three.js/examples/js/physics/OimoPhysics.js

( function () {
import { World, Vec3, OBoxGeometry, OSphereGeometry, ShapeConfig, RigidBodyConfig, RigidBodyType, RigidBody, Shape } from '../libs/OimoPhysics/index.js';

async function OimoPhysics() {
  const frameRate = 60;
  const world = new World(2, new Vec3(0, -9.8, 0)); //

  function getShape(geometry) {
    const parameters = geometry.parameters; // TODO change type to is*

    if (geometry.type === 'BoxGeometry') {
      const sx = parameters.width !== undefined ? parameters.width / 2 : 0.5;
      const sy = parameters.height !== undefined ? parameters.height / 2 : 0.5;
      const sz = parameters.depth !== undefined ? parameters.depth / 2 : 0.5;
      return new OBoxGeometry(new Vec3(sx, sy, sz));
    } else if (geometry.type === 'SphereGeometry' || geometry.type === 'IcosahedronGeometry') {
      const radius = parameters.radius !== undefined ? parameters.radius : 1;
      return new OSphereGeometry(radius);
    }

    return null;
  }

  const meshes = [];
  const meshMap = new WeakMap();

  function addMesh(mesh, mass = 0) {
    const shape = getShape(mesh.geometry);

    if (shape !== null) {
      if (mesh.isInstancedMesh) {
        handleInstancedMesh(mesh, mass, shape);
      } else if (mesh.isMesh) {
        handleMesh(mesh, mass, shape);
      }
    }
  }

  function handleMesh(mesh, mass, shape) {
    const shapeConfig = new ShapeConfig();
    shapeConfig.geometry = shape;
    const bodyConfig = new RigidBodyConfig();
    bodyConfig.type = mass === 0 ? RigidBodyType.STATIC : RigidBodyType.DYNAMIC;
    bodyConfig.position = new Vec3(mesh.position.x, mesh.position.y, mesh.position.z);
    const body = new RigidBody(bodyConfig);
    body.addShape(new Shape(shapeConfig));
    world.addRigidBody(body);

    if (mass > 0) {
      meshes.push(mesh);
      meshMap.set(mesh, body);
    }
  }

  function handleInstancedMesh(mesh, mass, shape) {
    const array = mesh.instanceMatrix.array;
    const bodies = [];

    for (let i = 0; i < mesh.count; i++) {
      const index = i * 16;
      const shapeConfig = new ShapeConfig();
      shapeConfig.geometry = shape;
      const bodyConfig = new RigidBodyConfig();
      bodyConfig.type = mass === 0 ? RigidBodyType.STATIC : RigidBodyType.DYNAMIC;
      bodyConfig.position = new Vec3(array[index + 12], array[index + 13], array[index + 14]);
      const body = new RigidBody(bodyConfig);
      body.addShape(new Shape(shapeConfig));
      world.addRigidBody(body);
      bodies.push(body);
    }

    if (mass > 0) {
      meshes.push(mesh);
      meshMap.set(mesh, bodies);
    }
  } //


  function setMeshPosition(mesh, position, index = 0) {
    if (mesh.isInstancedMesh) {
      const bodies = meshMap.get(mesh);
      const body = bodies[index];
      body.setPosition(new Vec3(position.x, position.y, position.z));
    } else if (mesh.isMesh) {
      const body = meshMap.get(mesh);
      body.setPosition(new Vec3(position.x, position.y, position.z));
    }
  } //


  let lastTime = 0;

  function step() {
    const time = performance.now();

    if (lastTime > 0) {
      // console.time( 'world.step' );
      world.step(1 / frameRate); // console.timeEnd( 'world.step' );
    }

    lastTime = time; //

    for (let i = 0, l = meshes.length; i < l; i++) {
      const mesh = meshes[i];

      if (mesh.isInstancedMesh) {
        const array = mesh.instanceMatrix.array;
        const bodies = meshMap.get(mesh);

        for (let j = 0; j < bodies.length; j++) {
          const body = bodies[j];
          compose(body.getPosition(), body.getOrientation(), array, j * 16);
        }

        mesh.instanceMatrix.needsUpdate = true;
      } else if (mesh.isMesh) {
        const body = meshMap.get(mesh);
        mesh.position.copy(body.getPosition());
        mesh.quaternion.copy(body.getOrientation());
      }
    }
  } // animate


  setInterval(step, 1000 / frameRate);
  return {
    addMesh: addMesh,
    setMeshPosition: setMeshPosition // addCompoundMesh

  };
}

function compose(position, quaternion, array, index) {
  const x = quaternion.x,
        y = quaternion.y,
        z = quaternion.z,
        w = quaternion.w;
  const x2 = x + x,
        y2 = y + y,
        z2 = z + z;
  const xx = x * x2,
        xy = x * y2,
        xz = x * z2;
  const yy = y * y2,
        yz = y * z2,
        zz = z * z2;
  const wx = w * x2,
        wy = w * y2,
        wz = w * z2;
  array[index + 0] = 1 - (yy + zz);
  array[index + 1] = xy + wz;
  array[index + 2] = xz - wy;
  array[index + 3] = 0;
  array[index + 4] = xy - wz;
  array[index + 5] = 1 - (xx + zz);
  array[index + 6] = yz + wx;
  array[index + 7] = 0;
  array[index + 8] = xz + wy;
  array[index + 9] = yz - wx;
  array[index + 10] = 1 - (xx + yy);
  array[index + 11] = 0;
  array[index + 12] = position.x;
  array[index + 13] = position.y;
  array[index + 14] = position.z;
  array[index + 15] = 1;
}

THREE.OimoPhysics = OimoPhysics;
} )();