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<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - gpgpu - flocking</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 {
background-color: #fff;
color: #444;
}
a {
color:#08f;
}
</style>
</head>
<body>
<div id="info">
<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - webgl gpgpu birds<br/>
Move mouse to disturb birds.
</div>
<!--
TODO: If you're reading this, you may wish to improve this example by
- Create a better shading for the birds?
-->
<!-- shader for bird's position -->
<script id="fragmentShaderPosition" type="x-shader/x-fragment">
uniform float time;
uniform float delta;
void main() {
vec2 uv = gl_FragCoord.xy / resolution.xy;
vec4 tmpPos = texture2D( texturePosition, uv );
vec3 position = tmpPos.xyz;
vec3 velocity = texture2D( textureVelocity, uv ).xyz;
float phase = tmpPos.w;
phase = mod( ( phase + delta +
length( velocity.xz ) * delta * 3. +
max( velocity.y, 0.0 ) * delta * 6. ), 62.83 );
gl_FragColor = vec4( position + velocity * delta * 15. , phase );
}
</script>
<!-- shader for bird's velocity -->
<script id="fragmentShaderVelocity" type="x-shader/x-fragment">
uniform float time;
uniform float testing;
uniform float delta; // about 0.016
uniform float separationDistance; // 20
uniform float alignmentDistance; // 40
uniform float cohesionDistance; //
uniform float freedomFactor;
uniform vec3 predator;
const float width = resolution.x;
const float height = resolution.y;
const float PI = 3.141592653589793;
const float PI_2 = PI * 2.0;
// const float VISION = PI * 0.55;
float zoneRadius = 40.0;
float zoneRadiusSquared = 1600.0;
float separationThresh = 0.45;
float alignmentThresh = 0.65;
const float UPPER_BOUNDS = BOUNDS;
const float LOWER_BOUNDS = -UPPER_BOUNDS;
const float SPEED_LIMIT = 9.0;
float rand( vec2 co ){
return fract( sin( dot( co.xy, vec2(12.9898,78.233) ) ) * 43758.5453 );
}
void main() {
zoneRadius = separationDistance + alignmentDistance + cohesionDistance;
separationThresh = separationDistance / zoneRadius;
alignmentThresh = ( separationDistance + alignmentDistance ) / zoneRadius;
zoneRadiusSquared = zoneRadius * zoneRadius;
vec2 uv = gl_FragCoord.xy / resolution.xy;
vec3 birdPosition, birdVelocity;
vec3 selfPosition = texture2D( texturePosition, uv ).xyz;
vec3 selfVelocity = texture2D( textureVelocity, uv ).xyz;
float dist;
vec3 dir; // direction
float distSquared;
float separationSquared = separationDistance * separationDistance;
float cohesionSquared = cohesionDistance * cohesionDistance;
float f;
float percent;
vec3 velocity = selfVelocity;
float limit = SPEED_LIMIT;
dir = predator * UPPER_BOUNDS - selfPosition;
dir.z = 0.;
// dir.z *= 0.6;
dist = length( dir );
distSquared = dist * dist;
float preyRadius = 150.0;
float preyRadiusSq = preyRadius * preyRadius;
// move birds away from predator
if ( dist < preyRadius ) {
f = ( distSquared / preyRadiusSq - 1.0 ) * delta * 100.;
velocity += normalize( dir ) * f;
limit += 5.0;
}
// if (testing == 0.0) {}
// if ( rand( uv + time ) < freedomFactor ) {}
// Attract flocks to the center
vec3 central = vec3( 0., 0., 0. );
dir = selfPosition - central;
dist = length( dir );
dir.y *= 2.5;
velocity -= normalize( dir ) * delta * 5.;
for ( float y = 0.0; y < height; y++ ) {
for ( float x = 0.0; x < width; x++ ) {
