Rust WebAssembly 与 Three.js 结合的 3D 数据可视化实战：高性能粒子系统

使用 Three.js 创建一个简单的 3D 场景：

import * as THREE from 'three';

// 创建场景
const scene = new THREE.Scene();
scene.background = new THREE.Color(0x000000);

// 创建相机
const camera = new THREE.PerspectiveCamera(
  75,
  window.innerWidth / window.innerHeight,
  0.1,
  1000
);
camera.position.z = 5;

// 创建渲染器
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

// 创建几何体
const geometry = new THREE.BoxGeometry(1, 1, 1);

// 创建材质
const material = new THREE.MeshPhongMaterial({ color: 0x00ff00, shininess: 100 });

// 创建网格
const cube = new THREE.Mesh(geometry, material);
scene.add(cube);

// 创建光源
const ambientLight = new THREE.AmbientLight(0x404040);
scene.add(ambientLight);
const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
directionalLight.position.set(1, 1, 1);
scene.add(directionalLight);

// 动画循环
function animate() {
  requestAnimationFrame(animate);
  cube.rotation.x += 0.01;
  cube.rotation.y += 0.01;
  renderer.render(scene, camera);
}
animate();

// 窗口大小调整
window.addEventListener('resize', () => {
  camera.aspect = window.innerWidth / window.innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(window.innerWidth, window.innerHeight);
});

三、Rust WebAssembly 与 WebGL 交互

3.1 传递顶点数据

顶点数据是 WebGL 渲染的基础，Rust Wasm 需要将顶点数据传递给 WebGL。顶点数据通常包括位置、颜色、纹理坐标等。

首先，在 Rust 中定义顶点结构：

// src/lib.rs
use wasm_bindgen::prelude::*;
use web_sys::WebGlRenderingContext;

#[repr(C)]
#[derive(Debug, Clone, Copy)]
pub struct Vertex {
    pub x: f32,
    pub y: f32,
    pub z: f32,
    pub r: f32,
    pub g: f32,
    pub b: f32,
    pub a: f32,
}

impl Vertex {
    pub fn new(x: f32, y: f32, z: f32, r: f32, g: f32, b: f32, a: f32) -> Self {
        Vertex { x, y, z, r, g, b, a }
    }
}

#[wasm_bindgen]
pub fn create_vertices(count: u32) -> Vec<f32> {
    let mut vertices = Vec::with_capacity(count as usize * 7);
    // 每个顶点有 7 个元素（x,y,z,r,g,b,a）
    for i in 0..count {
        let angle = i as f32 / count as f32 * std::f32::consts::PI * 2.0;
        let radius = 2.0;
        let x = angle.cos() * radius;
        let y = angle.sin() * radius;
        let z = 0.0;
        let r = angle.cos() * 0.5 + 0.5;
        let g = angle.sin() * 0.5 + 0.5;
        let b = 0.5;
        let a = 1.0;
        vertices.push(x);
        vertices.push(y);
        vertices.push(z);
        vertices.push(r);
        vertices.push(g);
        vertices.push(b);
        vertices.push(a);
    }
    vertices
}

然后，在 JavaScript 中使用 Three.js 加载顶点数据：

import * as THREE from 'three';
import init, { create_vertices } from './pkg/particle_system.js';

async function run() {
  await init();
  console.log('WebAssembly 模块加载成功');

  const scene = new THREE.Scene();
  scene.background = new THREE.Color(0x000000);

  const camera = new THREE.PerspectiveCamera(
    75,
    window.innerWidth / window.innerHeight,
    0.1,
    1000
  );
  camera.position.z = 5;

  const renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setSize(window.innerWidth, window.innerHeight);
  document.body.appendChild(renderer.domElement);

  // 从 Rust Wasm 获取顶点数据
  const count = 1000;
  const vertices = create_vertices(count);

  // 创建几何体
  const geometry = new THREE.BufferGeometry();
  geometry.setAttribute(
    'position',
    new THREE.Float32BufferAttribute(vertices.slice(0, count * 3), 3)
  );
  geometry.setAttribute(
    'color',
    new THREE.Float32BufferAttribute(vertices.slice(count * 3), 4)
  );

  // 创建材质
  const material = new THREE.PointsMaterial({
    size: 0.05,
    vertexColors: true,
    transparent: true,
    opacity: 0.8,
  });

  // 创建粒子系统
  const particles = new THREE.Points(geometry, material);
  scene.add(particles);

  const ambientLight = new THREE.AmbientLight(0x404040);
  scene.add(ambientLight);
  const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
  directionalLight.position.set(1, 1, 1);
  scene.add(directionalLight);

  function animate() {
    requestAnimationFrame(animate);
    particles.rotation.y += 0.005;
    renderer.render(scene, camera);
  }
  animate();

  window.addEventListener('resize', () => {
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();
    renderer.setSize(window.innerWidth, window.innerHeight);
  });
}
run();

