Agent skill

webgl

WebGL shaders and effects for JARVIS 3D HUD

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SKILL.md

WebGL Development Skill

File Organization: This skill uses split structure. See references/ for advanced patterns and security examples.

1. Overview

This skill provides WebGL expertise for creating custom shaders and visual effects in the JARVIS AI Assistant HUD. It focuses on GPU-accelerated rendering with security considerations.

Risk Level: MEDIUM - Direct GPU access, potential for resource exhaustion, driver vulnerabilities

Primary Use Cases:

  • Custom shaders for holographic effects
  • Post-processing effects (bloom, glitch)
  • Particle systems with compute shaders
  • Real-time data visualization

2. Core Responsibilities

2.1 Fundamental Principles

  1. TDD First: Write tests before implementation - test shaders, contexts, and resources
  2. Performance Aware: Optimize GPU usage - batch draws, reuse buffers, compress textures
  3. GPU Safety: Implement timeout mechanisms and resource limits
  4. Shader Validation: Validate all shader inputs before compilation
  5. Context Management: Handle context loss gracefully
  6. Performance Budgets: Set strict limits on draw calls and triangles
  7. Fallback Strategy: Provide non-WebGL fallbacks
  8. Memory Management: Track and limit texture/buffer usage

3. Technology Stack & Versions

3.1 Browser Support

Browser WebGL 2.0 Notes
Chrome 56+ Full support
Firefox 51+ Full support
Safari 15+ WebGL 2.0 support
Edge 79+ Chromium-based

3.2 Security Considerations

typescript
// Check WebGL support and capabilities
function getWebGLContext(canvas: HTMLCanvasElement): WebGL2RenderingContext | null {
  const gl = canvas.getContext('webgl2', {
    alpha: true,
    antialias: true,
    powerPreference: 'high-performance',
    failIfMajorPerformanceCaveat: true  // Fail if software rendering
  })

  if (!gl) {
    console.warn('WebGL 2.0 not supported')
    return null
  }

  return gl
}

4. Implementation Patterns

4.1 Safe Shader Compilation

typescript
// utils/shaderUtils.ts

// ✅ Safe shader compilation with error handling
export function compileShader(
  gl: WebGL2RenderingContext,
  source: string,
  type: number
): WebGLShader | null {
  const shader = gl.createShader(type)
  if (!shader) return null

  gl.shaderSource(shader, source)
  gl.compileShader(shader)

  if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
    const error = gl.getShaderInfoLog(shader)
    console.error('Shader compilation error:', error)
    gl.deleteShader(shader)
    return null
  }

  return shader
}

// ✅ Safe program linking
export function createProgram(
  gl: WebGL2RenderingContext,
  vertexShader: WebGLShader,
  fragmentShader: WebGLShader
): WebGLProgram | null {
  const program = gl.createProgram()
  if (!program) return null

  gl.attachShader(program, vertexShader)
  gl.attachShader(program, fragmentShader)
  gl.linkProgram(program)

  if (!gl.getProgramParameter(program, gl.LINK_STATUS)) {
    const error = gl.getProgramInfoLog(program)
    console.error('Program linking error:', error)
    gl.deleteProgram(program)
    return null
  }

  return program
}

4.2 Context Loss Handling

typescript
// composables/useWebGL.ts
export function useWebGL(canvas: Ref<HTMLCanvasElement | null>) {
  const gl = ref<WebGL2RenderingContext | null>(null)
  const contextLost = ref(false)

  onMounted(() => {
    if (!canvas.value) return

    // ✅ Handle context loss
    canvas.value.addEventListener('webglcontextlost', (e) => {
      e.preventDefault()
      contextLost.value = true
      console.warn('WebGL context lost')
    })

    canvas.value.addEventListener('webglcontextrestored', () => {
      contextLost.value = false
      initializeGL()
      console.info('WebGL context restored')
    })

    initializeGL()
  })

  function initializeGL() {
    gl.value = getWebGLContext(canvas.value!)
    // Reinitialize all resources
  }

  return { gl, contextLost }
}

4.3 Holographic Shader

glsl
// shaders/holographic.frag
#version 300 es
precision highp float;

uniform float uTime;
uniform vec3 uColor;
uniform float uScanlineIntensity;

in vec2 vUv;
out vec4 fragColor;

void main() {
  // Scanline effect
  float scanline = sin(vUv.y * 200.0 + uTime * 2.0) * 0.5 + 0.5;
  scanline = mix(1.0, scanline, uScanlineIntensity);

