demotool/shaders/lib/utils.glsl

//! type library


const float PI = 3.14159265;


// -----------------------------------------------------------------------------

float M_Hash(
	in vec2 p )
{
	p = fract(p * vec2(5.3987, 5.4421));
	p += dot(p.yx, p.xy + vec2(21.5351, 14.3137));
	return fract(p.x * p.y * 95.4307);
}

// -----------------------------------------------------------------------------

float M_Luminosity(
		in vec3 color )
{
	return dot( color , vec3( .3 , .6 , .1 ) );
}

vec3 M_NormalizeColor(
		in vec3 color )
{
	const float l = M_Luminosity( color );
	return l > 0 ? ( color / l ) : vec3( 1 );
}