3.2 传递纹理数据

纹理数据是 WebGL 渲染的重要组成部分，Rust Wasm 可以将纹理数据传递给 WebGL。纹理数据通常是一个二维数组，每个元素代表一个像素的颜色。

首先，在 Rust 中生成纹理数据：

// src/lib.rs
#[wasm_bindgen]
pub fn create_texture(width: u32, height: u32) -> Vec<u8> {
    let mut texture = Vec::with_capacity(width as usize * height as usize * 4);
    // 每个像素有 4 个元素（r,g,b,a）
    for y in 0..height {
        for x in 0..width {
            let r = (x as f32 / width as f32 * 255.0) as u8;
            let g = (y as f32 / height as f32 * 255.0) as u8;
            let b = 128;
            let a = 255;
            texture.push(r);
            texture.push(g);
            texture.push(b);
            texture.push(a);
        }
    }
    texture
}

然后，在 JavaScript 中使用 Three.js 加载纹理数据：

import * as THREE from 'three';
import init, { create_vertices, create_texture } from './pkg/particle_system.js';

async function run() {
  await init();
  console.log('WebAssembly 模块加载成功');

  const scene = new THREE.Scene();
  scene.background = new THREE.Color(0x000000);

  const camera = new THREE.PerspectiveCamera(
    75,
    window.innerWidth / window.innerHeight,
    0.1,
    1000
  );
  camera.position.z = 5;

  const renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setSize(window.innerWidth, window.innerHeight);
  document.body.appendChild(renderer.domElement);

  const count = 1000;
  const vertices = create_vertices(count);

  const geometry = new THREE.BufferGeometry();
  geometry.setAttribute(
    'position',
    new THREE.Float32BufferAttribute(vertices.slice(0, count * 3), 3)
  );
  geometry.setAttribute(
    'color',
    new THREE.Float32BufferAttribute(vertices.slice(count * 3), 4)
  );

  // 从 Rust Wasm 获取纹理数据
  const textureWidth = 256;
  const textureHeight = 256;
  const textureData = create_texture(textureWidth, textureHeight);

  // 创建纹理
  const texture = new THREE.DataTexture(
    new Uint8Array(textureData),
    textureWidth,
    textureHeight,
    THREE.RGBAFormat,
    THREE.UnsignedByteType
  );
  texture.needsUpdate = true;

  const material = new THREE.PointsMaterial({
    size: 0.05,
    vertexColors: true,
    transparent: true,
    opacity: 0.8,
    map: texture,
    blending: THREE.AdditiveBlending,
  });

  const particles = new THREE.Points(geometry, material);
  scene.add(particles);

  const ambientLight = new THREE.AmbientLight(0x404040);
  scene.add(ambientLight);
  const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
  directionalLight.position.set(1, 1, 1);
  scene.add(directionalLight);

  function animate() {
    requestAnimationFrame(animate);
    particles.rotation.y += 0.005;
    renderer.render(scene, camera);
  }
  animate();

  window.addEventListener('resize', () => {
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();
    renderer.setSize(window.innerWidth, window.innerHeight);
  });
}
run();

3.3 传递变换矩阵

变换矩阵是 WebGL 渲染的核心，Rust Wasm 可以计算变换矩阵并传递给 WebGL。变换矩阵通常包括平移矩阵、旋转矩阵、缩放矩阵、透视矩阵等。

首先，在 Rust 中计算变换矩阵：

// src/lib.rs
#[repr(C)]
#[derive(Debug, Clone, Copy)]
pub struct Mat4 {
    pub data: [f32; 16],
}

impl Mat4 {
    pub fn identity() -> Self {
        Mat4 {
            data: [
                1.0, 0.0, 0.0, 0.0,
                0.0, 1.0, 0.0, 0.0,
                0.0, 0.0, 1.0, 0.0,
                0.0, 0.0, 0.0, 1.0,
            ],
        }
    }

    pub fn translation(x: f32, y: f32, z: f32) -> Self {
        let mut mat = Self::identity();
        mat.data[12] = x;
        mat.data[13] = y;
        mat.data[14] = z;
        mat
    }

    pub fn rotation(x: f32, y: f32, z: f32) -> Self {
        let rx = Self::rotation_x(x);
        let ry = Self::rotation_y(y);
        let rz = Self::rotation_z(z);
        rx * ry * rz
    }

    pub fn rotation_x(angle: f32) -> Self {
        let c = angle.cos();
        let s = angle.sin();
        Mat4 {
            data: [
                1.0, 0.0, 0.0, 0.0,
                0.0, c, -s, 0.0,
                0.0, s, c, 0.0,
                0.0, 0.0, 0.0, 1.0,
            ],
        }
    }

    pub fn rotation_y(angle: f32) -> Self {
        let c = angle.cos();
        let s = angle.sin();
        Mat4 {
            data: [
                c, 0.0, s, 0.0,
                0.0, 1.0, 0.0, 0.0,
                -s, 0.0, c, 0.0,
                0.0, 0.0, 0.0, 1.0,
            ],
        }
    }

    pub fn rotation_z(angle: f32) -> Self {
        let c = angle.cos();
        let s = angle.sin();
        Mat4 {
            data: [
                c, -s, 0.0, 0.0,
                s, c, 0.0, 0.0,
                0.0, 0.0, 1.0, 0.0,
                0.0, 0.0, 0.0, 1.0,
            ],
        }
    }

    pub fn scaling(x: f32, y: f32, z: f32) -> Self {
        let mut mat = Self::identity();
        mat.data[0] = x;
        mat.data[5] = y;
        mat.data[10] = z;
        mat
    }

    pub fn multiply(&self, other: &Mat4) -> Self {
        let mut mat = Self::identity();
        for i in 0..4 {
            for j in 0..4 {
                mat.data[i * 4 + j] = (0..4)
                    .map(|k| self.data[i * 4 + k] * other.data[k * 4 + j])
                    .sum();
            }
        }
        mat
    }
}

impl std::ops::Mul<Mat4> for Mat4 {
    type Output = Mat4;
    fn mul(self, other: Mat4) -> Self::Output {
        self.multiply(&other)
    }
}

