WebGPU Shading Language

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WebGPU Shading Language
Latest versionW3C Candidate recommendation
(As of 2025)
Organization

Committee

  • GPU for the Web WG
  • GPU for the Web CG

Domain

WebGPU Shading Language (WGSL) is a high-level shading language with a syntax inspired by Rust. It was initially developed by the W3C GPU for the Web Community Group to provide developers with a modern, safe, and portable shading language for the WebGPU API. WGSL is designed to be compiled to SPIR-V or other intermediate representations, enabling execution across different graphics hardware while maintaining security and portability requirements essential for web applications.

Background

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Traditional web graphics programming relied on WebGL, which used GLSL ES for shader programming. However, as web applications became more sophisticated and demanded better performance, the need for a more modern graphics API became apparent. WebGPU was developed to address these needs, providing access to modern GPU features while maintaining the security and portability requirements of the web platform.

Shader types

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WGSL supports multiple shader stages:

Vertex shaders

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Process individual vertices, transforming positions and computing per-vertex data for rasterization.

Vertex shader example

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/* Transforms incoming positions by an MVP matrix and    passes per-vertex color through to the fragment stage. */  struct VertexInput {   @location(0) position : vec3<f32>,   @location(1) color : vec3<f32>, };  struct VertexOutput {   @builtin(position) clip_position : vec4<f32>,   @location(0) color : vec3<f32>, };  @group(0) @binding(0) var<uniform> mvp : mat4x4<f32>;  @vertex fn main(v_in : VertexInput) -> VertexOutput {   var v_out : VertexOutput;   v_out.clip_position = mvp * vec4<f32>(v_in.position, 1.0);   v_out.color = v_in.color;   return v_out; } 

Fragment shaders

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Execute for each fragment, computing final color values and depth information.

Fragment shader example

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/* Receives interpolated color and    writes it to the framebuffer. */  @fragment fn main(@location(0) color : vec3f) -> @location(0) vec4f {   return vec4<f32>(color, 1.0); // add opaque alpha } 

Compute shaders

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Perform general-purpose parallel computations on the GPU, supporting various algorithms beyond traditional graphics rendering.

Compute shader example

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/* Doubles every element in an input buffer and    stores the result in an output buffer. */  struct Params {   element_count : u32, };  @group(0) @binding(0) var<storage, read> in_data : array<f32>; @group(0) @binding(1) var<storage, read_write> out_data : array<f32>; @group(0) @binding(2) var<uniform> params : Params;  @compute @workgroup_size(64) fn main(@builtin(global_invocation_id) gid : vec3<u32>) {   let idx : u32 = gid.x;   if (idx >= params.element_count) {     return;   }   out_data[idx] = in_data[idx] * 2.0; } 

See also

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  • WebGPU, the graphics API that uses WGSL
  • SPIR-V, intermediate shader representation
  • W3C, the organization developing WebGPU and WGSL

Other shading languages

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References

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  1. ^ "WebGPU Shading Language". W3C. Retrieved 2024-01-20.
  2. ^ "WebGPU Explainer". W3C GPU for the Web Community Group. Retrieved 2024-01-20.
  3. ^ "WebGPU". W3C. Retrieved 2024-01-20.