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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="jsm/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": {
"v3d": "../build/v3d.module.js",
"v3d/addons/": "./jsm/"
}
}
</script>
<script type="module">
import * as v3d from 'v3d';
import Stats from 'v3d/addons/libs/stats.module.js';
import { OrbitControls } from 'v3d/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 v3d.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 v3d.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 v3d.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.2, 2000);
scene = new v3d.Scene();
scene.background = new v3d.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 v3d.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 v3d.MeshPhongMaterial({ color: 0xC7C7C7 });
terrainMesh = new v3d.Mesh(geometry, groundMaterial);
terrainMesh.receiveShadow = true;
terrainMesh.castShadow = true;
scene.add(terrainMesh);
const textureLoader = new v3d.TextureLoader();
textureLoader.load('textures/grid.png', function(texture) {
texture.wrapS = v3d.RepeatWrapping;
texture.wrapT = v3d.RepeatWrapping;
texture.repeat.set(terrainWidth - 1, terrainDepth - 1);
groundMaterial.map = texture;
groundMaterial.needsUpdate = true;
});
const light = new v3d.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 v3d.Mesh(new v3d.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 v3d.Mesh(new v3d.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 v3d.Mesh(new v3d.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 v3d.Mesh(new v3d.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 v3d.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>