  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.
