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<head>

<title>Ammo.js softbody volume demo</title>

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<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">

<meta property="og:title" content="Ammo.js softbody volume demo">

<meta property="og:type" content="website">

<meta property="og:url" content="https://threejs.org/examples/physics_ammo_volume.html">

<meta property="og:image" content="https://threejs.org/examples/screenshots/physics_ammo_volume.jpg">

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<style>

body {

color: #333;

}

</style>

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<body>

<div id="info">

Ammo.js physics soft body volume demo<br/>

Click to throw a ball

</div>

<div id="container"></div>

<script src="https://cdn.jsdelivr.net/gh/kripken/ammo.js@79190a1f03845794b1bba1777f30037349967658/builds/ammo.wasm.js"></script>

<script type="importmap">

{

"imports": {

"three": "../build/three.module.js",

"three/addons/": "./jsm/"

}

}

</script>

<script type="module">

import * as THREE from 'three';

import Stats from 'three/addons/libs/stats.module.js';

import { OrbitControls } from 'three/addons/controls/OrbitControls.js';

import * as BufferGeometryUtils from 'three/addons/utils/BufferGeometryUtils.js';

// Graphics variables

let container, stats;

let camera, controls, scene, renderer;

let textureLoader;

const timer = new THREE.Timer();

timer.connect( document );

let clickRequest = false;

const mouseCoords = new THREE.Vector2();

const raycaster = new THREE.Raycaster();

const ballMaterial = new THREE.MeshPhongMaterial( { color: 0x202020 } );

const pos = new THREE.Vector3();

const quat = new THREE.Quaternion();

// Physics variables

const gravityConstant = - 9.8;

let physicsWorld;

const rigidBodies = [];

const softBodies = [];

const margin = 0.05;

let transformAux1;

let softBodyHelpers;

Ammo().then( function ( AmmoLib ) {

Ammo = AmmoLib;

init();

} );

function init() {

initGraphics();

initPhysics();

createObjects();

initInput();

}

function initGraphics() {

container = document.getElementById( 'container' );

camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.2, 2000 );

scene = new THREE.Scene();

scene.background = new THREE.Color( 0xbfd1e5 );

camera.position.set( - 7, 5, 8 );

renderer = new THREE.WebGLRenderer( { antialias: true } );

renderer.setPixelRatio( window.devicePixelRatio );

renderer.setSize( window.innerWidth, window.innerHeight );

renderer.setAnimationLoop( animate );

renderer.shadowMap.enabled = true;

container.appendChild( renderer.domElement );

controls = new OrbitControls( camera, renderer.domElement );

controls.target.set( 0, 2, 0 );

controls.update();

textureLoader = new THREE.TextureLoader();

const ambientLight = new THREE.AmbientLight( 0xbbbbbb );

scene.add( ambientLight );

const light = new THREE.DirectionalLight( 0xffffff, 3 );

light.position.set( - 10, 10, 5 );

light.castShadow = true;

const d = 20;

light.shadow.camera.left = - d;

light.shadow.camera.right = d;

light.shadow.camera.top = d;

light.shadow.camera.bottom = - d;

light.shadow.camera.near = 2;

light.shadow.camera.far = 50;

light.shadow.mapSize.x = 1024;

light.shadow.mapSize.y = 1024;

scene.add( light );

stats = new Stats();

stats.domElement.style.position = 'absolute';

stats.domElement.style.top = '0px';

container.appendChild( stats.domElement );

window.addEventListener( 'resize', onWindowResize );

}

function initPhysics() {

// Physics configuration

const collisionConfiguration = new Ammo.btSoftBodyRigidBodyCollisionConfiguration();

const dispatcher = new Ammo.btCollisionDispatcher( collisionConfiguration );

const broadphase = new Ammo.btDbvtBroadphase();

const solver = new Ammo.btSequentialImpulseConstraintSolver();

const softBodySolver = new Ammo.btDefaultSoftBodySolver();

physicsWorld = new Ammo.btSoftRigidDynamicsWorld( dispatcher, broadphase, solver, collisionConfiguration, softBodySolver );

physicsWorld.setGravity( new Ammo.btVector3( 0, gravityConstant, 0 ) );

physicsWorld.getWorldInfo().set_m_gravity( new Ammo.btVector3( 0, gravityConstant, 0 ) );

transformAux1 = new Ammo.btTransform();

softBodyHelpers = new Ammo.btSoftBodyHelpers();

}

function createObjects() {

// Ground

pos.set( 0, - 0.5, 0 );

quat.set( 0, 0, 0, 1 );

const ground = createParalellepiped( 40, 1, 40, 0, pos, quat, new THREE.MeshPhongMaterial( { color: 0xFFFFFF } ) );

ground.castShadow = true;

ground.receiveShadow = true;

textureLoader.load( 'textures/grid.png', function ( texture ) {

texture.colorSpace = THREE.SRGBColorSpace;

texture.wrapS = THREE.RepeatWrapping;

texture.wrapT = THREE.RepeatWrapping;

texture.repeat.set( 40, 40 );

ground.material.map = texture;

ground.material.needsUpdate = true;

