\ Pixel Circle — sample a circle on a 32x32 grid

: pixel-position
  uv
  16.0 * floor
  0.5 +
  16.0 /
;

:: circle ( point radius -- mask )
   1.0
   radius point length step
   -
;

: main
  0.025 0.03 0.04 vec3
  1.0 0.34 0.12 vec3
  pixel-position 0.58 circle
  mix
  1.0 vec4
;