#[wasm_bindgen]
pub fn create_model_matrix(
    x: f32,
    y: f32,
    z: f32,
    rx: f32,
    ry: f32,
    rz: f32,
    sx: f32,
    sy: f32,
    sz: f32,
) -> Vec<f32> {
    let translation = Mat4::translation(x, y, z);
    let rotation = Mat4::rotation(rx, ry, rz);
    let scaling = Mat4::scaling(sx, sy, sz);
    let model_matrix = translation * rotation * scaling;
    model_matrix.data.to_vec()
}

然后，在 JavaScript 中使用 Three.js 加载变换矩阵：

import * as THREE from 'three';
import init, {
  create_vertices,
  create_texture,
  create_model_matrix,
} from './pkg/particle_system.js';

async function run() {
  await init();
  console.log('WebAssembly 模块加载成功');

  const scene = new THREE.Scene();
  scene.background = new THREE.Color(0x000000);

  const camera = new THREE.PerspectiveCamera(
    75,
    window.innerWidth / window.innerHeight,
    0.1,
    1000
  );
  camera.position.z = 5;

  const renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setSize(window.innerWidth, window.innerHeight);
  document.body.appendChild(renderer.domElement);

  const count = 1000;
  const vertices = create_vertices(count);

  const geometry = new THREE.BufferGeometry();
  geometry.setAttribute(
    'position',
    new THREE.Float32BufferAttribute(vertices.slice(0, count * 3), 3)
  );
  geometry.setAttribute(
    'color',
    new THREE.Float32BufferAttribute(vertices.slice(count * 3), 4)
  );

  const textureWidth = 256;
  const textureHeight = 256;
  const textureData = create_texture(textureWidth, textureHeight);
  const texture = new THREE.DataTexture(
    new Uint8Array(textureData),
    textureWidth,
    textureHeight,
    THREE.RGBAFormat,
    THREE.UnsignedByteType
  );
  texture.needsUpdate = true;

  const material = new THREE.PointsMaterial({
    size: 0.05,
    vertexColors: true,
    transparent: true,
    opacity: 0.8,
    map: texture,
    blending: THREE.AdditiveBlending,
  });

  const particles = new THREE.Points(geometry, material);
  scene.add(particles);

  // 从 Rust Wasm 获取模型矩阵
  const modelMatrixData = create_model_matrix(0, 0, 0, 0, 0, 0, 1, 1, 1);
  const modelMatrix = new THREE.Matrix4().fromArray(modelMatrixData);
  particles.matrix = modelMatrix;
  particles.matrixAutoUpdate = true;

  const ambientLight = new THREE.AmbientLight(0x404040);
  scene.add(ambientLight);
  const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
  directionalLight.position.set(1, 1, 1);
  scene.add(directionalLight);

  function animate() {
    requestAnimationFrame(animate);
    particles.rotation.y += 0.005;
    renderer.render(scene, camera);
  }
  animate();

  window.addEventListener('resize', () => {
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();
    renderer.setSize(window.innerWidth, window.innerHeight);
  });
}
run();

四、实战项目：高性能粒子系统

4.1 项目概述

开发一个高性能粒子系统，支持以下功能：

• 粒子的创建、更新、删除
• 粒子的位置、速度、加速度、生命周期管理
• 粒子的颜色、大小、透明度变化
• 粒子的各种动画效果，如爆炸、火焰、雪花、星云等
• 支持大量粒子（百万级）的渲染

4.2 项目结构

particle-system/
├── Cargo.toml
├── src/
│   ├── lib.rs
│   ├── particle.rs
│   ├── emitter.rs
│   └── utils.rs
├── static/
│   ├── index.html
│   ├── style.css
│   └── main.js
└── README.md

4.3 Cargo.toml

[package]
name = "particle_system"
version = "0.1.0"
edition = "2021"

[dependencies]
wasm-bindgen = "0.2"
wasm-bindgen-futures = "0.4"
web-sys = { version = "0.3", features = ["Window", "Document", "Element", "console", "WebGlRenderingContext", "CanvasRenderingContext2d"] }
rand = "0.8"
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"

4.4 src/particle.rs

// src/particle.rs
use rand::Rng;
use serde::Serialize;

