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earthquake_3d_viewer_front/three/examples/webgpu_compute_cloth.html

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<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgpu - compute cloth</title>
<meta charset="utf-8">
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<div id="info">
<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgpu - compute cloth<br />
Simple cloth simulation with a verlet system running in compute shaders
</div>
<script type="importmap">
{
"imports": {
"three": "../build/three.webgpu.js",
"three/webgpu": "../build/three.webgpu.js",
"three/tsl": "../build/three.tsl.js",
"three/addons/": "./jsm/"
}
}
</script>
<script type="module">
import * as THREE from 'three';
import { Fn, If, Return, instancedArray, instanceIndex, uniform, select, attribute, uint, Loop, float, transformNormalToView, cross, triNoise3D, time } from 'three/tsl';
import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { RGBELoader } from 'three/addons/loaders/RGBELoader.js';
let renderer, scene, camera, controls;
const clothWidth = 1;
const clothHeight = 1;
const clothNumSegmentsX = 30;
const clothNumSegmentsY = 30;
const sphereRadius = 0.15;
let vertexPositionBuffer, vertexForceBuffer, vertexParamsBuffer;
let springVertexIdBuffer, springRestLengthBuffer, springForceBuffer;
let springListBuffer;
let computeSpringForces, computeVertexForces;
let dampeningUniform, spherePositionUniform, stiffnessUniform, sphereUniform, windUniform;
let vertexWireframeObject, springWireframeObject;
let clothMesh, clothMaterial, sphere;
let timeSinceLastStep = 0;
let timestamp = 0;
const verletVertices = [];
const verletSprings = [];
const verletVertexColumns = [];
const clock = new THREE.Clock();
const params = {
wireframe: false,
sphere: true,
wind: 1.0,
};
const API = {
color: 0x204080, // sRGB
sheenColor: 0xffffff // sRGB
};
init();
async function init() {
renderer = new THREE.WebGPURenderer( { antialias: true } );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.toneMapping = THREE.NeutralToneMapping;
renderer.toneMappingExposure = 1;
document.body.appendChild( renderer.domElement );
scene = new THREE.Scene();
camera = new THREE.PerspectiveCamera( 40, window.innerWidth / window.innerHeight, 0.01, 10 );
camera.position.set( - 1.6, - 0.1, - 1.6 );
controls = new OrbitControls( camera, renderer.domElement );
controls.minDistance = 1;
controls.maxDistance = 3;
controls.target.set( 0, - 0.1, 0 );
controls.update();
const rgbeLoader = new RGBELoader().setPath( 'textures/equirectangular/' );
const hdrTexture = await rgbeLoader.loadAsync( 'royal_esplanade_1k.hdr' );
hdrTexture.mapping = THREE.EquirectangularReflectionMapping;
scene.background = hdrTexture;
scene.backgroundBlurriness = 0.5;
scene.environment = hdrTexture;
setupCloth();
const gui = new GUI();
gui.add( stiffnessUniform, 'value', 0.1, 0.5, 0.01 ).name( 'stiffness' );
gui.add( params, 'wireframe' );
gui.add( params, 'sphere' );
gui.add( params, 'wind', 0, 5, 0.1 );
const materialFolder = gui.addFolder( 'material' );
materialFolder.addColor( API, 'color' ).onChange( function ( color ) { clothMaterial.color.setHex( color ); } );
materialFolder.add( clothMaterial, 'roughness', 0.0, 1, 0.01 );
materialFolder.add( clothMaterial, 'sheen', 0.0, 1, 0.01 );
materialFolder.add( clothMaterial, 'sheenRoughness', 0.0, 1, 0.01 );
