Hey Guys!
I’m a newbie, so please be gentle.
I am trying to create Breakable Text just like we can break the shapes given in the example below.
https://threejs.org/examples/?q=physics#physics_ammo_break
What is happening is that Text Geometry does not react normally to adding physics to it. It starts moving around in ways that make no sense, and uses a lot of resources.
Additionally I am trying to throw the ball through a Torus (A Hoop on a pole, like in Quidditch), but even the open part of the Torus acts solid.
Please help
Here’s my code: (I have just copy pasted the Ammo Js Break code and I am making the changes in it to achieve what I want, because I’m learning)
<html lang="en">
<head>
<title>Convex object breaking example</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">Physics threejs demo with convex objects breaking in real time<br />Press mouse to throw balls and move the camera.</div>
<div id="container"></div>
<script src="jsm/libs/ammo.wasm.js"></script>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.6.3/dist/es-module-shims.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 { ConvexObjectBreaker } from 'three/addons/misc/ConvexObjectBreaker.js';
import { ConvexGeometry } from 'three/addons/geometries/ConvexGeometry.js';
import { FontLoader } from 'three/addons/loaders/FontLoader.js';
import { TextGeometry } from 'three/addons/geometries/TextGeometry.js';
import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
// import { ConvexGeometry } from 'three/addons/geometries/ConvexGeometry.js';
import * as BufferGeometryUtils from 'three/addons/utils/BufferGeometryUtils.js';
// import { QuickHull } from 'three/examples/js/QuickHull';
// import { ConvexBufferGeometry } from 'three/examples/js/ConvexBufferGeometry';
// import font from 'fonts/helvetiker_regular.typeface.json';
// import { ConvexBufferGeometry, QuickHull } from '/examples/jsm/geometries/ConvexGeometry.js';
let font;
function loadFont() {
const loader = new FontLoader();
loader.load( 'fonts/helvetiker_regular.typeface.json', function ( response ) {
font = response;
refreshText();
} );
}
loadFont();
// - Global variables -
// Graphics variables
let container, stats;
let camera, controls, scene, renderer;
let textureLoader;
const clock = new THREE.Clock();
const mouseCoords = new THREE.Vector2();
const raycaster = new THREE.Raycaster();
const ballMaterial = new THREE.MeshPhongMaterial( { color: 0x202020 } );
// Physics variables
const gravityConstant = 7.8;
let collisionConfiguration;
let dispatcher;
let broadphase;
let solver;
let physicsWorld;
const margin = 0.05;
const convexBreaker = new ConvexObjectBreaker();
// Rigid bodies include all movable objects
const rigidBodies = [];
const pos = new THREE.Vector3();
const quat = new THREE.Quaternion();
let transformAux1;
let tempBtVec3_1;
const objectsToRemove = [];
for ( let i = 0; i < 500; i ++ ) {
objectsToRemove[ i ] = null;
}
let numObjectsToRemove = 0;
const impactPoint = new THREE.Vector3();
const impactNormal = new THREE.Vector3();
// - Main code -
Ammo().then( function ( AmmoLib ) {
Ammo = AmmoLib;
init();
animate();
} );
// - Functions -
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( - 14, 8, 16 );
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
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( 0x707070 );
scene.add( ambientLight );
const light = new THREE.DirectionalLight( 0xffffff, 1 );
light.position.set( - 10, 18, 5 );
light.castShadow = true;
const d = 14;
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
collisionConfiguration = new Ammo.btDefaultCollisionConfiguration();
dispatcher = new Ammo.btCollisionDispatcher( collisionConfiguration );
broadphase = new Ammo.btDbvtBroadphase();
solver = new Ammo.btSequentialImpulseConstraintSolver();
physicsWorld = new Ammo.btDiscreteDynamicsWorld( dispatcher, broadphase, solver, collisionConfiguration );
physicsWorld.setGravity( new Ammo.btVector3( 0, - gravityConstant, 0 ) );
transformAux1 = new Ammo.btTransform();
tempBtVec3_1 = new Ammo.btVector3( 0, 0, 0 );
}
// materials = [
// new THREE.MeshPhongMaterial( { color: 0xffffff, flatShading: true } ), // front