vec2 ref = vec2( x + 0.5, y + 0.5 ) / resolution.xy;
birdPosition = texture2D( texturePosition, ref ).xyz;
dir = birdPosition - selfPosition;
dist = length( dir );
if ( dist < 0.0001 ) continue;
distSquared = dist * dist;
if ( distSquared > zoneRadiusSquared ) continue;
percent = distSquared / zoneRadiusSquared;
if ( percent < separationThresh ) { // low
// Separation - Move apart for comfort
f = ( separationThresh / percent - 1.0 ) * delta;
velocity -= normalize( dir ) * f;
} else if ( percent < alignmentThresh ) { // high
// Alignment - fly the same direction
float threshDelta = alignmentThresh - separationThresh;
float adjustedPercent = ( percent - separationThresh ) / threshDelta;
birdVelocity = texture2D( textureVelocity, ref ).xyz;
f = ( 0.5 - cos( adjustedPercent * PI_2 ) * 0.5 + 0.5 ) * delta;
velocity += normalize( birdVelocity ) * f;
} else {
// Attraction / Cohesion - move closer
float threshDelta = 1.0 - alignmentThresh;
float adjustedPercent;
if( threshDelta == 0. ) adjustedPercent = 1.;
else adjustedPercent = ( percent - alignmentThresh ) / threshDelta;
f = ( 0.5 - ( cos( adjustedPercent * PI_2 ) * -0.5 + 0.5 ) ) * delta;
velocity += normalize( dir ) * f;
}
}
}
// this make tends to fly around than down or up
// if (velocity.y > 0.) velocity.y *= (1. - 0.2 * delta);
// Speed Limits
if ( length( velocity ) > limit ) {
velocity = normalize( velocity ) * limit;
}
gl_FragColor = vec4( velocity, 1.0 );
}
</script>
<script type="x-shader/x-vertex" id="birdVS">
attribute vec2 reference;
attribute float birdVertex;
attribute vec3 birdColor;
uniform sampler2D texturePosition;
uniform sampler2D textureVelocity;
varying vec4 vColor;
varying float z;
uniform float time;
void main() {
vec4 tmpPos = texture2D( texturePosition, reference );
vec3 pos = tmpPos.xyz;
vec3 velocity = normalize(texture2D( textureVelocity, reference ).xyz);
vec3 newPosition = position;
if ( birdVertex == 4.0 || birdVertex == 7.0 ) {
// flap wings
newPosition.y = sin( tmpPos.w ) * 5.;
}
newPosition = mat3( modelMatrix ) * newPosition;
velocity.z *= -1.;
float xz = length( velocity.xz );
float xyz = 1.;
float x = sqrt( 1. - velocity.y * velocity.y );
float cosry = velocity.x / xz;
float sinry = velocity.z / xz;
float cosrz = x / xyz;
float sinrz = velocity.y / xyz;
mat3 maty = mat3(
cosry, 0, -sinry,
0 , 1, 0 ,
sinry, 0, cosry
);
mat3 matz = mat3(
cosrz , sinrz, 0,
-sinrz, cosrz, 0,
0 , 0 , 1
);
newPosition = maty * matz * newPosition;
newPosition += pos;
z = newPosition.z;
vColor = vec4( birdColor, 1.0 );
gl_Position = projectionMatrix * viewMatrix * vec4( newPosition, 1.0 );
}
</script>
<!-- bird geometry shader -->
<script type="x-shader/x-fragment" id="birdFS">
varying vec4 vColor;
varying float z;
uniform vec3 color;
void main() {
// Fake colors for now
float z2 = 0.2 + ( 1000. - z ) / 1000. * vColor.x;
gl_FragColor = vec4( z2, z2, z2, 1. );
}
</script>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/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 { GUI } from 'three/addons/libs/lil-gui.module.min.js';
import { GPUComputationRenderer } from 'three/addons/misc/GPUComputationRenderer.js';
/* TEXTURE WIDTH FOR SIMULATION */
const WIDTH = 32;
const BIRDS = WIDTH * WIDTH;
// Custom Geometry - using 3 triangles each. No UVs, no normals currently.
