threejs-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. body {
  10. margin: 0;
  11. }
  12. #c {
  13. width: 100vw;
  14. height: 100vh;
  15. display: block;
  16. }
  17. </style>
  18. </head>
  19. <body>
  20. <canvas id="c"></canvas>
  21. </body>
  22. <script type="module">
  23. import * as THREE from './resources/threejs/r114/build/three.module.js';
  24. function main() {
  25. const canvas = document.querySelector('#c');
  26. const renderer = new THREE.WebGLRenderer({
  27. canvas,
  28. preserveDrawingBuffer: true,
  29. alpha: true,
  30. });
  31. renderer.autoClearColor = false;
  32. const camera = new THREE.OrthographicCamera(-2, 2, 1, -1, -1, 1);
  33. const scene = new THREE.Scene();
  34. {
  35. const color = 0xFFFFFF;
  36. const intensity = 1;
  37. const light = new THREE.DirectionalLight(color, intensity);
  38. light.position.set(-1, 2, 4);
  39. scene.add(light);
  40. }
  41. const boxWidth = 1;
  42. const boxHeight = 1;
  43. const boxDepth = 1;
  44. const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
  45. const base = new THREE.Object3D();
  46. scene.add(base);
  47. base.scale.set(0.1, 0.1, 0.1);
  48. function makeInstance(geometry, color, x, y, z) {
  49. const material = new THREE.MeshPhongMaterial({color});
  50. const cube = new THREE.Mesh(geometry, material);
  51. base.add(cube);
  52. cube.position.set(x, y, z);
  53. return cube;
  54. }
  55. makeInstance(geometry, '#F00', -2, 0, 0);
  56. makeInstance(geometry, '#FF0', 2, 0, 0);
  57. makeInstance(geometry, '#0F0', 0, -2, 0);
  58. makeInstance(geometry, '#0FF', 0, 2, 0);
  59. makeInstance(geometry, '#00F', 0, 0, -2);
  60. makeInstance(geometry, '#F0F', 0, 0, 2);
  61. function resizeRendererToDisplaySize(renderer) {
  62. const canvas = renderer.domElement;
  63. const width = canvas.clientWidth;
  64. const height = canvas.clientHeight;
  65. const needResize = canvas.width !== width || canvas.height !== height;
  66. if (needResize) {
  67. renderer.setSize(width, height, false);
  68. }
  69. return needResize;
  70. }
  71. const state = { x: 0, y: 0 };
  72. function render(time) {
  73. time *= 0.001; // convert to seconds
  74. if (resizeRendererToDisplaySize(renderer)) {
  75. const canvas = renderer.domElement;
  76. camera.right = canvas.clientWidth / canvas.clientHeight;
  77. camera.left = -camera.right;
  78. camera.updateProjectionMatrix();
  79. }
  80. base.position.set(state.x, state.y, 0);
  81. base.rotation.x = time;
  82. base.rotation.y = time * 1.11;
  83. renderer.render(scene, camera);
  84. requestAnimationFrame(render);
  85. }
  86. requestAnimationFrame(render);
  87. function getCanvasRelativePosition(event) {
  88. const rect = canvas.getBoundingClientRect();
  89. return {
  90. x: (event.clientX - rect.left) * canvas.width / rect.width,
  91. y: (event.clientY - rect.top ) * canvas.height / rect.height,
  92. };
  93. }
  94. const temp = new THREE.Vector3();
  95. function setPosition(e) {
  96. const pos = getCanvasRelativePosition(e);
  97. const x = pos.x / canvas.width * 2 - 1;
  98. const y = pos.y / canvas.height * -2 + 1;
  99. temp.set(x, y, 0).unproject(camera);
  100. state.x = temp.x;
  101. state.y = temp.y;
  102. }
  103. canvas.addEventListener('mousemove', setPosition);
  104. canvas.addEventListener('touchmove', (e) => {
  105. e.preventDefault();
  106. setPosition(e.touches[0]);
  107. }, {passive: false});
  108. }
  109. main();
  110. </script>
  111. </html>