Hardware Oddity Shrek HILO1

Shrek's HILO_1 path

Evidence: Xbox observed, described by an original game programmer. Rich Geldreich describes the original Xbox Shrek deferred-lighting path. The early Microsoft pixel-shader assembler did not expose the HILO_1 mode needed to inject a constant 1.0 into texture-stage dot products, so the team configured texture and combiner structures manually. They also reinterpreted depth/stencil storage as RGBA texture data, reconstructed positions, and used a dependent 3D lookup for lighting direction and attenuation.

This is deliberate production rendering, not evidence that malformed resources generally work. A shader inspector that only reconstructs the old assembler's vocabulary will omit valid raw state.

Proposed test: preserve and replay the raw texture-stage/combiner configuration beside any reconstructed source. Compare intermediate values and rendered pixels with the original method sequence.

Source: Rich Geldreich, early history of deferred shading and lighting.

See also NV2A Graphics Architecture and Halo 2 resource aliasing and tiled pitch.