class BirdGeometry extends THREE.BufferGeometry {
constructor() {
super();
const trianglesPerBird = 3;
const triangles = BIRDS * trianglesPerBird;
const points = triangles * 3;
const vertices = new THREE.BufferAttribute( new Float32Array( points * 3 ), 3 );
const birdColors = new THREE.BufferAttribute( new Float32Array( points * 3 ), 3 );
const references = new THREE.BufferAttribute( new Float32Array( points * 2 ), 2 );
const birdVertex = new THREE.BufferAttribute( new Float32Array( points ), 1 );
this.setAttribute( 'position', vertices );
this.setAttribute( 'birdColor', birdColors );
this.setAttribute( 'reference', references );
this.setAttribute( 'birdVertex', birdVertex );
// this.setAttribute( 'normal', new Float32Array( points * 3 ), 3 );
let v = 0;
function verts_push() {
for ( let i = 0; i < arguments.length; i ++ ) {
vertices.array[ v ++ ] = arguments[ i ];
}
}
const wingsSpan = 20;
for ( let f = 0; f < BIRDS; f ++ ) {
// Body
verts_push(
0, - 0, - 20,
0, 4, - 20,
0, 0, 30
);
// Wings
verts_push(
0, 0, - 15,
- wingsSpan, 0, 0,
0, 0, 15
);
verts_push(
0, 0, 15,
wingsSpan, 0, 0,
0, 0, - 15
);
}
for ( let v = 0; v < triangles * 3; v ++ ) {
const triangleIndex = ~ ~ ( v / 3 );
const birdIndex = ~ ~ ( triangleIndex / trianglesPerBird );
const x = ( birdIndex % WIDTH ) / WIDTH;
const y = ~ ~ ( birdIndex / WIDTH ) / WIDTH;
const c = new THREE.Color(
0x444444 +
~ ~ ( v / 9 ) / BIRDS * 0x666666
);
birdColors.array[ v * 3 + 0 ] = c.r;
birdColors.array[ v * 3 + 1 ] = c.g;
birdColors.array[ v * 3 + 2 ] = c.b;
references.array[ v * 2 ] = x;
references.array[ v * 2 + 1 ] = y;
birdVertex.array[ v ] = v % 9;
}
this.scale( 0.2, 0.2, 0.2 );
}
}
//
let container, stats;
let camera, scene, renderer;
let mouseX = 0, mouseY = 0;
let windowHalfX = window.innerWidth / 2;
let windowHalfY = window.innerHeight / 2;
const BOUNDS = 800, BOUNDS_HALF = BOUNDS / 2;
let last = performance.now();
let gpuCompute;
let velocityVariable;
let positionVariable;
let positionUniforms;
let velocityUniforms;
let birdUniforms;
init();
animate();
function init() {
container = document.createElement( 'div' );
document.body.appendChild( container );
camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 1, 3000 );
camera.position.z = 350;
scene = new THREE.Scene();
scene.background = new THREE.Color( 0xffffff );
scene.fog = new THREE.Fog( 0xffffff, 100, 1000 );
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
container.appendChild( renderer.domElement );
initComputeRenderer();
stats = new Stats();
container.appendChild( stats.dom );
container.style.touchAction = 'none';
container.addEventListener( 'pointermove', onPointerMove );
//
window.addEventListener( 'resize', onWindowResize );
const gui = new GUI();
const effectController = {
separation: 20.0,
alignment: 20.0,
cohesion: 20.0,
freedom: 0.75
};
const valuesChanger = function () {
velocityUniforms[ 'separationDistance' ].value = effectController.separation;
velocityUniforms[ 'alignmentDistance' ].value = effectController.alignment;
velocityUniforms[ 'cohesionDistance' ].value = effectController.cohesion;
velocityUniforms[ 'freedomFactor' ].value = effectController.freedom;
};
valuesChanger();
gui.add( effectController, 'separation', 0.0, 100.0, 1.0 ).onChange( valuesChanger );
gui.add( effectController, 'alignment', 0.0, 100, 0.001 ).onChange( valuesChanger );
gui.add( effectController, 'cohesion', 0.0, 100, 0.025 ).onChange( valuesChanger );
gui.close();
initBirds();
}
function initComputeRenderer() {
gpuCompute = new GPUComputationRenderer( WIDTH, WIDTH, renderer );
if ( renderer.capabilities.isWebGL2 === false ) {
gpuCompute.setDataType( THREE.HalfFloatType );
}
const dtPosition = gpuCompute.createTexture();
const dtVelocity = gpuCompute.createTexture();
fillPositionTexture( dtPosition );
fillVelocityTexture( dtVelocity );
velocityVariable = gpuCompute.addVariable( 'textureVelocity', document.getElementById( 'fragmentShaderVelocity' ).textContent, dtVelocity );
