skate-3-rust-engine/docs/retail-renderer.md

Retail renderer

The world material adapter follows Alex's native renderer at f6e0ae8. The reference files are scene.hlsl, scene_common.hlsli, scene_frame_cb.hlsli, and hdr.hlsl. This is a Bevy implementation of those shading equations, not a port of the game hooks or the whole renderer.

Implemented:

• World families 1–13: diffuse/lightmap squaring, the family lighting terms, decal art, macro overlay, normal/detail lighting and specular masks.
• Reflective-family cube sampling with all six faces and a complete mip chain.
• The shared HDR tone curve, including environmentdiffuse's reduced curve. The final output accounts for Bevy's sRGB conversion instead of applying gamma twice. The HUD is drawn after this pass.
• Alpha-tested world materials use the reference's 30/255 threshold in both colour and depth passes. Foliage is two-sided.
• Lightmaps remain bilinear, clamped and fixed at mip zero. Repeating world textures have mipmaps.
• The three major districts use their actual sky geometry and diffuse texture from miscload.big. Texture selection follows material GUIDs through the RX2 reference table. Sky X/Z follow the camera; Y uses the reference's documented 165-metre default.

The converter reads scalar material channels at record offset 0x10. Earlier exports incorrectly read their string pointer and saved empty strings. Reconvert maps to obtain those constants and complete reflection cubes. Old packages still load; missing constants disable the relevant layer and single-face environment textures are not treated as cubes.

Remaining differences

This is not a claim of pixel parity. Native frame constants are supplied by game hooks in the reference; this engine does not yet recover that controller. Exposure 2.5, material multiplier 1, and tree/proxy values use documented day-capture defaults. Imported maps have no dynamic directional sun or realtime sun shadows: their world lighting comes from the baked lightmaps. Normal-map sign terms retain the adapter's fixed direction until native frame data is available; this adds no light energy or shadow map. The fog inputs are wired into the shader but remain disabled without authored frame rows.

Sky sun-gradient shading, park sky selection, native water, character shaders, SSAO, SSR, bloom and volumetric lighting are not yet ported. The character and unsupported world families still use Bevy materials beneath the shared tone curve. Reflection normals use the reference's analytic world-up construction; there has been no matched-camera pixel comparison against the recomp.

The shaders are embedded in the executable. Sky and map payloads are extracted from the user's game and must never be committed or bundled with releases.