[webGL学习]基于three.js构建WebGL实例第一讲

时间：2022-03-25 03:26:37

[webGL学习]基于three.js构建WebGL实例第一讲

我们主要做些的基本功能：创建一个场景，相机，渲染器，控制器（OrbitControls）。我们也将创建简单的定向光，加上一些对象（不同的几何形状）的阴影。为了使事情更快，我们决定采取一个最流行的WebGL框架——three.js。为什么使用three.js？ 事实上，它是开源的JavaScript框架，它也是增长最迅速的和讨论很热烈的引擎 。在这里，已经准备了很多会用到的东西，从基本的点和向量，到做准备工作的场景、着色器，甚至立体效果。

HTML结构

<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="utf-8" />
<meta name="author" content="Script Tutorials" />
<title>WebGL With Three.js - Lesson 1 | Script Tutorials</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<link href="css/main.css" rel="stylesheet" type="text/css" />
</head>
<body>
<script src="js/three.min.js"></script>
<script src="js/THREEx.WindowResize.js"></script>
<script src="js/OrbitControls.js"></script>
<script src="js/stats.min.js"></script>
<script src="js/script.js"></script>

<div style="position: absolute; top: 10px; left: 20px; text-align: center;">
</div>

<!-- Only used for Script Tutorial's Demo site. Please ignore and remove. -->
<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script> 
<script src="http://www.script-tutorials.com/assets/ads.js" async></script>
</body>
</html>

场景渲染

var lesson1 = {
    scene: null,
    camera: null,
    renderer: null,
    container: null,
    controls: null,
    clock: null,
    stats: null,

    init: function() { // Initialization

// create main scene
this.scene = new THREE.Scene();

var SCREEN_WIDTH = window.innerWidth,
            SCREEN_HEIGHT = window.innerHeight;

// prepare camera
var VIEW_ANGLE = 45, ASPECT = SCREEN_WIDTH / SCREEN_HEIGHT, NEAR = 1, FAR = 10000;
this.camera = new THREE.PerspectiveCamera( VIEW_ANGLE, ASPECT, NEAR, FAR);
this.scene.add(this.camera);
this.camera.position.set(-1000, 1000, 0);
this.camera.lookAt(new THREE.Vector3(0,0,0));

// prepare renderer
this.renderer = new THREE.WebGLRenderer({antialias:true, alpha: false});
this.renderer.setSize(SCREEN_WIDTH, SCREEN_HEIGHT);
this.renderer.setClearColor(0xffffff);

this.renderer.shadowMapEnabled = true;
this.renderer.shadowMapSoft = true;

// prepare container
this.container = document.createElement('div');
        document.body.appendChild(this.container);
this.container.appendChild(this.renderer.domElement);

// events
        THREEx.WindowResize(this.renderer, this.camera);

// prepare controls (OrbitControls)
this.controls = new THREE.OrbitControls(this.camera, this.renderer.domElement);
this.controls.target = new THREE.Vector3(0, 0, 0);

// prepare clock
this.clock = new THREE.Clock();

// prepare stats
this.stats = new Stats();
this.stats.domElement.style.position = 'absolute';
this.stats.domElement.style.bottom = '0px';
this.stats.domElement.style.zIndex = 10;
this.container.appendChild( this.stats.domElement );

// add directional light
var dLight = new THREE.DirectionalLight(0xffffff);
        dLight.position.set(1, 1000, 1);
        dLight.castShadow = true;
        dLight.shadowCameraVisible = true;
        dLight.shadowDarkness = 0.2;
        dLight.shadowMapWidth = dLight.shadowMapHeight = 1000;
this.scene.add(dLight);

// add particle of light
        particleLight = new THREE.Mesh( new THREE.SphereGeometry(10, 10, 10), new THREE.MeshBasicMaterial({ color: 0x44ff44 }));
        particleLight.position = dLight.position;
this.scene.add(particleLight);

// add simple ground
var groundGeometry = new THREE.PlaneGeometry(1000, 1000, 1, 1);
        ground = new THREE.Mesh(groundGeometry, new THREE.MeshLambertMaterial({
            color: this.getRandColor()
        }));
        ground.position.y = 0;
        ground.rotation.x = - Math.PI / 2;
        ground.receiveShadow = true;
this.scene.add(ground);