positionVariable = gpuCompute.addVariable( 'texturePosition', document.getElementById( 'fragmentShaderPosition' ).textContent, dtPosition );
gpuCompute.setVariableDependencies( velocityVariable, [ positionVariable, velocityVariable ] );
gpuCompute.setVariableDependencies( positionVariable, [ positionVariable, velocityVariable ] );
positionUniforms = positionVariable.material.uniforms;
velocityUniforms = velocityVariable.material.uniforms;
positionUniforms[ 'time' ] = { value: 0.0 };
positionUniforms[ 'delta' ] = { value: 0.0 };
velocityUniforms[ 'time' ] = { value: 1.0 };
velocityUniforms[ 'delta' ] = { value: 0.0 };
velocityUniforms[ 'testing' ] = { value: 1.0 };
velocityUniforms[ 'separationDistance' ] = { value: 1.0 };
velocityUniforms[ 'alignmentDistance' ] = { value: 1.0 };
velocityUniforms[ 'cohesionDistance' ] = { value: 1.0 };
velocityUniforms[ 'freedomFactor' ] = { value: 1.0 };
velocityUniforms[ 'predator' ] = { value: new THREE.Vector3() };
velocityVariable.material.defines.BOUNDS = BOUNDS.toFixed( 2 );
velocityVariable.wrapS = THREE.RepeatWrapping;
velocityVariable.wrapT = THREE.RepeatWrapping;
positionVariable.wrapS = THREE.RepeatWrapping;
positionVariable.wrapT = THREE.RepeatWrapping;
const error = gpuCompute.init();
if ( error !== null ) {
console.error( error );
}
}
function initBirds() {
const geometry = new BirdGeometry();
// For Vertex and Fragment
birdUniforms = {
'color': { value: new THREE.Color( 0xff2200 ) },
'texturePosition': { value: null },
'textureVelocity': { value: null },
'time': { value: 1.0 },
'delta': { value: 0.0 }
};
// THREE.ShaderMaterial
const material = new THREE.ShaderMaterial( {
uniforms: birdUniforms,
vertexShader: document.getElementById( 'birdVS' ).textContent,
fragmentShader: document.getElementById( 'birdFS' ).textContent,
side: THREE.DoubleSide
} );
const birdMesh = new THREE.Mesh( geometry, material );
birdMesh.rotation.y = Math.PI / 2;
birdMesh.matrixAutoUpdate = false;
birdMesh.updateMatrix();
scene.add( birdMesh );
}
function fillPositionTexture( texture ) {
const theArray = texture.image.data;
for ( let k = 0, kl = theArray.length; k < kl; k += 4 ) {
const x = Math.random() * BOUNDS - BOUNDS_HALF;
const y = Math.random() * BOUNDS - BOUNDS_HALF;
const z = Math.random() * BOUNDS - BOUNDS_HALF;
theArray[ k + 0 ] = x;
theArray[ k + 1 ] = y;
theArray[ k + 2 ] = z;
theArray[ k + 3 ] = 1;
}
}
function fillVelocityTexture( texture ) {
const theArray = texture.image.data;
for ( let k = 0, kl = theArray.length; k < kl; k += 4 ) {
const x = Math.random() - 0.5;
const y = Math.random() - 0.5;
const z = Math.random() - 0.5;
theArray[ k + 0 ] = x * 10;
theArray[ k + 1 ] = y * 10;
theArray[ k + 2 ] = z * 10;
theArray[ k + 3 ] = 1;
}
}
function onWindowResize() {
windowHalfX = window.innerWidth / 2;
windowHalfY = window.innerHeight / 2;
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
function onPointerMove( event ) {
if ( event.isPrimary === false ) return;
mouseX = event.clientX - windowHalfX;
mouseY = event.clientY - windowHalfY;
}
//
function animate() {
requestAnimationFrame( animate );
render();
stats.update();
}
function render() {
const now = performance.now();
let delta = ( now - last ) / 1000;
if ( delta > 1 ) delta = 1; // safety cap on large deltas
last = now;
positionUniforms[ 'time' ].value = now;
positionUniforms[ 'delta' ].value = delta;
velocityUniforms[ 'time' ].value = now;
velocityUniforms[ 'delta' ].value = delta;
birdUniforms[ 'time' ].value = now;
birdUniforms[ 'delta' ].value = delta;
velocityUniforms[ 'predator' ].value.set( 0.5 * mouseX / windowHalfX, - 0.5 * mouseY / windowHalfY, 0 );
mouseX = 10000;
mouseY = 10000;
gpuCompute.compute();
birdUniforms[ 'texturePosition' ].value = gpuCompute.getCurrentRenderTarget( positionVariable ).texture;
birdUniforms[ 'textureVelocity' ].value = gpuCompute.getCurrentRenderTarget( velocityVariable ).texture;
renderer.render( scene, camera );
}
</script>
</body>
</html>