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

Technique : base("ReflectionCubemap") =
{
	Language = "HLSL11";

	Pass =
	{
		Common = 
		{
			#define REFLECTION_MIP_OFFSET 2
		
			/**
			 * Calculates a mip level to sample from based on roughness value.
			 *
			 * @param 	roughness	Roughness in range [0, 1]. Higher values yield more roughness.
			 * @param	numMips		Total number of mip-map levels in the texture we'll be sampling from.
			 * @return				Index of the mipmap level to sample.
			 */		
			float getMipFromRoughness(float roughness, float numMips)
			{
				// Note: This is just a heuristic as we don't calculate the exact size of the specular lobe,
				// and neither do our filtered maps
			
				// We add an offset because we want to ignore the highest few mip levels
				return numMips - 1 - REFLECTION_MIP_OFFSET - log2(roughness);
			}
		};
	};
};

Technique : base("ReflectionCubemap") =
{
	Language = "GLSL";

	Pass =
	{
		Common = 
		{
			#define REFLECTION_MIP_OFFSET 2
		
			/**
			 * Calculates a mip level to sample from based on roughness value.
			 *
			 * @param 	roughness	Roughness in range [0, 1]. Higher values yield more roughness.
			 * @param	numMips		Total number of mip-map levels in the texture we'll be sampling from.
			 * @return				Index of the mipmap level to sample.
			 */		
			void getMipFromRoughness(float roughness, float numMips, out float mipLevel)
			{
				// Note: This is just a heuristic as we don't calculate the exact size of the specular lobe,
				// and neither do our filtered maps
			
				// We add an offset because we want to ignore the highest few mip levels
				mipLevel = numMips - 1 - REFLECTION_MIP_OFFSET - log2(roughness);
			}
		};
	};
};