WebGPU Shading Language Reflection Library
A WebGPU Shading Language parser and reflection library for Typescript and Javascript.
wgsl_reflect can parse a WGSL shader and analyze its contents, providing information about the shader. It can determine the bind group layout of the shader, resource bindings, uniform buffers, the members of a uniform buffer, their names, types, sizes, offsets into the buffer.
Usage
The wgsl_reflect.module.js file is a self-contained roll-up of the library that can be included in your project and imported with:
import { WgslReflect } from "./wgsl_reflect.module.js";
const reflect = new WgslReflect(shader_code);Try It Out
Documentation
class WgslReflect {
/// All top-level uniform vars in the shader.
uniforms: Array<VariableInfo>;
/// All top-level storage vars in the shader, including storage buffers and textures.
storage: Array<VariableInfo>;
/// All top-level texture vars in the shader;
textures: Array<VariableInfo>;
// All top-level sampler vars in the shader.
samplers: Array<VariableInfo>;
/// All top-level type aliases in the shader.
aliases: Array<AliasInfo>;
/// All top-level overrides in the shader.
overrides: Array<OverrideInfo> = [];
/// All top-level structs in the shader.
structs: Array<StructInfo>;
/// All entry functions in the shader: vertex, fragment, and/or compute.
entry: EntryFunctions;
// Get the bind groups used by the shader, bindGroups[group][binding].
getBindGroups(): Array<Array<VariableInfo>>;
}
enum ResourceType {
Uniform,
Storage,
Texture,
Sampler,
StorageTexture
}
class VariableInfo {
name: string; // The name of the variable
type: TypeInfo; // The type of the variable
group: number; // The binding group of the variable
binding: number; // The binding index of the variable
resourceType: ResourceType; // The resource type of the variable
access: string; // "", read, write, read_write
get isArray(): boolean; // True if it's an array type
get isStruct(): boolean; // True if it's a struct type
get isTemplate(): boolean; // True if it's a template type
get size(): number; // Size of the data, in bytes
get align(): number; // The alignment size if it's a struct, otherwise 0
get members(): Array<MemberInfo> | null; // The list of members if it's a struct, otherwise null
get format(): TypeInfo | null; // The format if it's a template or array, otherwise null
get count(): number; // The array size if it's an array, otherwise 0
get stride(): number; // The array stride if it's an array, otherwise 0
}
class TypeInfo {
name: string;
size: number; // Size of the data, in bytes
get isArray(): boolean;
get isStruct(): boolean;
get isTemplate(): boolean;
}
class StructInfo extends TypeInfo {
members: Array<MemberInfo>;
align: number;
}
class ArrayInfo extends TypeInfo {
format: TypeInfo;
count: number;
stride: number;
}
class TemplateInfo extends TypeInfo {
format: TypeInfo;
access: string; // "", read, write, read_write
}
class MemberInfo {
name: string;
type: TypeInfo;
offset: number;
size: number;
get isArray(): boolean;
get isStruct(): boolean;
get isTemplate(): boolean;
get align(): number;
get members(): Array<MemberInfo> | null;
get format(): TypeInfo | null;
get count(): number;
get stride(): number;
}
class AliasInfo {
name: string;
type: TypeInfo;
}
class FunctionInfo {
name: string;
stage: string | null;
inputs: Array<InputInfo>;
outputs: Array<OutputInfo>;
}
class InputInfo {
name: string;
type: TypeInfo | null;
locationType: string;
location: number | string;
interpolation: string | null;
}
class OutputInfo {
name: string;
type: TypeInfo | null;
locationType: string;
location: number | string;
}
class OverrideInfo {
name: string;
type: TypeInfo | null;
id: number;
}Examples
Calculate the bind group information in the shader:
import { WgslReflect } from "./wgsl_reflect.module.js";
const shader = `
struct ViewUniforms {
viewProjection: mat4x4<f32>
}
struct ModelUniforms {
model: mat4x4<f32>,
color: vec4<f32>,
intensity: f32
}
@binding(0) @group(0) var<uniform> viewUniforms: ViewUniforms;
@binding(1) @group(0) var<uniform> modelUniforms: ModelUniforms;
@binding(2) @group(0) var u_sampler: sampler;
@binding(3) @group(0) var u_texture: texture_2d<f32>;
struct VertexInput {
@location(0) a_position: vec3<f32>,
@location(1) a_normal: vec3<f32>,
@location(2) a_color: vec4<f32>,
@location(3) a_uv: vec2<f32>
}
struct VertexOutput {
@builtin(position) Position: vec4<f32>,
@location(0) v_position: vec4<f32>,
@location(1) v_normal: vec3<f32>,
@location(2) v_color: vec4<f32>,
@location(3) v_uv: vec2<f32>
}
@vertex
fn main(input: VertexInput) -> VertexOutput {
var output: VertexOutput;
output.Position = viewUniforms.viewProjection * modelUniforms.model * vec4<f32>(input.a_position, 1.0);
output.v_position = output.Position;
output.v_normal = input.a_normal;
output.v_color = input.a_color * modelUniforms.color * modelUniforms.intensity;
output.v_uv = input.a_uv;
return output;
}`;
const reflect = new WgslReflect(shader);
console.log(reflect.functions.length); // 1
console.log(reflect.structs.length); // 4
console.log(reflect.uniforms.length); // 2
// Shader entry points
console.log(reflect.entry.vertex.length); // 1, there is 1 vertex entry function.