} );

// Create soft volumes

const volumeMass = 15;

const sphereGeometry = new THREE.SphereGeometry( 1.5, 40, 25 );

sphereGeometry.translate( 5, 5, 0 );

createSoftVolume( sphereGeometry, volumeMass, 250 );

const boxGeometry = new THREE.BoxGeometry( 1, 1, 5, 4, 4, 20 );

boxGeometry.translate( - 2, 5, 0 );

createSoftVolume( boxGeometry, volumeMass, 120 );

// Ramp

pos.set( 3, 1, 0 );

quat.setFromAxisAngle( new THREE.Vector3( 0, 0, 1 ), 30 * Math.PI / 180 );

const obstacle = createParalellepiped( 10, 1, 4, 0, pos, quat, new THREE.MeshPhongMaterial( { color: 0x606060 } ) );

obstacle.castShadow = true;

obstacle.receiveShadow = true;

}

function processGeometry( bufGeometry ) {

// Ony consider the position values when merging the vertices

const posOnlyBufGeometry = new THREE.BufferGeometry();

posOnlyBufGeometry.setAttribute( 'position', bufGeometry.getAttribute( 'position' ) );

posOnlyBufGeometry.setIndex( bufGeometry.getIndex() );

// Merge the vertices so the triangle soup is converted to indexed triangles

const indexedBufferGeom = BufferGeometryUtils.mergeVertices( posOnlyBufGeometry );

// Create index arrays mapping the indexed vertices to bufGeometry vertices

mapIndices( bufGeometry, indexedBufferGeom );

}

function isEqual( x1, y1, z1, x2, y2, z2 ) {

const delta = 0.000001;

return Math.abs( x2 - x1 ) < delta &&

Math.abs( y2 - y1 ) < delta &&

Math.abs( z2 - z1 ) < delta;

}

function mapIndices( bufGeometry, indexedBufferGeom ) {

// Creates ammoVertices, ammoIndices and ammoIndexAssociation in bufGeometry

const vertices = bufGeometry.attributes.position.array;

const idxVertices = indexedBufferGeom.attributes.position.array;

const indices = indexedBufferGeom.index.array;

const numIdxVertices = idxVertices.length / 3;

const numVertices = vertices.length / 3;

bufGeometry.ammoVertices = idxVertices;

bufGeometry.ammoIndices = indices;

bufGeometry.ammoIndexAssociation = [];

for ( let i = 0; i < numIdxVertices; i ++ ) {

const association = [];

bufGeometry.ammoIndexAssociation.push( association );

const i3 = i * 3;

for ( let j = 0; j < numVertices; j ++ ) {

const j3 = j * 3;

if ( isEqual( idxVertices[ i3 ], idxVertices[ i3 + 1 ], idxVertices[ i3 + 2 ],

vertices[ j3 ], vertices[ j3 + 1 ], vertices[ j3 + 2 ] ) ) {

association.push( j3 );

}

}

}

}

function createSoftVolume( bufferGeom, mass, pressure ) {

processGeometry( bufferGeom );

const volume = new THREE.Mesh( bufferGeom, new THREE.MeshPhongMaterial( { color: 0xFFFFFF } ) );

volume.castShadow = true;

volume.receiveShadow = true;

volume.frustumCulled = false;

scene.add( volume );

textureLoader.load( 'textures/colors.png', function ( texture ) {

volume.material.map = texture;

volume.material.needsUpdate = true;

} );

// Volume physic object

const volumeSoftBody = softBodyHelpers.CreateFromTriMesh(

physicsWorld.getWorldInfo(),

bufferGeom.ammoVertices,

bufferGeom.ammoIndices,

bufferGeom.ammoIndices.length / 3,

true );

const sbConfig = volumeSoftBody.get_m_cfg();

sbConfig.set_viterations( 40 );

sbConfig.set_piterations( 40 );

// Soft-soft and soft-rigid collisions

sbConfig.set_collisions( 0x11 );

// Friction

sbConfig.set_kDF( 0.1 );

// Damping

sbConfig.set_kDP( 0.01 );

// Pressure

sbConfig.set_kPR( pressure );

// Stiffness

volumeSoftBody.get_m_materials().at( 0 ).set_m_kLST( 0.9 );

volumeSoftBody.get_m_materials().at( 0 ).set_m_kAST( 0.9 );

volumeSoftBody.setTotalMass( mass, false );

Ammo.castObject( volumeSoftBody, Ammo.btCollisionObject ).getCollisionShape().setMargin( margin );

physicsWorld.addSoftBody( volumeSoftBody, 1, - 1 );

volume.userData.physicsBody = volumeSoftBody;

// Disable deactivation

volumeSoftBody.setActivationState( 4 );

softBodies.push( volume );