materialFolder.addColor( API, 'sheenColor' ).onChange( function ( color ) { clothMaterial.sheenColor.setHex( color ); } );
window.addEventListener( 'resize', onWindowResize );
renderer.setAnimationLoop( render );
}
function setupVerletGeometry() {
// this function sets up the geometry of the verlet system, a grid of vertices connected by springs
const addVerletVertex = ( x, y, z, isFixed ) => {
const id = verletVertices.length;
const vertex = {
id,
position: new THREE.Vector3( x, y, z ),
isFixed,
springIds: [],
};
verletVertices.push( vertex );
return vertex;
};
const addVerletSpring = ( vertex0, vertex1 ) => {
const id = verletSprings.length;
const spring = {
id,
vertex0,
vertex1
};
vertex0.springIds.push( id );
vertex1.springIds.push( id );
verletSprings.push( spring );
return spring;
};
// create the cloth's verlet vertices
for ( let x = 0; x <= clothNumSegmentsX; x ++ ) {
const column = [];
for ( let y = 0; y <= clothNumSegmentsY; y ++ ) {
const posX = x * ( clothWidth / clothNumSegmentsX ) - clothWidth * 0.5;
const posZ = y * ( clothHeight / clothNumSegmentsY );
const isFixed = ( y === 0 ) && ( ( x % 5 ) === 0 ); // make some of the top vertices' positions fixed
const vertex = addVerletVertex( posX, clothHeight * 0.5, posZ, isFixed );
column.push( vertex );
}
verletVertexColumns.push( column );
}
// create the cloth's verlet springs
for ( let x = 0; x <= clothNumSegmentsX; x ++ ) {
for ( let y = 0; y <= clothNumSegmentsY; y ++ ) {
const vertex0 = verletVertexColumns[ x ][ y ];
if ( x > 0 ) addVerletSpring( vertex0, verletVertexColumns[ x - 1 ][ y ] );
if ( y > 0 ) addVerletSpring( vertex0, verletVertexColumns[ x ][ y - 1 ] );
if ( x > 0 && y > 0 ) addVerletSpring( vertex0, verletVertexColumns[ x - 1 ][ y - 1 ] );
if ( x > 0 && y < clothNumSegmentsY ) addVerletSpring( vertex0, verletVertexColumns[ x - 1 ][ y + 1 ] );
// You can make the cloth more rigid by adding more springs between further apart vertices
//if (x > 1) addVerletSpring(vertex0, verletVertexColumns[x - 2][y]);
//if (y > 1) addVerletSpring(vertex0, verletVertexColumns[x][y - 2]);
}
}
}
function setupVerletVertexBuffers() {
// setup the buffers holding the vertex data for the compute shaders
const vertexCount = verletVertices.length;
const springListArray = [];
// this springListArray will hold a list of spring ids, ordered by the id of the vertex affected by that spring.
// this is so the compute shader that accumulates the spring forces for each vertex can efficiently iterate over all springs affecting that vertex
const vertexPositionArray = new Float32Array( vertexCount * 3 );
const vertexParamsArray = new Uint32Array( vertexCount * 3 );
// the params Array holds three values for each verlet vertex:
// x: isFixed, y: springCount, z: springPointer
// isFixed is 1 if the verlet is marked as immovable, 0 if not
// springCount is the number of springs connected to that vertex
// springPointer is the index of the first spring in the springListArray that is connected to that vertex
for ( let i = 0; i < vertexCount; i ++ ) {
const vertex = verletVertices[ i ];
vertexPositionArray[ i * 3 ] = vertex.position.x;
vertexPositionArray[ i * 3 + 1 ] = vertex.position.y;
vertexPositionArray[ i * 3 + 2 ] = vertex.position.z;
vertexParamsArray[ i * 3 ] = vertex.isFixed ? 1 : 0;
if ( ! vertex.isFixed ) {
