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WebGPU fundamentals for high-performance canvas rendering. Covers device initialization, buffer management, WGSL shaders, render pipelines, compute shaders, and web component integration. Use when building GPU-accelerated graphics, particle systems, or compute-intensive visualizations.

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SKILL.md

name webgpu-canvas
description WebGPU fundamentals for high-performance canvas rendering. Covers device initialization, buffer management, WGSL shaders, render pipelines, compute shaders, and web component integration. Use when building GPU-accelerated graphics, particle systems, or compute-intensive visualizations.
allowed-tools Read, Write, Edit, Glob, Grep

WebGPU Canvas Development

Production patterns for WebGPU rendering integrated with web components. This skill covers device initialization, buffer management, shader development, and resource lifecycle management.

Related Skills

  • web-components: Component lifecycle for WebGPU cleanup, handleEvent pattern
  • javascript: Async initialization, AbortController, memory management
  • ux-accessibility: Reduced motion, canvas ARIA labels
  • ux-animation-motion: Animation timing, frame-rate independence
  • ipad-pro-design: Touch interactions, device pixel ratio

WebGPU Browser Support (2025)

Browser Status Notes
Chrome 113+ Full support Default enabled
Edge 113+ Full support Chromium-based
Safari 18+ Full support macOS/iOS
Firefox 139+ Behind flag Nightly only
// Feature detection
if (!navigator.gpu) {
  console.warn('WebGPU not supported, falling back to Canvas 2D');
  return;
}

Rule 1: Initialize Once, Reuse Forever

Adapter and device acquisition is expensive. Initialize once at startup, store references.

/**
 * WebGPU singleton for adapter/device management
 *
 * Skills applied:
 * - javascript: Singleton pattern, async initialization
 * - web-components: Integration with component lifecycle
 */
class WebGPUContext {
  static #adapter = null;
  static #device = null;
  static #initialized = false;
  static #initPromise = null;

  static async initialize() {
    // Prevent multiple initialization attempts
    if (this.#initPromise) return this.#initPromise;

    this.#initPromise = this.#doInitialize();
    return this.#initPromise;
  }

  static async #doInitialize() {
    if (this.#initialized) return { adapter: this.#adapter, device: this.#device };

    // Check support
    if (!navigator.gpu) {
      throw new Error('WebGPU not supported in this browser');
    }

    // Request adapter with fallback
    this.#adapter = await navigator.gpu.requestAdapter({
      powerPreference: 'high-performance' // or 'low-power' for battery
    });

    if (!this.#adapter) {
      throw new Error('No WebGPU adapter found');
    }

    // Request device with explicit limits
    this.#device = await this.#adapter.requestDevice({
      requiredFeatures: [],
      requiredLimits: {
        maxBindGroups: 4,
        maxUniformBufferBindingSize: 65536,
        maxStorageBufferBindingSize: 134217728 // 128MB
      }
    });

    // Handle device loss
    this.#device.lost.then((info) => {
      console.error('WebGPU device lost:', info.message);
      this.#initialized = false;
      this.#initPromise = null;

      // Attempt recovery if not destroyed intentionally
      if (info.reason !== 'destroyed') {
        this.initialize();
      }
    });

    this.#initialized = true;
    return { adapter: this.#adapter, device: this.#device };
  }

  static get adapter() { return this.#adapter; }
  static get device() { return this.#device; }
  static get initialized() { return this.#initialized; }
}

export { WebGPUContext };

Why: GPU device creation involves driver communication, memory allocation, and state setup. Multiple devices waste VRAM and cause performance issues.


Rule 2: Configure Canvas Context Correctly

Canvas context configuration determines swap chain format, color space, and presentation mode.

