tips-preservedrawingbuffer.html 3.7 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. <!-- Import maps polyfill -->
  24. <!-- Remove this when import maps will be widely supported -->
  25. <script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>
  26. <script type="importmap">
  27. {
  28. "imports": {
  29. "three": "../../build/three.module.js"
  30. }
  31. }
  32. </script>
  33. <script type="module">
  34. import * as THREE from 'three';
  35. function main() {
  36. const canvas = document.querySelector('#c');
  37. const renderer = new THREE.WebGLRenderer({
  38. canvas,
  39. preserveDrawingBuffer: true,
  40. alpha: true,
  41. antialias: true
  42. });
  43. renderer.autoClearColor = false;
  44. const camera = new THREE.OrthographicCamera(-2, 2, 1, -1, -1, 1);
  45. const scene = new THREE.Scene();
  46. {
  47. const color = 0xFFFFFF;
  48. const intensity = 1;
  49. const light = new THREE.DirectionalLight(color, intensity);
  50. light.position.set(-1, 2, 4);
  51. scene.add(light);
  52. }
  53. const boxWidth = 1;
  54. const boxHeight = 1;
  55. const boxDepth = 1;
  56. const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
  57. const base = new THREE.Object3D();
  58. scene.add(base);
  59. base.scale.set(0.1, 0.1, 0.1);
  60. function makeInstance(geometry, color, x, y, z) {
  61. const material = new THREE.MeshPhongMaterial({color});
  62. const cube = new THREE.Mesh(geometry, material);
  63. base.add(cube);
  64. cube.position.set(x, y, z);
  65. return cube;
  66. }
  67. makeInstance(geometry, '#F00', -2, 0, 0);
  68. makeInstance(geometry, '#FF0', 2, 0, 0);
  69. makeInstance(geometry, '#0F0', 0, -2, 0);
  70. makeInstance(geometry, '#0FF', 0, 2, 0);
  71. makeInstance(geometry, '#00F', 0, 0, -2);
  72. makeInstance(geometry, '#F0F', 0, 0, 2);
  73. function resizeRendererToDisplaySize(renderer) {
  74. const canvas = renderer.domElement;
  75. const width = canvas.clientWidth;
  76. const height = canvas.clientHeight;
  77. const needResize = canvas.width !== width || canvas.height !== height;
  78. if (needResize) {
  79. renderer.setSize(width, height, false);
  80. }
  81. return needResize;
  82. }
  83. const state = { x: 0, y: 0 };
  84. function render(time) {
  85. time *= 0.001; // convert to seconds
  86. if (resizeRendererToDisplaySize(renderer)) {
  87. const canvas = renderer.domElement;
  88. camera.right = canvas.clientWidth / canvas.clientHeight;
  89. camera.left = -camera.right;
  90. camera.updateProjectionMatrix();
  91. }
  92. base.position.set(state.x, state.y, 0);
  93. base.rotation.x = time;
  94. base.rotation.y = time * 1.11;
  95. renderer.render(scene, camera);
  96. requestAnimationFrame(render);
  97. }
  98. requestAnimationFrame(render);
  99. function getCanvasRelativePosition(event) {
  100. const rect = canvas.getBoundingClientRect();
  101. return {
  102. x: (event.clientX - rect.left) * canvas.width / rect.width,
  103. y: (event.clientY - rect.top ) * canvas.height / rect.height,
  104. };
  105. }
  106. const temp = new THREE.Vector3();
  107. function setPosition(e) {
  108. const pos = getCanvasRelativePosition(e);
  109. const x = pos.x / canvas.width * 2 - 1;
  110. const y = pos.y / canvas.height * -2 + 1;
  111. temp.set(x, y, 0).unproject(camera);
  112. state.x = temp.x;
  113. state.y = temp.y;
  114. }
  115. canvas.addEventListener('mousemove', setPosition);
  116. canvas.addEventListener('touchmove', (e) => {
  117. e.preventDefault();
  118. setPosition(e.touches[0]);
  119. }, {passive: false});
  120. }
  121. main();
  122. </script>
  123. </html>