BRDF Estimation

Precompute BRDF-related data for real-time rendering.

Perform cubemap GGX convolution, irradiance SH coefficients computation, and linearized BRDF look-up table precomputation.

See also

GPU::Frag::Cubemap_convo

GPU::Frag::Brdf_sampler

GPU::Frag::Skybox_shcoeffs

DeferredRendering

Functions
void	loadCubemap (const std::string &inputPath, Texture &cubemapInfos)
void	computeCubemapConvolution (const Texture &cubemapInfos, int levelsCount, int outputSide, int samplesCount, std::vector< Texture > &cubeLevels)
void	exportCubemapConvolution (std::vector< Texture > &cubeLevels, const std::string &outputPath)
void	computeAndExportLookupTable (const int outputSide, const std::string &outputPath)
int	main (int argc, char **argv)

Function Documentation

computeAndExportLookupTable()

void computeAndExportLookupTable	(	const int	outputSide,
		const std::string &	outputPath
	)

Compute and export a linearized BRDF look-up table.

Parameters

outputSide	the side size of the 2D output map
outputPath	the destination path

computeCubemapConvolution()

void computeCubemapConvolution	(	const Texture &	cubemapInfos,
		int	levelsCount,
		int	outputSide,
		int	samplesCount,
		std::vector< Texture > &	cubeLevels
	)

Compute a series of cubemaps convolved with a BRDF using increasing roughness values. The cubemaps form a mipmap pyramid.

Note

We choose to keep the levels in separate textures for easier visualisation. This could be revisited.

Parameters

cubemapInfos	the source HDR cubemap
levelsCount	the number of mipmap levels to generate
outputSide	the side size of the lvel 0 cubemap faces
samplesCount	the number of samples to use in the convolution
cubeLevels	will contain the texture infos for each level

exportCubemapConvolution()

void exportCubemapConvolution	(	std::vector< Texture > &	cubeLevels,
		const std::string &	outputPath
	)

Export the pre-convolved cubemap levels.

Parameters

cubeLevels	the textures to export as mipmap levels
outputPath	the based destination path

loadCubemap()

void loadCubemap	(	const std::string &	inputPath,
		Texture &	cubemapInfos
	)

Load a cubemap on both the CPU and GPU from an input path.

Parameters

inputPath	the base path on disk
cubemapInfos	will contain the cubemap infos once sent to the GPU

main()

int main	(	int	argc,
		char **	argv
	)

Compute either a series of cubemaps convolved with a BRDF using increasing roughness values, irradiance spherical harmonics coefficients, or generate a linearized BRDF look-up table.

Parameters

argc	the number of input arguments.
argv	a pointer to the raw input arguments.

Returns

a general error code.

Loading section.

Computations section.

Export section.

Visualisation section.

Rendering.