webgl_nearestneighbour.html 6.7 KB

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  1. <html>
  2. <head>
  3. <meta charset="utf-8">
  4. <title>three.js webgl - nearest neighbour</title>
  5. <style>
  6. html, body {
  7. width: 100%;
  8. height: 100%;
  9. }
  10. body {
  11. background-color: #ffffff;
  12. margin: 0;
  13. overflow: hidden;
  14. font-family: arial;
  15. }
  16. #info {
  17. text-align: center;
  18. padding: 5px;
  19. position: absolute;
  20. width: 100%;
  21. color: white;
  22. }
  23. </style>
  24. </head>
  25. <body>
  26. <div id="info"><a href="http://threejs.org" target="_blank">three.js</a> webgl - typed arrays - nearest neighbour for 500,000 sprites</div>
  27. <script src="../build/three.min.js"></script>
  28. <script src="js/TypedArrayUtils.js"></script>
  29. <script src="js/controls/FirstPersonControls.js"></script>
  30. <script type="x-shader/x-vertex" id="vertexshader">
  31. //uniform float zoom;
  32. attribute float alpha;
  33. varying float vAlpha;
  34. void main() {
  35. vAlpha = 1.0 - alpha;
  36. vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );
  37. gl_PointSize = 4.0 * ( 300.0 / length( mvPosition.xyz ) );
  38. gl_Position = projectionMatrix * mvPosition;
  39. }
  40. </script>
  41. <script type="x-shader/x-fragment" id="fragmentshader">
  42. uniform sampler2D tex1;
  43. varying float vAlpha;
  44. void main() {
  45. gl_FragColor = texture2D(tex1, gl_PointCoord);
  46. gl_FragColor.r = (1.0 - gl_FragColor.r) * vAlpha + gl_FragColor.r;
  47. }
  48. </script>
  49. <script>
  50. var camera, scene, renderer;
  51. var geometry, mesh;
  52. var controls;
  53. var objects = [];
  54. var amountOfParticles = 500000, maxDistance = Math.pow(120, 2);
  55. var positions, alphas, particles, _particleGeom;
  56. var clock = new THREE.Clock();
  57. var blocker = document.getElementById( 'blocker' );
  58. var instructions = document.getElementById( 'instructions' );
  59. function init() {
  60. camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 1, 1000000);
  61. scene = new THREE.Scene();
  62. controls = new THREE.FirstPersonControls( camera );
  63. controls.movementSpeed = 100;
  64. controls.lookSpeed = 0.1;
  65. var materials = [
  66. new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'textures/cube/skybox/px.jpg' ) } ), // right
  67. new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'textures/cube/skybox/nx.jpg' ) } ), // left
  68. new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'textures/cube/skybox/py.jpg' ) } ), // top
  69. new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'textures/cube/skybox/ny.jpg' ) } ), // bottom
  70. new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'textures/cube/skybox/pz.jpg' ) } ), // back
  71. new THREE.MeshBasicMaterial( { map: THREE.ImageUtils.loadTexture( 'textures/cube/skybox/nz.jpg' ) } ) // front
  72. ];
  73. mesh = new THREE.Mesh( new THREE.BoxGeometry( 10000, 10000, 10000, 7, 7, 7 ), new THREE.MeshFaceMaterial( materials ) );
  74. mesh.scale.x = - 1;
  75. scene.add(mesh);
  76. //
  77. renderer = new THREE.WebGLRenderer(); // Detector.webgl? new THREE.WebGLRenderer(): new THREE.CanvasRenderer()
  78. renderer.setPixelRatio( window.devicePixelRatio );
  79. renderer.setSize( window.innerWidth, window.innerHeight );
  80. document.body.appendChild( renderer.domElement );
  81. // create the custom shader
  82. var imagePreviewTexture = THREE.ImageUtils.loadTexture( 'textures/crate.gif');
  83. imagePreviewTexture.minFilter = THREE.LinearMipMapLinearFilter;