// add circle shape
var circle = new THREE.Mesh(new THREE.CircleGeometry(70, 50), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        circle.rotation.x = - Math.PI / 2;
        circle.rotation.y = - Math.PI / 3;
        circle.rotation.z = Math.PI / 3;
        circle.position.x = -300;
        circle.position.y = 150;
        circle.position.z = -300;
        circle.castShadow = circle.receiveShadow = true;
this.scene.add(circle);

// add cube shape
var cube = new THREE.Mesh(new THREE.CubeGeometry(100, 100, 100), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        cube.rotation.x = cube.rotation.z = Math.PI * 0.1;
        cube.position.x = -300;
        cube.position.y = 150;
        cube.position.z = -100;
        cube.castShadow = cube.receiveShadow = true;
this.scene.add(cube);

// add cylinder shape
var cube = new THREE.Mesh(new THREE.CylinderGeometry(60, 80, 90, 32), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        cube.rotation.x = cube.rotation.z = Math.PI * 0.1;
        cube.position.x = -300;
        cube.position.y = 150;
        cube.position.z = 100;
        cube.castShadow = cube.receiveShadow = true;
this.scene.add(cube);

// add extrude geometry shape
var extrudeSettings = {
            amount: 10,
            steps: 10,
            bevelSegments: 10,
            bevelSize: 10,
            bevelThickness: 10
        };
var triangleShape = new THREE.Shape();
        triangleShape.moveTo(  0, -50 );
        triangleShape.lineTo(  -50, 50 );
        triangleShape.lineTo( 50, 50 );
        triangleShape.lineTo(  0, -50 );

var extrude = new THREE.Mesh(new THREE.ExtrudeGeometry(triangleShape, extrudeSettings), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        extrude.rotation.y = Math.PI / 2;
        extrude.position.x = -300;
        extrude.position.y = 150;
        extrude.position.z = 300;
        extrude.castShadow = extrude.receiveShadow = true;
this.scene.add(extrude);

// add icosahedron shape
var icosahedron = new THREE.Mesh(new THREE.IcosahedronGeometry(70), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        icosahedron.position.x = -100;
        icosahedron.position.y = 150;
        icosahedron.position.z = -300;
        icosahedron.castShadow = icosahedron.receiveShadow = true;
this.scene.add(icosahedron);

// add octahedron shape
var octahedron = new THREE.Mesh(new THREE.OctahedronGeometry(70), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        octahedron.position.x = -100;
        octahedron.position.y = 150;
        octahedron.position.z = -100;
        octahedron.castShadow = octahedron.receiveShadow = true;
this.scene.add(octahedron);

// add ring shape
var ring = new THREE.Mesh(new THREE.RingGeometry(30, 70, 32), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        ring.rotation.y = -Math.PI / 2;
        ring.position.x = -100;
        ring.position.y = 150;
        ring.position.z = 100;
        ring.castShadow = ring.receiveShadow = true;
this.scene.add(ring);

// add shape geometry shape
var shapeG = new THREE.Mesh(new THREE.ShapeGeometry(triangleShape), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        shapeG.rotation.y = -Math.PI / 2;
        shapeG.position.x = -100;
        shapeG.position.y = 150;
        shapeG.position.z = 300;
        shapeG.castShadow = shapeG.receiveShadow = true;
this.scene.add(shapeG);

// add sphere shape
var sphere = new THREE.Mesh(new THREE.SphereGeometry(70, 32, 32), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        sphere.rotation.y = -Math.PI / 2;
        sphere.position.x = 100;
        sphere.position.y = 150;
        sphere.position.z = -300;
        sphere.castShadow = sphere.receiveShadow = true;
this.scene.add(sphere);

// add tetrahedron shape
var tetrahedron = new THREE.Mesh(new THREE.TetrahedronGeometry(70), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        tetrahedron.position.x = 100;
        tetrahedron.position.y = 150;
        tetrahedron.position.z = -100;
        tetrahedron.castShadow = tetrahedron.receiveShadow = true;
this.scene.add(tetrahedron);

// add torus shape
var torus = new THREE.Mesh(new THREE.TorusGeometry(70, 20, 16, 100), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        torus.rotation.y = -Math.PI / 2;
        torus.position.x = 100;
        torus.position.y = 150;
        torus.position.z = 100;
        torus.castShadow = torus.receiveShadow = true;
this.scene.add(torus);