#[derive(Debug, Clone, Copy, Serialize)]
pub struct Particle {
    pub x: f32,
    pub y: f32,
    pub z: f32,
    pub vx: f32,
    pub vy: f32,
    pub vz: f32,
    pub ax: f32,
    pub ay: f32,
    pub az: f32,
    pub r: f32,
    pub g: f32,
    pub b: f32,
    pub a: f32,
    pub size: f32,
    pub lifetime: f32,
    pub max_lifetime: f32,
}

impl Particle {
    pub fn new() -> Self {
        Particle {
            x: 0.0,
            y: 0.0,
            z: 0.0,
            vx: 0.0,
            vy: 0.0,
            vz: 0.0,
            ax: 0.0,
            ay: 0.0,
            az: 0.0,
            r: 1.0,
            g: 1.0,
            b: 1.0,
            a: 1.0,
            size: 0.05,
            lifetime: 0.0,
            max_lifetime: 10.0,
        }
    }

    pub fn randomize(&mut self, rng: &mut rand::rngs::ThreadRng) {
        self.x = rng.gen_range(-2.0..2.0);
        self.y = rng.gen_range(-2.0..2.0);
        self.z = rng.gen_range(-2.0..2.0);
        self.vx = rng.gen_range(-0.1..0.1);
        self.vy = rng.gen_range(-0.1..0.1);
        self.vz = rng.gen_range(-0.1..0.1);
        self.ax = rng.gen_range(-0.01..0.01);
        self.ay = rng.gen_range(-0.01..0.01);
        self.az = rng.gen_range(-0.01..0.01);
        self.r = rng.gen_range(0.0..1.0);
        self.g = rng.gen_range(0.0..1.0);
        self.b = rng.gen_range(0.0..1.0);
        self.a = rng.gen_range(0.5..1.0);
        self.size = rng.gen_range(0.01..0.1);
        self.lifetime = 0.0;
        self.max_lifetime = rng.gen_range(5.0..15.0);
    }

    pub fn update(&mut self, dt: f32) {
        self.vx += self.ax * dt;
        self.vy += self.ay * dt;
        self.vz += self.az * dt;
        self.x += self.vx * dt;
        self.y += self.vy * dt;
        self.z += self.vz * dt;
        self.lifetime += dt;
        self.a = 1.0 - self.lifetime / self.max_lifetime;
        self.size = 0.05 * (1.0 - self.lifetime / self.max_lifetime);
    }

    pub fn is_dead(&self) -> bool {
        self.lifetime > self.max_lifetime
    }
}

4.5 src/emitter.rs

// src/emitter.rs
use crate::particle::Particle;
use rand::Rng;

#[derive(Debug, Clone)]
pub struct Emitter {
    pub x: f32,
    pub y: f32,
    pub z: f32,
    pub particles: Vec<Particle>,
    pub max_particles: usize,
    pub emission_rate: f32,
    pub accumulated_time: f32,
    pub rng: rand::rngs::ThreadRng,
}

impl Emitter {
    pub fn new(
        x: f32,
        y: f32,
        z: f32,
        max_particles: usize,
        emission_rate: f32,
    ) -> Self {
        Emitter {
            x,
            y,
            z,
            particles: Vec::with_capacity(max_particles),
            max_particles,
            emission_rate,
            accumulated_time: 0.0,
            rng: rand::thread_rng(),
        }
    }

    pub fn update(&mut self, dt: f32) {
        self.accumulated_time += dt;

        // 发射新粒子
        let particles_to_spawn = (self.accumulated_time * self.emission_rate) as usize;
        if particles_to_spawn > 0 && self.particles.len() < self.max_particles {
            let spawn_count = (self.max_particles - self.particles.len())
                .min(particles_to_spawn);
            for _ in 0..spawn_count {
                let mut particle = Particle::new();
                particle.randomize(&mut self.rng);
                particle.x += self.x;
                particle.y += self.y;
                particle.z += self.z;
                self.particles.push(particle);
            }
            self.accumulated_time -= particles_to_spawn as f32 / self.emission_rate;
        }

        // 更新粒子
        for particle in &mut self.particles {
            particle.update(dt);
        }

        // 删除死亡粒子
        self.particles.retain(|particle| !particle.is_dead());
    }

    pub fn get_vertices(&self) -> Vec<f32> {
        let mut vertices = Vec::with_capacity(self.particles.len() * 7);
        for particle in &self.particles {
            vertices.push(particle.x);
            vertices.push(particle.y);
            vertices.push(particle.z);
            vertices.push(particle.r);
            vertices.push(particle.g);
            vertices.push(particle.b);
            vertices.push(particle.a);
        }
        vertices
    }

    pub fn get_sizes(&self) -> Vec<f32> {
        let mut sizes = Vec::with_capacity(self.particles.len());
        for particle in &self.particles {
            sizes.push(particle.size);
        }
        sizes
    }
}

4.6 src/utils.rs

// src/utils.rs
pub fn set_panic_hook() {
    #[cfg(feature = "console_error_panic_hook")]
    console_error_panic_hook::set_once();
}

4.7 src/lib.rs

// src/lib.rs
use wasm_bindgen::prelude::*;
use crate::emitter::Emitter;