vertexParamsArray[ i * 3 + 1 ] = vertex.springIds.length;
vertexParamsArray[ i * 3 + 2 ] = springListArray.length;
springListArray.push( ...vertex.springIds );
}
}
vertexPositionBuffer = instancedArray( vertexPositionArray, 'vec3' ).setPBO( true ); // setPBO(true) is only important for the WebGL Fallback
vertexForceBuffer = instancedArray( vertexCount, 'vec3' );
vertexParamsBuffer = instancedArray( vertexParamsArray, 'uvec3' );
springListBuffer = instancedArray( new Uint32Array( springListArray ), 'uint' ).setPBO( true );
}
function setupVerletSpringBuffers() {
// setup the buffers holding the spring data for the compute shaders
const springCount = verletSprings.length;
const springVertexIdArray = new Uint32Array( springCount * 2 );
const springRestLengthArray = new Float32Array( springCount );
for ( let i = 0; i < springCount; i ++ ) {
const spring = verletSprings[ i ];
springVertexIdArray[ i * 2 ] = spring.vertex0.id;
springVertexIdArray[ i * 2 + 1 ] = spring.vertex1.id;
springRestLengthArray[ i ] = spring.vertex0.position.distanceTo( spring.vertex1.position );
}
springVertexIdBuffer = instancedArray( springVertexIdArray, 'uvec2' ).setPBO( true );
springRestLengthBuffer = instancedArray( springRestLengthArray, 'float' );
springForceBuffer = instancedArray( springCount * 3, 'vec3' ).setPBO( true );
}
function setupUniforms() {
dampeningUniform = uniform( 0.99 );
spherePositionUniform = uniform( new THREE.Vector3( 0, 0, 0 ) );
sphereUniform = uniform( 1.0 );
windUniform = uniform( 1.0 );
stiffnessUniform = uniform( 0.2 );
}
function setupComputeShaders() {
// This function sets up the compute shaders for the verlet simulation
// There are two shaders that are executed for each simulation step
const vertexCount = verletVertices.length;
const springCount = verletSprings.length;
// 1. computeSpringForces:
// This shader computes a force for each spring, depending on the distance between the two vertices connected by that spring and the targeted rest length
computeSpringForces = Fn( () => {
If( instanceIndex.greaterThanEqual( uint( springCount ) ), () => {
// compute Shaders are executed in groups of 64, so instanceIndex might be bigger than the amount of springs.
// in that case, return.
Return();
} );
const vertexIds = springVertexIdBuffer.element( instanceIndex );
const restLength = springRestLengthBuffer.element( instanceIndex );
const vertex0Position = vertexPositionBuffer.element( vertexIds.x );
const vertex1Position = vertexPositionBuffer.element( vertexIds.y );
const delta = vertex1Position.sub( vertex0Position ).toVar();
const dist = delta.length().max( 0.000001 ).toVar();
const force = dist.sub( restLength ).mul( stiffnessUniform ).mul( delta ).mul( 0.5 ).div( dist );
springForceBuffer.element( instanceIndex ).assign( force );
} )().compute( springCount );
// 2. computeVertexForces:
// This shader accumulates the force for each vertex.
// First it iterates over all springs connected to this vertex and accumulates their forces.
// Then it adds a gravital force, wind force, and the collision with the sphere.
// In the end it adds the force to the vertex' position.
computeVertexForces = Fn( () => {
If( instanceIndex.greaterThanEqual( uint( vertexCount ) ), () => {
// compute Shaders are executed in groups of 64, so instanceIndex might be bigger than the amount of vertices.
// in that case, return.
