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().
||optional Scales diffuse and specular image-based lighting from the earth, sky, atmosphere and star skybox.|
||optional The sun's luminance at the zenith in kilo candela per meter squared to use for this model's procedural environment map.|
||Array.<Cartesian3>||optional The third order spherical harmonic coefficients used for the diffuse color of image-based lighting.|
||String||optional A URL to a KTX2 file that contains a cube map of the specular lighting and the convoluted specular mipmaps.|
imageBasedLightingFactor : Cartesian2
ImageBasedLighting#sphericalHarmonicCoefficientsare not defined.
sphericalHarmonicCoefficients : Array.<Cartesian3>
undefined, a diffuse irradiance computed from the atmosphere color is used.
There are nine
The order of the coefficients is: L0,0, L1,-1, L1,0, L1,1, L2,-2, L2,-1, L2,0, L2,1, L2,2
cmgentool of Google's Filament project. This will also generate a KTX file that can be supplied to