#[wasm_bindgen]
pub struct EmitterWrapper {
    emitter: Emitter,
}

#[wasm_bindgen]
impl EmitterWrapper {
    #[wasm_bindgen(constructor)]
    pub fn new(
        x: f32,
        y: f32,
        z: f32,
        max_particles: usize,
        emission_rate: f32,
    ) -> EmitterWrapper {
        EmitterWrapper {
            emitter: Emitter::new(x, y, z, max_particles, emission_rate),
        }
    }

    pub fn update(&mut self, dt: f32) {
        self.emitter.update(dt);
    }

    pub fn get_vertices(&self) -> Vec<f32> {
        self.emitter.get_vertices()
    }

    pub fn get_sizes(&self) -> Vec<f32> {
        self.emitter.get_sizes()
    }

    pub fn get_count(&self) -> usize {
        self.emitter.particles.len()
    }
}

#[wasm_bindgen]
pub fn init_panic_hook() {
    utils::set_panic_hook();
}

4.8 static/style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}
body {
    background-color: #000000;
    overflow: hidden;
}
canvas {
    display: block;
}
.controls {
    position: absolute;
    top: 20px;
    left: 20px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    padding: 20px;
    color: #ffffff;
}
.controls h2 {
    margin-bottom: 20px;
    font-size: 18px;
}
.controls .emitter {
    margin-bottom: 20px;
}
.controls .emitter label {
    display: block;
    margin-bottom: 5px;
    font-size: 14px;
}
.controls .emitter input {
    width: 100%;
    padding: 8px;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 14px;
    background-color: rgba(255, 255, 255, 0.2);
    color: #ffffff;
}
.controls .emitter input::placeholder {
    color: #cccccc;
}
.controls .emitter button {
    width: 100%;
    padding: 8px 16px;
    background-color: #007bff;
    color: #ffffff;
    border: none;
    border-radius: 4px;
    font-size: 14px;
    cursor: pointer;
}
.controls .emitter button:hover {
    background-color: #0056b3;
}
.controls .stats {
    margin-bottom: 20px;
    font-size: 14px;
}
.controls .stats div {
    margin-bottom: 5px;
}
.controls .reset {
    margin-bottom: 20px;
}
.controls .reset button {
    width: 100%;
    padding: 8px 16px;
    background-color: #6c757d;
    color: #ffffff;
    border: none;
    border-radius: 4px;
    font-size: 14px;
    cursor: pointer;
}
.controls .reset button:hover {
    background-color: #5a6268;
}

4.9 static/main.js

// static/main.js
import * as THREE from 'three';
import Stats from 'three/examples/jsm/libs/stats.module.js';
import init, { EmitterWrapper, init_panic_hook } from '../pkg/particle_system.js';

async function run() {
  await init();
  init_panic_hook();
  console.log('WebAssembly 模块加载成功');

  // 初始化 Stats
  const stats = new Stats();
  stats.domElement.style.position = 'absolute';
  stats.domElement.style.top = '20px';
  stats.domElement.style.right = '20px';
  document.body.appendChild(stats.domElement);

  // 创建场景
  const scene = new THREE.Scene();
  scene.background = new THREE.Color(0x000000);

  // 创建相机
  const camera = new THREE.PerspectiveCamera(
    75,
    window.innerWidth / window.innerHeight,
    0.1,
    1000
  );
  camera.position.z = 10;

  // 创建渲染器
  const renderer = new THREE.WebGLRenderer({ antialias: true });
  renderer.setSize(window.innerWidth, window.innerHeight);
  renderer.setPixelRatio(window.devicePixelRatio);
  document.body.appendChild(renderer.domElement);

  // 创建 Rust Wasm 粒子发射器
  const maxParticles = 100000;
  const emissionRate = 10000;
  const emitter = new EmitterWrapper(0, 0, 0, maxParticles, emissionRate);

  // 创建几何体
  const geometry = new THREE.BufferGeometry();
  const vertices = emitter.get_vertices();
  geometry.setAttribute(
    'position',
    new THREE.Float32BufferAttribute(
      vertices.slice(0, vertices.length / 7 * 3),
      3
    )
  );
  geometry.setAttribute(
    'color',
    new THREE.Float32BufferAttribute(
      vertices.slice(vertices.length / 7 * 3),
      4
    )
  );
  const sizes = emitter.get_sizes();
  geometry.setAttribute('size', new THREE.Float32BufferAttribute(sizes, 1));

  // 创建纹理
  const canvas = document.createElement('canvas');
  canvas.width = 32;
  canvas.height = 32;
  const ctx = canvas.getContext('2d');
  const gradient = ctx.createRadialGradient(16, 16, 0, 16, 16, 16);
  gradient.addColorStop(0, 'rgba(255, 255, 255, 1)');
  gradient.addColorStop(0.5, 'rgba(255, 255, 255, 0.5)');
  gradient.addColorStop(1, 'rgba(255, 255, 255, 0)');
  ctx.fillStyle = gradient;
  ctx.fillRect(0, 0, 32, 32);
  const texture = new THREE.CanvasTexture(canvas);

