Planet atmospheres, ray-sphere intersections.

From a channel Lumen includes in full: Martin Donald breaks down real-time graphics techniques from shipped games — vertex animation textures, SDF text, raymarching, PlayStation-style wobble — and rebuilds each one in shader code, explained clearly in short lessons.

A 7-minute video from Martin Donald's catalogue; the title names its topic.

Video by Martin Donald, played through YouTube's embedded player.