Accueil / npm / three@0.186.1 / examples / jsm / physics / AmmoPhysics.js
AmmoPhysics.js
const AMMO_PATH = 'https://cdn.jsdelivr.net/gh/kripken/ammo.js@79190a1f03845794b1bba1777f30037349967658/builds/ammo.wasm.js';
/**
* @classdesc Can be used to include Ammo.js as a Physics engine into
* `three.js` apps. The API can be initialized via:
* ```js
* const physics = await AmmoPhysics();
* ```
* The component automatically imports Ammo.js from a CDN so make sure
* to use the component with an active Internet connection.
*
* @name AmmoPhysics
* @class
* @hideconstructor
* @three_import import { AmmoPhysics } from 'three/addons/physics/AmmoPhysics.js';
*/
async function AmmoPhysics() {
if ( typeof Ammo === 'undefined' ) {
await new Promise( ( resolve, reject ) => {
const script = document.createElement( 'script' );
script.src = AMMO_PATH;
script.onload = resolve;
script.onerror = reject;
document.head.appendChild( script );
} );
}
const AmmoLib = await Ammo();
const frameRate = 60;
const collisionConfiguration = new AmmoLib.btDefaultCollisionConfiguration();
const dispatcher = new AmmoLib.btCollisionDispatcher( collisionConfiguration );
const broadphase = new AmmoLib.btDbvtBroadphase();
const solver = new AmmoLib.btSequentialImpulseConstraintSolver();
const world = new AmmoLib.btDiscreteDynamicsWorld( dispatcher, broadphase, solver, collisionConfiguration );
world.setGravity( new AmmoLib.btVector3( 0, - 9.8, 0 ) );
const worldTransform = new AmmoLib.btTransform();
//
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;
const shape = new AmmoLib.btBoxShape( new AmmoLib.btVector3( sx, sy, sz ) );
shape.setMargin( 0.05 );
return shape;
} else if ( geometry.type === 'SphereGeometry' || geometry.type === 'IcosahedronGeometry' ) {
const radius = parameters.radius !== undefined ? parameters.radius : 1;
const shape = new AmmoLib.btSphereShape( radius );
shape.setMargin( 0.05 );
return shape;
}
console.error( 'AmmoPhysics: Unsupported geometry type:', geometry.type );
return null;
}
const meshes = [];
const meshMap = new WeakMap();
function addScene( scene ) {
scene.traverse( function ( child ) {
if ( child.isMesh ) {
const physics = child.userData.physics;
if ( physics ) {
addMesh( child, physics.mass, physics.restitution );
}
}
} );
}
function addMesh( mesh, mass = 0, restitution = 0 ) {
const shape = getShape( mesh.geometry );
if ( shape !== null ) {
if ( mesh.isInstancedMesh ) {
handleInstancedMesh( mesh, shape, mass, restitution );
} else if ( mesh.isMesh ) {
handleMesh( mesh, shape, mass, restitution );
}
}
}
function handleMesh( mesh, shape, mass, restitution ) {
const position = mesh.position;
const quaternion = mesh.quaternion;
const transform = new AmmoLib.btTransform();
transform.setIdentity();
transform.setOrigin( new AmmoLib.btVector3( position.x, position.y, position.z ) );
transform.setRotation( new AmmoLib.btQuaternion( quaternion.x, quaternion.y, quaternion.z, quaternion.w ) );
const motionState = new AmmoLib.btDefaultMotionState( transform );
const localInertia = new AmmoLib.btVector3( 0, 0, 0 );
shape.calculateLocalInertia( mass, localInertia );
const rbInfo = new AmmoLib.btRigidBodyConstructionInfo( mass, motionState, shape, localInertia );
rbInfo.set_m_restitution( restitution );
const body = new AmmoLib.btRigidBody( rbInfo );
// body.setFriction( 4 );
world.addRigidBody( body );
if ( mass > 0 ) {
meshes.push( mesh );
meshMap.set( mesh, body );
}
}
function handleInstancedMesh( mesh, shape, mass, restitution ) {
const array = mesh.instanceMatrix.array;
