function parameters
w, h, x, y
t = current time (ms)
d[] = imageData array
r, g, b, a = color values
mousex, mousey

Math aliases
floor, ceil, round, abs, sign
pow, exp, sqrt
cos, sin, tan
acos, asin, atan, atan2
random()
E, PI, PHI

convenience functions
clamp(n,min,max)
lerp(n,a,b)
mix(n,a,b)
step(n,a,b)
smoothstep(n,a,b)
cosp, sinp (mapped to [0,1])
pixel(x,y) == 4*(y*w+h)
rand(n), randint(n)
choice(array)
deg(radians), rad(degrees)