Module texture_plan 

Per-preset user-texture binding plan + the tex2D rewriter that consumes it.

Built by the renderer at preset load time:

1. scan_user_samplers extracts sampler sampler_X; declarations from the preset’s HLSL.
2. The renderer resolves each name to a TextureSlot via its texture pool. sampler_rand0X becomes a deterministic pick; literal names become a pool lookup.
3. The slots are passed to crate::translate_shader_with_plan and the wrapper so the emitted WGSL points at the right binding.

Structs

TextureBindingPlan

Per-preset mapping from HLSL sampler names to the comp pass’s user-texture slots.

TextureSlot

One slot in a TextureBindingPlan. Carries the resolved pool texture name (or None when the renderer should fall back to the 1×1 white fallback) and the texture’s vec4<f32>(w, h, 1/w, 1/h) for the texsize_<NAME> constant the wrapper emits.

UserSamplerRef

One parsed sampler sampler_X; declaration. The renderer consumes this to populate a TextureBindingPlan.

Constants

MAX_USER_TEXTURE_SLOTS

Maximum simultaneously-bound user textures per preset. Sized to cover the in-the-wild distribution: a typical preset survey shows ≤ 4 distinct sampler sampler_X; declarations per shader; 8 leaves headroom without blowing past the comp pipeline’s bind-group budget. Presets that exceed this cap are translated with the first 8 slots used and the rest falling through to the standard fallback path (sampler_main).

Functions

decompose_sampler_name 🔒

Decompose an HLSL user-sampler name into (logical_name, sampler_kind). The logical name is what the renderer looks up in the texture pool; the sampler kind is the WGSL sampler binding used at the textureSample call site.

is_builtin_sampler_name 🔒

true for sampler names the codegen wrapper already binds. Filtering these out keeps the user-texture plan focused on disk-loaded textures.

noise_sampler_for 🔒

For a noise sampler name embedded in one of the 4 MD2 variants, pick the sampler binding. Plain sampler_noise_lq (no prefix) defaults to the point+wrap variant — that’s how MD2 samples noise pixel-by-pixel when the author wants the raw value.

replace_texture_sampling_with_plan 🔒

Rewrite tex2D(<sampler>, <uv>) to a WGSL textureSample call against the (texture, sampler) pair resolved from the MD2 sampler name. Paren-balanced because the uv expression often contains nested calls (tex2D(s, uv + offset(t))).

resolve_tex2d_sampler 🔒

Resolve an MD2 sampler name to the (texture_binding, sampler_binding, recognised) triple the WGSL wrapper actually exposes. recognised = true suppresses the /*was: …*/ debug comment for bindings we routed deliberately (vs. the fallback case).

scan_user_samplers

Extract every sampler sampler_X; declaration from a MilkDrop comp shader HLSL and return the logical name (the part after sampler_) for each occurrence that isn’t already a built-in.

user_texture_binding_name

WGSL binding name for user-texture slot slot. The codegen wrapper declares var sampler_user_<n>_texture: texture_2d<f32> for each slot 0..MAX_USER_TEXTURE_SLOTS, and this is what the translator emits in textureSample(...) calls for plan-routed samplers.