wgsl_drill: defines and bindings used by your WGSL shaders

[nicopap]

This is a tool aimed at bevy contributors more than bevy users.

See the repo at: https://github.com/nicopap/wgsl_drill

With wgsl_drill, you can explore what bindings your shaders use in the bevy dialect of wgsl (naga oil).

Following is a copy/paste of the README because why write it twice 🤷

How to use

Example:

wgsl_drill -s prepass.wgsl -d SKINNED path/to/bevy/repo

$ cargo run  -- -d TONEMAP -s sprite.wgsl bevy/
group(0) binding(0) var<uniform> view: View;
group(1) binding(0) var sprite_texture: texture_2d<f32>;
group(1) binding(1) var sprite_sampler: sampler;

$ cargo run  -- --list-defines -s sprite.wgsl bevy/
[
    "0",
    "TONEMAPPING_PASS",
    "TONEMAP_IN_SHADER",
    "TONEMAP_METHOD_ACES_FITTED",
    "TONEMAP_METHOD_AGX",
    "TONEMAP_METHOD_BLENDER_FILMIC",
# … …

$ cargo run  -- -d TONEMAPPING_PASS -d TONEMAP_IN_SHADER -s sprite.wgsl bevy/
group(0) binding(0) var<uniform> view: View;
group(0) binding(3) var dt_lut_texture: texture_3d<f32>;
group(0) binding(4) var dt_lut_sampler: sampler;
group(1) binding(0) var sprite_texture: texture_2d<f32>;
group(1) binding(1) var sprite_sampler: sampler;

Full description

Usage: wgsl_drill [OPTIONS] [SOURCE_DIRECTORIES]...

Arguments:
 [SOURCE_DIRECTORIES]...
     A list of directories to recursively walk to find wgsl source files

Options:
 -s, --shaders <SHADERS>
     The shader files for which to print the bindings.
     
     Accepts one or more shaders. If none provided, display a list.

 -d, --defines <DEFINES>
     The `#define`s to enable. To display a list, use --list-defines

 -l, --list-defines
     Display a list of all possible defines accessible from provided shaders

 -h, --help
     Print help (see a summary with '-h')

How it works

It parses only a subset of the naga-oil WGSL dialect.
Notably:

• The #ifdef, #else, #define_import_path, #import CPP-like (C pre-processor)
  statements
• The WGSL line & block comments
• top-level resource variable declaration with a group(x) binding(y) attributes

We construct a rudimentary AST of all of those, and go through it, checking if
defines are available etc. We also read imports inline and conditionally.