Three.js结合Cannon.js实现简单物理模拟应用

<script src="https://cdn.jsdelivr.net/npm/three@0.131.2/build/three.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/cannon@0.6.2/build/cannon.min.js"></script>

// 创建 Three.js 场景
const scene = new THREE.Scene();
// 创建 Cannon.js 物理世界
const world = new CANNON.World();
world.gravity.set(0, -9.82, 0);

// 创建一个立方体
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshBasicMaterial({ color: 0x00ff00 });
const cube = new THREE.Mesh(geometry, material);
// 将立方体添加到场景中
scene.add(cube);

// 创建 Cannon.js 物体
const shape = new CANNON.Box(new CANNON.Vec3(0.5, 0.5, 0.5));
const body = new CANNON.Body({ mass: 1 });
body.addShape(shape);
// 将 Cannon.js 物体与 Three.js 对象关联起来
const cubeBody = new THREE.Object3D();
cubeBody.position.copy(cube.position);
scene.add(cubeBody);
world.addBody(body);

function animate() {
  requestAnimationFrame(animate);
  // 更新 Cannon.js 物理世界
  world.step(1 / 60);
  // 更新 Three.js 对象的位置
  cube.position.copy(body.position);
  cube.quaternion.copy(body.quaternion);
  // 渲染场景
  renderer.render(scene, camera);
}
animate();

// 创建场景、相机和渲染器
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 1, 100000);
const renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
camera.position.set(0, 15, 25)
scene.fog = new THREE.Fog(0xffffff, 0, 500);
// 创建 Cannon.js 物理世界
const world = new CANNON.World();
world.gravity.set(0, -9.82, 0);
// 创建地面
const groundShape = new CANNON.Plane();
const groundBody = new CANNON.Body({ mass: 0 });
groundBody.addShape(groundShape);
groundBody.quaternion.setFromAxisAngle(new CANNON.Vec3(1, 0, 0), -Math.PI / 2);
// 将地面添加到场景中
const groundMaterial = new THREE.MeshBasicMaterial({ color: 0x999999 });
const groundGeometry = new THREE.PlaneGeometry(10000, 10000);
const ground = new THREE.Mesh(groundGeometry, groundMaterial);
ground.rotation.x = -Math.PI / 2;
scene.add(ground);
// 将 Cannon.js 物体与 Three.js 对象关联起来
const groundBodyMesh = new THREE.Object3D();
groundBodyMesh.position.copy(ground.position);
scene.add(groundBodyMesh);
world.addBody(groundBody);
// 灯光
const light = new THREE.DirectionalLight(0xffffff, 1);
light.position.set(0, 20, 10);
scene.add(light);
// 半球光
const light2 = new THREE.HemisphereLight(0xffffbb, 0x080820, 1);
scene.add(light2);
new THREE.OrbitControls(camera, renderer.domElement);
function createBall() {
  // 创建小球
  const radius = 5;
  const segments = 32;
  const geometry = new THREE.SphereGeometry(radius, segments, segments);
  // phhong材质
  const material = new THREE.MeshPhongMaterial({ color: 0xff0000 });
  const ball = new THREE.Mesh(geometry, material);
  // 设置小球的初始位置
  // x z 位置随机
  const x = Math.random() * 4 - 2;
  const z = Math.random() * 4 - 2;
  ball.position.set(x, 25, z);
  // 将小球添加到场景中
  scene.add(ball);
  // 创建 Cannon.js 物体
  const shape = new CANNON.Sphere(radius);
  const body = new CANNON.Body({ mass: 1 });
  body.addShape(shape);
  // 设置小球的初始位置和速度
  body.position.set(x, 25, z);
  body.velocity.set(0, -9.82, 0);
  // 将 Cannon.js 物体与 Three.js 对象关联起来
  const ballBody = new THREE.Object3D();
  ballBody.position.copy(ball.position);
  scene.add(ballBody);
  world.addBody(body);
  function animateBall() {
    // 更新 Cannon.js 物理世界
    world.step(1 / 60);
    // 更新 Three.js 对象的位置
    ball.position.copy(body.position);
    ball.quaternion.copy(body.quaternion);
    if (body.position.y < 0) {
      scene.remove(ball);
      world.removeBody(body);
      clearInterval(intervalId);
    }
    renderer.render(scene, camera);
  }
  const intervalId = setInterval(animateBall, 1000 / 60);
}
createBall();
setInterval(createBall, 3000);
function animate() {
  requestAnimationFrame(animate);
  renderer.render(scene, camera);
}
animate();