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241 lines
6.1 KiB
241 lines
6.1 KiB
<!DOCTYPE html>
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<html lang="en">
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<head>
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<title>three.js webgl - nearest neighbour</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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<style>
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html, body {
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width: 100%;
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height: 100%;
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}
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body {
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background-color: #ffffff;
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margin: 0;
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overflow: hidden;
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font-family: arial;
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}
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#info {
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text-align: center;
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padding: 5px;
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position: absolute;
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width: 100%;
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color: white;
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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"><a href="http://threejs.org" target="_blank" rel="noopener">three.js</a> webgl - typed arrays - nearest neighbour for 500,000 sprites</div>
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<script src="../build/three.js"></script>
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<script src="js/utils/TypedArrayUtils.js"></script>
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<script src="js/controls/FirstPersonControls.js"></script>
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<script type="x-shader/x-vertex" id="vertexshader">
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//uniform float zoom;
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attribute float alpha;
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varying float vAlpha;
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void main() {
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vAlpha = 1.0 - alpha;
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vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );
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gl_PointSize = 4.0 * ( 300.0 / -mvPosition.z );
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gl_Position = projectionMatrix * mvPosition;
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}
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</script>
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<script type="x-shader/x-fragment" id="fragmentshader">
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uniform sampler2D tex1;
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varying float vAlpha;
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void main() {
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gl_FragColor = texture2D( tex1, gl_PointCoord );
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gl_FragColor.r = ( 1.0 - gl_FragColor.r ) * vAlpha + gl_FragColor.r;
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}
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</script>
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<script>
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var camera, scene, renderer;
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var controls;
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var amountOfParticles = 500000, maxDistance = Math.pow( 120, 2 );
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var positions, alphas, particles, _particleGeom;
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var kdtree;
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var clock = new THREE.Clock();
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function init() {
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camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 1, 1000000 );
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scene = new THREE.Scene();
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controls = new THREE.FirstPersonControls( camera );
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controls.movementSpeed = 100;
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controls.lookSpeed = 0.1;
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controls.lookAt( 500, 500, 500 );
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// add a skybox background
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var cubeTextureLoader = new THREE.CubeTextureLoader();
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cubeTextureLoader.setPath( 'textures/cube/skybox/' );
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var cubeTexture = cubeTextureLoader.load( [
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'px.jpg', 'nx.jpg',
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'py.jpg', 'ny.jpg',
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'pz.jpg', 'nz.jpg',
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] );
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scene.background = cubeTexture;
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//
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renderer = new THREE.WebGLRenderer();
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renderer.setPixelRatio( window.devicePixelRatio );
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renderer.setSize( window.innerWidth, window.innerHeight );
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document.body.appendChild( renderer.domElement );
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// create the custom shader
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var textureLoader = new THREE.TextureLoader();
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var imagePreviewTexture = textureLoader.load( 'textures/crate.gif' );
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imagePreviewTexture.minFilter = THREE.LinearMipMapLinearFilter;
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imagePreviewTexture.magFilter = THREE.LinearFilter;
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var pointShaderMaterial = new THREE.ShaderMaterial( {
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uniforms: {
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tex1: { value: imagePreviewTexture },
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zoom: { value: 9.0 }
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},
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vertexShader: document.getElementById( 'vertexshader' ).textContent,
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fragmentShader: document.getElementById( 'fragmentshader' ).textContent,
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transparent: true
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} );
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//create particles with buffer geometry
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var distanceFunction = function ( a, b ) {
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return Math.pow( a[ 0 ] - b[ 0 ], 2 ) + Math.pow( a[ 1 ] - b[ 1 ], 2 ) + Math.pow( a[ 2 ] - b[ 2 ], 2 );
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};
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positions = new Float32Array( amountOfParticles * 3 );
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alphas = new Float32Array( amountOfParticles );
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_particleGeom = new THREE.BufferGeometry();
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_particleGeom.addAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );
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_particleGeom.addAttribute( 'alpha', new THREE.BufferAttribute( alphas, 1 ) );
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particles = new THREE.Points( _particleGeom, pointShaderMaterial );
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for ( var x = 0; x < amountOfParticles; x ++ ) {
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positions[ x * 3 + 0 ] = Math.random() * 1000;
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positions[ x * 3 + 1 ] = Math.random() * 1000;
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positions[ x * 3 + 2 ] = Math.random() * 1000;
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alphas[ x ] = 1.0;
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}
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var measureStart = new Date().getTime();
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// creating the kdtree takes a lot of time to execute, in turn the nearest neighbour search will be much faster
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kdtree = new THREE.TypedArrayUtils.Kdtree( positions, distanceFunction, 3 );
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console.log( 'TIME building kdtree', new Date().getTime() - measureStart );
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// display particles after the kd-tree was generated and the sorting of the positions-array is done
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scene.add( particles );
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window.addEventListener( 'resize', onWindowResize, false );
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}
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function onWindowResize() {
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camera.aspect = window.innerWidth / window.innerHeight;
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camera.updateProjectionMatrix();
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renderer.setSize( window.innerWidth, window.innerHeight );
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controls.handleResize();
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}
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function animate() {
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requestAnimationFrame( animate );
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//
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displayNearest( camera.position );
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controls.update( clock.getDelta() );
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renderer.render( scene, camera );
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}
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function displayNearest( position ) {
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// take the nearest 200 around him. distance^2 'cause we use the manhattan distance and no square is applied in the distance function
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var imagePositionsInRange = kdtree.nearest( [ position.x, position.y, position.z ], 100, maxDistance );
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// We combine the nearest neighbour with a view frustum. Doesn't make sense if we change the sprites not in our view... well maybe it does. Whatever you want.
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var _frustum = new THREE.Frustum();
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var _projScreenMatrix = new THREE.Matrix4();
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_projScreenMatrix.multiplyMatrices( camera.projectionMatrix, camera.matrixWorldInverse );
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_frustum.setFromMatrix( _projScreenMatrix );
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for ( var i = 0, il = imagePositionsInRange.length; i < il; i ++ ) {
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var object = imagePositionsInRange[ i ];
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var objectPoint = new THREE.Vector3().fromArray( object[ 0 ].obj );
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if ( _frustum.containsPoint( objectPoint ) ) {
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var objectIndex = object[ 0 ].pos;
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// set the alpha according to distance
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alphas[ objectIndex ] = 1.0 / maxDistance * object[ 1 ];
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// update the attribute
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_particleGeom.attributes.alpha.needsUpdate = true;
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}
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}
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}
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init();
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animate();
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</script>
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</body>
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</html>
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