const bodies = [];
for ( let i = 0; i < mesh.count; i ++ ) {
const index = i * 16;
const transform = new AmmoLib.btTransform();
transform.setFromOpenGLMatrix( array.slice( index, index + 16 ) );
const motionState = new AmmoLib.btDefaultMotionState( transform );
const localInertia = new AmmoLib.btVector3( 0, 0, 0 );
shape.calculateLocalInertia( mass, localInertia );
const rbInfo = new AmmoLib.btRigidBodyConstructionInfo( mass, motionState, shape, localInertia );
rbInfo.set_m_restitution( restitution );
const body = new AmmoLib.btRigidBody( rbInfo );
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.setAngularVelocity( new AmmoLib.btVector3( 0, 0, 0 ) );
body.setLinearVelocity( new AmmoLib.btVector3( 0, 0, 0 ) );
worldTransform.setIdentity();
worldTransform.setOrigin( new AmmoLib.btVector3( position.x, position.y, position.z ) );
body.setWorldTransform( worldTransform );
} else if ( mesh.isMesh ) {
const body = meshMap.get( mesh );
body.setAngularVelocity( new AmmoLib.btVector3( 0, 0, 0 ) );
body.setLinearVelocity( new AmmoLib.btVector3( 0, 0, 0 ) );
worldTransform.setIdentity();
worldTransform.setOrigin( new AmmoLib.btVector3( position.x, position.y, position.z ) );
body.setWorldTransform( worldTransform );
}
}
//
let lastTime = 0;
function step() {
const time = performance.now();
if ( lastTime > 0 ) {
const delta = ( time - lastTime ) / 1000;
world.stepSimulation( delta, 10 );
//
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 ];
const motionState = body.getMotionState();
motionState.getWorldTransform( worldTransform );
const position = worldTransform.getOrigin();
const quaternion = worldTransform.getRotation();
compose( position, quaternion, array, j * 16 );
}
mesh.instanceMatrix.needsUpdate = true;
mesh.computeBoundingSphere();
} else if ( mesh.isMesh ) {
const body = meshMap.get( mesh );
const motionState = body.getMotionState();
motionState.getWorldTransform( worldTransform );
const position = worldTransform.getOrigin();
const quaternion = worldTransform.getRotation();
mesh.position.set( position.x(), position.y(), position.z() );
mesh.quaternion.set( quaternion.x(), quaternion.y(), quaternion.z(), quaternion.w() );
}
}
}
lastTime = time;
}
// animate
setInterval( step, 1000 / frameRate );
return {
/**
* Adds the given scene to this physics simulation. Only meshes with a
* `physics` object in their {@link Object3D#userData} field will be honored.
* The object can be used to store the mass of the mesh. E.g.:
* ```js
* box.userData.physics = { mass: 1 };
* ```
*
* @method
* @name AmmoPhysics#addScene
* @param {Object3D} scene The scene or any type of 3D object to add.
*/
addScene: addScene,
/**
* Adds the given mesh to this physics simulation.
*
* @method
* @name AmmoPhysics#addMesh
* @param {Mesh} mesh The mesh to add.
* @param {number} [mass=0] The mass in kg of the mesh.
* @param {number} [restitution=0] The restitution of the mesh, usually from 0 to 1. Represents how "bouncy" objects are when they collide with each other.
*/
addMesh: addMesh,
/**
* Set the position of the given mesh which is part of the physics simulation. Calling this
* method will reset the current simulated velocity of the mesh.
*
* @method
* @name AmmoPhysics#setMeshPosition
* @param {Mesh} mesh The mesh to update the position for.
* @param {Vector3} position - The new position.
* @param {number} [index=0] - If the mesh is instanced, the index represents the instanced ID.
*/
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;
}
export { AmmoPhysics };