console.log(reflect.entry.fragment.length); // 0, there are no fragment entry functions.
console.log(reflect.entry.compute.length); // 0, there are no compute entry functions.
console.log(reflect.entry.vertex[0].name); // "main", the name of the vertex entry function.
// Vertex shader inputs
console.log(reflect.entry.vertex[0].inputs.length); // 4, inputs to "main"
console.log(reflect.entry.vertex[0].inputs[0].name); // "a_position"
console.log(reflect.entry.vertex[0].inputs[0].location); // 0
console.log(reflect.entry.vertex[0].inputs[0].locationType); // "location" (can be "builtin")
console.log(reflect.entry.vertex[0].inputs[0].type.name); // "vec3"
console.log(reflect.entry.vertex[0].inputs[0].type.format.name); // "f32"
// Gather the bind groups used by the shader.
const groups = reflect.getBindGroups();
console.log(groups.length); // 1
console.log(groups[0].length); // 4, bindings in group(0)
console.log(groups[0][1].resourceType); // ResourceType.Uniform, the type of resource at group(0) binding(1)
console.log(groups[0][1].size); // 108, the size of the uniform buffer.
console.log(groups[0][1].members.length); // 3, members in ModelUniforms.
console.log(groups[0][1].members[0].name); // "model", the name of the first member in the uniform buffer.
console.log(groups[0][1].members[0].offset); // 0, the offset of 'model' in the uniform buffer.
console.log(groups[0][1].members[0].size); // 64, the size of 'model'.
console.log(groups[0][1].members[0].type.name); // "mat4x4", the type of 'model'.
console.log(groups[0][1].members[0].type.format.name); // "f32", the format of the mat4x4.
console.log(groups[0][2].resourceType); // ResourceType.Sampler
console.log(groups[0][3].resourceType); // ResourceType.Texture
console.log(groups[0][3].type.name); // "texture_2d"
console.log(groups[0][3].type.format.name); // "f32"Calculate the member information for a uniform buffer block:
import { WgslReflect } from "./wgsl_reflect.module.js";
// WgslReflect can calculate the size and offset for members of a uniform buffer block.
const shader = `
struct A { // align(8) size(32)
u: f32, // offset(0) align(4) size(4)
v: f32, // offset(4) align(4) size(4)
w: vec2<f32>, // offset(8) align(8) size(8)
@size(16) x: f32 // offset(16) align(4) size(16)
}
struct B { // align(16) size(208)
a: vec2<f32>, // offset(0) align(8) size(8)
// -- implicit member alignment padding -- // offset(8) size(8)
b: vec3<f32>, // offset(16) align(16) size(12)
c: f32, // offset(28) align(4) size(4)
d: f32, // offset(32) align(4) size(4)
// -- implicit member alignment padding -- // offset(36) size(12)
@align(16) e: A, // offset(48) align(16) size(32)
f: vec3<f32>, // offset(80) align(16) size(12)
// -- implicit member alignment padding -- // offset(92) size(4)
g: @stride(32) array<A, 3>, // offset(96) align(8) size(96)
h: i32, // offset(192) align(4) size(4)
// -- implicit struct size padding -- // offset(196) size(12)
}
@group(0) @binding(0)
var<uniform> uniform_buffer: B;`;
const reflect = new WgslReflect(shader);
const u = reflect.uniforms[0];
console.log(u.size); // 208, the size of the uniform buffer in bytes
console.log(u.group); // 0
console.log(u.binding); // 0
console.log(u.members.length); // 7, members in B
console.log(u.members[0].name); // "a"
console.log(u.members[0].offset); // 0, the offset of 'a' in the buffer
console.log(u.members[0].size); // 8, the size of 'a' in bytes
console.log(u.members[0].type.name); // "vec2", the type of 'a'
console.log(u.members[0].type.format.name); // "f32", the format of the vec2.
console.log(u.members[4].name); // "e"
console.log(u.members[4].offset); // 48, the offset of 'e' in the buffer
console.log(u.members[4].size); // 32, the size of 'e' in the buffer