/**
 * Configure WebGPU canvas context
 *
 * @param {HTMLCanvasElement} canvas - Target canvas element
 * @param {GPUDevice} device - WebGPU device
 * @returns {GPUCanvasContext} Configured context
 */
function configureCanvasContext(canvas, device) {
  const context = canvas.getContext('webgpu');

  if (!context) {
    throw new Error('Failed to get WebGPU context from canvas');
  }

  // Get preferred format for this adapter
  const format = navigator.gpu.getPreferredCanvasFormat();

  context.configure({
    device,
    format,
    alphaMode: 'premultiplied', // or 'opaque' if no transparency needed
    colorSpace: 'srgb',         // Standard color space
    usage: GPUTextureUsage.RENDER_ATTACHMENT | GPUTextureUsage.COPY_SRC
  });

  return context;
}

// Handle device pixel ratio for crisp rendering
function resizeCanvasToDisplaySize(canvas) {
  const dpr = window.devicePixelRatio || 1;
  const displayWidth = Math.floor(canvas.clientWidth * dpr);
  const displayHeight = Math.floor(canvas.clientHeight * dpr);

  if (canvas.width !== displayWidth || canvas.height !== displayHeight) {
    canvas.width = displayWidth;
    canvas.height = displayHeight;
    return true; // Canvas was resized
  }
  return false;
}

Alpha Mode Selection

Mode Use Case
'opaque' Full-screen renders, no transparency
'premultiplied' Compositing with HTML (default)

Why: Wrong alpha mode causes artifacts when compositing WebGPU content with HTML elements.


Rule 3: Buffer Creation Patterns

Buffers are GPU memory allocations. Choose the right usage flags and update strategy.

Buffer Usage Flags

Flag Purpose
GPUBufferUsage.VERTEX Vertex data (positions, UVs, normals)
GPUBufferUsage.INDEX Index data for indexed drawing
GPUBufferUsage.UNIFORM Small, frequently updated data (matrices)
GPUBufferUsage.STORAGE Large read/write data (compute, particles)
GPUBufferUsage.COPY_SRC Source for copy operations
GPUBufferUsage.COPY_DST Destination for writes
GPUBufferUsage.MAP_READ CPU-readable (readback)
GPUBufferUsage.MAP_WRITE CPU-writable (staging)

Vertex Buffer

function createVertexBuffer(device, data) {
  const buffer = device.createBuffer({
    size: data.byteLength,
    usage: GPUBufferUsage.VERTEX | GPUBufferUsage.COPY_DST,
    mappedAtCreation: true
  });

  // Write data while mapped
  new Float32Array(buffer.getMappedRange()).set(data);
  buffer.unmap();

  return buffer;
}

// Usage
const positions = new Float32Array([
  // Triangle: x, y, z for each vertex
  0.0,  0.5, 0.0,
 -0.5, -0.5, 0.0,
  0.5, -0.5, 0.0
]);

const vertexBuffer = createVertexBuffer(device, positions);

Uniform Buffer

function createUniformBuffer(device, size) {
  return device.createBuffer({
    size: Math.max(size, 16), // Minimum 16 bytes for alignment
    usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST
  });
}

// Update uniform buffer
function updateUniformBuffer(device, buffer, data) {
  device.queue.writeBuffer(buffer, 0, data);
}

// Usage: MVP matrix (64 bytes = 16 floats)
const uniformBuffer = createUniformBuffer(device, 64);
const mvpMatrix = new Float32Array(16);
// ... compute matrix
updateUniformBuffer(device, uniformBuffer, mvpMatrix);

Storage Buffer (Compute/Particles)

function createStorageBuffer(device, size, initialData = null) {
  const buffer = device.createBuffer({
    size,
    usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST | GPUBufferUsage.COPY_SRC,
    mappedAtCreation: !!initialData
  });

  if (initialData) {
    new Float32Array(buffer.getMappedRange()).set(initialData);
    buffer.unmap();
  }

  return buffer;
}

// Particle system: position (vec3) + velocity (vec3) + life (f32) = 7 floats per particle
const PARTICLE_COUNT = 10000;
const PARTICLE_STRIDE = 7 * 4; // 28 bytes
const particleBuffer = createStorageBuffer(device, PARTICLE_COUNT * PARTICLE_STRIDE);

Why: Correct usage flags enable GPU optimizations. Missing COPY_DST prevents updates; missing STORAGE prevents compute access.


Rule 4: WGSL Shader Fundamentals

WGSL (WebGPU Shading Language) is the shader language for WebGPU. Write type-safe, GPU-optimized code.

