tips-preservedrawingbuffer.html 3.4 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="module">
  24. import * as THREE from '../../build/three.module.js';
  25. function main() {
  26. const canvas = document.querySelector('#c');
  27. const renderer = new THREE.WebGLRenderer({
  28. canvas,
  29. preserveDrawingBuffer: true,
  30. alpha: true,
  31. });
  32. renderer.autoClearColor = false;
  33. const camera = new THREE.OrthographicCamera(-2, 2, 1, -1, -1, 1);
  34. const scene = new THREE.Scene();
  35. {
  36. const color = 0xFFFFFF;
  37. const intensity = 1;
  38. const light = new THREE.DirectionalLight(color, intensity);
  39. light.position.set(-1, 2, 4);
  40. scene.add(light);
  41. }
  42. const boxWidth = 1;
  43. const boxHeight = 1;
  44. const boxDepth = 1;
  45. const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
  46. const base = new THREE.Object3D();
  47. scene.add(base);
  48. base.scale.set(0.1, 0.1, 0.1);
  49. function makeInstance(geometry, color, x, y, z) {
  50. const material = new THREE.MeshPhongMaterial({color});
  51. const cube = new THREE.Mesh(geometry, material);
  52. base.add(cube);
  53. cube.position.set(x, y, z);
  54. return cube;
  55. }
  56. makeInstance(geometry, '#F00', -2, 0, 0);
  57. makeInstance(geometry, '#FF0', 2, 0, 0);
  58. makeInstance(geometry, '#0F0', 0, -2, 0);
  59. makeInstance(geometry, '#0FF', 0, 2, 0);
  60. makeInstance(geometry, '#00F', 0, 0, -2);
  61. makeInstance(geometry, '#F0F', 0, 0, 2);
  62. function resizeRendererToDisplaySize(renderer) {
  63. const canvas = renderer.domElement;
  64. const width = canvas.clientWidth;
  65. const height = canvas.clientHeight;
  66. const needResize = canvas.width !== width || canvas.height !== height;
  67. if (needResize) {
  68. renderer.setSize(width, height, false);
  69. }
  70. return needResize;
  71. }
  72. const state = { x: 0, y: 0 };
  73. function render(time) {
  74. time *= 0.001; // convert to seconds
  75. if (resizeRendererToDisplaySize(renderer)) {
  76. const canvas = renderer.domElement;
  77. camera.right = canvas.clientWidth / canvas.clientHeight;
  78. camera.left = -camera.right;
  79. camera.updateProjectionMatrix();
  80. }
  81. base.position.set(state.x, state.y, 0);
  82. base.rotation.x = time;
  83. base.rotation.y = time * 1.11;
  84. renderer.render(scene, camera);
  85. requestAnimationFrame(render);
  86. }
  87. requestAnimationFrame(render);
  88. function getCanvasRelativePosition(event) {
  89. const rect = canvas.getBoundingClientRect();
  90. return {
  91. x: (event.clientX - rect.left) * canvas.width / rect.width,
  92. y: (event.clientY - rect.top ) * canvas.height / rect.height,
  93. };
  94. }
  95. const temp = new THREE.Vector3();
  96. function setPosition(e) {
  97. const pos = getCanvasRelativePosition(e);
  98. const x = pos.x / canvas.width * 2 - 1;
  99. const y = pos.y / canvas.height * -2 + 1;
  100. temp.set(x, y, 0).unproject(camera);
  101. state.x = temp.x;
  102. state.y = temp.y;
  103. }
  104. canvas.addEventListener('mousemove', setPosition);
  105. canvas.addEventListener('touchmove', (e) => {
  106. e.preventDefault();
  107. setPosition(e.touches[0]);
  108. }, {passive: false});
  109. }
  110. main();
  111. </script>
  112. </html>