  // 创建材质
  const material = new THREE.ShaderMaterial({
    uniforms: {
      pointTexture: { value: texture },
    },
    vertexShader: `
      attribute float size;
      attribute vec4 color;
      varying vec4 vColor;
      void main() {
        vColor = color;
        vec4 mvPosition = modelViewMatrix * vec4(position, 1.0);
        gl_PointSize = size * (300.0 / -mvPosition.z);
        gl_Position = projectionMatrix * mvPosition;
      }
    `,
    fragmentShader: `
      uniform sampler2D pointTexture;
      varying vec4 vColor;
      void main() {
        gl_FragColor = vColor * texture2D(pointTexture, gl_PointCoord);
      }
    `,
    blending: THREE.AdditiveBlending,
    depthTest: false,
    transparent: true,
    vertexColors: true,
  });

  // 创建粒子系统
  const particles = new THREE.Points(geometry, material);
  scene.add(particles);

  // 创建光源
  const ambientLight = new THREE.AmbientLight(0x404040);
  scene.add(ambientLight);
  const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
  directionalLight.position.set(1, 1, 1);
  scene.add(directionalLight);

  // 创建控制器
  const controlsDiv = document.createElement('div');
  controlsDiv.className = 'controls';
  controlsDiv.innerHTML = `
    <h2>粒子系统控制器</h2>
    <div>
      <label for="x">X 坐标</label>
      <input type="number" value="0" step="0.1">
      <label for="y">Y 坐标</label>
      <input type="number" value="0" step="0.1">
      <label for="z">Z 坐标</label>
      <input type="number" value="0" step="0.1">
      <label for="maxParticles">最大粒子数</label>
      <input type="number" value="${maxParticles}" step="1000">
      <label for="emissionRate">发射率</label>
      <input type="number" value="${emissionRate}" step="1000">
      <button>更新发射器</button>
    </div>
    <div>
      <div>粒子数：<span>${emitter.get_count()}</span></div>
      <div>FPS：<span>0</span></div>
    </div>
    <div>
      <button>重置</button>
    </div>
  `;
  document.body.appendChild(controlsDiv);

  // 绑定事件
  const xInput = document.getElementById('x');
  const yInput = document.getElementById('y');
  const zInput = document.getElementById('z');
  const maxParticlesInput = document.getElementById('maxParticles');
  const emissionRateInput = document.getElementById('emissionRate');
  const updateEmitterButton = document.getElementById('updateEmitter');
  const resetButton = document.getElementById('reset');
  const particleCountSpan = document.getElementById('particleCount');
  const fpsSpan = document.getElementById('fps');

  updateEmitterButton.addEventListener('click', () => {
    const x = parseFloat(xInput.value);
    const y = parseFloat(yInput.value);
    const z = parseFloat(zInput.value);
    const newMaxParticles = parseInt(maxParticlesInput.value);
    const newEmissionRate = parseInt(emissionRateInput.value);
    emitter.x = x;
    emitter.y = y;
    emitter.z = z;
    emitter.max_particles = newMaxParticles;
    emitter.emission_rate = newEmissionRate;
  });

  resetButton.addEventListener('click', () => {
    xInput.value = '0';
    yInput.value = '0';
    zInput.value = '0';
    maxParticlesInput.value = maxParticles.toString();
    emissionRateInput.value = emissionRate.toString();
    emitter.x = 0;
    emitter.y = 0;
    emitter.z = 0;
    emitter.max_particles = maxParticles;
    emitter.emission_rate = emissionRate;
    particles.geometry.setAttribute('position', new THREE.Float32BufferAttribute([], 3));
    particles.geometry.setAttribute('color', new THREE.Float32BufferAttribute([], 4));
    particles.geometry.setAttribute('size', new THREE.Float32BufferAttribute([], 1));
  });

  // 动画循环
  let lastTime = performance.now();
  function animate() {
    stats.begin();
    const currentTime = performance.now();
    const dt = (currentTime - lastTime) / 1000; // 转换为秒
    lastTime = currentTime;

    // 更新粒子发射器
    emitter.update(dt);

    // 更新粒子数据
    const vertices = emitter.get_vertices();
    const sizes = emitter.get_sizes();
    if (vertices.length > 0) {
      particles.geometry.attributes.position.array = new Float32Array(
        vertices.slice(0, vertices.length / 7 * 3)
      );
      particles.geometry.attributes.color.array = new Float32Array(
        vertices.slice(vertices.length / 7 * 3)
      );
      particles.geometry.attributes.size.array = new Float32Array(sizes);
      particles.geometry.attributes.position.needsUpdate = true;
      particles.geometry.attributes.color.needsUpdate = true;
      particles.geometry.attributes.size.needsUpdate = true;
      particles.geometry.computeBoundingSphere();
    }

    // 更新统计信息
    particleCountSpan.textContent = emitter.get_count();
    fpsSpan.textContent = Math.round(1 / dt);

    // 相机围绕场景旋转
    camera.position.x = Math.sin(currentTime * 0.0005) * 10;
    camera.position.z = Math.cos(currentTime * 0.0005) * 10;
    camera.lookAt(0, 0, 0);

    renderer.render(scene, camera);
    stats.end();
    requestAnimationFrame(animate);
  }
  animate();

  // 窗口大小调整
  window.addEventListener('resize', () => {
    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();
    renderer.setSize(window.innerWidth, window.innerHeight);
  });
}
run();

4.10 static/index.html

<!-- static/index.html -->
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Rust WebAssembly 粒子系统</title>
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <script type="module"> import './main.js'; </script>
</body>
</html>

4.11 编译项目

wasm-pack build --target web

4.12 测试项目

npx serve .

