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Javascript 3D Physics Tut 3 contact manifold check two
<html>
<head>
<meta charset="utf-8">
<title>Collision JS 3D Physics</title>
<style>
body { margin: 0; }
</style>
</head>
<body>
<script src="js/three.js"></script>
<script src="js/ammo.js"></script>
<script>
//variable declaration section
let physicsWorld, scene, camera, renderer, rigidBodies = [], pos = new THREE.Vector3(), tmpTrans = null;
let mouseCoords = new THREE.Vector2(), raycaster = new THREE.Raycaster();
let wall, ball;
let ttl = 3, ttlCounter = 0, ballInWorld = false;
const STATE = { DISABLE_DEACTIVATION : 4 };
//Ammojs Initialization
Ammo().then(start)
function start (){
tmpTrans = new Ammo.btTransform();
setupPhysicsWorld();
setupGraphics();
createWall();
setupEventHandlers();
renderFrame();
}
function setupPhysicsWorld(){
let collisionConfiguration = new Ammo.btDefaultCollisionConfiguration(),
dispatcher = new Ammo.btCollisionDispatcher(collisionConfiguration),
overlappingPairCache = new Ammo.btDbvtBroadphase(),
solver = new Ammo.btSequentialImpulseConstraintSolver();
physicsWorld = new Ammo.btDiscreteDynamicsWorld(dispatcher, overlappingPairCache, solver, collisionConfiguration);
physicsWorld.setGravity(new Ammo.btVector3(0, 0, 0));
}
function setupGraphics(){
//create clock for timing
clock = new THREE.Clock();
//create the scene
scene = new THREE.Scene();
scene.background = new THREE.Color( 0xabfeff );
//create camera
camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.2, 5000 );
camera.position.set( 0, 20, 50 );
camera.lookAt(new THREE.Vector3(0, 20, 0));
//Add hemisphere light
let hemiLight = new THREE.HemisphereLight( 0xffffff, 0xffffff, 0.1 );
hemiLight.color.setHSL( 0.6, 0.6, 0.6 );
hemiLight.groundColor.setHSL( 0.1, 1, 0.4 );
hemiLight.position.set( 0, 50, 0 );
scene.add( hemiLight );
//Add directional light
let dirLight = new THREE.DirectionalLight( 0xffffff , 1);
dirLight.color.setHSL( 0.1, 1, 0.95 );
dirLight.position.set( -1, 1.75, 1 );
dirLight.position.multiplyScalar( 100 );
scene.add( dirLight );
dirLight.castShadow = true;
dirLight.shadow.mapSize.width = 2048;
dirLight.shadow.mapSize.height = 2048;
let d = 50;
dirLight.shadow.camera.left = -d;
dirLight.shadow.camera.right = d;
dirLight.shadow.camera.top = d;
dirLight.shadow.camera.bottom = -d;
dirLight.shadow.camera.far = 13500;
//Setup the renderer
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setClearColor( 0xbfd1e5 );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
renderer.gammaInput = true;
renderer.gammaOutput = true;
renderer.shadowMap.enabled = true;
}
function renderFrame(){
let deltaTime = clock.getDelta();
//update ball time to live if ball in world
if( ballInWorld ) ttlCounter += deltaTime;
//if time to live has been exceeded then delete the ball
if( ttlCounter > ttl ){
physicsWorld.removeRigidBody( ball.userData.physicsBody );
scene.remove(ball);
ttlCounter = 0;
ballInWorld = false;
}
updatePhysics( deltaTime );
renderer.render( scene, camera );
requestAnimationFrame( renderFrame );
}
function setupEventHandlers(){
window.addEventListener( 'resize', onWindowResize, false );
window.addEventListener( 'mousedown', onMouseDown, false );
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function onMouseDown ( event ) {
if( ballInWorld ) return;
mouseCoords.set( ( event.clientX / window.innerWidth ) * 2 - 1, - ( event.clientY / window.innerHeight ) * 2 + 1 );
raycaster.setFromCamera( mouseCoords, camera );
// Create a ball
pos.copy( raycaster.ray.direction );
pos.add( raycaster.ray.origin );
ball = createBall(pos);
//shoot out the ball
let ballBody = ball.userData.physicsBody;
pos.copy( raycaster.ray.direction );
pos.multiplyScalar( 70 );
ballBody.setLinearVelocity( new Ammo.btVector3( pos.x, pos.y, pos.z ) );
ballInWorld = true;
}
function createWall(){
let pos = {x: 0, y: 25, z: -15};
let scale = {x: 50, y: 50, z: 2};
let quat = {x: 0, y: 0, z: 0, w: 1};
let mass = 0;
//threeJS Section
wall = new THREE.Mesh(new THREE.BoxBufferGeometry(), new THREE.MeshPhongMaterial({color: 0x42f5bf}));
wall.position.set(pos.x, pos.y, pos.z);
wall.scale.set(scale.x, scale.y, scale.z);
wall.castShadow = true;
wall.receiveShadow = true;
scene.add(wall);
//Ammojs Section
let 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 ) );
