three
Version:
JavaScript 3D library
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JavaScript
import { Clock, Vector3, Quaternion, Matrix4 } from 'three';
const RAPIER_PATH = 'https://cdn.skypack.dev/@dimforge/rapier3d-compat@0.12.0';
const frameRate = 60;
const _scale = new Vector3( 1, 1, 1 );
const ZERO = new Vector3();
let RAPIER = null;
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 RAPIER.ColliderDesc.cuboid( sx, sy, sz );
} else if ( geometry.type === 'SphereGeometry' || geometry.type === 'IcosahedronGeometry' ) {
const radius = parameters.radius !== undefined ? parameters.radius : 1;
return RAPIER.ColliderDesc.ball( radius );
} else if ( geometry.type === 'CylinderGeometry' ) {
const radius = parameters.radiusBottom !== undefined ? parameters.radiusBottom : 0.5;
const length = parameters.height !== undefined ? parameters.height : 0.5;
return RAPIER.ColliderDesc.cylinder( length / 2, radius );
} else if ( geometry.type === 'CapsuleGeometry' ) {
const radius = parameters.radius !== undefined ? parameters.radius : 0.5;
const length = parameters.height !== undefined ? parameters.height : 0.5;
return RAPIER.ColliderDesc.capsule( length / 2, radius );
} else if ( geometry.type === 'BufferGeometry' ) {
const vertices = [];
const vertex = new Vector3();
const position = geometry.getAttribute( 'position' );
for ( let i = 0; i < position.count; i ++ ) {
vertex.fromBufferAttribute( position, i );
vertices.push( vertex.x, vertex.y, vertex.z );
}
// if the buffer is non-indexed, generate an index buffer
const indices = geometry.getIndex() === null
? Uint32Array.from( Array( parseInt( vertices.length / 3 ) ).keys() )
: geometry.getIndex().array;
return RAPIER.ColliderDesc.trimesh( vertices, indices );
}
return null;
}
/**
* @classdesc Can be used to include Rapier as a Physics engine into
* `three.js` apps. The API can be initialized via:
* ```js
* const physics = await RapierPhysics();
* ```
* The component automatically imports Rapier from a CDN so make sure
* to use the component with an active Internet connection.
*
* @name RapierPhysics
* @class
* @hideconstructor
* @three_import import { RapierPhysics } from 'three/addons/physics/RapierPhysics.js';
*/
async function RapierPhysics() {
if ( RAPIER === null ) {
RAPIER = await import( `${RAPIER_PATH}` );
await RAPIER.init();
}
// Docs: https://rapier.rs/docs/api/javascript/JavaScript3D/
const gravity = new Vector3( 0.0, - 9.81, 0.0 );
const world = new RAPIER.World( gravity );
const meshes = [];
const meshMap = new WeakMap();
const _vector = new Vector3();
const _quaternion = new Quaternion();
const _matrix = new Matrix4();
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 ) return;
shape.setMass( mass );
shape.setRestitution( restitution );
const body = mesh.isInstancedMesh
? createInstancedBody( mesh, mass, shape )
: createBody( mesh.position, mesh.quaternion, mass, shape );
if ( ! mesh.userData.physics ) mesh.userData.physics = {};
mesh.userData.physics.body = body;
if ( mass > 0 ) {
meshes.push( mesh );
meshMap.set( mesh, body );
}
}
function createInstancedBody( mesh, mass, shape ) {
const array = mesh.instanceMatrix.array;
const bodies = [];
for ( let i = 0; i < mesh.count; i ++ ) {
const position = _vector.fromArray( array, i * 16 + 12 );
bodies.push( createBody( position, null, mass, shape ) );
}
return bodies;
}
function createBody( position, quaternion, mass, shape ) {
const desc = mass > 0 ? RAPIER.RigidBodyDesc.dynamic() : RAPIER.RigidBodyDesc.fixed();
desc.setTranslation( ...position );
if ( quaternion !== null ) desc.setRotation( quaternion );
const body = world.createRigidBody( desc );
world.createCollider( shape, body );
return body;
}
function setMeshPosition( mesh, position, index = 0 ) {
let body = meshMap.get( mesh );
if ( mesh.isInstancedMesh ) {
body = body[ index ];
}
body.setAngvel( ZERO );
body.setLinvel( ZERO );
body.setTranslation( position );
}
function setMeshVelocity( mesh, velocity, index = 0 ) {
let body = meshMap.get( mesh );
if ( mesh.isInstancedMesh ) {
body = body[ index ];
}
body.setLinvel( velocity );
}
function addHeightfield( mesh, width, depth, heights, scale ) {
const shape = RAPIER.ColliderDesc.heightfield( width, depth, heights, scale );
const bodyDesc = RAPIER.RigidBodyDesc.fixed();
bodyDesc.setTranslation( mesh.position.x, mesh.position.y, mesh.position.z );
bodyDesc.setRotation( mesh.quaternion );
const body = world.createRigidBody( bodyDesc );
world.createCollider( shape, body );
if ( ! mesh.userData.physics ) mesh.userData.physics = {};
mesh.userData.physics.body = body;
return body;
}
//
const clock = new Clock();
function step() {
world.timestep = clock.getDelta();
world.step();
//
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 position = body.translation();
_quaternion.copy( body.rotation() );
_matrix.compose( position, _quaternion, _scale ).toArray( array, j * 16 );
}
mesh.instanceMatrix.needsUpdate = true;
mesh.computeBoundingSphere();
} else {
const body = meshMap.get( mesh );
mesh.position.copy( body.translation() );
mesh.quaternion.copy( body.rotation() );
}
}
}
// animate
setInterval( step, 1000 / frameRate );
return {
RAPIER,
world,
/**
* 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 and restitution of the mesh. E.g.:
* ```js
* box.userData.physics = { mass: 1, restitution: 0 };
* ```
*
* @method
* @name RapierPhysics#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 RapierPhysics#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/friction of the mesh.
*/
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 RapierPhysics#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,
/**
* Set the velocity of the given mesh which is part of the physics simulation.
*
* @method
* @name RapierPhysics#setMeshVelocity
* @param {Mesh} mesh The mesh to update the velocity for.
* @param {Vector3} velocity - The new velocity.
* @param {number} [index=0] - If the mesh is instanced, the index represents the instanced ID.
*/
setMeshVelocity: setMeshVelocity,
/**
* Adds a heightfield terrain to the physics simulation.
*
* @method
* @name RapierPhysics#addHeightfield
* @param {Mesh} mesh - The Three.js mesh representing the terrain.
* @param {number} width - The number of vertices along the width (x-axis) of the heightfield.
* @param {number} depth - The number of vertices along the depth (z-axis) of the heightfield.
* @param {Float32Array} heights - Array of height values for each vertex in the heightfield.
* @param {Object} scale - Scale factors for the heightfield dimensions.
* @param {number} scale.x - Scale factor for width.
* @param {number} scale.y - Scale factor for height.
* @param {number} scale.z - Scale factor for depth.
* @returns {RigidBody} The created Rapier rigid body for the heightfield.
*/
addHeightfield: addHeightfield
};
}
export { RapierPhysics };