Fbo

Pixel-perfect mouse picking with mousePick. Fifty mixed primitives — boxes, spheres, torii, cones, cylinders — drawn at random positions and tagged with a unique integer id encoded as a CSS hex colour by tag. Each frame the scene renders twice: once into a 1×1 framebuffer with each shape filled by its id, then gl.readPixels returns whichever id sits under the cursor; the visible pass renders normally and lights up the hit. Cost is one extra geometry submission per frame regardless of object count, and the answer is exactly the rendered pixel — through the hole of a torus, behind a partially-occluding box, anywhere a real fragment landed. ...