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https://github.com/brendan-duncan/wgsl_reflect

A WebGPU Shading Language parser and reflection library for Javascript.
https://github.com/brendan-duncan/wgsl_reflect

javascript webgpu wgsl

Last synced: 5 days ago
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A WebGPU Shading Language parser and reflection library for Javascript.

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README 

        
# 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



From NPM

```

npm install wgsl_reflect

```



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:



```javascript

import { WgslReflect } from "wgsl_reflect/wgsl_reflect.module.js";

const reflect = new WgslReflect(shader_code);

```



## Example



[WGSL Reflect Example](https://brendan-duncan.github.io/wgsl_reflect/example.html)



## Documentation



```javascript

// A collection of gathered reflection information about the shader.

class WgslReflect {

  // All top-level uniform vars in the shader.

  uniforms: Array;

  // All top-level storage vars in the shader, including storage buffers and textures.

  storage: Array;

  // All top-level texture vars in the shader;

  textures: Array;

  // All top-level sampler vars in the shader.

  samplers: Array;

  // All top-level type aliases in the shader.

  aliases: Array;

  // All top-level overrides in the shader.

  overrides: Array = [];

  // All top-level structs in the shader.

  structs: Array;

  // All entry functions in the shader: vertex, fragment, and/or compute.

  entry: EntryFunctions;

  // All functions in the shader, including entry functions.

  functions: Array;



  // Parse the given WGSL shader code, populating the info properties of this class.

  constructor(shader?: string);



  // Parse the given WGSL shader code, adding to the info properties of this class.

  update(shader: string);



  // Find a resource by its group and binding.

  findResource(group: number, binding: number): VariableInfo | null;



  // Get the bind groups used by the shader, bindGroups[group][binding].

  getBindGroups(): Array>;

}



// A variable can be a resource passed to the shader, of this type.

enum ResourceType {

  Uniform, // Uniform buffer

  Storage, // Storage buffer

  Texture, // Texture

  Sampler, // Sampler to sample a Texture

  StorageTexture // StorageTexture

}



// Information about a resource variable. This will be a uniform buffer,

// storage buffer, texture, sampler, or storageTexture.

class VariableInfo {

  // The name of the variable.

  name: string;

  // The type of the variable.

  type: TypeInfo;

  // The binding group of the variable.

  group: number;

  // The binding index of the variable.

  binding: number;

  // The resource type of the variable.

  resourceType: ResourceType;

  // The access mode of the variable, can be: "", "read", "write", or "read_write".

  access: string;



  // True if the type of the variable is an array.

  get isArray(): boolean;

  // True if the type of the variable is a struct.

  get isStruct(): boolean;

  // True if the type of the variable is a template.

  get isTemplate(): boolean;

  // Size of the data pointed to by the variable, in bytes.

  get size(): number;

  // The alignment size if the variable type is a struct, otherwise 0.

  get align(): number;

  // The list of members of the variable type if it's a struct, otherwise null.

  get members(): Array | null;

  // The format if the type is a template or array, otherwise null.

  get format(): TypeInfo | null;

  // The array size if it's an array, otherwise 0.

  get count(): number;

  // The array stride if it's an array, otherwise 0.

  get stride(): number;

}



// Base class for variable types.

class TypeInfo {

  // The name of the type declaration.

  name: string;

  // Size of the data used by this type, in bytes

  size: number;



  // True if this is an array type, can be cast to ArrayInfo.

  get isArray(): boolean;

  // True if this is a struct type, can be cast to StructInfo.

  get isStruct(): boolean;

  // True if this is a template type, can be cast to TemplateInfo.

  get isTemplate(): boolean;

}



// Information about struct type declarations

class StructInfo extends TypeInfo {

  // The list of members of the struct.

  members: Array;

  // The alignment, in bytes, for the structs data.

  align: number;

  // The line in the shader code the type declaration starts at.

  startLine: number;

  // The line in the shader code the type declaration ends at.

  endLine: number;

  // True if the struct is used by a uniform, storage, or directly or indirectly by an entry function.

  inUse: boolean;

}



// Information about array type declarations

class ArrayInfo extends TypeInfo {

  // The format for the data in the array

  format: TypeInfo;

  // The number of elements in the array

  count: number;

  // The stride, in bytes, of the array. This is the alignment of elements in the array data, including padding.

  stride: number;

}



// Information about template type declarations

class TemplateInfo extends TypeInfo {

  // The format type of the template

  format: TypeInfo;

  // Access mode of the template, which can be: "", "read", "write", or "read_write"

  access: string;

}



// Information about a struct member declaration.

class MemberInfo {

  // The name of the struct member.

  name: string;

  // The type of the struct member.

  type: TypeInfo;

  // The offset, in bytes, of the member from the start of the struct data.

  offset: number;

  // The size of the members data, in bytes.

  size: number;



  // True if the member type is an array and can be cast to ArrayInfo

  get isArray(): boolean;

  // True if the member type is a struct and can be cast to StructInfo.

  get isStruct(): boolean;

  // True if the member type is a template and can be cast to TemplateInfo.

  get isTemplate(): boolean;

  // If the member type is a struct, the alignment of the struct in bytes, otherwise 0.

  get align(): number;

  // If the member type is a struct, the members of the struct, otherwise null.

  get members(): Array | null;

  // If the member type is an array or template, the format of the type, otherwise null.

  get format(): TypeInfo | null;

  // If the member type is an array, the number of elements in the array, otherwise 0.

  get count(): number;

  // If the member type is an array, the stride of the array elements in bytes, otherwise 0.

  get stride(): number;

}



// Information about type aliases declared in the shader.

class AliasInfo {

  // The name of the alias type.

  name: string;

  // The information of the type being aliased.

  type: TypeInfo;

}



// The lists of shader vertex, fragment, and/or compute entry functions.

class EntryFunctions {

  // Any vertex entry points in the shader.

  vertex: Array;

  // Any fragment entry points in the shader.

  fragment: Array;

  // Any compute entry points in the shader.

  compute: Array;

}



// Information about a function in the shader.

class FunctionInfo {

  // The name of the function.

  name: string;

  // If the function is an entry function, which stage is it for, either "vertex", "fragment", "compute", or null if none.

  stage: string | null;

  // The list of shader inputs used by the function, which includes vertex and index buffers.

  inputs: Array;

  // The list of shader outputs updated by the function, such as inter-stage buffers.

  outputs: Array;

  // The arguments of the function.

  arguments: Array;

  // The return type of the function, or null if the function returns void.

  returnType: TypeInfo | null;

  // The resources used by the function, including uniform buffers, storage buffers, textures,

  // samplers, and storage textures.

  resources: Array;

  // The line in the shader the function definition starts at.

  startLine: number;

  // The line in the shader the function definition ends at.

  endLine: number;

  // True if called directly or indirectly by an entry function.

  inUse: boolean;

  // All custom functions called directly by this function.

  calls: Set;

}



// Information about a shader inputs.

class InputInfo {

  // The name of the input variable

  name: string;

  // The type of the input variable.

  type: TypeInfo | null;

  // The location type of the input.

  locationType: string;

  // The location index or built-in location name.

  location: number | string;

  // The interpolation mode of the binding.

  interpolation: string | null;

}



// Information about a shader output.

class OutputInfo {

  // The name of the output variable.

  name: string;

  // The type of the output variable.

  type: TypeInfo | null;

  // The location type of the output.

  locationType: string;

  // The location index or built-in location name.

  location: number | string;

}



// Information about override constants in the shader.

class OverrideInfo {

  // The name of the override constant.

  name: string;

  // The type of the override constant.

  type: TypeInfo | null;

  // A unique ID given to the override constant.

  id: number;

}



// Information about a function argument.

class ArgumentInfo {

  // Then ame of the argument variable.

  name: string;

  // The type of the argument variable.

  type: TypeInfo;

}

