Per-surface env_cubemap selection for envmap reflections #21

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opened 2026-03-18 02:35:18 +00:00 by kit · 0 comments

kit commented

2026-03-18 02:35:18 +00:00

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Currently we use a single skybox-derived cubemap as a global fallback for all $envmap reflections. Source maps contain env_cubemap entities at specific positions, each with a baked cubemap texture stored in the BSP's cubemap lump. The engine selects the nearest env_cubemap to each surface for its reflections.

Requirements

Parse env_cubemap entities from the BSP entity lump (position + cubemap size)
Extract baked cubemap textures from the BSP pakfile or cubemap lump
For each surface with $envmap "env_cubemap", select the nearest env_cubemap and assign its cubemap texture
Fall back to the skybox cubemap when no baked cubemap is available

Context

env_cubemap entities are placed by mappers at key reflection points
Materials reference them via $envmap "env_cubemap" (which means "use nearest")
The baked cubemaps are stored as VTF files inside the BSP pakfile, named like c{x}_{y}_{z}.vtf
Current envmap implementation: client/src/bsp/loader.js (loadSkyboxCubemap, _applyPendingEnvmaps)
This would significantly improve reflection quality since different areas of the map would have context-appropriate reflections

Currently we use a single skybox-derived cubemap as a global fallback for all `$envmap` reflections. Source maps contain `env_cubemap` entities at specific positions, each with a baked cubemap texture stored in the BSP's cubemap lump. The engine selects the nearest `env_cubemap` to each surface for its reflections. ## Requirements - Parse `env_cubemap` entities from the BSP entity lump (position + cubemap size) - Extract baked cubemap textures from the BSP pakfile or cubemap lump - For each surface with `$envmap "env_cubemap"`, select the nearest `env_cubemap` and assign its cubemap texture - Fall back to the skybox cubemap when no baked cubemap is available ## Context - `env_cubemap` entities are placed by mappers at key reflection points - Materials reference them via `$envmap "env_cubemap"` (which means "use nearest") - The baked cubemaps are stored as VTF files inside the BSP pakfile, named like `c{x}_{y}_{z}.vtf` - Current envmap implementation: `client/src/bsp/loader.js` (`loadSkyboxCubemap`, `_applyPendingEnvmaps`) - This would significantly improve reflection quality since different areas of the map would have context-appropriate reflections