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

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

	Pass =
	{
		Common = 
		{
			float3 getDirFromCubeFace(uint cubeFace, float2 uv)
			{
				float3 dir;
				if(cubeFace == 0)
					dir = float3(1.0f, -uv.y, -uv.x);
				else if(cubeFace == 1)
					dir = float3(-1.0f, -uv.y, uv.x);
				else if(cubeFace == 2)
					dir = float3(uv.x, 1.0f, uv.y);
				else if(cubeFace == 3)
					dir = float3(uv.x, -1.0f, -uv.y);
				else if(cubeFace == 4)
					dir = float3(uv.x, -uv.y, 1.0f);
				else
					dir = float3(-uv.x, -uv.y, -1.0f);
					
				return dir;
			}
			
			/**
			 * 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 mapRoughnessToMipLevel(float roughness, int numMips)
			{
				// We use the following equation:
				//    mipLevel = log10(roughness) / log10(dropPercent)
				//
				// Where dropPercent represent by what % to drop the roughness with each mip level.
				// We convert to log2 and a assume a drop percent value of 0.6. This gives us:
				//    mipLevel = -1.35692 * log2( roughness);

				return max(0, (float)numMips - 1.0f - (-1.35692f * log2(roughness)));
			}
			
			/**
			 * Calculates a roughness value from the provided mip level.
			 *
			 * @param 	mipLevel	Mip level to determine roughness for.
			 * @param	numMips		Total number of mip-map levels in the texture we'll be sampling from.
			 * @return				Roughness value for the specific mip level.
			 */				
			float mapMipLevelToRoughness(int mipLevel, int numMips)
			{
				// mapRoughnessToMipLevel() solved for roughness
				return saturate(exp2(((float)mipLevel - (float)numMips + 1.0f) / 1.35692));
			}	
		};
	};
};

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

	Pass =
	{
		Common = 
		{
			vec3 getDirFromCubeFace(uint cubeFace, vec2 uv)
			{
				vec3 dir;
				if(cubeFace == 0)
					dir = vec3(1.0f, -uv.y, -uv.x);
				else if(cubeFace == 1)
					dir = vec3(-1.0f, -uv.y, uv.x);
				else if(cubeFace == 2)
					dir = vec3(uv.x, 1.0f, uv.y);
				else if(cubeFace == 3)
					dir = vec3(uv.x, -1.0f, -uv.y);
				else if(cubeFace == 4)
					dir = vec3(uv.x, -uv.y, 1.0f);
				else
					dir = vec3(-uv.x, -uv.y, -1.0f);
					
				return dir;
			}			
		};
	};
};