Optimisations for Real-Time Volumetric Cloudscapes

TL;DR

This paper introduces a novel optimization technique for real-time volumetric cloud rendering that significantly reduces computational cost while maintaining visual quality through analytical integration and temporal anti-aliasing.

Contribution

It presents an alternative approach that decreases raymarching steps and employs analytical integration, achieving efficient real-time volumetric cloud rendering.

Findings

Produces visually similar cloudscapes with 1/16 the raymarching steps

Reduces rendering cost significantly compared to previous methods

Maintains image quality using temporal anti-aliasing

Abstract

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.