// add torus knot shape
var torusK = new THREE.Mesh(new THREE.TorusKnotGeometry(70, 20, 16, 100), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        torusK.rotation.y = -Math.PI / 2;
        torusK.position.x = 100;
        torusK.position.y = 150;
        torusK.position.z = 300;
        torusK.castShadow = torusK.receiveShadow = true;
this.scene.add(torusK);

// add tube shape
var points = [];
for (var i = 0; i < 10; i++) {
var randomX = -100 + Math.round(Math.random() * 200);
var randomY = -100 + Math.round(Math.random() * 200);
var randomZ = -100 + Math.round(Math.random() * 200);

            points.push(new THREE.Vector3(randomX, randomY, randomZ));
        }
var tube = new THREE.Mesh(new THREE.TubeGeometry(new THREE.SplineCurve3(points), 64, 20), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        tube.rotation.y = -Math.PI / 2;
        tube.position.x = 0;
        tube.position.y = 500;
        tube.position.z = 0;
        tube.castShadow = tube.receiveShadow = true;
this.scene.add(tube);
    },
    getRandColor: function() {
return colors[Math.floor(Math.random() * colors.length)];
    }
};

// Animate the scene
function animate() {
    requestAnimationFrame(animate);
    render();
    update();
}

// Update controls and stats
function update() {
    lesson1.controls.update(lesson1.clock.getDelta());
    lesson1.stats.update();

// smoothly move the particleLight
var timer = Date.now() * 0.000025;
    particleLight.position.x = Math.sin(timer * 5) * 300;
    particleLight.position.z = Math.cos(timer * 5) * 300;
}

// Render the scene
function render() {
if (lesson1.renderer) {
        lesson1.renderer.render(lesson1.scene, lesson1.camera);
    }
}

// Initialize lesson on page load
function initializeLesson() {
    lesson1.init();
    animate();
}

这是用 three.js 建应用的常用结构。几乎所有的东西都将在init方法里创建。

场景创建、相机和渲染

// 创建主要场景
this.scene = new THREE.Scene();

var SCREEN_WIDTH = window.innerWidth,
    SCREEN_HEIGHT = window.innerHeight;

// 准备相机
var VIEW_ANGLE = 45, ASPECT = SCREEN_WIDTH / SCREEN_HEIGHT, NEAR = 1, FAR = 10000;
this.camera = new THREE.PerspectiveCamera( VIEW_ANGLE, ASPECT, NEAR, FAR);
this.scene.add(this.camera);
this.camera.position.set(-1000, 1000, 0);
this.camera.lookAt(new THREE.Vector3(0,0,0));

// 准备渲染
this.renderer = new THREE.WebGLRenderer({antialias:true, alpha: false});
this.renderer.setSize(SCREEN_WIDTH, SCREEN_HEIGHT);
this.renderer.setClearColor(0xffffff);

this.renderer.shadowMapEnabled = true;
this.renderer.shadowMapSoft = true;

// 准备容器
this.container = document.createElement('div');
document.body.appendChild(this.container);
this.container.appendChild(this.renderer.domElement);

// 事件
// events
        THREEx.WindowResize(this.renderer, this.camera);

我们将相机把相机放在45度角，设为全屏幕大小，WebGLRenderer设为白色，再把我们的场景添加到HTML文档中，而且在浏览器窗口大小变化时，用THREEx.WindowResize 来控制渲染和相机的变化。

OrbitControls 和 Stats

为了能够在某种程度上控制相机的 —— three.js 给我们提供了现成的控件。其中之一是 OrbitControls，它能在场景中绕其轴线旋转。一个小插件stats.min.js将有助于我们看到场景的统计（FPS）。

        // 准备控制器
this.controls = new THREE.OrbitControls(this.camera, this.renderer.domElement);
this.controls.target = new THREE.Vector3(0, 0, 0);

// 开始计数
this.clock = new THREE.Clock();

//开始统计
this.stats = new Stats();
this.stats.domElement.style.position = 'absolute';
this.stats.domElement.style.bottom = '0px';
this.stats.domElement.style.zIndex = 10;
this.container.a

