Class: PMREMGenerator

PMREMGenerator()

This class generates a Prefiltered, Mipmapped Radiance Environment Map (PMREM) from a cubeMap environment texture. This allows different levels of blur to be quickly accessed based on material roughness. It is packed into a special CubeUV format that allows us to perform custom interpolation so that we can support nonlinear formats such as RGBE. Unlike a traditional mipmap chain, it only goes down to the LOD_MIN level (above), and then creates extra even more filtered 'mips' at the same LOD_MIN resolution, associated with higher roughness levels. In this way we maintain resolution to smoothly interpolate diffuse lighting while limiting sampling computation. Paper: Fast, Accurate Image-Based Lighting https://drive.google.com/file/d/15y8r_UpKlU9SvV4ILb0C3qCPecS8pvLz/view

Constructor

new PMREMGenerator()

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Methods

_blur()

This is a two-pass Gaussian blur for a cubemap. Normally this is done vertically and horizontally, but this breaks down on a cube. Here we apply the blur latitudinally (around the poles), and then longitudinally (towards the poles) to approximate the orthogonally-separable blur. It is least accurate at the poles, but still does a decent job.
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compileCubemapShader()

Pre-compiles the cubemap shader. You can get faster start-up by invoking this method during your texture's network fetch for increased concurrency.
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compileEquirectangularShader()

Pre-compiles the equirectangular shader. You can get faster start-up by invoking this method during your texture's network fetch for increased concurrency.
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dispose()

Disposes of the PMREMGenerator's internal memory. Note that PMREMGenerator is a static class, so you should not need more than one PMREMGenerator object. If you do, calling dispose() on one of them will cause any others to also become unusable.
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fromCubemap()

Generates a PMREM from an cubemap texture, which can be either LDR or HDR. The ideal input cube size is 256 x 256, as this matches best with the 256 x 256 cubemap output.
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fromEquirectangular()

Generates a PMREM from an equirectangular texture, which can be either LDR or HDR. The ideal input image size is 1k (1024 x 512), as this matches best with the 256 x 256 cubemap output.
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fromScene()

Generates a PMREM from a supplied Scene, which can be faster than using an image if networking bandwidth is low. Optional sigma specifies a blur radius in radians to be applied to the scene before PMREM generation. Optional near and far planes ensure the scene is rendered in its entirety (the cubeCamera is placed at the origin).
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