```



## Examples



Calculate the bind group information in the shader:



```javascript

import { WgslReflect } from "./wgsl_reflect.module.js";



const shader = `

struct ViewUniforms {

    viewProjection: mat4x4

}



struct ModelUniforms {

    model: mat4x4,

    color: vec4,

    intensity: f32

}



@binding(0) @group(0) var viewUniforms: ViewUniforms;

@binding(1) @group(0) var modelUniforms: ModelUniforms;

@binding(2) @group(0) var u_sampler: sampler;

@binding(3) @group(0) var u_texture: texture_2d;



struct VertexInput {

    @location(0) a_position: vec3,

    @location(1) a_normal: vec3,

    @location(2) a_color: vec4,

    @location(3) a_uv: vec2

}



struct VertexOutput {

    @builtin(position) Position: vec4,

    @location(0) v_position: vec4,

    @location(1) v_normal: vec3,

    @location(2) v_color: vec4,

    @location(3) v_uv: vec2

}



@vertex

fn main(input: VertexInput) -> VertexOutput {

    var output: VertexOutput;

    output.Position = viewUniforms.viewProjection * modelUniforms.model * vec4(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.



console.log(reflect.entry.vertex[0].resources.length); // 2, main uses modelUniforms and viewUniforms resource bindings.

console.log(reflect.entry.vertex[0].resources[0].name); // viewUniforms

console.log(reflect.entry.vertex[0].resources[1].name); // modelUniforms



// 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); // 96, 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:



```javascript

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,                              // offset(8)   align(8)  size(8)

    @size(16) x: f32                          // offset(16)  align(4)  size(16)

}



struct B {                                     //             align(16) size(208)

    a: vec2,                              // offset(0)   align(8)  size(8)

    // -- implicit member alignment padding -- // offset(8)             size(8)

    b: vec3,                              // 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,                              // offset(80)  align(16) size(12)

    // -- implicit member alignment padding -- // offset(92)            size(4)

    g: @stride(32) array,                // 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_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); // 8, 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

```