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<!DOCTYPE html>
<html lang="en">
<head>
<title>Ammo.js terrain heightfield 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="container"></div>
<div id="info">Ammo.js physics terrain heightfield demo</div>
<script src="js/libs/ammo.wasm.js"></script>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/[email protected]/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';
// Heightfield parameters
const terrainWidthExtents = 100;
const terrainDepthExtents = 100;
const terrainWidth = 128;
const terrainDepth = 128;
const terrainHalfWidth = terrainWidth / 2;
const terrainHalfDepth = terrainDepth / 2;
const terrainMaxHeight = 8;
const terrainMinHeight = - 2;
// Graphics variables
let container, stats;
let camera, scene, renderer;
let terrainMesh;
const clock = new THREE.Clock();
// Physics variables
let collisionConfiguration;
let dispatcher;
let broadphase;
let solver;
let physicsWorld;
const dynamicObjects = [];
let transformAux1;
let heightData = null;
let ammoHeightData = null;
let time = 0;
const objectTimePeriod = 3;
let timeNextSpawn = time + objectTimePeriod;
const maxNumObjects = 30;
Ammo().then( function ( AmmoLib ) {
Ammo = AmmoLib;
init();
animate();
} );
function init() {
heightData = generateHeight( terrainWidth, terrainDepth, terrainMinHeight, terrainMaxHeight );
initGraphics();
initPhysics();
}
function initGraphics() {
container = document.getElementById( 'container' );
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.shadowMap.enabled = true;
container.appendChild( renderer.domElement );
stats = new Stats();
stats.domElement.style.position = 'absolute';
stats.domElement.style.top = '0px';
container.appendChild( stats.domElement );
camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.2, 2000 );
scene = new THREE.Scene();
scene.background = new THREE.Color( 0xbfd1e5 );
camera.position.y = heightData[ terrainHalfWidth + terrainHalfDepth * terrainWidth ] * ( terrainMaxHeight - terrainMinHeight ) + 5;
camera.position.z = terrainDepthExtents / 2;
camera.lookAt( 0, 0, 0 );
const controls = new OrbitControls( camera, renderer.domElement );
controls.enableZoom = false;
const geometry = new THREE.PlaneGeometry( terrainWidthExtents, terrainDepthExtents, terrainWidth - 1, terrainDepth - 1 );
geometry.rotateX( - Math.PI / 2 );
const vertices = geometry.attributes.position.array;
for ( let i = 0, j = 0, l = vertices.length; i < l; i ++, j += 3 ) {
// j + 1 because it is the y component that we modify
vertices[ j + 1 ] = heightData[ i ];
}
geometry.computeVertexNormals();
const groundMaterial = new THREE.MeshPhongMaterial( { color: 0xC7C7C7 } );
terrainMesh = new THREE.Mesh( geometry, groundMaterial );
terrainMesh.receiveShadow = true;
terrainMesh.castShadow = true;
scene.add( terrainMesh );
const textureLoader = new THREE.TextureLoader();
textureLoader.load( 'textures/grid.png', function ( texture ) {
texture.wrapS = THREE.RepeatWrapping;
texture.wrapT = THREE.RepeatWrapping;
texture.repeat.set( terrainWidth - 1, terrainDepth - 1 );
groundMaterial.map = texture;
groundMaterial.needsUpdate = true;
} );
const light = new THREE.DirectionalLight( 0xffffff, 1 );
light.position.set( 100, 100, 50 );
light.castShadow = true;
const dLight = 200;
const sLight = dLight * 0.25;
light.shadow.camera.left = - sLight;
light.shadow.camera.right = sLight;
light.shadow.camera.top = sLight;
light.shadow.camera.bottom = - sLight;
light.shadow.camera.near = dLight / 30;
light.shadow.camera.far = dLight;
light.shadow.mapSize.x = 1024 * 2;
light.shadow.mapSize.y = 1024 * 2;
scene.add( light );
window.addEventListener( 'resize', onWindowResize );
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
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, - 6, 0 ) );
// Create the terrain body
const groundShape = createTerrainShape();
const groundTransform = new Ammo.btTransform();
groundTransform.setIdentity();
// Shifts the terrain, since bullet re-centers it on its bounding box.
groundTransform.setOrigin( new Ammo.btVector3( 0, ( terrainMaxHeight + terrainMinHeight ) / 2, 0 ) );
const groundMass = 0;
const groundLocalInertia = new Ammo.btVector3( 0, 0, 0 );
const groundMotionState = new Ammo.btDefaultMotionState( groundTransform );
const groundBody = new Ammo.btRigidBody( new Ammo.btRigidBodyConstructionInfo( groundMass, groundMotionState, groundShape, groundLocalInertia ) );
physicsWorld.addRigidBody( groundBody );
transformAux1 = new Ammo.btTransform();
}
function generateHeight( width, depth, minHeight, maxHeight ) {
// Generates the height data (a sinus wave)
const size = width * depth;
const data = new Float32Array( size );
const hRange = maxHeight - minHeight;
const w2 = width / 2;
const d2 = depth / 2;
const phaseMult = 12;
let p = 0;
for ( let j = 0; j < depth; j ++ ) {
for ( let i = 0; i < width; i ++ ) {
const radius = Math.sqrt(
Math.pow( ( i - w2 ) / w2, 2.0 ) +
Math.pow( ( j - d2 ) / d2, 2.0 ) );
const height = ( Math.sin( radius * phaseMult ) + 1 ) * 0.5 * hRange + minHeight;
data[ p ] = height;
p ++;
}
}
return data;
}
function createTerrainShape() {
// This parameter is not really used, since we are using PHY_FLOAT height data type and hence it is ignored
const heightScale = 1;
// Up axis = 0 for X, 1 for Y, 2 for Z. Normally 1 = Y is used.