Basic Vertex Shader

// Uniforms bound to group 0, binding 0
struct Uniforms {
  mvp: mat4x4<f32>,
  time: f32,
}

@group(0) @binding(0) var<uniform> uniforms: Uniforms;

// Vertex input
struct VertexInput {
  @location(0) position: vec3<f32>,
  @location(1) color: vec3<f32>,
}

// Vertex output (to fragment shader)
struct VertexOutput {
  @builtin(position) position: vec4<f32>,
  @location(0) color: vec3<f32>,
}

@vertex
fn vs_main(input: VertexInput) -> VertexOutput {
  var output: VertexOutput;
  output.position = uniforms.mvp * vec4<f32>(input.position, 1.0);
  output.color = input.color;
  return output;
}

Basic Fragment Shader

struct FragmentInput {
  @location(0) color: vec3<f32>,
}

@fragment
fn fs_main(input: FragmentInput) -> @location(0) vec4<f32> {
  return vec4<f32>(input.color, 1.0);
}

Compute Shader (Particle Update)

struct Particle {
  position: vec3<f32>,
  velocity: vec3<f32>,
  life: f32,
}

struct SimParams {
  deltaTime: f32,
  gravity: vec3<f32>,
}

@group(0) @binding(0) var<uniform> params: SimParams;
@group(0) @binding(1) var<storage, read_write> particles: array<Particle>;

@compute @workgroup_size(256)
fn cs_main(@builtin(global_invocation_id) id: vec3<u32>) {
  let index = id.x;

  // Bounds check
  if (index >= arrayLength(&particles)) {
    return;
  }

  var p = particles[index];

  // Skip dead particles
  if (p.life <= 0.0) {
    return;
  }

  // Update physics
  p.velocity += params.gravity * params.deltaTime;
  p.position += p.velocity * params.deltaTime;
  p.life -= params.deltaTime;

  particles[index] = p;
}

WGSL Type Reference

WGSL Type Size Description
f32 4 bytes 32-bit float
i32 4 bytes 32-bit signed int
u32 4 bytes 32-bit unsigned int
vec2<f32> 8 bytes 2D float vector
vec3<f32> 12 bytes 3D float vector
vec4<f32> 16 bytes 4D float vector
mat4x4<f32> 64 bytes 4x4 float matrix

Alignment rules: vec3 aligns to 16 bytes in uniform buffers. Use vec4 or pad manually.


Rule 5: Render Pipeline Creation

Pipelines define the complete render state. Create once, reuse every frame.

async function createRenderPipeline(device, format, shaderCode) {
  const shaderModule = device.createShaderModule({
    code: shaderCode
  });

  // Check for compilation errors
  const compilationInfo = await shaderModule.getCompilationInfo();
  for (const message of compilationInfo.messages) {
    if (message.type === 'error') {
      throw new Error(`Shader error: ${message.message}`);
    }
    console.warn(`Shader ${message.type}: ${message.message}`);
  }

  return device.createRenderPipeline({
    layout: 'auto', // Auto-generate bind group layout
    vertex: {
      module: shaderModule,
      entryPoint: 'vs_main',
      buffers: [
        {
          arrayStride: 24, // 6 floats: position (3) + color (3)
          attributes: [
            { shaderLocation: 0, offset: 0, format: 'float32x3' },  // position
            { shaderLocation: 1, offset: 12, format: 'float32x3' }  // color
          ]
        }
      ]
    },
    fragment: {
      module: shaderModule,
      entryPoint: 'fs_main',
      targets: [{ format }]
    },
    primitive: {
      topology: 'triangle-list',
      cullMode: 'back',
      frontFace: 'ccw'
    },
    depthStencil: {
      format: 'depth24plus',
      depthWriteEnabled: true,
      depthCompare: 'less'
    }
  });
}

Vertex Format Reference

Format Components Bytes
'float32' 1 4
'float32x2' 2 8
'float32x3' 3 12
'float32x4' 4 16
'uint32' 1 4
'sint32' 1 4
'uint8x4' 4 4
'unorm8x4' 4 4

Rule 6: Bind Groups and Resources

Bind groups connect shader bindings to actual GPU resources.

function createBindGroup(device, pipeline, uniformBuffer, texture, sampler) {
  return device.createBindGroup({
    layout: pipeline.getBindGroupLayout(0), // Group 0
    entries: [
      {
        binding: 0,
        resource: { buffer: uniformBuffer }
      },
      {
        binding: 1,
        resource: texture.createView()
      },
      {
        binding: 2,
        resource: sampler
      }
    ]
  });
}

