A couple of problems with rendering to cubemap

mvaligursky · March 10, 2021, 4:07pm

When cubemap gets rendered, it’s not automatically filtered, and that’s what is needed to be able to handle materials with different level of glossiness. Our viewer uses this code currently to prefilter source environment texture (not a cubemap in that case, but cubemap would work as well)

github.com

playcanvas/model-viewer/blob/50e453bd4be7bb9806bff8ae85c78251c7799ef1/src/viewer.ts#L345-L404


      
          private initSkyboxFromTexture(skybox: pc.Texture) {
              const app = this.app;
              const device = app.graphicsDevice;
          
              const cubemaps = [];
          
              const reprojectToCubemap = function (src: pc.Texture, size: number) {
                  // generate faces cubemap
                  const faces = new pc.Texture(device, {
                      name: 'skyboxFaces',
                      cubemap: true,
                      width: size,
                      height: size,
                      type: pc.TEXTURETYPE_RGBM.toString(),
                      addressU: pc.ADDRESS_CLAMP_TO_EDGE,
                      addressV: pc.ADDRESS_CLAMP_TO_EDGE,
                      fixCubemapSeams: false,
                      mipmaps: false
                  });
                  pc.reprojectTexture(device, src, faces);

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this based on a single cubemap generates 6 prefiltered cubemaps, which are used for image based lighting. In the near future (couple of months hopefuly) we’re hoping to address this by some easy to use interface.

Here’s a similar thread where something similar was tested

You can also see PlayCanvas Examples where rendered cubemap is prefiltered to another representation (only a single for testing, not 6 as needed for image based lighting)