let motionState = new Ammo.btDefaultMotionState( transform );
let colShape = new Ammo.btBoxShape( new Ammo.btVector3( scale.x * 0.5, scale.y * 0.5, scale.z * 0.5 ) );
colShape.setMargin( 0.05 );
let localInertia = new Ammo.btVector3( 0, 0, 0 );
colShape.calculateLocalInertia( mass, localInertia );
let rbInfo = new Ammo.btRigidBodyConstructionInfo( mass, motionState, colShape, localInertia );
let body = new Ammo.btRigidBody( rbInfo );
body.setFriction(4);
body.setRollingFriction(10);
physicsWorld.addRigidBody( body );
//Let's overlay the wall with a grid for visual calibration
const gridHelper = new THREE.GridHelper( 50, 50, 0x1111aa, 0xaa1111 );
scene.add( gridHelper );
gridHelper.rotateX( THREE.Math.degToRad(90));
gridHelper.position.y = 25;
gridHelper.position.z = -14;
wall.userData.tag = "wall";
body.threeObject = wall;
}
function createBall(pos){
let radius = 0.8;
let quat = {x: 0, y: 0, z: 0, w: 1};
let mass = 35;
//threeJS Section
let ball = ballObject = new THREE.Mesh(new THREE.SphereBufferGeometry(radius), new THREE.MeshPhongMaterial({color: 0x05ff1e}));
ball.position.set(pos.x, pos.y, pos.z);
ball.castShadow = true;
ball.receiveShadow = true;
scene.add(ball);
//Ammojs Section
let 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 ) );
let motionState = new Ammo.btDefaultMotionState( transform );
let colShape = new Ammo.btSphereShape( radius );
colShape.setMargin( 0.05 );
let localInertia = new Ammo.btVector3( 0, 0, 0 );
colShape.calculateLocalInertia( mass, localInertia );
let rbInfo = new Ammo.btRigidBodyConstructionInfo( mass, motionState, colShape, localInertia );
let body = new Ammo.btRigidBody( rbInfo );
body.setFriction(4);
body.setRollingFriction(10);
body.setActivationState( STATE.DISABLE_DEACTIVATION )
physicsWorld.addRigidBody( body );
rigidBodies.push(ball);
ball.userData.physicsBody = body;
ball.userData.tag = "ball";
body.threeObject = ball;
return ball;
}
function updatePhysics( deltaTime ){
// Step world
physicsWorld.stepSimulation( deltaTime, 10 );
// Update rigid bodies
for ( let i = 0; i < rigidBodies.length; i++ ) {
let objThree = rigidBodies[ i ];
let objAmmo = objThree.userData.physicsBody;
let ms = objAmmo.getMotionState();
if ( ms ) {
ms.getWorldTransform( tmpTrans );
let p = tmpTrans.getOrigin();
let q = tmpTrans.getRotation();
objThree.position.set( p.x(), p.y(), p.z() );
objThree.quaternion.set( q.x(), q.y(), q.z(), q.w() );
}
}
detectCollision();
}
function detectCollision(){
let dispatcher = physicsWorld.getDispatcher();
let numManifolds = dispatcher.getNumManifolds();
for ( let i = 0; i < numManifolds; i ++ ) {
let contactManifold = dispatcher.getManifoldByIndexInternal( i );
let rb0 = Ammo.castObject( contactManifold.getBody0(), Ammo.btRigidBody );
let rb1 = Ammo.castObject( contactManifold.getBody1(), Ammo.btRigidBody );
let threeObject0 = rb0.threeObject;
let threeObject1 = rb1.threeObject;
if ( ! threeObject0 && ! threeObject1 ) continue;
let userData0 = threeObject0 ? threeObject0.userData : null;
let userData1 = threeObject1 ? threeObject1.userData : null;
let tag0 = userData0 ? userData0.tag : "none";
let tag1 = userData1 ? userData1.tag : "none";
let numContacts = contactManifold.getNumContacts();
for ( let j = 0; j < numContacts; j++ ) {
let contactPoint = contactManifold.getContactPoint( j );
let distance = contactPoint.getDistance();
if( distance > 0.0 ) continue;
let velocity0 = rb0.getLinearVelocity();
let velocity1 = rb1.getLinearVelocity();
let worldPos0 = contactPoint.get_m_positionWorldOnA();
let worldPos1 = contactPoint.get_m_positionWorldOnB();
let localPos0 = contactPoint.get_m_localPointA();
let localPos1 = contactPoint.get_m_localPointB();
console.log({
manifoldIndex: i,
contactIndex: j,
distance: distance,
object0:{
tag: tag0,
velocity: {x: velocity0.x(), y: velocity0.y(), z: velocity0.z()},
worldPos: {x: worldPos0.x(), y: worldPos0.y(), z: worldPos0.z()},
localPos: {x: localPos0.x(), y: localPos0.y(), z: localPos0.z()}
},
object1:{
tag: tag1,
velocity: {x: velocity1.x(), y: velocity1.y(), z: velocity1.z()},
worldPos: {x: worldPos1.x(), y: worldPos1.y(), z: worldPos1.z()},
localPos: {x: localPos1.x(), y: localPos1.y(), z: localPos1.z()}
}
});
}
}
}
</script>
</body>
</html>
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