tips-preservedrawingbuffer.html 3.5 KB

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  1. <!-- Licensed under a BSD license. See license.html for license -->
  2. <!DOCTYPE html>
  3. <html>
  4. <head>
  5. <meta charset="utf-8">
  6. <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
  7. <title>Three.js - PreserveDrawingBuffer</title>
  8. <style>
  9. html, body {
  10. height: 100%;
  11. margin: 0;
  12. }
  13. #c {
  14. width: 100%;
  15. height: 100%;
  16. display: block;
  17. }
  18. </style>
  19. </head>
  20. <body>
  21. <canvas id="c"></canvas>
  22. </body>
  23. <script type="importmap">
  24. {
  25. "imports": {
  26. "three": "../../build/three.module.js"
  27. }
  28. }
  29. </script>
  30. <script type="module">
  31. import * as THREE from 'three';
  32. function main() {
  33. const canvas = document.querySelector( '#c' );
  34. const renderer = new THREE.WebGLRenderer( {
  35. canvas,
  36. preserveDrawingBuffer: true,
  37. alpha: true,
  38. antialias: true
  39. } );
  40. renderer.autoClearColor = false;
  41. const camera = new THREE.OrthographicCamera( - 2, 2, 1, - 1, - 1, 1 );
  42. const scene = new THREE.Scene();
  43. {
  44. const color = 0xFFFFFF;
  45. const intensity = 3;
  46. const light = new THREE.DirectionalLight( color, intensity );
  47. light.position.set( - 1, 2, 4 );
  48. scene.add( light );
  49. }
  50. const boxWidth = 1;
  51. const boxHeight = 1;
  52. const boxDepth = 1;
  53. const geometry = new THREE.BoxGeometry( boxWidth, boxHeight, boxDepth );
  54. const base = new THREE.Object3D();
  55. scene.add( base );
  56. base.scale.set( 0.1, 0.1, 0.1 );
  57. function makeInstance( geometry, color, x, y, z ) {
  58. const material = new THREE.MeshPhongMaterial( { color } );
  59. const cube = new THREE.Mesh( geometry, material );
  60. base.add( cube );
  61. cube.position.set( x, y, z );
  62. return cube;
  63. }
  64. makeInstance( geometry, '#F00', - 2, 0, 0 );
  65. makeInstance( geometry, '#FF0', 2, 0, 0 );
  66. makeInstance( geometry, '#0F0', 0, - 2, 0 );
  67. makeInstance( geometry, '#0FF', 0, 2, 0 );
  68. makeInstance( geometry, '#00F', 0, 0, - 2 );
  69. makeInstance( geometry, '#F0F', 0, 0, 2 );
  70. function resizeRendererToDisplaySize( renderer ) {
  71. const canvas = renderer.domElement;
  72. const width = canvas.clientWidth;
  73. const height = canvas.clientHeight;
  74. const needResize = canvas.width !== width || canvas.height !== height;
  75. if ( needResize ) {
  76. renderer.setSize( width, height, false );
  77. }
  78. return needResize;
  79. }
  80. const state = { x: 0, y: 0 };
  81. function render( time ) {
  82. time *= 0.001; // convert to seconds
  83. if ( resizeRendererToDisplaySize( renderer ) ) {
  84. const canvas = renderer.domElement;
  85. camera.right = canvas.clientWidth / canvas.clientHeight;
  86. camera.left = - camera.right;
  87. camera.updateProjectionMatrix();
  88. }
  89. base.position.set( state.x, state.y, 0 );
  90. base.rotation.x = time;
  91. base.rotation.y = time * 1.11;
  92. renderer.render( scene, camera );
  93. requestAnimationFrame( render );
  94. }
  95. requestAnimationFrame( render );
  96. function getCanvasRelativePosition( event ) {
  97. const rect = canvas.getBoundingClientRect();
  98. return {
  99. x: ( event.clientX - rect.left ) * canvas.width / rect.width,
  100. y: ( event.clientY - rect.top ) * canvas.height / rect.height,
  101. };
  102. }
  103. const temp = new THREE.Vector3();
  104. function setPosition( e ) {
  105. const pos = getCanvasRelativePosition( e );
  106. const x = pos.x / canvas.width * 2 - 1;
  107. const y = pos.y / canvas.height * - 2 + 1;
  108. temp.set( x, y, 0 ).unproject( camera );
  109. state.x = temp.x;
  110. state.y = temp.y;
  111. }
  112. canvas.addEventListener( 'mousemove', setPosition );
  113. canvas.addEventListener( 'touchmove', ( e ) => {
  114. e.preventDefault();
  115. setPosition( e.touches[ 0 ] );
  116. }, { passive: false } );
  117. }
  118. main();
  119. </script>
  120. </html>