  // Edge glow
  float edge = smoothstep(0.0, 0.1, vUv.x) *
               smoothstep(1.0, 0.9, vUv.x) *
               smoothstep(0.0, 0.1, vUv.y) *
               smoothstep(1.0, 0.9, vUv.y);

  vec3 color = uColor * scanline * edge;
  float alpha = edge * 0.8;

  fragColor = vec4(color, alpha);
}

4.4 Resource Management

typescript
// utils/resourceManager.ts
export class WebGLResourceManager {
  private textures: Set<WebGLTexture> = new Set()
  private buffers: Set<WebGLBuffer> = new Set()
  private programs: Set<WebGLProgram> = new Set()

  private textureMemory = 0
  private readonly MAX_TEXTURE_MEMORY = 256 * 1024 * 1024  // 256MB

  constructor(private gl: WebGL2RenderingContext) {}

  createTexture(width: number, height: number): WebGLTexture | null {
    const size = width * height * 4  // RGBA

    // ✅ Enforce memory limits
    if (this.textureMemory + size > this.MAX_TEXTURE_MEMORY) {
      console.error('Texture memory limit exceeded')
      return null
    }

    const texture = this.gl.createTexture()
    if (texture) {
      this.textures.add(texture)
      this.textureMemory += size
    }
    return texture
  }

  dispose(): void {
    this.textures.forEach(t => this.gl.deleteTexture(t))
    this.buffers.forEach(b => this.gl.deleteBuffer(b))
    this.programs.forEach(p => this.gl.deleteProgram(p))
    this.textureMemory = 0
  }
}

4.5 Uniform Validation

typescript
// ✅ Type-safe uniform setting
export function setUniforms(
  gl: WebGL2RenderingContext,
  program: WebGLProgram,
  uniforms: Record<string, number | number[] | Float32Array>
): void {
  for (const [name, value] of Object.entries(uniforms)) {
    const location = gl.getUniformLocation(program, name)
    if (!location) {
      console.warn(`Uniform '${name}' not found`)
      continue
    }

    if (typeof value === 'number') {
      gl.uniform1f(location, value)
    } else if (Array.isArray(value)) {
      switch (value.length) {
        case 2: gl.uniform2fv(location, value); break
        case 3: gl.uniform3fv(location, value); break
        case 4: gl.uniform4fv(location, value); break
        case 16: gl.uniformMatrix4fv(location, false, value); break
      }
    }
  }
}

5. Implementation Workflow (TDD)

5.1 Step-by-Step Process

  1. Write failing test -> 2. Implement minimum -> 3. Refactor -> 4. Verify
typescript
// Step 1: tests/webgl/shaderCompilation.test.ts
import { describe, it, expect, beforeEach } from 'vitest'
import { compileShader } from '@/utils/shaderUtils'

describe('WebGL Shader Compilation', () => {
  let gl: WebGL2RenderingContext

  beforeEach(() => {
    gl = document.createElement('canvas').getContext('webgl2')!
  })

  it('should compile valid shader', () => {
    const source = `#version 300 es
      in vec4 aPosition;
      void main() { gl_Position = aPosition; }`
    expect(compileShader(gl, source, gl.VERTEX_SHADER)).not.toBeNull()
  })

  it('should return null for invalid shader', () => {
    expect(compileShader(gl, 'invalid', gl.FRAGMENT_SHADER)).toBeNull()
  })
})

// Step 2-3: Implement and refactor (see section 4.1)
// Step 4: npm test && npm run typecheck && npm run build

5.2 Testing Context and Resources

typescript
describe('WebGL Context', () => {
  it('should handle context loss', async () => {
    const { gl, contextLost } = useWebGL(ref(canvas))
    gl.value?.getExtension('WEBGL_lose_context')?.loseContext()
    await nextTick()
    expect(contextLost.value).toBe(true)
  })
})

describe('Resource Manager', () => {
  it('should enforce memory limits', () => {
    const manager = new WebGLResourceManager(gl)
    expect(manager.createTexture(1024, 1024)).not.toBeNull()
    expect(manager.createTexture(16384, 16384)).toBeNull() // Exceeds limit
  })
})

6. Performance Patterns

6.1 Buffer Reuse

typescript
// Bad - Creates new buffer every frame
const buffer = gl.createBuffer()
gl.bufferData(gl.ARRAY_BUFFER, data, gl.DYNAMIC_DRAW)
gl.deleteBuffer(buffer)

// Good - Reuse buffer, update only data
gl.bufferSubData(gl.ARRAY_BUFFER, 0, data)  // Update existing buffer

6.2 Draw Call Batching

typescript
// Bad - One draw call per object
objects.forEach(obj => {
  gl.useProgram(obj.program)
  gl.drawElements(...)
})

// Good - Batch by material/shader
const batches = groupByMaterial(objects)
batches.forEach(batch => {
  gl.useProgram(batch.program)
  batch.objects.forEach(obj => gl.drawElements(...))
})

6.3 Texture Compression

typescript
// Bad - Always uncompressed RGBA
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, image)

// Good - Use compressed formats when available
const ext = gl.getExtension('WEBGL_compressed_texture_s3tc')
if (ext) gl.compressedTexImage2D(gl.TEXTURE_2D, 0, ext.COMPRESSED_RGBA_S3TC_DXT5_EXT, ...)

