BansheeEngine/Data/Raw/Engine/Includes/ColorSpace.bslinc

mixin ColorSpace
{
	code
	{
		/**
		 * Converts a color in RGB space into YCoCg color space. Note that Co and Cg
		 * components are in [-0.5, 0.5] range and therefore cannot be stored as-is
		 * in a normal color texture.
		 */
		float3 RGBToYCoCg(float3 input)
		{
			float Y = dot(input, float3(0.25f, 0.5f, 0.25f));
			float Co = input.r * 0.5f + input.b * -0.5f;
			float Cg = dot(input, float3(-0.25f, 0.5f, -0.25f));
			
			return float3(Y, Co, Cg);
		}
		
		/**
		 * Converts a color in YCoCg color space into RGB color space.
		 */
		float3 YCoCg(float3 input)
		{
			float R = input.r + input.g - input.b;
			float G = input.r + input.b;
			float B = input.r - input.g - input.b;
			
			return float3(R, G, B);
		}
		
		/** Calculates luminance from a color in RGB color space. */
		float LuminanceRGB(float3 input)
		{
			return 0.299f * input.r + 0.587f * input.g + 0.114f * input.b;
		}
	};
};