Optimisations for Real-Time Volumetric Cloudscapes

09/17/2016

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by   Alastair Toft, et al.

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Volumetric cloudscapes are prohibitively expensive to render in real time without extensive optimisations. Previous approaches render the clouds to an offscreen buffer at one quarter resolution and update a fraction of the pixels per frame, drawing the remaining pixels by temporal reprojection. We present an alternative approach, reducing the number of raymarching steps and adding a randomly jittered offset to the raymarch. We use an analytical integration technique to make results consistent with a lower number of raymarching steps. To remove noise from the resulting image we apply a temporal anti-aliasing implementation. The result is a technique producing visually similar results with 1/16 the number of steps.