在浏览器中访问 http://localhost:3000/static/index.html，查看粒子系统的效果。

五、性能优化

5.1 编译器优化

在 Cargo.toml 中添加优化配置：

[profile.release]
lto = true
codegen-units = 1
opt-level = 3

5.2 数据布局优化

使用 #[repr(C)] 属性对齐结构体，减少内存对齐开销：

// src/particle.rs
#[repr(C)]
#[derive(Debug, Clone, Copy, Serialize)]
pub struct Particle {
    pub x: f32,
    pub y: f32,
    pub z: f32,
    pub vx: f32,
    pub vy: f32,
    pub vz: f32,
    pub ax: f32,
    pub ay: f32,
    pub az: f32,
    pub r: f32,
    pub g: f32,
    pub b: f32,
    pub a: f32,
    pub size: f32,
    pub lifetime: f32,
    pub max_lifetime: f32,
}

5.3 内存管理优化

使用栈分配代替堆分配，减少内存分配次数：

// src/particle.rs
impl Particle {
    pub fn update(&mut self, dt: f32) {
        self.vx += self.ax * dt;
        self.vy += self.ay * dt;
        self.vz += self.az * dt;
        self.x += self.vx * dt;
        self.y += self.vy * dt;
        self.z += self.vz * dt;
        self.lifetime += dt;
        self.a = 1.0 - self.lifetime / self.max_lifetime;
        self.size = 0.05 * (1.0 - self.lifetime / self.max_lifetime);
    }
}

5.4 算法优化

使用 SIMD 指令优化粒子更新算法：

// src/particle.rs
#[cfg(target_arch = "wasm32")]
use wasm_simd::*;

impl Particle {
    #[cfg(target_arch = "wasm32")]
    pub fn update_batch(particles: &mut [Particle], dt: f32) {
        const BATCH_SIZE: usize = 8; // 每次处理 8 个粒子
        for i in (0..particles.len()).step_by(BATCH_SIZE) {
            let batch_end = (i + BATCH_SIZE).min(particles.len());
            let batch = &mut particles[i..batch_end];
            let dt_vec = f32x4_splat(dt);
            for particle in batch {
                // 计算加速度
                let ax = f32x4_splat(particle.ax);
                let ay = f32x4_splat(particle.ay);
                let az = f32x4_splat(particle.az);
                let a_vec = f32x4(particle.ax, particle.ay, particle.az, 0.0);

                // 计算速度
                let vx = f32x4_splat(particle.vx);
                let vy = f32x4_splat(particle.vy);
                let vz = f32x4_splat(particle.vz);
                let v_vec = f32x4(particle.vx, particle.vy, particle.vz, 0.0);
                let v_new = v_vec + a_vec * dt_vec;
                particle.vx = f32x4_extract_lane(v_new, 0);
                particle.vy = f32x4_extract_lane(v_new, 1);
                particle.vz = f32x4_extract_lane(v_new, 2);

                // 计算位置
                let x = f32x4_splat(particle.x);
                let y = f32x4_splat(particle.y);
                let z = f32x4_splat(particle.z);
                let pos_vec = f32x4(particle.x, particle.y, particle.z, 0.0);
                let pos_new = pos_vec + v_new * dt_vec;
                particle.x = f32x4_extract_lane(pos_new, 0);
                particle.y = f32x4_extract_lane(pos_new, 1);
                particle.z = f32x4_extract_lane(pos_new, 2);

                // 计算生命周期和透明度
                particle.lifetime += dt;
                particle.a = 1.0 - particle.lifetime / particle.max_lifetime;
                particle.size = 0.05 * (1.0 - particle.lifetime / particle.max_lifetime);
            }
        }
    }
}

5.5 Web Workers 并行计算

使用 Web Workers 将粒子更新任务并行化：

// static/worker.js
import init, { EmitterWrapper, init_panic_hook } from '../pkg/particle_system.js';

let emitter;
let maxParticles;
let emissionRate;

self.onmessage = async (e) => {
  const { type, data } = e.data;
  switch (type) {
    case 'init':
      await init();
      init_panic_hook();
      maxParticles = data.maxParticles;
      emissionRate = data.emissionRate;
      emitter = new EmitterWrapper(data.x, data.y, data.z, data.maxParticles, data.emissionRate);
      break;
    case 'update':
      emitter.update(data.dt);
      const vertices = emitter.get_vertices();
      const sizes = emitter.get_sizes();
      const count = emitter.get_count();
      self.postMessage({
        type: 'update',
        data: { vertices, sizes, count },
      });
      break;
    case 'updateEmitter':
      emitter.x = data.x;
      emitter.y = data.y;
      emitter.z = data.z;
      if (data.maxParticles !== maxParticles) {
        maxParticles = data.maxParticles;
        emitter.max_particles = maxParticles;
      }
      if (data.emissionRate !== emissionRate) {
        emissionRate = data.emissionRate;
        emitter.emission_rate = emissionRate;
      }
      break;
    case 'reset':
      emitter.x = 0;
      emitter.y = 0;
      emitter.z = 0;
      emitter.max_particles = maxParticles;
      emitter.emission_rate = emissionRate;
      self.postMessage({ type: 'reset' });
      break;
  }
};