// Create sampler
const sampler = device.createSampler({
  magFilter: 'linear',
  minFilter: 'linear',
  mipmapFilter: 'linear',
  addressModeU: 'repeat',
  addressModeV: 'repeat',
  maxAnisotropy: 16
});

Bind Group Layout

For explicit control, define layouts manually:

const bindGroupLayout = device.createBindGroupLayout({
  entries: [
    {
      binding: 0,
      visibility: GPUShaderStage.VERTEX | GPUShaderStage.FRAGMENT,
      buffer: { type: 'uniform' }
    },
    {
      binding: 1,
      visibility: GPUShaderStage.FRAGMENT,
      texture: { sampleType: 'float' }
    },
    {
      binding: 2,
      visibility: GPUShaderStage.FRAGMENT,
      sampler: { type: 'filtering' }
    }
  ]
});

const pipelineLayout = device.createPipelineLayout({
  bindGroupLayouts: [bindGroupLayout]
});

Rule 7: Render Pass Encoding

Command encoders record GPU commands. Submit batched commands for efficiency.

function render(device, context, pipeline, vertexBuffer, bindGroup, vertexCount) {
  // Get current swap chain texture
  const textureView = context.getCurrentTexture().createView();

  // Create command encoder
  const commandEncoder = device.createCommandEncoder();

  // Begin render pass
  const renderPass = commandEncoder.beginRenderPass({
    colorAttachments: [{
      view: textureView,
      clearValue: { r: 0.1, g: 0.1, b: 0.15, a: 1.0 },
      loadOp: 'clear',
      storeOp: 'store'
    }],
    depthStencilAttachment: {
      view: depthTextureView,
      depthClearValue: 1.0,
      depthLoadOp: 'clear',
      depthStoreOp: 'store'
    }
  });

  // Set pipeline and resources
  renderPass.setPipeline(pipeline);
  renderPass.setBindGroup(0, bindGroup);
  renderPass.setVertexBuffer(0, vertexBuffer);

  // Draw
  renderPass.draw(vertexCount);

  // End pass
  renderPass.end();

  // Submit commands
  device.queue.submit([commandEncoder.finish()]);
}

Load/Store Operations

Operation loadOp storeOp Use Case
Clear then render 'clear' 'store' Normal rendering
Preserve previous 'load' 'store' Multi-pass rendering
Don't care 'load' 'discard' Depth-only pass

Rule 8: Compute Shader Dispatch

Compute shaders run parallel workgroups. Calculate dispatch size correctly.

async function createComputePipeline(device, shaderCode) {
  const shaderModule = device.createShaderModule({ code: shaderCode });

  return device.createComputePipeline({
    layout: 'auto',
    compute: {
      module: shaderModule,
      entryPoint: 'cs_main'
    }
  });
}

function dispatchCompute(device, pipeline, bindGroup, workgroupCount) {
  const commandEncoder = device.createCommandEncoder();
  const computePass = commandEncoder.beginComputePass();

  computePass.setPipeline(pipeline);
  computePass.setBindGroup(0, bindGroup);

  // Dispatch workgroups
  computePass.dispatchWorkgroups(
    workgroupCount.x,
    workgroupCount.y || 1,
    workgroupCount.z || 1
  );

  computePass.end();
  device.queue.submit([commandEncoder.finish()]);
}

// Calculate workgroup count
function calculateWorkgroups(itemCount, workgroupSize = 256) {
  return {
    x: Math.ceil(itemCount / workgroupSize),
    y: 1,
    z: 1
  };
}

// Usage: 10000 particles, workgroup size 256
const workgroups = calculateWorkgroups(10000, 256); // { x: 40, y: 1, z: 1 }
dispatchCompute(device, computePipeline, computeBindGroup, workgroups);

Workgroup Size Guidelines

Use Case Recommended Size Notes
1D data (particles) 256 Good occupancy
2D data (images) 16x16 (256) Cache-friendly
3D data (volumes) 8x8x4 (256) Balance dimensions

Rule 9: Texture Creation and Loading

Textures store 2D image data on the GPU.

async function loadTexture(device, url) {
  // Fetch image
  const response = await fetch(url);
  const blob = await response.blob();
  const imageBitmap = await createImageBitmap(blob);