// new THREE.MeshPhongMaterial( { color: 0xffffff } ) // side
// ];
function createObject( mass, halfExtents, pos, quat, material ) {
const object = new THREE.Mesh( new THREE.BoxGeometry( halfExtents.x * 2, halfExtents.y * 2, halfExtents.z * 2 ), material );
object.position.copy( pos );
object.quaternion.copy( quat );
convexBreaker.prepareBreakableObject( object, mass, new THREE.Vector3(), new THREE.Vector3(), true );
// createDebrisFromBreakableObject( object );
}
function createObjects() {
//Text
console.log(font);
const textGeo = new TextGeometry( 'HELLO', {
font: font,
size: 8,
height: 0.5,
curveSegments: 3,
bevelThickness: 1,
bevelSize: 0.1,
bevelEnabled: true,
} );
textGeo.computeBoundingBox();
const textMesh1 = new THREE.Mesh( textGeo, new THREE.MeshPhongMaterial( { color: 0xffffff, flatShading: true } ) );
// console.log(textMesh1);
pos.set( - 15, 0, 0 );
quat.set( 0, 0, 0, 1 );
textMesh1.position.copy( pos );
textMesh1.quaternion.copy( quat );
// Create the physics shape using Ammo.btConvexHullShape
const textShape = new Ammo.btConvexHullShape();
for (let i = 0; i < textGeo.attributes.position.count; i++) {
textShape.addPoint(new Ammo.btVector3(
textGeo.attributes.position.array[i * 3 + 0],
textGeo.attributes.position.array[i * 3 + 1],
textGeo.attributes.position.array[i * 3 + 2]
));
}
// Create a rigid body using the physics shape and add it to the physics world
const textBody = new Ammo.btRigidBody(new Ammo.btRigidBodyConstructionInfo(0, null, textShape, new Ammo.btVector3(0, 0, 0)));
physicsWorld.addRigidBody(textBody);
textMesh1.userData.physicsBody = textBody;
createRigidBody( textMesh1, textShape, 100000, pos, quat );
//ring 2 (Torus)
const geometryRing = new THREE.TorusGeometry( 2, 0.5, 16, 100 );
const materialRing = new THREE.MeshBasicMaterial( { color: 0xffff00 } );
const torus = new THREE.Mesh( geometryRing, materialRing );
pos.set( 0, 5, 0 );
torus.position.copy( pos );
convexBreaker.prepareBreakableObject( torus, 1200, new THREE.Vector3(), new THREE.Vector3(), false );
createDebrisFromBreakableObject( torus );
// scene.add( torus );
}
function createParalellepipedWithPhysics( sx, sy, sz, mass, pos, quat, material ) {
const object = 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( object, shape, mass, pos, quat );
return object;
}
function createDebrisFromBreakableObject( object ) {
object.castShadow = true;
object.receiveShadow = true;
const shape = createConvexHullPhysicsShape( object.geometry.attributes.position.array );
shape.setMargin( margin );
const body = createRigidBody( object, shape, object.userData.mass, null, null, object.userData.velocity, object.userData.angularVelocity );
// Set pointer back to the three object only in the debris objects
const btVecUserData = new Ammo.btVector3( 0, 0, 0 );
btVecUserData.threeObject = object;
body.setUserPointer( btVecUserData );
}
function removeDebris( object ) {
scene.remove( object );
physicsWorld.removeRigidBody( object.userData.physicsBody );
}
function createConvexHullPhysicsShape( coords ) {
const shape = new Ammo.btConvexHullShape();
for ( let i = 0, il = coords.length; i < il; i += 3 ) {
tempBtVec3_1.setValue( coords[ i ], coords[ i + 1 ], coords[ i + 2 ] );
const lastOne = ( i >= ( il - 3 ) );
shape.addPoint( tempBtVec3_1, lastOne );
}
return shape;
}
function createRigidBody( object, physicsShape, mass, pos, quat, vel, angVel ) {
if ( pos ) {
object.position.copy( pos );
} else {
pos = object.position;
}
if ( quat ) {
object.quaternion.copy( quat );
} else {
quat = object.quaternion;
}
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 );
body.setFriction( 0.5 );
if ( vel ) {
body.setLinearVelocity( new Ammo.btVector3( vel.x, vel.y, vel.z ) );
}
if ( angVel ) {
body.setAngularVelocity( new Ammo.btVector3( angVel.x, angVel.y, angVel.z ) );
}
object.userData.physicsBody = body;
object.userData.collided = false;
scene.add( object );
if ( mass > 0 ) {
rigidBodies.push( object );
// Disable deactivation
body.setActivationState( 4 );
}
physicsWorld.addRigidBody( body );
return body;
}
function createRandomColor() {
return Math.floor( Math.random() * ( 1 << 24 ) );
}
function createMaterial( color ) {
