WebGPU Rendering

import { WebGPURenderer } from 'three/webgpu';
import { 
  StorageInstancedBufferAttribute,
  StorageBufferAttribute,
  WebGPUCoordinateSystem
} from 'three/webgpu';

/**
 * WebGPU-based renderer with compute shader support and advanced rendering features
 */
class WebGPURenderer extends Renderer {
  /**
   * Create WebGPU renderer
   * @param parameters - Renderer configuration options
   */
  constructor(parameters?: WebGPURendererParameters);
  
  /** HTML canvas element for rendering */
  domElement: HTMLCanvasElement;
  
  /** Whether renderer has been initialized */
  isWebGPURenderer: true;
  
  /** Coordinate system used (WebGPU vs WebGL differences) */
  coordinateSystem: typeof WebGPUCoordinateSystem;
  
  /**
   * Initialize WebGPU context and resources
   * @returns Promise that resolves when initialization is complete
   */
  init(): Promise<WebGPURenderer>;
  
  /**
   * Render scene with camera
   * @param scene - Scene to render
   * @param camera - Camera defining viewpoint
   * @returns This renderer for chaining
   */
  render(scene: Object3D, camera: Camera): this;
  
  /**
   * Render scene to render target
   * @param scene - Scene to render
   * @param camera - Camera defining viewpoint  
   * @param renderTarget - Target to render to
   * @param forceClear - Whether to force clear before rendering
   */
  setRenderTarget(renderTarget: RenderTarget | null, activeCubeFace?: number, activeMipmapLevel?: number): void;
  
  /**
   * Execute compute shader operations
   * @param computeNodes - Array of compute nodes to execute
   * @returns Promise that resolves when compute is complete
   */
  compute(computeNodes: Node[]): Promise<void>;
  
  /**
   * Execute compute shader operations asynchronously
   * @param computeNodes - Array of compute nodes to execute
   * @returns Promise that resolves when compute is complete
   */
  computeAsync(computeNodes: Node[]): Promise<void>;
  
  /**
   * Set size of renderer and canvas
   * @param width - Width in pixels
   * @param height - Height in pixels
   * @param updateStyle - Whether to update CSS styles
   */
  setSize(width: number, height: number, updateStyle?: boolean): void;
  
  /**
   * Set device pixel ratio for high-DPI displays
   * @param value - Device pixel ratio (window.devicePixelRatio)
   */
  setPixelRatio(value: number): void;
  
  /**
   * Set viewport within canvas
   * @param x - X offset in pixels
   * @param y - Y offset in pixels
   * @param width - Viewport width in pixels
   * @param height - Viewport height in pixels
   */
  setViewport(x: number, y: number, width: number, height: number): void;
  
  /**
   * Set scissor test region
   * @param x - X offset in pixels
   * @param y - Y offset in pixels
   * @param width - Scissor width in pixels
   * @param height - Scissor height in pixels
   */
  setScissor(x: number, y: number, width: number, height: number): void;
  
  /**
   * Enable or disable scissor test
   * @param boolean - Whether scissor test is enabled
   */
  setScissorTest(boolean: boolean): void;
  
  /**
   * Set clear color for background
   * @param color - Clear color
   * @param alpha - Alpha value for clear color
   */
  setClearColor(color: ColorRepresentation, alpha?: number): void;
  
  /**
   * Set clear alpha value
   * @param alpha - Alpha value (0-1)
   */
  setClearAlpha(alpha: number): void;
  
  /**
   * Clear render buffers
   * @param color - Whether to clear color buffer
   * @param depth - Whether to clear depth buffer
   * @param stencil - Whether to clear stencil buffer
   */
  clear(color?: boolean, depth?: boolean, stencil?: boolean): void;
  
  /**
   * Dispose of WebGPU resources
   */
  dispose(): void;
  
  /**
   * Get current render target
   * @returns Active render target or null
   */
  getRenderTarget(): RenderTarget | null;
  
  /**
   * Get WebGPU device capabilities
   * @returns Object describing supported features and limits
   */
  getCapabilities(): WebGPUCapabilities;
  
  /**
   * Get rendering context information
   * @returns WebGPU context information
   */
  getContext(): GPUCanvasContext;
  
  /**
   * Copy render target to another render target
   * @param source - Source render target
   * @param target - Destination render target
   * @param viewport - Optional viewport for partial copy
   */
  copyFramebufferToTexture(texture: Texture, position?: Vector2, level?: number): void;
  
  /**
   * Copy texture to render target  
   * @param position - Position to copy to
   * @param texture - Source texture
   * @param level - Mipmap level
   */
  copyTextureToTexture(position: Vector2, srcTexture: Texture, dstTexture: Texture, level?: number): void;
}

interface WebGPURendererParameters {
  /** Canvas element to render to */
  canvas?: HTMLCanvasElement;
  