  // Create texture
  const texture = device.createTexture({
    size: [imageBitmap.width, imageBitmap.height, 1],
    format: 'rgba8unorm',
    usage: GPUTextureUsage.TEXTURE_BINDING |
           GPUTextureUsage.COPY_DST |
           GPUTextureUsage.RENDER_ATTACHMENT
  });

  // Copy image to texture
  device.queue.copyExternalImageToTexture(
    { source: imageBitmap },
    { texture },
    [imageBitmap.width, imageBitmap.height]
  );

  return texture;
}

// Create depth texture
function createDepthTexture(device, width, height) {
  return device.createTexture({
    size: [width, height, 1],
    format: 'depth24plus',
    usage: GPUTextureUsage.RENDER_ATTACHMENT
  });
}

Texture Formats

Format Use Case
'rgba8unorm' Standard color textures
'rgba8unorm-srgb' sRGB color textures
'depth24plus' Depth buffer
'depth32float' High-precision depth
'r32float' Single-channel float
'rgba16float' HDR textures
'rgba32float' Compute textures

Rule 10: Web Component Integration

Integrate WebGPU with web components following project patterns.

/**
 * WebGPU Canvas Component
 *
 * Skills applied:
 * - web-components: No querySelector, handleEvent, cleanup
 * - javascript: Async initialization, AbortController
 * - webgpu-canvas: All rules
 */
class GPUCanvas extends HTMLElement {
  // Direct element references - NO querySelector
  #canvas;
  #device = null;
  #context = null;
  #pipeline = null;
  #animationId = null;
  #resizeObserver = null;
  #lastTime = 0;

  constructor() {
    super();
    this.attachShadow({ mode: 'open' });

    // Build DOM imperatively
    const style = document.createElement('style');
    style.textContent = `
      :host {
        display: block;
        contain: strict;
      }
      canvas {
        width: 100%;
        height: 100%;
        display: block;
      }
    `;

    this.#canvas = document.createElement('canvas');
    this.#canvas.setAttribute('part', 'canvas');

    this.shadowRoot.appendChild(style);
    this.shadowRoot.appendChild(this.#canvas);
  }

  async connectedCallback() {
    // Initialize WebGPU
    try {
      const { device } = await WebGPUContext.initialize();
      this.#device = device;
      this.#context = configureCanvasContext(this.#canvas, device);
      await this.#createResources();

      // Observe resize
      this.#resizeObserver = new ResizeObserver(() => this.#handleResize());
      this.#resizeObserver.observe(this);

      // Start render loop
      this.#startRenderLoop();
    } catch (error) {
      console.error('WebGPU initialization failed:', error);
      this.dispatchEvent(new CustomEvent('gpu-error', {
        bubbles: true,
        detail: { error }
      }));
    }
  }

  disconnectedCallback() {
    // Cancel animation loop
    if (this.#animationId) {
      cancelAnimationFrame(this.#animationId);
      this.#animationId = null;
    }

    // Disconnect resize observer
    if (this.#resizeObserver) {
      this.#resizeObserver.disconnect();
      this.#resizeObserver = null;
    }

    // Destroy GPU resources
    this.#destroyResources();
  }

  #handleResize() {
    if (resizeCanvasToDisplaySize(this.#canvas)) {
      this.#recreateDepthTexture();
    }
  }

  async #createResources() {
    // Create pipeline, buffers, etc.
    // Implementation depends on specific use case
  }

  #destroyResources() {
    // Destroy buffers explicitly
    // Note: WebGPU resources are garbage collected, but explicit
    // destruction is good practice for large resources
  }

  #startRenderLoop() {
    const frame = (timestamp) => {
      // Calculate delta time (frame-rate independent)
      const deltaTime = (timestamp - this.#lastTime) / 1000;
      this.#lastTime = timestamp;

      // Render
      this.#render(deltaTime);

      // Request next frame
      this.#animationId = requestAnimationFrame(frame);
    };

    this.#animationId = requestAnimationFrame(frame);
  }

  #render(deltaTime) {
    // Check for reduced motion preference
    const prefersReducedMotion = window.matchMedia(
      '(prefers-reduced-motion: reduce)'
    ).matches;