光和场地的创作

光是一个场景中的重要元素，在我们的第一个教程，我们将创建最简单的定向光线，因为我们要添加基本的阴影：

// 添加定向光线
var dLight = new THREE.DirectionalLight(0xffffff);
dLight.position.set(1, 1000, 1);
dLight.castShadow = true;
dLight.shadowCameraVisible = true;
dLight.shadowDarkness = 0.2;
dLight.shadowMapWidth = dLight.shadowMapHeight = 1000;
this.scene.add(dLight);

// 添加粒子光线
particleLight = new THREE.Mesh( new THREE.SphereGeometry(10, 10, 10), new THREE.MeshBasicMaterial({ color: 0x44ff44 }));
particleLight.position = dLight.position;
this.scene.add(particleLight);

// 添加简单的场地
var groundGeometry = new THREE.PlaneGeometry(1000, 1000, 1, 1);
ground = new THREE.Mesh(groundGeometry, new THREE.MeshLambertMaterial({
    color: this.getRandColor()
}));
ground.position.y = 0;
ground.rotation.x = - Math.PI / 2;
ground.receiveShadow = true;
this.scene.add(ground);

当我们创建灯光时，用了两个参数 castShadow 和 shadowCameraVisible。这将使我们能够直观地看到光在哪里，理解构造的过程（和边界）的阴影。
你也可能会注意到，在添加光后，我们增加了一个球形物体——为你准备的，以便直观地知道我们的定向光源在什么位置。我们用一个平面作为地面去接收阴影——我们设置的receiveShadow参数为true。

颜色设置

var colors = [
0xFF62B0,
0x9A03FE,
0x62D0FF,
0x48FB0D,
0xDFA800,
0xC27E3A,
0x990099,
0x9669FE,
0x23819C,
0x01F33E,
0xB6BA18,
0xFF800D,
0xB96F6F,
0x4A9586
];

getRandColor: function() {
return colors[Math.floor(Math.random() * colors.length)];
}

我们将在场景中添加额外的对象。我用一个方法来生成不同颜色的部件。这个方法将从颜色列表中随机返回一个预定义的颜色。

建模型

 // add simple ground
        var groundGeometry = new THREE.PlaneGeometry(1000, 1000, 1, 1);
        ground = new THREE.Mesh(groundGeometry, new THREE.MeshLambertMaterial({
            color: this.getRandColor()
        }));
        ground.position.y = 0;
        ground.rotation.x = - Math.PI / 2;
        ground.receiveShadow = true;
        this.scene.add(ground);

        // add circle shape
        var circle = new THREE.Mesh(new THREE.CircleGeometry(70, 50), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        circle.rotation.x = - Math.PI / 2;
        circle.rotation.y = - Math.PI / 3;
        circle.rotation.z = Math.PI / 3;
        circle.position.x = -300;
        circle.position.y = 150;
        circle.position.z = -300;
        circle.castShadow = circle.receiveShadow = true;
        this.scene.add(circle);

        // add cube shape
        var cube = new THREE.Mesh(new THREE.CubeGeometry(100, 100, 100), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        cube.rotation.x = cube.rotation.z = Math.PI * 0.1;
        cube.position.x = -300;
        cube.position.y = 150;
        cube.position.z = -100;
        cube.castShadow = cube.receiveShadow = true;
        this.scene.add(cube);

        // add cylinder shape
        var cube = new THREE.Mesh(new THREE.CylinderGeometry(60, 80, 90, 32), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        cube.rotation.x = cube.rotation.z = Math.PI * 0.1;
        cube.position.x = -300;
        cube.position.y = 150;
        cube.position.z = 100;
        cube.castShadow = cube.receiveShadow = true;
        this.scene.add(cube);

        // add extrude geometry shape
        var extrudeSettings = {
            amount: 10,
            steps: 10,
            bevelSegments: 10,
            bevelSize: 10,
            bevelThickness: 10
        };
        var triangleShape = new THREE.Shape();
        triangleShape.moveTo(  0, -50 );
        triangleShape.lineTo(  -50, 50 );
        triangleShape.lineTo( 50, 50 );
        triangleShape.lineTo(  0, -50 );

        var extrude = new THREE.Mesh(new THREE.ExtrudeGeometry(triangleShape, extrudeSettings), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        extrude.rotation.y = Math.PI / 2;
        extrude.position.x = -300;
        extrude.position.y = 150;
        extrude.position.z = 300;
        extrude.castShadow = extrude.receiveShadow = true;
        this.scene.add(extrude);