color = color || createRandomColor();
return new THREE.MeshPhongMaterial( { color: color } );
}
function initInput() {
window.addEventListener( 'pointerdown', function ( event ) {
mouseCoords.set(
( event.clientX / window.innerWidth ) * 2 - 1,
- ( event.clientY / window.innerHeight ) * 2 + 1
);
raycaster.setFromCamera( mouseCoords, camera );
// Creates a ball and throws it
const ballMass = 32;
const ballRadius = 0.4;
const ball = new THREE.Mesh( new THREE.SphereGeometry( ballRadius, 14, 10 ), 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 );
pos.copy( raycaster.ray.direction );
pos.multiplyScalar( 24 );
ballBody.setLinearVelocity( new Ammo.btVector3( pos.x, pos.y, pos.z ) );
} );
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function animate() {
requestAnimationFrame( animate );
render();
stats.update();
}
function render() {
const deltaTime = clock.getDelta();
updatePhysics( deltaTime );
renderer.render( scene, camera );
}
function updatePhysics( deltaTime ) {
// Step world
physicsWorld.stepSimulation( deltaTime, 10 );
// 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() );
objThree.userData.collided = false;
}
}
for ( let i = 0, il = dispatcher.getNumManifolds(); i < il; i ++ ) {
const contactManifold = dispatcher.getManifoldByIndexInternal( i );
const rb0 = Ammo.castObject( contactManifold.getBody0(), Ammo.btRigidBody );
const rb1 = Ammo.castObject( contactManifold.getBody1(), Ammo.btRigidBody );
const threeObject0 = Ammo.castObject( rb0.getUserPointer(), Ammo.btVector3 ).threeObject;
const threeObject1 = Ammo.castObject( rb1.getUserPointer(), Ammo.btVector3 ).threeObject;
if ( ! threeObject0 && ! threeObject1 ) {
continue;
}
const userData0 = threeObject0 ? threeObject0.userData : null;
const userData1 = threeObject1 ? threeObject1.userData : null;
const breakable0 = userData0 ? userData0.breakable : false;
const breakable1 = userData1 ? userData1.breakable : false;
const collided0 = userData0 ? userData0.collided : false;
const collided1 = userData1 ? userData1.collided : false;
if ( ( ! breakable0 && ! breakable1 ) || ( collided0 && collided1 ) ) {
continue;
}
let contact = false;
let maxImpulse = 0;
for ( let j = 0, jl = contactManifold.getNumContacts(); j < jl; j ++ ) {
const contactPoint = contactManifold.getContactPoint( j );
if ( contactPoint.getDistance() < 0 ) {
contact = true;
const impulse = contactPoint.getAppliedImpulse();
if ( impulse > maxImpulse ) {
maxImpulse = impulse;
const pos = contactPoint.get_m_positionWorldOnB();
const normal = contactPoint.get_m_normalWorldOnB();
impactPoint.set( pos.x(), pos.y(), pos.z() );
impactNormal.set( normal.x(), normal.y(), normal.z() );
}
break;
}
}
// If no point has contact, abort
if ( ! contact ) continue;
// Subdivision
const fractureImpulse = 250;
if ( breakable0 && ! collided0 && maxImpulse > fractureImpulse ) {
const debris = convexBreaker.subdivideByImpact( threeObject0, impactPoint, impactNormal, 1, 2, 1.5 );
const numObjects = debris.length;
for ( let j = 0; j < numObjects; j ++ ) {
const vel = rb0.getLinearVelocity();
const angVel = rb0.getAngularVelocity();
const fragment = debris[ j ];
fragment.userData.velocity.set( vel.x(), vel.y(), vel.z() );
fragment.userData.angularVelocity.set( angVel.x(), angVel.y(), angVel.z() );
createDebrisFromBreakableObject( fragment );
}
objectsToRemove[ numObjectsToRemove ++ ] = threeObject0;
userData0.collided = true;
}
if ( breakable1 && ! collided1 && maxImpulse > fractureImpulse ) {
const debris = convexBreaker.subdivideByImpact( threeObject1, impactPoint, impactNormal, 1, 2, 1.5 );
const numObjects = debris.length;
for ( let j = 0; j < numObjects; j ++ ) {
const vel = rb1.getLinearVelocity();
const angVel = rb1.getAngularVelocity();
const fragment = debris[ j ];
fragment.userData.velocity.set( vel.x(), vel.y(), vel.z() );
fragment.userData.angularVelocity.set( angVel.x(), angVel.y(), angVel.z() );
createDebrisFromBreakableObject( fragment );
}
objectsToRemove[ numObjectsToRemove ++ ] = threeObject1;
userData1.collided = true;
}
}
for ( let i = 0; i < numObjectsToRemove; i ++ ) {
removeDebris( objectsToRemove[ i ] );
}
numObjectsToRemove = 0;
}
</script>
</body>
</html>
