static
This commit is contained in:
蔡玲
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<title>three.js webgl - cloth simulation</title>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
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<link type="text/css" rel="stylesheet" href="main.css">
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<style>
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body {
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background-color: #cce0ff;
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color: #000;
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}
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a {
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color: #080;
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}
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</style>
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</head>
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<body>
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<div id="info">Simple Cloth Simulation<br/>
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Verlet integration with relaxed constraints<br/>
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</div>
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<script type="module">
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import * as THREE from '../build/three.module.js';
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import Stats from './jsm/libs/stats.module.js';
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import { GUI } from './jsm/libs/dat.gui.module.js';
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import { OrbitControls } from './jsm/controls/OrbitControls.js';
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/*
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* Cloth Simulation using a relaxed constraints solver
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*/
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// Suggested Readings
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// Advanced Character Physics by Thomas Jakobsen Character
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// http://freespace.virgin.net/hugo.elias/models/m_cloth.htm
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// http://en.wikipedia.org/wiki/Cloth_modeling
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// http://cg.alexandra.dk/tag/spring-mass-system/
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// Real-time Cloth Animation http://www.darwin3d.com/gamedev/articles/col0599.pdf
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const params = {
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enableWind: true,
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showBall: false,
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togglePins: togglePins
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};
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const DAMPING = 0.03;
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const DRAG = 1 - DAMPING;
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const MASS = 0.1;
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const restDistance = 25;
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const xSegs = 10;
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const ySegs = 10;
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const clothFunction = plane( restDistance * xSegs, restDistance * ySegs );
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const GRAVITY = 981 * 1.4;
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const gravity = new THREE.Vector3( 0, - GRAVITY, 0 ).multiplyScalar( MASS );
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const TIMESTEP = 18 / 1000;
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const TIMESTEP_SQ = TIMESTEP * TIMESTEP;
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let pins = [];
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const windForce = new THREE.Vector3( 0, 0, 0 );
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const ballPosition = new THREE.Vector3( 0, - 45, 0 );
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const ballSize = 60; //40
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const tmpForce = new THREE.Vector3();
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const diff = new THREE.Vector3();
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class Particle {
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constructor( x, y, z, mass ) {
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this.position = new THREE.Vector3();
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this.previous = new THREE.Vector3();
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this.original = new THREE.Vector3();
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this.a = new THREE.Vector3( 0, 0, 0 ); // acceleration
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this.mass = mass;
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this.invMass = 1 / mass;
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this.tmp = new THREE.Vector3();
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this.tmp2 = new THREE.Vector3();
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// init
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clothFunction( x, y, this.position ); // position
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clothFunction( x, y, this.previous ); // previous
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clothFunction( x, y, this.original );
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}
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// Force -> Acceleration
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addForce( force ) {
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this.a.add(
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this.tmp2.copy( force ).multiplyScalar( this.invMass )
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);
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}
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// Performs Verlet integration
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integrate( timesq ) {
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const newPos = this.tmp.subVectors( this.position, this.previous );
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newPos.multiplyScalar( DRAG ).add( this.position );
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newPos.add( this.a.multiplyScalar( timesq ) );
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this.tmp = this.previous;
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this.previous = this.position;
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this.position = newPos;
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this.a.set( 0, 0, 0 );
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}
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}
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class Cloth {
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constructor( w = 10, h = 10 ) {
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this.w = w;
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this.h = h;
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const particles = [];
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const constraints = [];
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// Create particles
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for ( let v = 0; v <= h; v ++ ) {
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for ( let u = 0; u <= w; u ++ ) {
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particles.push(
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new Particle( u / w, v / h, 0, MASS )
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);
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}
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}
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// Structural
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for ( let v = 0; v < h; v ++ ) {
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for ( let u = 0; u < w; u ++ ) {
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constraints.push( [
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particles[ index( u, v ) ],
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particles[ index( u, v + 1 ) ],
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restDistance
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] );
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constraints.push( [
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particles[ index( u, v ) ],
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particles[ index( u + 1, v ) ],
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restDistance
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] );
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}
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}
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for ( let u = w, v = 0; v < h; v ++ ) {
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constraints.push( [
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particles[ index( u, v ) ],
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particles[ index( u, v + 1 ) ],
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restDistance
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] );
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}
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for ( let v = h, u = 0; u < w; u ++ ) {
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constraints.push( [
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particles[ index( u, v ) ],
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particles[ index( u + 1, v ) ],
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restDistance
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] );
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}
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// While many systems use shear and bend springs,
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// the relaxed constraints model seems to be just fine
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// using structural springs.