  /** GPU device to use (auto-selected if not specified) */
  device?: GPUDevice;
  
  /** GPU adapter to use (auto-selected if not specified) */
  adapter?: GPUAdapter;
  
  /** Antialiasing configuration */
  antialias?: boolean;
  
  /** Whether canvas has alpha channel */
  alpha?: boolean;
  
  /** Whether to premultiply alpha */
  premultipliedAlpha?: boolean;
  
  /** Whether to preserve drawing buffer */
  preserveDrawingBuffer?: boolean;
  
  /** Power preference for GPU selection */
  powerPreference?: 'low-power' | 'high-performance';
  
  /** Required features for WebGPU device */
  requiredFeatures?: Iterable<GPUFeatureName>;
  
  /** Required limits for WebGPU device */
  requiredLimits?: Record<string, GPUSize64>;
  
  /** Fallback adapter options */
  fallbackAdapters?: GPURequestAdapterOptions[];
}

interface WebGPUCapabilities {
  /** Whether WebGPU is supported */
  isWebGPU: boolean;
  
  /** Maximum texture size */
  maxTextures: number;
  
  /** Maximum vertex attributes */
  maxVertexAttributes: number;
  
  /** Maximum vertex uniform vectors */
  maxVertexUniforms: number;
  
  /** Maximum fragment uniform vectors */
  maxFragmentUniforms: number;
  
  /** Maximum samples for multisampling */
  maxSamples: number;
  
  /** Supported texture formats */
  textureFormats: Set<string>;
  
  /** Device features */
  features: Set<string>;
  
  /** Device limits */
  limits: GPUSupportedLimits;
}

import { WebGPURenderer } from 'three/webgpu';
import * as THREE from 'three';

async function initWebGPU() {
  // Check WebGPU support
  if (!navigator.gpu) {
    throw new Error('WebGPU not supported');
  }
  
  // Create renderer
  const renderer = new WebGPURenderer({
    antialias: true,
    requiredFeatures: ['timestamp-query'],
    powerPreference: 'high-performance'
  });
  
  // Initialize WebGPU context
  await renderer.init();
  
  // Set up canvas
  renderer.setSize(window.innerWidth, window.innerHeight);
  renderer.setPixelRatio(window.devicePixelRatio);
  document.body.appendChild(renderer.domElement);
  
  // Create scene
  const scene = new THREE.Scene();
  const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
  
  // Render loop
  function animate() {
    requestAnimationFrame(animate);
    renderer.render(scene, camera);
  }
  animate();
}

initWebGPU().catch(console.error);

/**
 * Node-based compute shader system for GPU computation
 */
interface ComputeNode extends Node {
  /** Number of compute workgroups in X dimension */
  workgroupSize: number;
  
  /** Compute shader function */
  computeNode: Node;
  
  /**
   * Execute compute shader
   * @param renderer - WebGPU renderer
   * @returns Promise resolving when compute is complete
   */
  compute(renderer: WebGPURenderer): Promise<void>;
}

/**
 * Create compute node for GPU computation
 * @param computeShader - Compute shader function as node
 * @param count - Number of compute invocations
 * @param workgroupSize - Size of compute workgroup
 * @returns Compute node ready for execution
 */
declare function compute(computeShader: Node, count: number, workgroupSize?: number): ComputeNode;

/**
 * Storage buffer for compute shader data exchange
 */
class StorageBufferNode extends BufferNode {
  /**
   * Create storage buffer node
   * @param value - Initial buffer data
   * @param bufferType - Type of storage buffer
   * @param bufferCount - Number of elements
   */
  constructor(value: ArrayLike<number>, bufferType?: string, bufferCount?: number);
  
  /** Buffer access mode */
  access: 'read' | 'write' | 'read_write';
}

import { WebGPURenderer, compute, storage, uniform } from 'three/webgpu';
import { wgsl } from 'three/tsl';

async function runCompute() {
  const renderer = new WebGPURenderer();
  await renderer.init();
  
  // Create storage buffers for input/output data
  const inputBuffer = storage(new Float32Array([1, 2, 3, 4, 5]), 'vec4<f32>', 1);
  const outputBuffer = storage(new Float32Array(4), 'vec4<f32>', 1);
  
  // Define compute shader using WGSL
  const computeShader = wgsl(`
    @compute @workgroup_size(1)
    fn main(@builtin(global_invocation_id) global_id : vec3<u32>) {
      let index = global_id.x;
      outputBuffer[index] = inputBuffer[index] * 2.0;
    }
  `);
  
  // Create compute node
  const computeNode = compute(computeShader, 1);
  
  // Execute compute shader
  await renderer.compute([computeNode]);
  
  // Read results
  const results = await renderer.readStorageBuffer(outputBuffer);
  console.log('Compute results:', results);
}

