学习threejs，使用Lensflare模拟镜头眩光

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文章目录

一、🍀前言
- 1.1 ☘️THREE.Lensflare
二、🍀使用Lensflare模拟镜头眩光
- 1. ☘️实现思路
- 2. ☘️代码样例

一、🍀前言

本文详细介绍如何基于threejs在三维场景中使用Lensflare模拟镜头眩光，亲测可用。希望能帮助到您。一起学习，加油！加油！

Lensflarefont_10">1.1 ☘️THREE.Lensflare

THREE.Lensflare 是一种用来模拟镜头光晕效果的类，常用于创建光源周围的光晕或耀斑效果，特别是当镜头朝向强光源（如太阳或强烈的灯光）时。它通过一个或多个纹理贴图来实现这种效果。

构造函数：
THREE.Lensflare(texture, size, distance, blending, color )

texture：镜头炫光的纹理，决定炫光的样子
size：镜头炫光的大小，单位是像素
distance：设值炫光与当前位置的距离。
lending：融合模式决定他们将如何融合在一起,默认的融合模式是THREE.AdditiveBlending,提供半透明的炫光
color：镜头炫光显示的颜色

方法：

add(element) 向镜头眩光效果中添加一个元素。 element：一个包含 texture、color、distance、size 和 lending 属性的对象。
remove(element) 从镜头眩光效果中移除一个元素。 element：要移除的眩光元素对象。
dispose() 释放镜头眩光使用的资源。当不再需要镜头眩光效果时可以调用此方法来释放相关资源。

Lensflarefont_27">二、🍀使用Lensflare模拟镜头眩光

1. ☘️实现思路

1、初始化renderer渲染器
2、初始化Scene三维场景scene
3、初始化camera相机，定义相机位置 camera.position.set，设置相机方向camera.lookAt。
4、创建THREE.AmbientLight环境光源ambiLight，scene场景加入环境光源ambiLight。创建THREE.SpotLight聚光灯光源spotLight0，设置光源位置和方向，scene场景加入spotLight0。创建THREE.DirectionalLight平行光源spotLight，设置平行光源位置、投影信息，scene添加平行光源spotLight。
5、加载几何模型：创建二维平面网格对象plane，plane使用‘grasslight-big.jpg’草地贴图，设置plane的旋转角度，scene场景加入plane。创建立方体网格对象cube，设置cube的位置和投影，scene场景加入cube。创建球体网格对象sphere，设置sphere的位置和投影，scene场景加入sphere。创建THREE.LensFlare镜头炫光控件lensFlare，lensFlare添加5种炫光要素，scene场景加入lensFlare。定义render方法，实现立方体cube旋转，球体sphere跳动的方法。具体代码参考下面代码样例。
6、加入stats监控器，监控帧数信息。

2. ☘️代码样例

<!DOCTYPE html>

<html>

<head>
    <title>学习threejs，使用Lensflare模拟镜头眩光</title>
    <script type="text/javascript" src="../libs/three.js"></script>
    <script type="text/javascript" src="../libs/stats.js"></script>
    <script type="text/javascript" src="../libs/dat.gui.js"></script>
    <style>
        body {
            /* set margin to 0 and overflow to hidden, to go fullscreen */
            margin: 0;
            overflow: hidden;
        }
    </style>
</head>
<body>

<div id="Stats-output">
</div>
<!-- Div which will hold the Output -->
<div id="WebGL-output">
</div>

<!-- js 代码 -->
<script type="text/javascript">

    // 初始化
    function init() {

        var stats = initStats();

        // 创建场景，设置场景云雾效果
        var scene = new THREE.Scene();
        scene.fog = new THREE.Fog(0xaaaaaa, 0.010, 200);

        // 创建投影相机
        var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);


        // 创建渲染器，并设置大小
        var renderer = new THREE.WebGLRenderer({antialias: true, alpha: true});

        renderer.setClearColor(new THREE.Color(0xaaaaff, 1.0));
        renderer.setSize(window.innerWidth, window.innerHeight);
        renderer.shadowMapEnabled = true;


        // 创建草地地面
        var textureGrass = THREE.ImageUtils.loadTexture("../assets/textures/ground/grasslight-big.jpg");
        textureGrass.wrapS = THREE.RepeatWrapping;
        textureGrass.wrapT = THREE.RepeatWrapping;
        textureGrass.repeat.set(4, 4);


        var planeGeometry = new THREE.PlaneGeometry(1000, 200, 20, 20);
        var planeMaterial = new THREE.MeshLambertMaterial({map: textureGrass});
        var plane = new THREE.Mesh(planeGeometry, planeMaterial);
        plane.receiveShadow = true;