Return();
} );
const params = vertexParamsBuffer.element( instanceIndex ).toVar();
const isFixed = params.x;
const springCount = params.y;
const springPointer = params.z;
If( isFixed, () => {
// don't need to calculate vertex forces if the vertex is set as immovable
Return();
} );
const position = vertexPositionBuffer.element( instanceIndex ).toVar( 'vertexPosition' );
const force = vertexForceBuffer.element( instanceIndex ).toVar( 'vertexForce' );
force.mulAssign( dampeningUniform );
const ptrStart = springPointer.toVar( 'ptrStart' );
const ptrEnd = ptrStart.add( springCount ).toVar( 'ptrEnd' );
Loop( { start: ptrStart, end: ptrEnd, type: 'uint', condition: '<' }, ( { i } ) => {
const springId = springListBuffer.element( i ).toVar( 'springId' );
const springForce = springForceBuffer.element( springId );
const springVertexIds = springVertexIdBuffer.element( springId );
const factor = select( springVertexIds.x.equal( instanceIndex ), 1.0, - 1.0 );
force.addAssign( springForce.mul( factor ) );
} );
// gravity
force.y.subAssign( 0.00005 );
// wind
const noise = triNoise3D( position, 1, time ).sub( 0.2 ).mul( 0.0001 );
const windForce = noise.mul( windUniform );
force.z.subAssign( windForce );
// collision with sphere
const deltaSphere = position.add( force ).sub( spherePositionUniform );
const dist = deltaSphere.length();
const sphereForce = float( sphereRadius ).sub( dist ).max( 0 ).mul( deltaSphere ).div( dist ).mul( sphereUniform );
force.addAssign( sphereForce );
vertexForceBuffer.element( instanceIndex ).assign( force );
vertexPositionBuffer.element( instanceIndex ).addAssign( force );
} )().compute( vertexCount );
}
function setupWireframe() {
// adds helpers to visualize the verlet system
// verlet vertex visualizer
const vertexWireframeMaterial = new THREE.SpriteNodeMaterial();
vertexWireframeMaterial.positionNode = vertexPositionBuffer.element( instanceIndex );
vertexWireframeObject = new THREE.Mesh( new THREE.PlaneGeometry( 0.01, 0.01 ), vertexWireframeMaterial );
vertexWireframeObject.frustumCulled = false;
vertexWireframeObject.count = verletVertices.length;
scene.add( vertexWireframeObject );
// verlet spring visualizer
const springWireframePositionBuffer = new THREE.BufferAttribute( new Float32Array( 6 ), 3, false );
const springWireframeIndexBuffer = new THREE.BufferAttribute( new Uint32Array( [ 0, 1 ] ), 1, false );
const springWireframeMaterial = new THREE.LineBasicNodeMaterial();
springWireframeMaterial.positionNode = Fn( () => {
const vertexIds = springVertexIdBuffer.element( instanceIndex );
const vertexId = select( attribute( 'vertexIndex' ).equal( 0 ), vertexIds.x, vertexIds.y );
return vertexPositionBuffer.element( vertexId );
} )();
const springWireframeGeometry = new THREE.InstancedBufferGeometry();
springWireframeGeometry.setAttribute( 'position', springWireframePositionBuffer );
springWireframeGeometry.setAttribute( 'vertexIndex', springWireframeIndexBuffer );
springWireframeGeometry.instanceCount = verletSprings.length;
springWireframeObject = new THREE.Line( springWireframeGeometry, springWireframeMaterial );
springWireframeObject.frustumCulled = false;
springWireframeObject.count = verletSprings.length;
scene.add( springWireframeObject );
}
function setupSphere() {
const geometry = new THREE.IcosahedronGeometry( sphereRadius * 0.95, 4 );
const material = new THREE.MeshStandardNodeMaterial();
sphere = new THREE.Mesh( geometry, material );
scene.add( sphere );
}
function setupClothMesh() {
// This function generates a three Geometry and Mesh to render the cloth based on the verlet systems position data.
// Therefore it creates a plane mesh, in which each vertex will be centered in the center of 4 verlet vertices.
