Genuary 2023 Day 8 - Signed Distance Functions

-- genuary #8 2023
-- signed distance functions
-- by carson kompon
-- huge thanks to piter pasma's explanation video on sdfs
function dist(x,y)
	return sqrt((x*x+y*y))
end

function sdf_circle(x,y,cx,cy,r)
	x-=cx
	y-=cy
	return dist(x,y) - r
end

function sdf(x,y)
	dd = 1.5
	circle1 = sdf_circle(x,y,cos(t()/16+.5)/dd,sin(t()/16+.5)/dd,.2+sin(t()/16)/20)
	circle1 = abs(circle1)-.1
	circle2sub = sdf_circle(x,y,cos(t()/16)/dd-.15,sin(t()/16)/dd,.2+sin(t()/16+.5)/20)
	circle2norm = sdf_circle(x,y,cos(t()/16)/dd,sin(t()/16)/dd,.3+sin(t()/16+.5)/20)
	circle2 = max(-circle2sub,circle2norm)
	waves = -y+.3+sin(t()+x)/64
	waves = waves/2
	return min(min(circle1, circle2), waves)
end

pal({[0]=0,128,133,141,133,0,0,0,12,140,1,129,130,132,9,10},1)

::_::
	x=rnd(2)-1
	y=rnd(2)-1
	d=sdf(x,y)
	c=0
	if(d<-.02)c=d*16
	if(d>.02)c=1+(1+y*2+t()/4)%4
	circfill((x+1)*64,(y+1)*64,1,c)
goto _