    // Implement render logic
    // Update uniforms, encode commands, submit
  }

  #recreateDepthTexture() {
    // Recreate depth texture on resize
  }
}

customElements.define('gpu-canvas', GPUCanvas);

Rule 11: Error Handling and Device Recovery

Handle GPU errors gracefully with recovery strategies.

class RobustGPUContext {
  #device = null;
  #onDeviceLost = null;

  async initialize(onDeviceLost) {
    this.#onDeviceLost = onDeviceLost;

    const adapter = await navigator.gpu?.requestAdapter();
    if (!adapter) {
      throw new Error('No WebGPU adapter available');
    }

    this.#device = await adapter.requestDevice();

    // Handle device loss
    this.#device.lost.then(async (info) => {
      console.error(`WebGPU device lost: ${info.reason}`, info.message);

      if (info.reason === 'destroyed') {
        // Intentional destruction, don't recover
        return;
      }

      // Notify and attempt recovery
      this.#onDeviceLost?.(info);

      try {
        await this.initialize(this.#onDeviceLost);
        console.log('WebGPU device recovered');
      } catch (error) {
        console.error('WebGPU recovery failed:', error);
      }
    });

    return this.#device;
  }

  // Validation error handling
  pushErrorScope(filter = 'validation') {
    this.#device.pushErrorScope(filter);
  }

  async popErrorScope() {
    const error = await this.#device.popErrorScope();
    if (error) {
      console.error(`WebGPU ${error.constructor.name}:`, error.message);
    }
    return error;
  }
}

// Usage with error scope
const gpu = new RobustGPUContext();
await gpu.initialize((info) => {
  showUserMessage('Graphics reset, please wait...');
});

gpu.pushErrorScope('validation');
// ... WebGPU operations
const error = await gpu.popErrorScope();
if (error) {
  // Handle validation error
}

Error Types

Error Type Cause Recovery
GPUValidationError Invalid API usage Fix code, re-run
GPUOutOfMemoryError VRAM exhausted Free resources, retry
Device lost (destroyed) Tab closed, context lost Reinitialize
Device lost (unknown) Driver crash, GPU reset Auto-recover

Rule 12: Performance Optimization

Optimize for consistent frame times and efficient GPU utilization.

Double/Triple Buffering

class BufferPool {
  #buffers = [];
  #currentIndex = 0;
  #size;

  constructor(device, size, usage, count = 3) {
    this.#size = size;
    for (let i = 0; i < count; i++) {
      this.#buffers.push(device.createBuffer({ size, usage }));
    }
  }

  // Get next buffer (round-robin)
  next() {
    const buffer = this.#buffers[this.#currentIndex];
    this.#currentIndex = (this.#currentIndex + 1) % this.#buffers.length;
    return buffer;
  }
}

// Usage: Triple-buffered uniform updates
const uniformPool = new BufferPool(
  device,
  256,
  GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
  3
);

// Each frame, use next buffer
function updateFrame(data) {
  const buffer = uniformPool.next();
  device.queue.writeBuffer(buffer, 0, data);
  return buffer;
}

Batch Rendering

// Bad: One draw call per object
for (const obj of objects) {
  renderPass.setVertexBuffer(0, obj.buffer);
  renderPass.draw(obj.vertexCount);
}

// Good: Instance rendering
const instanceBuffer = createInstanceBuffer(device, instanceData);
renderPass.setVertexBuffer(0, vertexBuffer);
renderPass.setVertexBuffer(1, instanceBuffer);
renderPass.draw(vertexCount, instanceCount);

Timing Queries (Debug)

async function measureGPUTime(device, commandEncoder, operation) {
  // Check for timestamp query support
  if (!device.features.has('timestamp-query')) {
    operation();
    return null;
  }

  const querySet = device.createQuerySet({
    type: 'timestamp',
    count: 2
  });

  const resolveBuffer = device.createBuffer({
    size: 16,
    usage: GPUBufferUsage.QUERY_RESOLVE | GPUBufferUsage.COPY_SRC
  });

  commandEncoder.writeTimestamp(querySet, 0);
  operation();
  commandEncoder.writeTimestamp(querySet, 1);

  commandEncoder.resolveQuerySet(querySet, 0, 2, resolveBuffer, 0);

  // Read back results (requires additional staging buffer)
  // Returns time in nanoseconds
}