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// Shear
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// const diagonalDist = Math.sqrt(restDistance * restDistance * 2);
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// for (v=0;v<h;v++) {
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// for (u=0;u<w;u++) {
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// constraints.push([
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// particles[index(u, v)],
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// particles[index(u+1, v+1)],
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// diagonalDist
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// ]);
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// constraints.push([
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// particles[index(u+1, v)],
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// particles[index(u, v+1)],
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// diagonalDist
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// ]);
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// }
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// }
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this.particles = particles;
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this.constraints = constraints;
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function index( u, v ) {
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return u + v * ( w + 1 );
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}
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this.index = index;
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}
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}
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function plane( width, height ) {
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return function ( u, v, target ) {
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const x = ( u - 0.5 ) * width;
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const y = ( v + 0.5 ) * height;
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const z = 0;
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target.set( x, y, z );
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};
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}
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function satisfyConstraints( p1, p2, distance ) {
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diff.subVectors( p2.position, p1.position );
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const currentDist = diff.length();
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if ( currentDist === 0 ) return; // prevents division by 0
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const correction = diff.multiplyScalar( 1 - distance / currentDist );
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const correctionHalf = correction.multiplyScalar( 0.5 );
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p1.position.add( correctionHalf );
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p2.position.sub( correctionHalf );
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}
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function simulate( now ) {
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const windStrength = Math.cos( now / 7000 ) * 20 + 40;
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windForce.set( Math.sin( now / 2000 ), Math.cos( now / 3000 ), Math.sin( now / 1000 ) );
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windForce.normalize();
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windForce.multiplyScalar( windStrength );
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// Aerodynamics forces
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const particles = cloth.particles;
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if ( params.enableWind ) {
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let indx;
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const normal = new THREE.Vector3();
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const indices = clothGeometry.index;
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const normals = clothGeometry.attributes.normal;
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for ( let i = 0, il = indices.count; i < il; i += 3 ) {
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for ( let j = 0; j < 3; j ++ ) {
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indx = indices.getX( i + j );
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normal.fromBufferAttribute( normals, indx );
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tmpForce.copy( normal ).normalize().multiplyScalar( normal.dot( windForce ) );
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particles[ indx ].addForce( tmpForce );
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}
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}
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}
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for ( let i = 0, il = particles.length; i < il; i ++ ) {
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const particle = particles[ i ];
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particle.addForce( gravity );
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particle.integrate( TIMESTEP_SQ );
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}
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// Start Constraints
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const constraints = cloth.constraints;
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const il = constraints.length;
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for ( let i = 0; i < il; i ++ ) {
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const constraint = constraints[ i ];
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satisfyConstraints( constraint[ 0 ], constraint[ 1 ], constraint[ 2 ] );
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}
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// Ball Constraints
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ballPosition.z = - Math.sin( now / 600 ) * 90; //+ 40;
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ballPosition.x = Math.cos( now / 400 ) * 70;
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if ( params.showBall ) {
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sphere.visible = true;
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for ( let i = 0, il = particles.length; i < il; i ++ ) {
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const particle = particles[ i ];
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const pos = particle.position;
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diff.subVectors( pos, ballPosition );
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if ( diff.length() < ballSize ) {
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// collided
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diff.normalize().multiplyScalar( ballSize );
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pos.copy( ballPosition ).add( diff );
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}
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}
