CPU proximity picking

Sat, 25 Apr 2026 14:30:00 -0500

Zero-GPU hit testing with mouseHit. Ten waypoint nodes around a soft loop — each one tested every frame against the cursor by projecting its origin to screen space and comparing against a configurable radius. The hit zone is drawn explicitly with bullsEye, which takes the same size and shape parameters as mouseHit — the gizmo is the hit zone, no guessing where the click registers. Use the panel to tune the radius and switch between circular and square hit shapes.

GPU color-ID picking

Sat, 25 Apr 2026 14:00:00 -0500

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.

Picking on blog

CPU proximity picking

GPU color-ID picking