const upAxis = 1;
// hdt, height data type. "PHY_FLOAT" is used. Possible values are "PHY_FLOAT", "PHY_UCHAR", "PHY_SHORT"
const hdt = 'PHY_FLOAT';
// Set this to your needs (inverts the triangles)
const flipQuadEdges = false;
// Creates height data buffer in Ammo heap
ammoHeightData = Ammo._malloc( 4 * terrainWidth * terrainDepth );
// Copy the javascript height data array to the Ammo one.
let p = 0;
let p2 = 0;
for ( let j = 0; j < terrainDepth; j ++ ) {
for ( let i = 0; i < terrainWidth; i ++ ) {
// write 32-bit float data to memory
Ammo.HEAPF32[ ammoHeightData + p2 >> 2 ] = heightData[ p ];
p ++;
// 4 bytes/float
p2 += 4;
}
}
// Creates the heightfield physics shape
const heightFieldShape = new Ammo.btHeightfieldTerrainShape(
terrainWidth,
terrainDepth,
ammoHeightData,
heightScale,
terrainMinHeight,
terrainMaxHeight,
upAxis,
hdt,
flipQuadEdges
);
// Set horizontal scale
const scaleX = terrainWidthExtents / ( terrainWidth - 1 );
const scaleZ = terrainDepthExtents / ( terrainDepth - 1 );
heightFieldShape.setLocalScaling( new Ammo.btVector3( scaleX, 1, scaleZ ) );
heightFieldShape.setMargin( 0.05 );
return heightFieldShape;
}
function generateObject() {
const numTypes = 4;
const objectType = Math.ceil( Math.random() * numTypes );
let threeObject = null;
let shape = null;
const objectSize = 3;
const margin = 0.05;
let radius, height;
switch ( objectType ) {
case 1:
// Sphere
radius = 1 + Math.random() * objectSize;
threeObject = new THREE.Mesh( new THREE.SphereGeometry( radius, 20, 20 ), createObjectMaterial() );
shape = new Ammo.btSphereShape( radius );
shape.setMargin( margin );
break;
case 2:
// Box
const sx = 1 + Math.random() * objectSize;
const sy = 1 + Math.random() * objectSize;
const sz = 1 + Math.random() * objectSize;
threeObject = new THREE.Mesh( new THREE.BoxGeometry( sx, sy, sz, 1, 1, 1 ), createObjectMaterial() );
shape = new Ammo.btBoxShape( new Ammo.btVector3( sx * 0.5, sy * 0.5, sz * 0.5 ) );
shape.setMargin( margin );
break;
case 3:
// Cylinder
radius = 1 + Math.random() * objectSize;
height = 1 + Math.random() * objectSize;
threeObject = new THREE.Mesh( new THREE.CylinderGeometry( radius, radius, height, 20, 1 ), createObjectMaterial() );
shape = new Ammo.btCylinderShape( new Ammo.btVector3( radius, height * 0.5, radius ) );
shape.setMargin( margin );
break;
default:
// Cone
radius = 1 + Math.random() * objectSize;
height = 2 + Math.random() * objectSize;
threeObject = new THREE.Mesh( new THREE.ConeGeometry( radius, height, 20, 2 ), createObjectMaterial() );
shape = new Ammo.btConeShape( radius, height );
break;
}
threeObject.position.set( ( Math.random() - 0.5 ) * terrainWidth * 0.6, terrainMaxHeight + objectSize + 2, ( Math.random() - 0.5 ) * terrainDepth * 0.6 );
const mass = objectSize * 5;
const localInertia = new Ammo.btVector3( 0, 0, 0 );
shape.calculateLocalInertia( mass, localInertia );
const transform = new Ammo.btTransform();
transform.setIdentity();
const pos = threeObject.position;
transform.setOrigin( new Ammo.btVector3( pos.x, pos.y, pos.z ) );
const motionState = new Ammo.btDefaultMotionState( transform );
const rbInfo = new Ammo.btRigidBodyConstructionInfo( mass, motionState, shape, localInertia );
const body = new Ammo.btRigidBody( rbInfo );
threeObject.userData.physicsBody = body;
threeObject.receiveShadow = true;
threeObject.castShadow = true;
scene.add( threeObject );
dynamicObjects.push( threeObject );
physicsWorld.addRigidBody( body );
}
function createObjectMaterial() {
const c = Math.floor( Math.random() * ( 1 << 24 ) );
return new THREE.MeshPhongMaterial( { color: c } );
}
function animate() {
requestAnimationFrame( animate );
render();
stats.update();
}
function render() {
const deltaTime = clock.getDelta();
if ( dynamicObjects.length < maxNumObjects && time > timeNextSpawn ) {
generateObject();
timeNextSpawn = time + objectTimePeriod;
}
updatePhysics( deltaTime );
renderer.render( scene, camera );
time += deltaTime;
}
function updatePhysics( deltaTime ) {
physicsWorld.stepSimulation( deltaTime, 10 );
// Update objects
for ( let i = 0, il = dynamicObjects.length; i < il; i ++ ) {
const objThree = dynamicObjects[ 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>