}

function createParalellepiped( sx, sy, sz, mass, pos, quat, material ) {

const threeObject = new THREE.Mesh( new THREE.BoxGeometry( sx, sy, sz, 1, 1, 1 ), material );

const shape = new Ammo.btBoxShape( new Ammo.btVector3( sx * 0.5, sy * 0.5, sz * 0.5 ) );

shape.setMargin( margin );

createRigidBody( threeObject, shape, mass, pos, quat );

return threeObject;

}

function createRigidBody( threeObject, physicsShape, mass, pos, quat ) {

threeObject.position.copy( pos );

threeObject.quaternion.copy( quat );

const transform = new Ammo.btTransform();

transform.setIdentity();

transform.setOrigin( new Ammo.btVector3( pos.x, pos.y, pos.z ) );

transform.setRotation( new Ammo.btQuaternion( quat.x, quat.y, quat.z, quat.w ) );

const motionState = new Ammo.btDefaultMotionState( transform );

const localInertia = new Ammo.btVector3( 0, 0, 0 );

physicsShape.calculateLocalInertia( mass, localInertia );

const rbInfo = new Ammo.btRigidBodyConstructionInfo( mass, motionState, physicsShape, localInertia );

const body = new Ammo.btRigidBody( rbInfo );

threeObject.userData.physicsBody = body;

scene.add( threeObject );

if ( mass > 0 ) {

rigidBodies.push( threeObject );

// Disable deactivation

body.setActivationState( 4 );

}

physicsWorld.addRigidBody( body );

return body;

}

function initInput() {

window.addEventListener( 'pointerdown', function ( event ) {

if ( ! clickRequest ) {

mouseCoords.set(

( event.clientX / window.innerWidth ) * 2 - 1,

- ( event.clientY / window.innerHeight ) * 2 + 1

);

clickRequest = true;

}

} );

}

function processClick() {

if ( clickRequest ) {

raycaster.setFromCamera( mouseCoords, camera );

// Creates a ball

const ballMass = 3;

const ballRadius = 0.4;

const ball = new THREE.Mesh( new THREE.SphereGeometry( ballRadius, 18, 16 ), ballMaterial );

ball.castShadow = true;

ball.receiveShadow = true;

const ballShape = new Ammo.btSphereShape( ballRadius );

ballShape.setMargin( margin );

pos.copy( raycaster.ray.direction );

pos.add( raycaster.ray.origin );

quat.set( 0, 0, 0, 1 );

const ballBody = createRigidBody( ball, ballShape, ballMass, pos, quat );

ballBody.setFriction( 0.5 );

pos.copy( raycaster.ray.direction );

pos.multiplyScalar( 14 );

ballBody.setLinearVelocity( new Ammo.btVector3( pos.x, pos.y, pos.z ) );

clickRequest = false;

}

}

function onWindowResize() {

camera.aspect = window.innerWidth / window.innerHeight;

camera.updateProjectionMatrix();

renderer.setSize( window.innerWidth, window.innerHeight );

}

function animate() {

timer.update();

render();

stats.update();

}

function render() {

const deltaTime = timer.getDelta();

updatePhysics( deltaTime );

processClick();

renderer.render( scene, camera );

}

function updatePhysics( deltaTime ) {

// Step world

physicsWorld.stepSimulation( deltaTime, 10 );

// Update soft volumes

for ( let i = 0, il = softBodies.length; i < il; i ++ ) {

const volume = softBodies[ i ];

const geometry = volume.geometry;

const softBody = volume.userData.physicsBody;

const volumePositions = geometry.attributes.position.array;

const volumeNormals = geometry.attributes.normal.array;

const association = geometry.ammoIndexAssociation;

const numVerts = association.length;

const nodes = softBody.get_m_nodes();

for ( let j = 0; j < numVerts; j ++ ) {

const node = nodes.at( j );

const nodePos = node.get_m_x();

const x = nodePos.x();

const y = nodePos.y();

const z = nodePos.z();

const nodeNormal = node.get_m_n();

const nx = nodeNormal.x();

const ny = nodeNormal.y();

const nz = nodeNormal.z();

const assocVertex = association[ j ];

for ( let k = 0, kl = assocVertex.length; k < kl; k ++ ) {

let indexVertex = assocVertex[ k ];

volumePositions[ indexVertex ] = x;

volumeNormals[ indexVertex ] = nx;

indexVertex ++;

volumePositions[ indexVertex ] = y;

volumeNormals[ indexVertex ] = ny;

indexVertex ++;

volumePositions[ indexVertex ] = z;

volumeNormals[ indexVertex ] = nz;

}

}

geometry.attributes.position.needsUpdate = true;

geometry.attributes.normal.needsUpdate = true;

}

// Update rigid bodies

for ( let i = 0, il = rigidBodies.length; i < il; i ++ ) {

const objThree = rigidBodies[ i ];

const objPhys = objThree.userData.physicsBody;

const ms = objPhys.getMotionState();

if ( ms ) {

ms.getWorldTransform( transformAux1 );

const p = transformAux1.getOrigin();

const q = transformAux1.getRotation();

objThree.position.set( p.x(), p.y(), p.z() );

objThree.quaternion.set( q.x(), q.y(), q.z(), q.w() );

}

}

}

</script>

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