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160 lines
3.8 KiB
160 lines
3.8 KiB
2 years ago
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<title>three.js webgl - materials - canvas texture</title>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
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<link type="text/css" rel="stylesheet" href="main.css">
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<style>
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#drawing-canvas {
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position: absolute;
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background-color: #000000;
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top: 0px;
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right: 0px;
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z-index: 3000;
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cursor: crosshair;
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touch-action: none;
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}
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</style>
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</head>
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<body>
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<div id="info">
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<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - webgl - canvas as a texture
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<div>click and draw in the white box</div>
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</div>
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<canvas id="drawing-canvas" height="128" width="128"></canvas>
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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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"three/addons/": "./jsm/"
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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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let camera, scene, renderer, mesh, material;
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const drawStartPos = new THREE.Vector2();
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init();
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setupCanvasDrawing();
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animate();
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function init() {
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camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 1, 2000 );
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camera.position.z = 500;
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scene = new THREE.Scene();
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material = new THREE.MeshBasicMaterial();
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mesh = new THREE.Mesh( new THREE.BoxGeometry( 200, 200, 200 ), material );
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scene.add( mesh );
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renderer = new THREE.WebGLRenderer( { antialias: true } );
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renderer.setPixelRatio( window.devicePixelRatio );
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renderer.setSize( window.innerWidth, window.innerHeight );
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document.body.appendChild( renderer.domElement );
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window.addEventListener( 'resize', onWindowResize );
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}
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// Sets up the drawing canvas and adds it as the material map
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function setupCanvasDrawing() {
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// get canvas and context
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const drawingCanvas = document.getElementById( 'drawing-canvas' );
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const drawingContext = drawingCanvas.getContext( '2d' );
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// draw white background
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drawingContext.fillStyle = '#FFFFFF';
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drawingContext.fillRect( 0, 0, 128, 128 );
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// set canvas as material.map (this could be done to any map, bump, displacement etc.)
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material.map = new THREE.CanvasTexture( drawingCanvas );
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// set the variable to keep track of when to draw
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let paint = false;
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// add canvas event listeners
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drawingCanvas.addEventListener( 'pointerdown', function ( e ) {
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paint = true;
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drawStartPos.set( e.offsetX, e.offsetY );
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} );
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drawingCanvas.addEventListener( 'pointermove', function ( e ) {
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if ( paint ) draw( drawingContext, e.offsetX, e.offsetY );
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} );
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drawingCanvas.addEventListener( 'pointerup', function () {
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paint = false;
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} );
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drawingCanvas.addEventListener( 'pointerleave', function () {
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paint = false;
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} );
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}
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function draw( drawContext, x, y ) {
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drawContext.moveTo( drawStartPos.x, drawStartPos.y );
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drawContext.strokeStyle = '#000000';
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drawContext.lineTo( x, y );
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drawContext.stroke();
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// reset drawing start position to current position.
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drawStartPos.set( x, y );
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// need to flag the map as needing updating.
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material.map.needsUpdate = true;
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}
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function onWindowResize() {
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camera.aspect = window.innerWidth / window.innerHeight;
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camera.updateProjectionMatrix();
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renderer.setSize( window.innerWidth, window.innerHeight );
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}
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function animate() {
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requestAnimationFrame( animate );
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mesh.rotation.x += 0.01;
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mesh.rotation.y += 0.01;
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renderer.render( scene, camera );
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}
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</script>
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</body>
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</html>
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