6.4 Instanced Rendering

typescript
// Bad - Individual draw calls for particles
particles.forEach(p => {
  gl.uniform3fv(uPosition, p.position)
  gl.drawArrays(gl.TRIANGLES, 0, 6)
})

// Good - Single instanced draw call
gl.drawArraysInstanced(gl.TRIANGLES, 0, 6, particles.length)

6.5 VAO Usage

typescript
// Bad - Rebind attributes every frame
gl.enableVertexAttribArray(0)
gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0)

// Good - Use VAO to store attribute state
const vao = gl.createVertexArray()
gl.bindVertexArray(vao)
// Set up once, then just bind VAO for rendering

7. Security Standards

7.1 Known Vulnerabilities

CVE Severity Description Mitigation
CVE-2024-11691 HIGH Apple M series memory corruption Update browser, OS patches
CVE-2023-1531 HIGH Chrome use-after-free Update Chrome

7.2 OWASP Top 10 Coverage

OWASP Category Risk Mitigation
A06 Vulnerable Components HIGH Keep browsers updated
A10 SSRF LOW Context isolation by browser

7.3 GPU Resource Protection

typescript
// ✅ Implement resource limits
const LIMITS = {
  maxDrawCalls: 100,
  maxTriangles: 1_000_000,
  maxTextures: 32,
  maxTextureSize: 4096
}

function checkLimits(stats: RenderStats): boolean {
  if (stats.drawCalls > LIMITS.maxDrawCalls) {
    console.error('Draw call limit exceeded')
    return false
  }
  if (stats.triangles > LIMITS.maxTriangles) {
    console.error('Triangle limit exceeded')
    return false
  }
  return true
}

8. Common Mistakes & Anti-Patterns

8.1 Critical Security Anti-Patterns

Never: Skip Context Loss Handling

typescript
// ❌ DANGEROUS - App crashes on context loss
const gl = canvas.getContext('webgl2')
// No context loss handler!

// ✅ SECURE - Handle gracefully
canvas.addEventListener('webglcontextlost', handleLoss)
canvas.addEventListener('webglcontextrestored', handleRestore)

Never: Unlimited Resource Allocation

typescript
// ❌ DANGEROUS - GPU memory exhaustion
for (let i = 0; i < userCount; i++) {
  textures.push(gl.createTexture())
}

// ✅ SECURE - Enforce limits
if (textureCount < MAX_TEXTURES) {
  textures.push(gl.createTexture())
}

8.2 Performance Anti-Patterns

Avoid: Excessive State Changes

typescript
// ❌ BAD - Unbatched draw calls
objects.forEach(obj => {
  gl.useProgram(obj.program)
  gl.bindTexture(gl.TEXTURE_2D, obj.texture)
  gl.drawElements(...)
})

// ✅ GOOD - Batch by material
batches.forEach(batch => {
  gl.useProgram(batch.program)
  gl.bindTexture(gl.TEXTURE_2D, batch.texture)
  batch.objects.forEach(obj => gl.drawElements(...))
})

9. Pre-Implementation Checklist

Phase 1: Before Writing Code

  • Write failing tests for shaders, context, and resources
  • Define performance budgets (draw calls <100, memory <256MB)
  • Identify required WebGL extensions

Phase 2: During Implementation

  • Context loss handling with recovery
  • Resource limits and memory tracking
  • Shader validation before compilation
  • Use VAOs, batch draws, reuse buffers
  • Instanced rendering for particles

Phase 3: Before Committing

  • Tests pass: npm test -- --run tests/webgl/
  • Type check: npm run typecheck
  • Build: npm run build
  • Performance verified (draws, memory)
  • Fallback for no WebGL tested

10. Summary

WebGL provides GPU-accelerated graphics for JARVIS HUD. Key principles: handle context loss, enforce resource limits, validate shaders, track memory, batch draw calls, minimize state changes.

Remember: WebGL bypasses browser sandboxing - always protect against resource exhaustion. References: references/advanced-patterns.md, references/security-examples.md

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