webgpu-syntax-render-pipeline

WebGPU Render Pipeline

Create an immutable GPURenderPipeline that captures vertex layout, fragment targets, blending, primitive topology, and depth-stencil state without triggering WebGPU pipeline-creation validation errors.

Quick Reference

WebGPU 1.0-stable baseline: Chrome 113+, Safari 26+, Firefox 141+.

device.createRenderPipeline(descriptor) returns a GPURenderPipeline. device.createRenderPipelineAsync(descriptor) returns Promise<GPURenderPipeline> and compiles off the content timeline.

Descriptor field	Required	Purpose
label	No	Diagnostic name quoted in GPUError messages
layout	Yes	GPUPipelineLayout or the string "auto"
vertex	Yes	Vertex stage: shader module, entry point, vertex buffer layouts
primitive	No	Topology, strip index format, winding, cull mode
depthStencil	No	Depth-stencil attachment format and test/write state
multisample	No	MSAA sample count, coverage mask
fragment	No	Fragment stage: shader module, entry point, color targets

vertex is { module, entryPoint?, constants?, buffers? }. buffers is an array of GPUVertexBufferLayout: { arrayStride, stepMode?, attributes }. Each attribute is { shaderLocation, offset, format }.

fragment is { module, entryPoint?, constants?, targets }. Each target is { format, blend?, writeMask? }. blend is { color, alpha } with each side { srcFactor?, dstFactor?, operation? }.

primitive is { topology?, stripIndexFormat?, frontFace?, cullMode? }. depthStencil is { format, depthWriteEnabled?, depthCompare?, stencilFront?, stencilBack?, stencilReadMask?, stencilWriteMask?, depthBias?, depthBiasSlopeScale?, depthBiasClamp? }. multisample is { count?, mask?, alphaToCoverageEnabled? }.

The layout field is "auto" (implicit per-pipeline layouts) or an explicit GPUPipelineLayout. See webgpu-core-pipeline-architecture for the layout choice.

Full field tables, every enum value, and defaults: see references/methods.md.

Decision Tree

Vertex data: vertex buffers or vertex-pulling

Drawing a fixed-size full-screen pass (3 vertices)?
  YES -> generate vertices in WGSL from @builtin(vertex_index); omit vertex.buffers
  NO  -> need per-vertex mesh data
         Data accessed only as sequential vertex stream?
           YES -> vertex.buffers with GPUVertexBufferLayout entries
           NO (random index, compute reads same data) -> bind as storage buffer
               and read via @builtin(vertex_index) in WGSL (vertex-pulling)

Blend setup

Fragment output fully replaces the target (opaque geometry)?
  YES -> omit blend entirely on the target
  NO  -> alpha-composite over existing pixels
         Source alpha already multiplied into RGB (premultiplied)?
           YES -> color { srcFactor "one", dstFactor "one-minus-src-alpha" }
           NO  -> color { srcFactor "src-alpha", dstFactor "one-minus-src-alpha" }
         alpha { srcFactor "one", dstFactor "one-minus-src-alpha", operation "add" }

Depth setup

Pipeline draws into a render pass that has a depthStencilAttachment?
  NO  -> omit depthStencil entirely
  YES -> set depthStencil.format to the EXACT depth attachment texture format
         Geometry should occlude what is behind it?
           YES -> depthWriteEnabled true, depthCompare "less"
           NO (transparent overlay, read-only depth) -> depthWriteEnabled false,
               depthCompare "less-equal", and depthReadOnly true on the attachment

Core Patterns

ALWAYS match the fragment target format to the color attachment format

The format of each fragment.targets[i] MUST equal the GPUTextureView format of colorAttachments[i] in the render pass. For the canvas, ALWAYS use the value from navigator.gpu.getPreferredCanvasFormat() for both.

const format = navigator.gpu.getPreferredCanvasFormat();
context.configure({ device, format });
const pipeline = device.createRenderPipeline({
  label: "triangle",
  layout: "auto",
  vertex: { module, entryPoint: "vs" },
  fragment: { module, entryPoint: "fs", targets: [{ format }] },
});

ALWAYS match vertex attribute offset and shaderLocation to the WGSL @location

Each attribute shaderLocation MUST equal a WGSL @location(n) on a vertex-stage input. The offset is the byte offset of that attribute inside one vertex; the format component count and type MUST match the WGSL type. arrayStride is the total byte size of one vertex.