然后，在主进程中使用 Web Workers：

// static/main.js
const worker = new Worker('worker.js', { type: 'module' });

// 初始化 Web Workers
worker.postMessage({
  type: 'init',
  data: {
    x: 0,
    y: 0,
    z: 0,
    maxParticles: 100000,
    emissionRate: 10000,
  },
});

// 更新粒子发射器
worker.postMessage({
  type: 'updateEmitter',
  data: {
    x: parseFloat(xInput.value),
    y: parseFloat(yInput.value),
    z: parseFloat(zInput.value),
    maxParticles: parseInt(maxParticlesInput.value),
    emissionRate: parseInt(emissionRateInput.value),
  },
});

// 更新粒子
worker.postMessage({
  type: 'update',
  data: {
    dt: (currentTime - lastTime) / 1000,
  },
});

// 监听 Web Workers 消息
worker.onmessage = (e) => {
  const { type, data } = e.data;
  switch (type) {
    case 'update':
      const vertices = data.vertices;
      const sizes = data.sizes;
      if (vertices.length > 0) {
        particles.geometry.attributes.position.array = new Float32Array(
          vertices.slice(0, vertices.length / 7 * 3)
        );
        particles.geometry.attributes.color.array = new Float32Array(
          vertices.slice(vertices.length / 7 * 3)
        );
        particles.geometry.attributes.size.array = new Float32Array(sizes);
        particles.geometry.attributes.position.needsUpdate = true;
        particles.geometry.attributes.color.needsUpdate = true;
        particles.geometry.attributes.size.needsUpdate = true;
        particles.geometry.computeBoundingSphere();
      }
      particleCountSpan.textContent = data.count;
      break;
    case 'reset':
      particles.geometry.setAttribute('position', new THREE.Float32BufferAttribute([], 3));
      particles.geometry.setAttribute('color', new THREE.Float32BufferAttribute([], 4));
      particles.geometry.setAttribute('size', new THREE.Float32BufferAttribute([], 1));
      break;
  }
};

六、项目部署

6.1 使用 Vite 打包

安装 Vite：

npm init -y
npm install -D vite

创建 vite.config.js：

import { defineConfig } from 'vite';
export default defineConfig({
  root: 'static',
  build: {
    outDir: '../dist',
    assetsDir: 'assets',
    rollupOptions: {
      input: {
        main: './static/index.html',
      },
    },
  },
  server: {
    port: 3000,
    open: true,
  },
});

在 package.json 中添加脚本：

{
  "name": "particle-system",
  "version": "1.0.0",
  "type": "module",
  "scripts": {
    "dev": "vite",
    "build": "vite build",
    "preview": "vite preview"
  },
  "devDependencies": {
    "vite": "^5.0.0"
  },
  "dependencies": {
    "three": "^0.160.0"
  }
}

6.2 部署到 Netlify

创建 netlify.toml：

[build]
base = "static"
publish = "dist"
command = "npm run build"

在 Netlify 上创建项目，连接到 GitHub 仓库，部署项目。

6.3 部署到 Vercel

创建 vercel.json：

{
  "buildCommand": "npm run build",
  "outputDirectory": "dist",
  "devCommand": "npm run dev",
  "framework": "vite"
}

在 Vercel 上创建项目，连接到 GitHub 仓库，部署项目。

七、总结

本文介绍了如何使用 Rust WebAssembly 与 Three.js 结合开发高性能粒子系统，实现了粒子的创建、更新、删除，以及各种动画效果。通过 Rust 的高性能和内存安全特性，粒子系统可以支持大量粒子（百万级）的渲染，提供了出色的性能和用户体验。

7.1 技术栈

• Rust：开发语言
• wasm-bindgen：Rust 与 JavaScript 交互库
• web-sys：Web API 封装库
• wasm-pack：WebAssembly 开发工具
• Three.js：3D 图形库
• Vite：打包工具
• HTML/CSS/JavaScript：前端开发语言

7.2 核心功能

• 粒子管理：粒子的创建、更新、删除
• 粒子属性：位置、速度、加速度、生命周期、颜色、大小、透明度
• 粒子动画：爆炸、火焰、雪花、星云等
• 性能优化：编译器优化、数据布局优化、内存管理优化、算法优化、Web Workers 并行计算

7.3 未来改进

• 添加更多粒子类型：如雪花粒子、火焰粒子、爆炸粒子、星云粒子等
• 添加物理引擎：支持重力、风力、碰撞检测等物理效果
• 添加用户界面优化：如拖拽发射器、实时调整参数、保存和加载配置等
• 添加网络支持：支持多人协同操作和数据同步
• 优化性能：使用 WebGL2、WebGPU、WebVR/AR 等技术提高渲染性能

通过本文的学习，读者可以深入理解 Rust WebAssembly 与 Three.js 结合开发 3D 数据可视化应用的工作原理和实现方法，并在实际项目中应用这些技术。同时，本文也介绍了如何优化粒子系统的性能，帮助读者构建高性能的 3D 数据可视化应用。