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} else {
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sphere.visible = false;
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}
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// Floor Constraints
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for ( let i = 0, il = particles.length; i < il; i ++ ) {
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const particle = particles[ i ];
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const pos = particle.position;
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if ( pos.y < - 250 ) {
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pos.y = - 250;
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}
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}
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// Pin Constraints
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for ( let i = 0, il = pins.length; i < il; i ++ ) {
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const xy = pins[ i ];
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const p = particles[ xy ];
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p.position.copy( p.original );
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p.previous.copy( p.original );
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}
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}
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/* testing cloth simulation */
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const cloth = new Cloth( xSegs, ySegs );
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const pinsFormation = [];
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pins = [ 6 ];
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pinsFormation.push( pins );
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pins = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ];
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pinsFormation.push( pins );
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pins = [ 0 ];
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pinsFormation.push( pins );
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pins = []; // cut the rope ;)
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pinsFormation.push( pins );
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pins = [ 0, cloth.w ]; // classic 2 pins
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pinsFormation.push( pins );
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pins = pinsFormation[ 1 ];
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function togglePins() {
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pins = pinsFormation[ ~ ~ ( Math.random() * pinsFormation.length ) ];
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}
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let container, stats;
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let camera, scene, renderer;
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let clothGeometry;
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let sphere;
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let object;
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init();
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animate( 0 );
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function init() {
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container = document.createElement( 'div' );
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document.body.appendChild( container );
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// scene
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scene = new THREE.Scene();
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scene.background = new THREE.Color( 0xcce0ff );
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scene.fog = new THREE.Fog( 0xcce0ff, 500, 10000 );
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// camera
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camera = new THREE.PerspectiveCamera( 30, window.innerWidth / window.innerHeight, 1, 10000 );
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camera.position.set( 1000, 50, 1500 );
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// lights
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scene.add( new THREE.AmbientLight( 0x666666 ) );
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const light = new THREE.DirectionalLight( 0xdfebff, 1 );
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light.position.set( 50, 200, 100 );
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light.position.multiplyScalar( 1.3 );
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light.castShadow = true;
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light.shadow.mapSize.width = 1024;
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light.shadow.mapSize.height = 1024;
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const d = 300;
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light.shadow.camera.left = - d;
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light.shadow.camera.right = d;
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light.shadow.camera.top = d;
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light.shadow.camera.bottom = - d;
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light.shadow.camera.far = 1000;
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scene.add( light );
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// cloth material
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const loader = new THREE.TextureLoader();
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const clothTexture = loader.load( 'textures/patterns/circuit_pattern.png' );
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clothTexture.anisotropy = 16;
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const clothMaterial = new THREE.MeshLambertMaterial( {
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map: clothTexture,
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side: THREE.DoubleSide,
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alphaTest: 0.5
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} );
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// cloth geometry
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clothGeometry = new THREE.ParametricBufferGeometry( clothFunction, cloth.w, cloth.h );
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// cloth mesh
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object = new THREE.Mesh( clothGeometry, clothMaterial );
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object.position.set( 0, 0, 0 );
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object.castShadow = true;
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scene.add( object );
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object.customDepthMaterial = new THREE.MeshDepthMaterial( {
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depthPacking: THREE.RGBADepthPacking,
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map: clothTexture,
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alphaTest: 0.5
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} );