// WGSL: @vertex fn vs(@location(0) pos: vec3f, @location(1) uv: vec2f)
vertex: {
  module, entryPoint: "vs",
  buffers: [{
    arrayStride: 20, // 3*4 + 2*4
    attributes: [
      { shaderLocation: 0, offset: 0,  format: "float32x3" },
      { shaderLocation: 1, offset: 12, format: "float32x2" },
    ],
  }],
}

ALWAYS set depthStencil.format to the depth attachment's exact texture format

If the render pass has a depthStencilAttachment, the pipeline MUST declare depthStencil with a format equal to that depth texture's format. NEVER omit depthStencil when the pass uses a depth attachment.

depthStencil: {
  format: "depth24plus",
  depthWriteEnabled: true,
  depthCompare: "less",
}

ALWAYS create the pipeline once and reuse it every frame

GPURenderPipeline objects are immutable and expensive to build. Create them at load time and reuse the same object across all frames. NEVER call createRenderPipeline inside requestAnimationFrame.

ALWAYS set stripIndexFormat for strip topologies used with indexed draws

When topology is "line-strip" or "triangle-strip" AND the pipeline is used with drawIndexed, stripIndexFormat MUST be set and MUST equal the index format passed to setIndexBuffer ("uint16" or "uint32"). For list topologies, omit stripIndexFormat.

ALWAYS keep multisample.count equal to the attachment sampleCount

multisample.count MUST equal the sampleCount of every color and depth attachment texture. Valid values are 1 and 4. A mismatch fails pipeline or render-pass validation.

Common Anti-Patterns

Fragment target format not matching the attachment format

NEVER hardcode "bgra8unorm" for a canvas target. The preferred canvas format is platform-dependent. WHY it fails: pipeline creation succeeds, but beginRenderPass or the draw call fails validation because the pipeline target format does not equal the color attachment view format, producing a blank canvas or a validation error.

Vertex attribute offset or shaderLocation not matching WGSL

NEVER set offset, shaderLocation, or format without checking the WGSL vertex input. WHY it fails: a shaderLocation with no matching WGSL @location fails validation; a wrong offset or format reads the wrong bytes and the mesh renders as garbage geometry with no error.

Recreating the pipeline every frame

NEVER call createRenderPipeline inside the render loop. WHY it fails: it is not a validation error, but each call recompiles and re-validates shader and state, causing severe per-frame jank and dropped frames.

Critical Warnings

• NEVER omit depthStencil when the render pass has a depthStencilAttachment; the pipeline-versus-attachment depth mismatch fails validation.
• NEVER set depthStencil.format to a value different from the depth attachment texture format.
• NEVER set a fragment.targets[i].format that differs from the matching colorAttachments[i] view format.
• NEVER use a strip topology with drawIndexed without a matching stripIndexFormat.
• NEVER set multisample.count to a value other than the attachment sampleCount.
• NEVER call device.queue as a function; it is a read-only property.
• NEVER reuse an "auto"-layout bind group across pipelines; it binds to the one pipeline that produced its layout.

Reference Files

• references/methods.md : complete GPURenderPipelineDescriptor field tables, GPUVertexBufferLayout, GPUBlendState, and every enum value with defaults.
• references/examples.md : verified working code for a minimal triangle pipeline and a pipeline with vertex buffers, blending, and depth.
• references/anti-patterns.md : pipeline mistakes with WHY-it-fails explanations.

Related skills: webgpu-core-pipeline-architecture (layout choice, immutability), webgpu-syntax-bind-groups (explicit layouts and resource binding), webgpu-wgsl-vertex-shaders (vertex stage and @location matching), webgpu-wgsl-fragment-shaders (fragment outputs and MRT), webgpu-impl-render-targets (render pass attachments and formats).