volumetricSky

The cloud layer's render passes.

The layer is raymarched for the camera being drawn, copied into the target the composite reads, temporally accumulated where there is a previous frame of that view to accumulate against, and laid over the frame behind whatever the depth buffer holds.

Every pass but the accumulation runs for each view the frame draws, an environment cube's six faces included — which is what puts the clouds into reflections. The accumulation blends against the previous frame of the same view, and a cube face is rendered once with no previous frame, so it declares environmentCapture = false and the copy before it is what those faces read.

VolumetricSky creates this feature; it is not meant to be created by hand.