examples/physics_ammo_volume.html

<html lang="en">
	<head>
		<title>Ammo.js softbody volume demo</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
		<style>
			body {
				color: #333;
			}
		</style>
	</head>
	<body>
		<div id="info">
			Ammo.js physics soft body volume demo<br/>
			Click to throw a ball
		</div>
		<div id="container"></div>

		<script src="jsm/libs/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 clock = new THREE.Clock();
			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() {

				render();
				stats.update();

			}

			function render() {

				const deltaTime = clock.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>

	</body>
</html>