91 3D: Software finite-light evaluation🔗ℹ

3D reference map · First 3D picture

The software renderer evaluates point and spot lights per rasterized fragment. The rasterizer perspective-correctly interpolates camera-space positions and normals, transforms authored finite lights into that camera space once per prepared frame, and accumulates the authored light list in its declared order. For a point source it applies the named attenuation and optional range. For a spot it additionally applies the named smoothstep cone from the outward light direction. These factors multiply both the Lambert diffuse and the Blinn–Phong specular terms; material emission remains independent of lights.

Double-sided materials use their interpolated outward normal for a front face and flip that normal toward the viewing side for a back face. This is a fixed illustration policy, rather than an inferred rendering accident.

Current limitation. The software path is the deterministic conformance reference. The OpenGL path evaluates matching finite-light records and directional/spot shadow maps, but it has fixed four-directional/eight-point/ four-spot light limits and no separate persistent finite-light buffer cache. Point/spot attenuation, range, and cone values are fixed during a light-animation clip; only the exposed light fields are animated.