/**
 * Storage buffer attribute for compute shader data exchange
 */
class StorageBufferAttribute extends BufferAttribute {
  /**
   * Create storage buffer attribute
   * @param array - Typed array containing attribute data
   * @param itemSize - Number of components per vertex
   * @param offset - Byte offset into buffer
   * @param normalized - Whether to normalize integer values
   */
  constructor(array: TypedArray, itemSize: number, offset?: number, normalized?: boolean);
  
  /** Buffer usage flags for WebGPU */
  usage: GPUBufferUsageFlags;
  
  /** Whether buffer can be read by CPU */
  isStorageBufferAttribute: true;
}

/**
 * Instanced storage buffer attribute for compute-driven instancing
 */
class StorageInstancedBufferAttribute extends StorageBufferAttribute {
  /**
   * Create storage instanced buffer attribute
   * @param array - Typed array containing instance data
   * @param itemSize - Number of components per instance
   * @param meshPerAttribute - Number of meshes per attribute (for multidraw)
   * @param offset - Byte offset into buffer
   * @param normalized - Whether to normalize integer values
   */
  constructor(
    array: TypedArray, 
    itemSize: number, 
    meshPerAttribute?: number, 
    offset?: number, 
    normalized?: boolean
  );
  
  /** Number of meshes per attribute */
  meshPerAttribute: number;
  
  /** Whether this is an instanced attribute */
  isInstancedBufferAttribute: true;
}

/**
 * Query system for GPU timing and performance metrics
 */
class TimestampQuery {
  /** Query name/identifier */
  name: string;
  
  /** Whether query is active */
  active: boolean;
  
  /**
   * Get query results in nanoseconds
   * @returns GPU time in nanoseconds or null if not ready
   */
  getResult(): number | null;
  
  /**
   * Reset query for reuse
   */
  reset(): void;
}

/**
 * Create timestamp query for GPU timing
 * @param name - Query identifier
 * @returns Timestamp query object
 */
declare function createTimestampQuery(name: string): TimestampQuery;

/**
 * WebGPU render bundle for optimized draw call recording
 */
interface RenderBundle {
  /** Bundle identifier */
  id: string;
  
  /** Recorded draw calls */
  drawCalls: DrawCall[];
  
  /**
   * Execute bundle on GPU
   * @param renderer - WebGPU renderer
   */
  execute(renderer: WebGPURenderer): void;
}

/**
 * Create render bundle for draw call batching
 * @param scene - Scene to record
 * @param camera - Camera for rendering
 * @returns Render bundle with recorded draw calls
 */
declare function createRenderBundle(scene: Object3D, camera: Camera): RenderBundle;

/**
 * WebGPU-specific node types for advanced rendering
 */

/**
 * Compute texture node for procedural texture generation
 */
class ComputeTextureNode extends TempNode {
  /**
   * Create compute texture node
   * @param computeShader - Compute shader for texture generation
   * @param width - Texture width
   * @param height - Texture height
   * @param format - Texture format
   */
  constructor(computeShader: Node, width: number, height: number, format?: PixelFormat);
  
  /** Texture dimensions */
  width: number;
  height: number;
  
  /** Texture format */
  format: PixelFormat;
}

/**
 * GPU particle system using compute shaders
 */
class GPUParticleSystem extends Object3D {
  /**
   * Create GPU particle system
   * @param maxParticles - Maximum number of particles
   * @param computeShader - Particle update compute shader
   */
  constructor(maxParticles: number, computeShader: Node);
  
  /** Maximum particle count */
  maxParticles: number;
  
  /** Current active particle count */
  particleCount: number;
  
  /** Particle position buffer */
  positionBuffer: StorageBufferAttribute;
  
  /** Particle velocity buffer */
  velocityBuffer: StorageBufferAttribute;
  
  /**
   * Update particle system
   * @param deltaTime - Time delta for simulation
   */
  update(deltaTime: number): void;
  
  /**
   * Reset all particles
   */
  reset(): void;
  
  /**
   * Emit new particles
   * @param count - Number of particles to emit
   * @param position - Emission position
   * @param velocity - Initial velocity
   */
  emit(count: number, position: Vector3, velocity: Vector3): void;
}

// WebGPU-specific type definitions
interface GPUDevice extends EventTarget {
  features: GPUSupportedFeatures;
  limits: GPUSupportedLimits;
  queue: GPUQueue;
  createBuffer(descriptor: GPUBufferDescriptor): GPUBuffer;
  createTexture(descriptor: GPUTextureDescriptor): GPUTexture;
  createSampler(descriptor?: GPUSamplerDescriptor): GPUSampler;
  createShaderModule(descriptor: GPUShaderModuleDescriptor): GPUShaderModule;
  createComputePipeline(descriptor: GPUComputePipelineDescriptor): GPUComputePipeline;
  createRenderPipeline(descriptor: GPURenderPipelineDescriptor): GPURenderPipeline;
}

interface GPUAdapter {
  features: GPUSupportedFeatures;
  limits: GPUSupportedLimits;
  info: GPUAdapterInfo;
  requestDevice(descriptor?: GPUDeviceDescriptor): Promise<GPUDevice>;
}

type GPUBufferUsageFlags = number;
type GPUTextureUsageFlags = number;
type GPUShaderStageFlags = number;