const vertexCount = clothNumSegmentsX * clothNumSegmentsY;
const geometry = new THREE.BufferGeometry();
// verletVertexIdArray will hold the 4 verlet vertex ids that contribute to each geometry vertex's position
const verletVertexIdArray = new Uint32Array( vertexCount * 4 );
const indices = [];
const getIndex = ( x, y ) => {
return y * clothNumSegmentsX + x;
};
for ( let x = 0; x < clothNumSegmentsX; x ++ ) {
for ( let y = 0; y < clothNumSegmentsX; y ++ ) {
const index = getIndex( x, y );
verletVertexIdArray[ index * 4 ] = verletVertexColumns[ x ][ y ].id;
verletVertexIdArray[ index * 4 + 1 ] = verletVertexColumns[ x + 1 ][ y ].id;
verletVertexIdArray[ index * 4 + 2 ] = verletVertexColumns[ x ][ y + 1 ].id;
verletVertexIdArray[ index * 4 + 3 ] = verletVertexColumns[ x + 1 ][ y + 1 ].id;
if ( x > 0 && y > 0 ) {
indices.push( getIndex( x, y ), getIndex( x - 1, y ), getIndex( x - 1, y - 1 ) );
indices.push( getIndex( x, y ), getIndex( x - 1, y - 1 ), getIndex( x, y - 1 ) );
}
}
}
const verletVertexIdBuffer = new THREE.BufferAttribute( verletVertexIdArray, 4, false );
const positionBuffer = new THREE.BufferAttribute( new Float32Array( vertexCount * 3 ), 3, false );
geometry.setAttribute( 'position', positionBuffer );
geometry.setAttribute( 'vertexIds', verletVertexIdBuffer );
geometry.setIndex( indices );
clothMaterial = new THREE.MeshPhysicalNodeMaterial( {
color: new THREE.Color().setHex( API.color ),
side: THREE.DoubleSide,
transparent: true,
opacity: 0.85,
sheen: 1.0,
sheenRoughness: 0.5,
sheenColor: new THREE.Color().setHex( API.sheenColor ),
} );
clothMaterial.positionNode = Fn( ( { material } ) => {
// gather the position of the 4 verlet vertices and calculate the center position and normal from that
const vertexIds = attribute( 'vertexIds' );
const v0 = vertexPositionBuffer.element( vertexIds.x ).toVar();
const v1 = vertexPositionBuffer.element( vertexIds.y ).toVar();
const v2 = vertexPositionBuffer.element( vertexIds.z ).toVar();
const v3 = vertexPositionBuffer.element( vertexIds.w ).toVar();
const top = v0.add( v1 );
const right = v1.add( v3 );
const bottom = v2.add( v3 );
const left = v0.add( v2 );
const tangent = right.sub( left ).normalize();
const bitangent = bottom.sub( top ).normalize();
const normal = cross( tangent, bitangent );
// send the normalView from the vertex shader to the fragment shader
material.normalNode = transformNormalToView( normal ).toVarying();
return v0.add( v1 ).add( v2 ).add( v3 ).mul( 0.25 );
} )();
clothMesh = new THREE.Mesh( geometry, clothMaterial );
clothMesh.frustumCulled = false;
scene.add( clothMesh );
}
function setupCloth() {
setupVerletGeometry();
setupVerletVertexBuffers();
setupVerletSpringBuffers();
setupUniforms();
setupComputeShaders();
setupWireframe();
setupSphere();
setupClothMesh();
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function updateSphere() {
sphere.position.set( Math.sin( timestamp * 2.1 ) * 0.1, 0, Math.sin( timestamp * 0.8 ) );
spherePositionUniform.value.copy( sphere.position );
}
async function render() {
sphere.visible = params.sphere;
sphereUniform.value = params.sphere ? 1 : 0;
windUniform.value = params.wind;
clothMesh.visible = ! params.wireframe;
vertexWireframeObject.visible = params.wireframe;
springWireframeObject.visible = params.wireframe;
const deltaTime = Math.min( clock.getDelta(), 1 / 60 ); // don't advance the time too far, for example when the window is out of focus
const stepsPerSecond = 360; // ensure the same amount of simulation steps per second on all systems, independent of refresh rate
const timePerStep = 1 / stepsPerSecond;
timeSinceLastStep += deltaTime;
while ( timeSinceLastStep >= timePerStep ) {
// run a verlet system simulation step
timestamp += timePerStep;
timeSinceLastStep -= timePerStep;
updateSphere();
await renderer.computeAsync( computeSpringForces );
await renderer.computeAsync( computeVertexForces );
}
await renderer.renderAsync( scene, camera );
}
</script>
</body>
</html>