LIT

gistfile1.txt

#define LIT(dest, src) dest = _out(dest,_LIT(_in(src)))
vec4 _LIT(vec4 src)
{

vec4 s = src;
float epsilon=1.0/256.0;
s.w = clamp(s.w,-(128.0-epsilon),128.0-epsilon);
s.x = max(s.x,0.0);
s.y = max(s.y,0.0);

vec4 t = vec4(1.0, 0.0, 0.0, 1.0);
t.y = s.x;
t.z = (s.x > 0.0) ? exp2(s.w*log2(s.y)) : 0.0;

  return t;
}