webgl_read_float_buffer.html 5.6 KB

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  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4. <title>three.js webgl - read float pixels</title>
  5. <meta charset="utf-8">
  6. <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
  7. <link type="text/css" rel="stylesheet" href="main.css">
  8. </head>
  9. <body>
  10. <div id="container"></div>
  11. <div id="info">
  12. <a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> read linear-srgb float pixel data<br/>
  13. <span id="values"></span>
  14. </div>
  15. <script id="fragment_shader_screen" type="x-shader/x-fragment">
  16. varying vec2 vUv;
  17. uniform sampler2D tDiffuse;
  18. void main() {
  19. gl_FragColor = texture2D( tDiffuse, vUv );
  20. #include <colorspace_fragment>
  21. }
  22. </script>
  23. <script id="fragment_shader_pass_1" type="x-shader/x-fragment">
  24. varying vec2 vUv;
  25. uniform float time;
  26. void main() {
  27. float r = vUv.x;
  28. if( vUv.y < 0.5 ) r = 0.0;
  29. float g = vUv.y;
  30. if( vUv.x < 0.5 ) g = 0.0;
  31. gl_FragColor = vec4( r, g, time, 1.0 );
  32. }
  33. </script>
  34. <script id="vertexShader" type="x-shader/x-vertex">
  35. varying vec2 vUv;
  36. void main() {
  37. vUv = uv;
  38. gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
  39. }
  40. </script>
  41. <script type="importmap">
  42. {
  43. "imports": {
  44. "three": "../build/three.module.js",
  45. "three/addons/": "./jsm/"
  46. }
  47. }
  48. </script>
  49. <script type="module">
  50. import * as THREE from 'three';
  51. import Stats from 'three/addons/libs/stats.module.js';
  52. let container, stats;
  53. let cameraRTT, sceneRTT, sceneScreen, renderer, zmesh1, zmesh2;
  54. let mouseX = 0, mouseY = 0;
  55. const windowHalfX = window.innerWidth / 2;
  56. const windowHalfY = window.innerHeight / 2;
  57. let rtTexture, material, quad;
  58. let delta = 0.01;
  59. let valueNode;
  60. init();
  61. function init() {
  62. container = document.getElementById( 'container' );
  63. cameraRTT = new THREE.OrthographicCamera( window.innerWidth / - 2, window.innerWidth / 2, window.innerHeight / 2, window.innerHeight / - 2, - 10000, 10000 );
  64. cameraRTT.position.z = 100;
  65. //
  66. sceneRTT = new THREE.Scene();
  67. sceneScreen = new THREE.Scene();
  68. let light = new THREE.DirectionalLight( 0xffffff, 3 );
  69. light.position.set( 0, 0, 1 ).normalize();
  70. sceneRTT.add( light );
  71. light = new THREE.DirectionalLight( 0xffd5d5, 4.5 );
  72. light.position.set( 0, 0, - 1 ).normalize();
  73. sceneRTT.add( light );
  74. rtTexture = new THREE.WebGLRenderTarget( window.innerWidth, window.innerHeight, { minFilter: THREE.LinearFilter, magFilter: THREE.NearestFilter, format: THREE.RGBAFormat, type: THREE.FloatType } );
  75. material = new THREE.ShaderMaterial( {
  76. uniforms: { 'time': { value: 0.0 } },
  77. vertexShader: document.getElementById( 'vertexShader' ).textContent,
  78. fragmentShader: document.getElementById( 'fragment_shader_pass_1' ).textContent
  79. } );
  80. const materialScreen = new THREE.ShaderMaterial( {
  81. uniforms: { 'tDiffuse': { value: rtTexture.texture } },
  82. vertexShader: document.getElementById( 'vertexShader' ).textContent,
  83. fragmentShader: document.getElementById( 'fragment_shader_screen' ).textContent,
  84. depthWrite: false
  85. } );
  86. const plane = new THREE.PlaneGeometry( window.innerWidth, window.innerHeight );
  87. quad = new THREE.Mesh( plane, material );
  88. quad.position.z = - 100;
  89. sceneRTT.add( quad );
  90. const geometry = new THREE.TorusGeometry( 100, 25, 15, 30 );
  91. const mat1 = new THREE.MeshPhongMaterial( { color: 0x9c9c9c, specular: 0xffaa00, shininess: 5 } );
  92. const mat2 = new THREE.MeshPhongMaterial( { color: 0x9c0000, specular: 0xff2200, shininess: 5 } );
  93. zmesh1 = new THREE.Mesh( geometry, mat1 );
  94. zmesh1.position.set( 0, 0, 100 );
  95. zmesh1.scale.set( 1.5, 1.5, 1.5 );
  96. sceneRTT.add( zmesh1 );
  97. zmesh2 = new THREE.Mesh( geometry, mat2 );
  98. zmesh2.position.set( 0, 150, 100 );
  99. zmesh2.scale.set( 0.75, 0.75, 0.75 );
  100. sceneRTT.add( zmesh2 );
  101. quad = new THREE.Mesh( plane, materialScreen );
  102. quad.position.z = - 100;
  103. sceneScreen.add( quad );
  104. renderer = new THREE.WebGLRenderer();
  105. renderer.setPixelRatio( window.devicePixelRatio );
  106. renderer.setSize( window.innerWidth, window.innerHeight );
  107. renderer.setAnimationLoop( animate );
  108. renderer.autoClear = false;
  109. container.appendChild( renderer.domElement );
  110. stats = new Stats();
  111. container.appendChild( stats.dom );
  112. valueNode = document.getElementById( 'values' );
  113. document.addEventListener( 'mousemove', onDocumentMouseMove );
  114. }
  115. function onDocumentMouseMove( event ) {
  116. mouseX = ( event.clientX - windowHalfX );
  117. mouseY = ( event.clientY - windowHalfY );
  118. }
  119. //
  120. function animate() {
  121. render();
  122. stats.update();
  123. }
  124. function render() {
  125. const time = Date.now() * 0.0015;
  126. if ( zmesh1 && zmesh2 ) {
  127. zmesh1.rotation.y = - time;
  128. zmesh2.rotation.y = - time + Math.PI / 2;
  129. }
  130. if ( material.uniforms[ 'time' ].value > 1 || material.uniforms[ 'time' ].value < 0 ) {
  131. delta *= - 1;
  132. }
  133. material.uniforms[ 'time' ].value += delta;
  134. renderer.clear();
  135. // Render first scene into texture
  136. renderer.setRenderTarget( rtTexture );
  137. renderer.clear();
  138. renderer.render( sceneRTT, cameraRTT );
  139. // Render full screen quad with generated texture
  140. renderer.setRenderTarget( null );
  141. renderer.render( sceneScreen, cameraRTT );
  142. const read = new Float32Array( 4 );
  143. renderer.readRenderTargetPixels( rtTexture, windowHalfX + mouseX, windowHalfY - mouseY, 1, 1, read );
  144. valueNode.innerHTML = 'r:' + read[ 0 ] + '<br/>g:' + read[ 1 ] + '<br/>b:' + read[ 2 ];
  145. }
  146. </script>
  147. </body>
  148. </html>