ImageBasedLighting

new Cesium.ImageBasedLighting(options)
engine/Source/Scene/ImageBasedLighting.js 28

Properties for managing image-based lighting on tilesets and models. Also manages the necessary resources and textures.

If specular environment maps are used, ImageBasedLighting#destroy must be called when the image-based lighting is no longer needed to clean up GPU resources properly. If a model or tileset creates an instance of ImageBasedLighting, it will handle this. Otherwise, the application is responsible for calling destroy().

Name Type Description
options object optional Object with the following properties:
Name Type Default Description
imageBasedLightingFactor Cartesian2 Cartesian2(1.0, 1.0) optional Scales diffuse and specular image-based lighting from the earth, sky, atmosphere and star skybox.
luminanceAtZenith number 0.2 optional The sun's luminance at the zenith in kilo candela per meter squared to use for this model's procedural environment map.
sphericalHarmonicCoefficients Array.<Cartesian3> optional The third order spherical harmonic coefficients used for the diffuse color of image-based lighting.
specularEnvironmentMaps string optional A URL to a KTX2 file that contains a cube map of the specular lighting and the convoluted specular mipmaps.

Members

imageBasedLightingFactor : Cartesian2
engine/Source/Scene/ImageBasedLighting.js 121

Cesium adds lighting from the earth, sky, atmosphere, and star skybox. This cartesian is used to scale the final diffuse and specular lighting contribution from those sources to the final color. A value of 0.0 will disable those light sources.
Default Value: Cartesian2(1.0, 1.0)

luminanceAtZenith : number
engine/Source/Scene/ImageBasedLighting.js 171

The sun's luminance at the zenith in kilo candela per meter squared to use for this model's procedural environment map. This is used when ImageBasedLighting#specularEnvironmentMaps and ImageBasedLighting#sphericalHarmonicCoefficients are not defined.
Default Value: 0.2

specularEnvironmentMaps : string
engine/Source/Scene/ImageBasedLighting.js 224

A URL to a KTX2 file that contains a cube map of the specular lighting and the convoluted specular mipmaps.
Demo:
See:

sphericalHarmonicCoefficients : Array.<Cartesian3>
engine/Source/Scene/ImageBasedLighting.js 199

The third order spherical harmonic coefficients used for the diffuse color of image-based lighting. When undefined, a diffuse irradiance computed from the atmosphere color is used.

There are nine Cartesian3 coefficients. The order of the coefficients is: L0,0, L1,-1, L1,0, L1,1, L2,-2, L2,-1, L2,0, L2,1, L2,2

These values can be obtained by preprocessing the environment map using the cmgen tool of Google's Filament project. This will also generate a KTX file that can be supplied to Model#specularEnvironmentMaps.
Demo:
See:
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