Rule 13: Memory Management

Track and limit GPU memory usage to prevent crashes.

class GPUResourceTracker {
  #allocations = new Map();
  #totalBytes = 0;
  #maxBytes;

  constructor(maxBytes = 512 * 1024 * 1024) { // 512MB default limit
    this.#maxBytes = maxBytes;
  }

  track(resource, bytes, label = 'unnamed') {
    if (this.#totalBytes + bytes > this.#maxBytes) {
      console.warn(`GPU memory limit exceeded, cannot allocate ${label}`);
      return false;
    }

    this.#allocations.set(resource, { bytes, label });
    this.#totalBytes += bytes;
    return true;
  }

  release(resource) {
    const allocation = this.#allocations.get(resource);
    if (allocation) {
      this.#totalBytes -= allocation.bytes;
      this.#allocations.delete(resource);
    }
  }

  get used() { return this.#totalBytes; }
  get available() { return this.#maxBytes - this.#totalBytes; }

  report() {
    console.log(`GPU Memory: ${(this.#totalBytes / 1024 / 1024).toFixed(2)} MB used`);
    for (const [resource, info] of this.#allocations) {
      console.log(`  ${info.label}: ${(info.bytes / 1024).toFixed(2)} KB`);
    }
  }
}

Complete Example: Particle System

// particle-system.js
const PARTICLE_SHADER = `
struct Particle {
  position: vec3<f32>,
  velocity: vec3<f32>,
  life: f32,
  _padding: f32, // Align to 32 bytes
}

struct SimParams {
  deltaTime: f32,
  gravity: f32,
  _padding: vec2<f32>,
}

@group(0) @binding(0) var<uniform> params: SimParams;
@group(0) @binding(1) var<storage, read_write> particles: array<Particle>;

@compute @workgroup_size(256)
fn update(@builtin(global_invocation_id) id: vec3<u32>) {
  let idx = id.x;
  if (idx >= arrayLength(&particles)) { return; }

  var p = particles[idx];
  if (p.life <= 0.0) { return; }

  p.velocity.y -= params.gravity * params.deltaTime;
  p.position += p.velocity * params.deltaTime;
  p.life -= params.deltaTime;

  particles[idx] = p;
}
`;

class ParticleSystem extends HTMLElement {
  static PARTICLE_COUNT = 10000;
  static PARTICLE_STRIDE = 32; // 8 floats, aligned

  #canvas;
  #device = null;
  #computePipeline = null;
  #particleBuffer = null;
  #uniformBuffer = null;
  #bindGroup = null;
  #animationId = null;
  #lastTime = 0;

  constructor() {
    super();
    this.attachShadow({ mode: 'open' });

    const style = document.createElement('style');
    style.textContent = `:host { display: block; } canvas { width: 100%; height: 100%; }`;

    this.#canvas = document.createElement('canvas');
    this.shadowRoot.append(style, this.#canvas);
  }

  async connectedCallback() {
    const { device } = await WebGPUContext.initialize();
    this.#device = device;

    await this.#initializeParticles();
    this.#startLoop();
  }

  disconnectedCallback() {
    if (this.#animationId) {
      cancelAnimationFrame(this.#animationId);
    }
  }

  async #initializeParticles() {
    const device = this.#device;

    // Create compute pipeline
    const shaderModule = device.createShaderModule({ code: PARTICLE_SHADER });
    this.#computePipeline = device.createComputePipeline({
      layout: 'auto',
      compute: { module: shaderModule, entryPoint: 'update' }
    });

    // Initialize particle data
    const initialData = new Float32Array(ParticleSystem.PARTICLE_COUNT * 8);
    for (let i = 0; i < ParticleSystem.PARTICLE_COUNT; i++) {
      const offset = i * 8;
      initialData[offset + 0] = (Math.random() - 0.5) * 2; // x
      initialData[offset + 1] = Math.random() * 2;          // y
      initialData[offset + 2] = (Math.random() - 0.5) * 2; // z
      initialData[offset + 3] = (Math.random() - 0.5) * 0.5; // vx
      initialData[offset + 4] = Math.random() * 2;           // vy
      initialData[offset + 5] = (Math.random() - 0.5) * 0.5; // vz
      initialData[offset + 6] = Math.random() * 5 + 2;       // life
      initialData[offset + 7] = 0;                           // padding
    }

    this.#particleBuffer = createStorageBuffer(
      device,
      initialData.byteLength,
      initialData
    );

    this.#uniformBuffer = createUniformBuffer(device, 16);

    this.#bindGroup = device.createBindGroup({
      layout: this.#computePipeline.getBindGroupLayout(0),
      entries: [
        { binding: 0, resource: { buffer: this.#uniformBuffer } },
        { binding: 1, resource: { buffer: this.#particleBuffer } }
      ]
    });
  }