        // add icosahedron shape
        var icosahedron = new THREE.Mesh(new THREE.IcosahedronGeometry(70), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        icosahedron.position.x = -100;
        icosahedron.position.y = 150;
        icosahedron.position.z = -300;
        icosahedron.castShadow = icosahedron.receiveShadow = true;
        this.scene.add(icosahedron);

        // add octahedron shape
        var octahedron = new THREE.Mesh(new THREE.OctahedronGeometry(70), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        octahedron.position.x = -100;
        octahedron.position.y = 150;
        octahedron.position.z = -100;
        octahedron.castShadow = octahedron.receiveShadow = true;
        this.scene.add(octahedron);

        // add ring shape
        var ring = new THREE.Mesh(new THREE.RingGeometry(30, 70, 32), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        ring.rotation.y = -Math.PI / 2;
        ring.position.x = -100;
        ring.position.y = 150;
        ring.position.z = 100;
        ring.castShadow = ring.receiveShadow = true;
        this.scene.add(ring);

        // add shape geometry shape
        var shapeG = new THREE.Mesh(new THREE.ShapeGeometry(triangleShape), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        shapeG.rotation.y = -Math.PI / 2;
        shapeG.position.x = -100;
        shapeG.position.y = 150;
        shapeG.position.z = 300;
        shapeG.castShadow = shapeG.receiveShadow = true;
        this.scene.add(shapeG);

        // add sphere shape
        var sphere = new THREE.Mesh(new THREE.SphereGeometry(70, 32, 32), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        sphere.rotation.y = -Math.PI / 2;
        sphere.position.x = 100;
        sphere.position.y = 150;
        sphere.position.z = -300;
        sphere.castShadow = sphere.receiveShadow = true;
        this.scene.add(sphere);

        // add tetrahedron shape
        var tetrahedron = new THREE.Mesh(new THREE.TetrahedronGeometry(70), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        tetrahedron.position.x = 100;
        tetrahedron.position.y = 150;
        tetrahedron.position.z = -100;
        tetrahedron.castShadow = tetrahedron.receiveShadow = true;
        this.scene.add(tetrahedron);

        // add torus shape
        var torus = new THREE.Mesh(new THREE.TorusGeometry(70, 20, 16, 100), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        torus.rotation.y = -Math.PI / 2;
        torus.position.x = 100;
        torus.position.y = 150;
        torus.position.z = 100;
        torus.castShadow = torus.receiveShadow = true;
        this.scene.add(torus);

        // add torus knot shape
        var torusK = new THREE.Mesh(new THREE.TorusKnotGeometry(70, 20, 16, 100), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        torusK.rotation.y = -Math.PI / 2;
        torusK.position.x = 100;
        torusK.position.y = 150;
        torusK.position.z = 300;
        torusK.castShadow = torusK.receiveShadow = true;
        this.scene.add(torusK);

        // add tube shape
        var points = [];
        for (var i = 0; i < 10; i++) {
            var randomX = -100 + Math.round(Math.random() * 200);
            var randomY = -100 + Math.round(Math.random() * 200);
            var randomZ = -100 + Math.round(Math.random() * 200);

            points.push(new THREE.Vector3(randomX, randomY, randomZ));
        }
        var tube = new THREE.Mesh(new THREE.TubeGeometry(new THREE.SplineCurve3(points), 64, 20), new THREE.MeshLambertMaterial({ color: this.getRandColor() }));
        tube.rotation.y = -Math.PI / 2;
        tube.position.x = 0;
        tube.position.y = 500;
        tube.position.z = 0;
        tube.castShadow = tube.receiveShadow = true;
        this.scene.add(tube);
    },
    getRandColor: function() {
        return colors[Math.floor(Math.random() * colors.length)];
    }
};

设置运动样式

为了顺利地将光，我们只需要在update方法里添加以下代码：

// Update controls and stats
function update() {
    lesson1.controls.update(lesson1.clock.getDelta());
    lesson1.stats.update();

    // smoothly move the particleLight
    var timer = Date.now() * 0.000025;
    particleLight.position.x = Math.sin(timer * 5) * 300;
    particleLight.position.z = Math.cos(timer * 5) * 300;
}

结束

源码下载请关注我的微信公众号
[webGL学习]基于three.js构建WebGL实例第一讲

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