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@BlueMagnificent
Last active Jul 31, 2021
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Javascript 3D Physics Snippet Three
<html>
<head>
<meta charset="utf-8">
<title>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 = []
//Ammojs Initialization
Ammo().then(start)
function start (){
tmpTrans = new Ammo.btTransform();
setupPhysicsWorld();
setupGraphics();
createBlock();
createBall();
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, -10, 0));
}
function setupGraphics(){
//create clock for timing
clock = new THREE.Clock();
//create the scene
scene = new THREE.Scene();
scene.background = new THREE.Color( 0xbfd1e5 );
//create camera
camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.2, 5000 );
camera.position.set( 0, 30, 70 );
camera.lookAt(new THREE.Vector3(0, 0, 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();
updatePhysics( deltaTime );
renderer.render( scene, camera );
requestAnimationFrame( renderFrame );
}
function createBlock(){
let pos = {x: 0, y: 0, z: 0};
let scale = {x: 50, y: 2, z: 50};
let quat = {x: 0, y: 0, z: 0, w: 1};
let mass = 0;
//threeJS Section
let blockPlane = new THREE.Mesh(new THREE.BoxBufferGeometry(), new THREE.MeshPhongMaterial({color: 0xa0afa4}));
blockPlane.position.set(pos.x, pos.y, pos.z);
blockPlane.scale.set(scale.x, scale.y, scale.z);
blockPlane.castShadow = true;
blockPlane.receiveShadow = true;
scene.add(blockPlane);
//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 );
physicsWorld.addRigidBody( body );
}
function createBall(){
let pos = {x: 0, y: 20, z: 0};
let radius = 2;
let quat = {x: 0, y: 0, z: 0, w: 1};
let mass = 1;
//threeJS Section
let ball = new THREE.Mesh(new THREE.SphereBufferGeometry(radius), new THREE.MeshPhongMaterial({color: 0xff0505}));
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 );
physicsWorld.addRigidBody( body );
ball.userData.physicsBody = body;
rigidBodies.push(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() );
}
}
}
</script>
</body>
</html>
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