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// sphere
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const ballGeo = new THREE.SphereGeometry( ballSize, 32, 16 );
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const ballMaterial = new THREE.MeshLambertMaterial();
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sphere = new THREE.Mesh( ballGeo, ballMaterial );
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sphere.castShadow = true;
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sphere.receiveShadow = true;
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sphere.visible = false;
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scene.add( sphere );
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// ground
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const groundTexture = loader.load( 'textures/terrain/grasslight-big.jpg' );
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groundTexture.wrapS = groundTexture.wrapT = THREE.RepeatWrapping;
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groundTexture.repeat.set( 25, 25 );
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groundTexture.anisotropy = 16;
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groundTexture.encoding = THREE.sRGBEncoding;
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const groundMaterial = new THREE.MeshLambertMaterial( { map: groundTexture } );
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let mesh = new THREE.Mesh( new THREE.PlaneGeometry( 20000, 20000 ), groundMaterial );
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mesh.position.y = - 250;
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mesh.rotation.x = - Math.PI / 2;
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mesh.receiveShadow = true;
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scene.add( mesh );
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// poles
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const poleGeo = new THREE.BoxGeometry( 5, 375, 5 );
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const poleMat = new THREE.MeshLambertMaterial();
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mesh = new THREE.Mesh( poleGeo, poleMat );
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mesh.position.x = - 125;
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mesh.position.y = - 62;
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mesh.receiveShadow = true;
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mesh.castShadow = true;
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scene.add( mesh );
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mesh = new THREE.Mesh( poleGeo, poleMat );
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mesh.position.x = 125;
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mesh.position.y = - 62;
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mesh.receiveShadow = true;
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mesh.castShadow = true;
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scene.add( mesh );
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mesh = new THREE.Mesh( new THREE.BoxGeometry( 255, 5, 5 ), poleMat );
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mesh.position.y = - 250 + ( 750 / 2 );
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mesh.position.x = 0;
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mesh.receiveShadow = true;
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mesh.castShadow = true;
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scene.add( mesh );
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const gg = new THREE.BoxGeometry( 10, 10, 10 );
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mesh = new THREE.Mesh( gg, poleMat );
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mesh.position.y = - 250;
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mesh.position.x = 125;
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mesh.receiveShadow = true;
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mesh.castShadow = true;
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scene.add( mesh );
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mesh = new THREE.Mesh( gg, poleMat );
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mesh.position.y = - 250;
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mesh.position.x = - 125;
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mesh.receiveShadow = true;
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mesh.castShadow = true;
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scene.add( mesh );
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// renderer
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renderer = new THREE.WebGLRenderer( { antialias: true } );
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renderer.setPixelRatio( window.devicePixelRatio );
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renderer.setSize( window.innerWidth, window.innerHeight );
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container.appendChild( renderer.domElement );
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renderer.outputEncoding = THREE.sRGBEncoding;
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renderer.shadowMap.enabled = true;
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// controls
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const controls = new OrbitControls( camera, renderer.domElement );
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controls.maxPolarAngle = Math.PI * 0.5;
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controls.minDistance = 1000;
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controls.maxDistance = 5000;
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// performance monitor
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||||
stats = new Stats();
|
||||
container.appendChild( stats.dom );
|
||||
|
||||
//
|
||||
|
||||
window.addEventListener( 'resize', onWindowResize );
|
||||
|
||||
//
|
||||
|
||||
const gui = new GUI();
|
||||
gui.add( params, 'enableWind' ).name( 'Enable wind' );
|
||||
gui.add( params, 'showBall' ).name( 'Show ball' );
|
||||
gui.add( params, 'togglePins' ).name( 'Toggle pins' );
|
||||
|
||||
}
|
||||
|
||||
//
|
||||
|
||||
function onWindowResize() {
|
||||
|
||||
camera.aspect = window.innerWidth / window.innerHeight;
|
||||
camera.updateProjectionMatrix();
|
||||
|
||||
renderer.setSize( window.innerWidth, window.innerHeight );
|
||||
|
||||
}
|
||||
|
||||
//
|
||||
|
||||
function animate( now ) {
|
||||
|
||||
requestAnimationFrame( animate );
|
||||
simulate( now );
|
||||
render();
|
||||
stats.update();
|
||||
|
||||
}
|
||||
|
||||
function render() {
|
||||
|
||||
const p = cloth.particles;
|
||||
|
||||
for ( let i = 0, il = p.length; i < il; i ++ ) {
|
||||
|
||||
const v = p[ i ].position;
|
||||
|
||||
clothGeometry.attributes.position.setXYZ( i, v.x, v.y, v.z );
|
||||
|
||||
}
|
||||
|
||||
clothGeometry.attributes.position.needsUpdate = true;
|
||||
|
||||
clothGeometry.computeVertexNormals();
|
||||
|
||||
sphere.position.copy( ballPosition );
|
||||
|
||||
renderer.render( scene, camera );
|
||||
|
||||
}
|
||||
|
||||
</script>
|
||||
</body>
|
||||
</html>
|
||||
Reference in New Issue
Block a user