  84. imagePreviewTexture.magFilter = THREE.LinearFilter;
  85. pointShaderMaterial = new THREE.ShaderMaterial( {
  86. uniforms: {
  87. tex1: { type: "t", value: imagePreviewTexture },
  88. zoom: { type: 'f', value: 9.0 },
  89. },
  90. vertexShader: document.getElementById( 'vertexshader' ).textContent,
  91. fragmentShader: document.getElementById( 'fragmentshader' ).textContent,
  92. transparent: true
  93. });
  94. //create particles with buffer geometry
  95. var distanceFunction = function(a, b){
  96. return Math.pow(a[0] - b[0], 2) + Math.pow(a[1] - b[1], 2) + Math.pow(a[2] - b[2], 2);
  97. };
  98. positions = new Float32Array( amountOfParticles * 3 );
  99. alphas = new Float32Array( amountOfParticles );
  100. _particleGeom = new THREE.BufferGeometry();
  101. _particleGeom.addAttribute( 'position', new THREE.BufferAttribute( positions, 3 ) );
  102. _particleGeom.addAttribute( 'alpha', new THREE.BufferAttribute( alphas, 1 ) );
  103. particles = new THREE.Points( _particleGeom, pointShaderMaterial );
  104. for (var x = 0; x < amountOfParticles; x++) {
  105. positions[ x * 3 + 0 ] = Math.random() * 1000;
  106. positions[ x * 3 + 1 ] = Math.random() * 1000;
  107. positions[ x * 3 + 2 ] = Math.random() * 1000;
  108. alphas[x] = 1.0;
  109. }
  110. var measureStart = new Date().getTime();
  111. // creating the kdtree takes a lot of time to execute, in turn the nearest neighbour search will be much faster
  112. kdtree = new THREE.TypedArrayUtils.Kdtree( positions, distanceFunction, 3 );
  113. console.log('TIME building kdtree', new Date().getTime() - measureStart);
  114. // display particles after the kd-tree was generated and the sorting of the positions-array is done
  115. scene.add(particles);
  116. window.addEventListener( 'resize', onWindowResize, false );
  117. }
  118. function onWindowResize() {
  119. camera.aspect = window.innerWidth / window.innerHeight;
  120. camera.updateProjectionMatrix();
  121. renderer.setSize( window.innerWidth, window.innerHeight );
  122. controls.handleResize();
  123. }
  124. function animate() {
  125. requestAnimationFrame( animate );
  126. //
  127. displayNearest(camera.position);
  128. controls.update( clock.getDelta() );
  129. renderer.render( scene, camera );
  130. }
  131. function displayNearest(position) {
  132. // take the nearest 200 around him. distance^2 'cause we use the manhattan distance and no square is applied in the distance function
  133. var imagePositionsInRange = kdtree.nearest([position.x, position.y, position.z], 100, maxDistance);
  134. // 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.
  135. var _frustum = new THREE.Frustum();
  136. var _projScreenMatrix = new THREE.Matrix4();
  137. camera.matrixWorldInverse.getInverse( camera.matrixWorld );
  138. _projScreenMatrix.multiplyMatrices( camera.projectionMatrix, camera.matrixWorldInverse );
  139. _frustum.setFromMatrix( _projScreenMatrix );
  140. for ( i = 0, il = imagePositionsInRange.length; i < il; i ++ ) {
  141. var object = imagePositionsInRange[i];
  142. var objectPoint = new THREE.Vector3().fromArray( object[ 0 ].obj );
  143. if (_frustum.containsPoint(objectPoint)){
  144. var objectIndex = object[0].pos;
  145. // set the alpha according to distance
  146. alphas[ objectIndex ] = 1.0 / maxDistance * object[1];
  147. // update the attribute
  148. _particleGeom.attributes.alpha.needsUpdate = true;
  149. }
  150. }
  151. }
  152. init();
  153. animate();
  154. </script>
  155. </body>
  156. </html>