  #startLoop() {
    const frame = (timestamp) => {
      const deltaTime = Math.min((timestamp - this.#lastTime) / 1000, 0.1);
      this.#lastTime = timestamp;

      this.#update(deltaTime);
      this.#animationId = requestAnimationFrame(frame);
    };

    this.#animationId = requestAnimationFrame(frame);
  }

  #update(deltaTime) {
    const device = this.#device;

    // Update uniforms
    const uniforms = new Float32Array([deltaTime, 9.8, 0, 0]);
    device.queue.writeBuffer(this.#uniformBuffer, 0, uniforms);

    // Dispatch compute
    const commandEncoder = device.createCommandEncoder();
    const computePass = commandEncoder.beginComputePass();

    computePass.setPipeline(this.#computePipeline);
    computePass.setBindGroup(0, this.#bindGroup);
    computePass.dispatchWorkgroups(
      Math.ceil(ParticleSystem.PARTICLE_COUNT / 256)
    );

    computePass.end();
    device.queue.submit([commandEncoder.finish()]);
  }
}

customElements.define('particle-system', ParticleSystem);

Checklist

Before shipping WebGPU code:

  • Feature detection with graceful fallback
  • Device/adapter initialized once (singleton)
  • Canvas context configured with correct format and alpha mode
  • Device pixel ratio handled for crisp rendering
  • Resize observer for canvas size changes
  • Render loop uses requestAnimationFrame
  • Frame-rate independent updates (delta time)
  • Device lost handler with recovery
  • Error scopes for validation during development
  • Resources cleaned up in disconnectedCallback
  • Reduced motion preference respected
  • WGSL shaders checked for compilation errors
  • Buffer alignment correct (16 bytes for uniforms)
  • Workgroup sizes optimized for target hardware

Quick Reference

Initialization

const adapter = await navigator.gpu.requestAdapter();
const device = await adapter.requestDevice();
const context = canvas.getContext('webgpu');
context.configure({ device, format: navigator.gpu.getPreferredCanvasFormat() });

Buffer Creation

// Vertex
device.createBuffer({ size, usage: GPUBufferUsage.VERTEX | GPUBufferUsage.COPY_DST });

// Uniform
device.createBuffer({ size, usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST });

// Storage (compute)
device.createBuffer({ size, usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST });

Render Loop

const frame = (timestamp) => {
  const deltaTime = (timestamp - lastTime) / 1000;
  lastTime = timestamp;

  // Update & render
  update(deltaTime);
  render();

  requestAnimationFrame(frame);
};
requestAnimationFrame(frame);

Command Submission

const encoder = device.createCommandEncoder();
const pass = encoder.beginRenderPass({ colorAttachments: [{ view, loadOp: 'clear', storeOp: 'store' }] });
pass.setPipeline(pipeline);
pass.setBindGroup(0, bindGroup);
pass.setVertexBuffer(0, vertexBuffer);
pass.draw(vertexCount);
pass.end();
device.queue.submit([encoder.finish()]);

Files

This skill integrates with:

  • js/utils/webgpu-context.js - Singleton WebGPU context
  • css/styles/accessibility.css - Reduced motion tokens
  • js/components/ - Web component integration patterns

Project WebGPU Effects

The project includes these ready-to-use WebGPU effect components:

Component File Purpose
<magical-motes> js/components/effects/magical-motes.js Ambient floating particles
<ink-trail> js/components/effects/ink-trail.js Typing feedback particles
<particle-burst> js/components/effects/particle-burst.js Celebration explosions
<rank-aura> js/components/effects/rank-aura.js Wizard rank orbital glow

Import all effects:

import '/js/components/effects/index.js';