examples/webgl_decals.html

<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - decal splatter</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
	</head>
	<body>

		<div id="container"></div>
		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - decal splatter<br/>
			click to shoot
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'three/addons/libs/stats.module.js';
			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
			import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
			import { DecalGeometry } from 'three/addons/geometries/DecalGeometry.js';

			const container = document.getElementById( 'container' );

			let renderer, scene, camera, stats;
			let mesh;
			let raycaster;
			let line;

			const intersection = {
				intersects: false,
				point: new THREE.Vector3(),
				normal: new THREE.Vector3()
			};
			const mouse = new THREE.Vector2();
			const intersects = [];

			const textureLoader = new THREE.TextureLoader();
			const decalDiffuse = textureLoader.load( 'textures/decal/decal-diffuse.png' );
			decalDiffuse.colorSpace = THREE.SRGBColorSpace;
			const decalNormal = textureLoader.load( 'textures/decal/decal-normal.jpg' );

			const decalMaterial = new THREE.MeshPhongMaterial( {
				specular: 0x444444,
				map: decalDiffuse,
				normalMap: decalNormal,
				normalScale: new THREE.Vector2( 1, 1 ),
				shininess: 30,
				transparent: true,
				depthTest: true,
				depthWrite: false,
				polygonOffset: true,
				polygonOffsetFactor: - 4,
				wireframe: false
			} );

			const decals = [];
			let mouseHelper;
			const position = new THREE.Vector3();
			const orientation = new THREE.Euler();
			const size = new THREE.Vector3( 10, 10, 10 );

			const params = {
				minScale: 10,
				maxScale: 20,
				rotate: true,
				clear: function () {

					removeDecals();

				}
			};

			init();

			function init() {

				renderer = new THREE.WebGLRenderer( { antialias: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( animate );
				container.appendChild( renderer.domElement );

				stats = new Stats();
				container.appendChild( stats.dom );

				scene = new THREE.Scene();

				camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 1000 );
				camera.position.z = 120;

				const controls = new OrbitControls( camera, renderer.domElement );
				controls.minDistance = 50;
				controls.maxDistance = 200;

				scene.add( new THREE.AmbientLight( 0x666666 ) );

				const dirLight1 = new THREE.DirectionalLight( 0xffddcc, 3 );
				dirLight1.position.set( 1, 0.75, 0.5 );
				scene.add( dirLight1 );

				const dirLight2 = new THREE.DirectionalLight( 0xccccff, 3 );
				dirLight2.position.set( - 1, 0.75, - 0.5 );
				scene.add( dirLight2 );

				const geometry = new THREE.BufferGeometry();
				geometry.setFromPoints( [ new THREE.Vector3(), new THREE.Vector3() ] );

				line = new THREE.Line( geometry, new THREE.LineBasicMaterial() );
				scene.add( line );

				loadLeePerrySmith();

				raycaster = new THREE.Raycaster();

				mouseHelper = new THREE.Mesh( new THREE.BoxGeometry( 1, 1, 10 ), new THREE.MeshNormalMaterial() );
				mouseHelper.visible = false;
				scene.add( mouseHelper );

				window.addEventListener( 'resize', onWindowResize );

				let moved = false;

				controls.addEventListener( 'change', function () {

					moved = true;

				} );

				window.addEventListener( 'pointerdown', function () {

					moved = false;

				} );

				window.addEventListener( 'pointerup', function ( event ) {

					if ( moved === false ) {

						checkIntersection( event.clientX, event.clientY );

						if ( intersection.intersects ) shoot();

					}

				} );

				window.addEventListener( 'pointermove', onPointerMove );

				function onPointerMove( event ) {

					if ( event.isPrimary ) {

						checkIntersection( event.clientX, event.clientY );

					}

				}

				function checkIntersection( x, y ) {

					if ( mesh === undefined ) return;

					mouse.x = ( x / window.innerWidth ) * 2 - 1;
					mouse.y = - ( y / window.innerHeight ) * 2 + 1;

					raycaster.setFromCamera( mouse, camera );
					raycaster.intersectObject( mesh, false, intersects );

					if ( intersects.length > 0 ) {

						const p = intersects[ 0 ].point;
						mouseHelper.position.copy( p );
						intersection.point.copy( p );

						const normalMatrix = new THREE.Matrix3().getNormalMatrix( mesh.matrixWorld );

						const n = intersects[ 0 ].face.normal.clone();
						n.applyNormalMatrix( normalMatrix );
						n.multiplyScalar( 10 );
						n.add( intersects[ 0 ].point );

						intersection.normal.copy( intersects[ 0 ].face.normal );
						mouseHelper.lookAt( n );

						const positions = line.geometry.attributes.position;
						positions.setXYZ( 0, p.x, p.y, p.z );
						positions.setXYZ( 1, n.x, n.y, n.z );
						positions.needsUpdate = true;

						intersection.intersects = true;

						intersects.length = 0;

					} else {

						intersection.intersects = false;

					}

				}

				const gui = new GUI();

				gui.add( params, 'minScale', 1, 30 );
				gui.add( params, 'maxScale', 1, 30 );
				gui.add( params, 'rotate' );
				gui.add( params, 'clear' );
				gui.open();

			}

			function loadLeePerrySmith() {

				const map = textureLoader.load( 'models/gltf/LeePerrySmith/Map-COL.jpg' );
				map.colorSpace = THREE.SRGBColorSpace;
				const specularMap = textureLoader.load( 'models/gltf/LeePerrySmith/Map-SPEC.jpg' );
				const normalMap = textureLoader.load( 'models/gltf/LeePerrySmith/Infinite-Level_02_Tangent_SmoothUV.jpg' );

				const loader = new GLTFLoader();

				loader.load( 'models/gltf/LeePerrySmith/LeePerrySmith.glb', function ( gltf ) {

					mesh = gltf.scene.children[ 0 ];
					mesh.material = new THREE.MeshPhongMaterial( {
						specular: 0x111111,
						map: map,
						specularMap: specularMap,
						normalMap: normalMap,
						shininess: 25
					} );

					scene.add( mesh );
					mesh.scale.multiplyScalar( 10 );

				} );

			}

			function shoot() {

				position.copy( intersection.point );
				orientation.copy( mouseHelper.rotation );

				if ( params.rotate ) orientation.z = Math.random() * 2 * Math.PI;

				const scale = params.minScale + Math.random() * ( params.maxScale - params.minScale );
				size.set( scale, scale, scale );

				const material = decalMaterial.clone();
				material.color.setHex( Math.random() * 0xffffff );

				const m = new THREE.Mesh( new DecalGeometry( mesh, position, orientation, size ), material );
				m.renderOrder = decals.length; // give decals a fixed render order

				decals.push( m );

				mesh.attach( m );

			}

			function removeDecals() {

				decals.forEach( function ( d ) {

					mesh.remove( d );

				} );

				decals.length = 0;

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function animate() {

				renderer.render( scene, camera );

				stats.update();

			}

		</script>

	</body>
</html>