Harmonics.h File Reference

Spherical harmonics functionality. More...

#include <MaterialXRender/Export.h>
#include <MaterialXRender/Image.h>
#include <MaterialXRender/Types.h>

Go to the source code of this file.

Classes
class	ShCoeffs< C, B >
	Class template for a vector of spherical harmonic coefficients. More...

Typedefs
using	Sh3ScalarCoeffs = ShCoeffs< double, 3 >
	Double-precision scalar coefficients for third-order spherical harmonics.
using	Sh3ColorCoeffs = ShCoeffs< Color3d, 3 >
	Double-precision color coefficients for third-order spherical harmonics.

Functions
MX_RENDER_API Sh3ColorCoeffs	projectEnvironment (ConstImagePtr env, bool irradiance=false)
	Project an environment map to third-order SH, with an optional convolution to convert radiance to irradiance. More...
MX_RENDER_API ImagePtr	normalizeEnvironment (ConstImagePtr env, float envRadiance, float maxTexelRadiance)
	Normalize an environment to the given radiance. More...
MX_RENDER_API void	computeDominantLight (ConstImagePtr env, Vector3 &lightDir, Color3 &lightColor)
	Compute the dominant light direction and color of an environment map. More...
MX_RENDER_API ImagePtr	renderEnvironment (const Sh3ColorCoeffs &shEnv, unsigned int width, unsigned int height)
	Render the given spherical harmonic signal to an environment map. More...
MX_RENDER_API ImagePtr	renderReferenceIrradiance (ConstImagePtr env, unsigned int width, unsigned int height)
	Render a reference irradiance map from the given environment map, using brute-force computations for a slow but accurate result. More...

Detailed Description

Spherical harmonics functionality.

Function Documentation

computeDominantLight()

MX_RENDER_API void computeDominantLight	(	ConstImagePtr	env,
		Vector3 &	lightDir,
		Color3 &	lightColor
	)

Compute the dominant light direction and color of an environment map.

Parameters

env	An environment map in lat-long format.
lightDir	Returns the dominant light direction of the environment.
lightColor	Returns the color of the light from the dominant direction.

normalizeEnvironment()

MX_RENDER_API ImagePtr normalizeEnvironment	(	ConstImagePtr	env,
		float	envRadiance,
		float	maxTexelRadiance
	)

Normalize an environment to the given radiance.

Parameters

env	An environment map in lat-long format.
envRadiance	The radiance to which the environment map should be normalized.
maxTexelRadiance	The maximum radiance allowed for any individual texel of the map.

Returns

A new normalized environment map, in the same format as the original.

projectEnvironment()

MX_RENDER_API Sh3ColorCoeffs projectEnvironment	(	ConstImagePtr	env,
		bool	irradiance = false
	)

Project an environment map to third-order SH, with an optional convolution to convert radiance to irradiance.

Parameters

env	An environment map in lat-long format.
irradiance	If true, then the returned signal will be convolved by a clamped cosine kernel to generate irradiance.

Returns

The projection of the environment to third-order SH.

renderEnvironment()

MX_RENDER_API ImagePtr renderEnvironment	(	const Sh3ColorCoeffs &	shEnv,
		unsigned int	width,
		unsigned int	height
	)

Render the given spherical harmonic signal to an environment map.

Parameters

shEnv	The color signal of the environment encoded as third-order SH.
width	The width of the output environment map.
height	The height of the output environment map.

Returns

An environment map in the lat-long format.

renderReferenceIrradiance()

MX_RENDER_API ImagePtr renderReferenceIrradiance	(	ConstImagePtr	env,
		unsigned int	width,
		unsigned int	height
	)

Render a reference irradiance map from the given environment map, using brute-force computations for a slow but accurate result.

Parameters

env	An environment map in lat-long format.
width	The width of the output irradiance map.
height	The height of the output irradiance map.

Returns

An irradiance map in the lat-long format.