,yc,r-1,r,r*2.5,1,0,360,0)
end
add_hook("draw2d","",function() set_color(0,0,0,1) draw_circle_b(500,300,50) draw_circle_n(700,500,10) draw_circle_n(700,500,100) end)
First one is a lua translation of Bresenham's circle algorithm, second one is a simplified version of draw_disk adapted for circles.
The hook provided is an example.
Parameters are x position, y position and radius of the circle on both functions.