// WebGPU coordinate system constant
declare const WebGPUCoordinateSystem: 2001;

import { WebGPURenderer, compute, storage, uniform } from 'three/webgpu';
import { wgsl, vec3, float } from 'three/tsl';
import * as THREE from 'three';

class ComputeParticleSystem {
  constructor(particleCount = 10000) {
    this.particleCount = particleCount;
    this.init();
  }
  
  async init() {
    this.renderer = new WebGPURenderer();
    await this.renderer.init();
    
    // Create particle data buffers
    this.positions = new Float32Array(this.particleCount * 3);
    this.velocities = new Float32Array(this.particleCount * 3);
    
    // Initialize with random positions and velocities
    for (let i = 0; i < this.particleCount; i++) {
      const i3 = i * 3;
      this.positions[i3] = (Math.random() - 0.5) * 10;
      this.positions[i3 + 1] = (Math.random() - 0.5) * 10;
      this.positions[i3 + 2] = (Math.random() - 0.5) * 10;
      
      this.velocities[i3] = (Math.random() - 0.5) * 2;
      this.velocities[i3 + 1] = (Math.random() - 0.5) * 2;
      this.velocities[i3 + 2] = (Math.random() - 0.5) * 2;
    }
    
    // Create storage buffers
    this.positionBuffer = storage(this.positions, 'vec3<f32>');
    this.velocityBuffer = storage(this.velocities, 'vec3<f32>');
    
    // Simulation parameters
    this.timeUniform = uniform(0);
    this.deltaTimeUniform = uniform(0.016);
    this.gravityUniform = uniform(vec3(0, -9.81, 0));
    
    // Create compute shader for particle simulation
    this.updateShader = wgsl(`
      @group(0) @binding(0) var<storage, read_write> positions: array<vec3<f32>>;
      @group(0) @binding(1) var<storage, read_write> velocities: array<vec3<f32>>;
      @group(1) @binding(0) var<uniform> deltaTime: f32;
      @group(1) @binding(1) var<uniform> gravity: vec3<f32>;
      
      @compute @workgroup_size(64)
      fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
        let index = global_id.x;
        if (index >= ${this.particleCount}u) { return; }
        
        // Apply gravity
        velocities[index] += gravity * deltaTime;
        
        // Update position
        positions[index] += velocities[index] * deltaTime;
        
        // Simple ground collision
        if (positions[index].y < -5.0) {
          positions[index].y = -5.0;
          velocities[index].y = abs(velocities[index].y) * 0.8;
        }
        
        // Simple boundary collision
        for (var i = 0; i < 3; i++) {
          if (abs(positions[index][i]) > 10.0) {
            positions[index][i] = sign(positions[index][i]) * 10.0;
            velocities[index][i] *= -0.9;
          }
        }
      }
    `);
    
    // Create compute node
    const workgroupSize = 64;
    const workgroupCount = Math.ceil(this.particleCount / workgroupSize);
    this.computeNode = compute(this.updateShader, workgroupCount);
    
    this.setupRenderObjects();
  }
  
  setupRenderObjects() {
    // Create geometry for particles
    this.geometry = new THREE.BufferGeometry();
    this.geometry.setAttribute('position', new THREE.BufferAttribute(this.positions, 3));
    
    // Create particle material
    this.material = new THREE.PointsMaterial({
      color: 0x88ccff,
      size: 0.1,
      sizeAttenuation: true
    });
    
    // Create points object
    this.points = new THREE.Points(this.geometry, this.material);
  }
  
  async update(deltaTime) {
    // Update uniforms
    this.deltaTimeUniform.value = deltaTime;
    
    // Run compute shader
    await this.renderer.compute([this.computeNode]);
    
    // Update geometry with new positions
    this.geometry.attributes.position.needsUpdate = true;
  }
  
  addToScene(scene) {
    scene.add(this.points);
  }
}

// Usage
async function createParticleDemo() {
  const scene = new THREE.Scene();
  const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
  camera.position.set(0, 0, 15);
  
  const particleSystem = new ComputeParticleSystem(50000);
  await particleSystem.init();
  particleSystem.addToScene(scene);
  
  const clock = new THREE.Clock();
  
  function animate() {
    const deltaTime = clock.getDelta();
    
    particleSystem.update(deltaTime);
    particleSystem.renderer.render(scene, camera);
    
    requestAnimationFrame(animate);
  }
  
  animate();
}