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261 lines
7.5 KiB
261 lines
7.5 KiB
<!-- Licensed under a BSD license. See license.html for license -->
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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
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<title>Three.js - Picking - RayCaster w/Transparency</title>
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<style>
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html, body {
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height: 100%;
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margin: 0;
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}
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#c {
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width: 100%;
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height: 100%;
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display: block;
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}
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</style>
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</head>
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<body>
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<canvas id="c"></canvas>
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</body>
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<!-- Import maps polyfill -->
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<!-- Remove this when import maps will be widely supported -->
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<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
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<script type="importmap">
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{
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"imports": {
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"three": "../../build/three.module.js"
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}
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}
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</script>
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<script type="module">
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import * as THREE from 'three';
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function main() {
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const canvas = document.querySelector('#c');
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const renderer = new THREE.WebGLRenderer({canvas});
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const fov = 60;
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const aspect = 2; // the canvas default
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const near = 0.1;
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const far = 200;
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const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
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camera.position.z = 30;
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const scene = new THREE.Scene();
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scene.background = new THREE.Color('white');
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const pickingScene = new THREE.Scene();
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pickingScene.background = new THREE.Color(0);
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// put the camera on a pole (parent it to an object)
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// so we can spin the pole to move the camera around the scene
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const cameraPole = new THREE.Object3D();
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scene.add(cameraPole);
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cameraPole.add(camera);
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{
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const color = 0xFFFFFF;
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const intensity = 1;
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const light = new THREE.DirectionalLight(color, intensity);
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light.position.set(-1, 2, 4);
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camera.add(light);
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}
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const boxWidth = 1;
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const boxHeight = 1;
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const boxDepth = 1;
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const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
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function rand(min, max) {
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if (max === undefined) {
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max = min;
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min = 0;
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}
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return min + (max - min) * Math.random();
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}
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function randomColor() {
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return `hsl(${rand(360) | 0}, ${rand(50, 100) | 0}%, 50%)`;
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}
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const loader = new THREE.TextureLoader();
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const texture = loader.load('resources/images/frame.png');
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const idToObject = {};
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const numObjects = 100;
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for (let i = 0; i < numObjects; ++i) {
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const id = i + 1;
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const material = new THREE.MeshPhongMaterial({
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color: randomColor(),
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map: texture,
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transparent: true,
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side: THREE.DoubleSide,
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alphaTest: 0.5,
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});
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const cube = new THREE.Mesh(geometry, material);
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scene.add(cube);
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idToObject[id] = cube;
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cube.position.set(rand(-20, 20), rand(-20, 20), rand(-20, 20));
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cube.rotation.set(rand(Math.PI), rand(Math.PI), 0);
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cube.scale.set(rand(3, 6), rand(3, 6), rand(3, 6));
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const pickingMaterial = new THREE.MeshPhongMaterial({
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emissive: new THREE.Color(id),
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color: new THREE.Color(0, 0, 0),
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specular: new THREE.Color(0, 0, 0),
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map: texture,
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transparent: true,
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side: THREE.DoubleSide,
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alphaTest: 0.5,
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blending: THREE.NoBlending,
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});
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const pickingCube = new THREE.Mesh(geometry, pickingMaterial);
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pickingScene.add(pickingCube);
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pickingCube.position.copy(cube.position);
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pickingCube.rotation.copy(cube.rotation);
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pickingCube.scale.copy(cube.scale);
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}
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function resizeRendererToDisplaySize(renderer) {
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const canvas = renderer.domElement;
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const width = canvas.clientWidth;
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const height = canvas.clientHeight;
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const needResize = canvas.width !== width || canvas.height !== height;
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if (needResize) {
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renderer.setSize(width, height, false);
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}
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return needResize;
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}
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class GPUPickHelper {
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constructor() {
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// create a 1x1 pixel render target
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this.pickingTexture = new THREE.WebGLRenderTarget(1, 1);
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this.pixelBuffer = new Uint8Array(4);
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this.pickedObject = null;
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this.pickedObjectSavedColor = 0;
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}
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pick(cssPosition, scene, camera, time) {
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const {pickingTexture, pixelBuffer} = this;
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// restore the color if there is a picked object
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if (this.pickedObject) {
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this.pickedObject.material.emissive.setHex(this.pickedObjectSavedColor);
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this.pickedObject = undefined;
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}
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// set the view offset to represent just a single pixel under the mouse
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const pixelRatio = renderer.getPixelRatio();
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camera.setViewOffset(
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renderer.getContext().drawingBufferWidth, // full width
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renderer.getContext().drawingBufferHeight, // full top
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cssPosition.x * pixelRatio | 0, // rect x
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cssPosition.y * pixelRatio | 0, // rect y
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1, // rect width
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1, // rect height
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);
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// render the scene
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renderer.setRenderTarget(pickingTexture);
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renderer.render(scene, camera);
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renderer.setRenderTarget(null);
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// clear the view offset so rendering returns to normal
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camera.clearViewOffset();
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//read the pixel
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renderer.readRenderTargetPixels(
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pickingTexture,
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0, // x
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0, // y
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1, // width
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1, // height
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pixelBuffer);
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const id =
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(pixelBuffer[0] << 16) |
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(pixelBuffer[1] << 8) |
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(pixelBuffer[2] );
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const intersectedObject = idToObject[id];
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if (intersectedObject) {
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// pick the first object. It's the closest one
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this.pickedObject = intersectedObject;
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// save its color
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this.pickedObjectSavedColor = this.pickedObject.material.emissive.getHex();
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// set its emissive color to flashing red/yellow
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this.pickedObject.material.emissive.setHex((time * 8) % 2 > 1 ? 0xFFFF00 : 0xFF0000);
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}
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}
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}
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const pickPosition = {x: 0, y: 0};
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const pickHelper = new GPUPickHelper();
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clearPickPosition();
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function render(time) {
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time *= 0.001; // convert to seconds;
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if (resizeRendererToDisplaySize(renderer)) {
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const canvas = renderer.domElement;
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camera.aspect = canvas.clientWidth / canvas.clientHeight;
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camera.updateProjectionMatrix();
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}
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cameraPole.rotation.y = time * .1;
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pickHelper.pick(pickPosition, pickingScene, camera, time);
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renderer.render(scene, camera);
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requestAnimationFrame(render);
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}
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requestAnimationFrame(render);
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function getCanvasRelativePosition(event) {
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const rect = canvas.getBoundingClientRect();
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return {
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x: (event.clientX - rect.left) * canvas.width / rect.width,
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y: (event.clientY - rect.top ) * canvas.height / rect.height,
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};
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}
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function setPickPosition(event) {
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const pos = getCanvasRelativePosition(event);
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pickPosition.x = pos.x;
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pickPosition.y = pos.y;
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}
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function clearPickPosition() {
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// unlike the mouse which always has a position
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// if the user stops touching the screen we want
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// to stop picking. For now we just pick a value
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// unlikely to pick something
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pickPosition.x = -100000;
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pickPosition.y = -100000;
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}
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window.addEventListener('mousemove', setPickPosition);
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window.addEventListener('mouseout', clearPickPosition);
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window.addEventListener('mouseleave', clearPickPosition);
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window.addEventListener('touchstart', (event) => {
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// prevent the window from scrolling
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event.preventDefault();
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setPickPosition(event.touches[0]);
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}, {passive: false});
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window.addEventListener('touchmove', (event) => {
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setPickPosition(event.touches[0]);
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});
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window.addEventListener('touchend', clearPickPosition);
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}
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main();
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</script>
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</html>
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