        // 旋转草地平面角度
        plane.rotation.x = -0.5 * Math.PI;
        plane.position.x = 15;
        plane.position.y = 0;
        plane.position.z = 0;

        // 场景中添加草地平面
        scene.add(plane);

        // 创建立方体几何体
        var cubeGeometry = new THREE.BoxGeometry(4, 4, 4);
        var cubeMaterial = new THREE.MeshLambertMaterial({color: 0xff3333});
        var cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
        cube.castShadow = true;

        // 设置立方体位置
        cube.position.x = -4;
        cube.position.y = 3;
        cube.position.z = 0;

        // 三维场景中添加立方体
        scene.add(cube);
		
		// 创建球体几何体
        var sphereGeometry = new THREE.SphereGeometry(4, 25, 25);
        var sphereMaterial = new THREE.MeshLambertMaterial({color: 0x7777ff});
        var sphere = new THREE.Mesh(sphereGeometry, sphereMaterial);

        // 设置球体位置和投影
        sphere.position.x = 10;
        sphere.position.y = 5;
        sphere.position.z = 10;
        sphere.castShadow = true;

        // 三维场景中添加球体
        scene.add(sphere);

        // 设置相机位置和方向
        camera.position.x = -20;
        camera.position.y = 15;
        camera.position.z = 45;
        camera.lookAt(new THREE.Vector3(10, 0, 0));

        // 创建并添加环境光
        var ambiColor = "#1c1c1c";
        var ambientLight = new THREE.AmbientLight(ambiColor);
        scene.add(ambientLight);

        // 创建并添加聚光灯光源
        var spotLight0 = new THREE.SpotLight(0xcccccc);
        spotLight0.position.set(-40, 60, -10);
        spotLight0.lookAt(plane);
        scene.add(spotLight0);


        var target = new THREE.Object3D();
        target.position = new THREE.Vector3(5, 0, 0);


        var pointColor = "#ffffff";
//    var spotLight = new THREE.SpotLight( pointColor);
		// 创建平行光源
        var spotLight = new THREE.DirectionalLight(pointColor);
        spotLight.position.set(30, 10, -50);
        spotLight.castShadow = true;
        spotLight.shadowCameraNear = 0.1;
        spotLight.shadowCameraFar = 100;
        spotLight.shadowCameraFov = 50;
        spotLight.target = plane;
        spotLight.distance = 0;
        spotLight.shadowCameraNear = 2;
        spotLight.shadowCameraFar = 200;
        spotLight.shadowCameraLeft = -100;
        spotLight.shadowCameraRight = 100;
        spotLight.shadowCameraTop = 100;
        spotLight.shadowCameraBottom = -100;
        spotLight.shadowMapWidth = 2048;
        spotLight.shadowMapHeight = 2048;


        scene.add(spotLight);


        // renderer渲染器绑定页面要素
        document.getElementById("WebGL-output").appendChild(renderer.domElement);

        // call the render function
        var step = 0;

        // used to determine the switch point for the light animation
        var invert = 1;
        var phase = 0;

        var controls = new function () {
            this.rotationSpeed = 0.03;
            this.bouncingSpeed = 0.03;
            this.ambientColor = ambiColor;
            this.pointColor = pointColor;
            this.intensity = 0.1;
            this.distance = 0;
            this.exponent = 30;
            this.angle = 0.1;
            this.debug = false;
            this.castShadow = true;
            this.onlyShadow = false;
            this.target = "Plane";

        };

        var gui = new dat.GUI();
        gui.addColor(controls, 'ambientColor').onChange(function (e) {
            ambientLight.color = new THREE.Color(e);
        });

        gui.addColor(controls, 'pointColor').onChange(function (e) {
            spotLight.color = new THREE.Color(e);
        });

        gui.add(controls, 'intensity', 0, 5).onChange(function (e) {
            spotLight.intensity = e;
        });


        var textureFlare0 = THREE.ImageUtils.loadTexture("../assets/textures/lensflare/lensflare0.png");
        var textureFlare3 = THREE.ImageUtils.loadTexture("../assets/textures/lensflare/lensflare3.png");

        var flareColor = new THREE.Color(0xffaacc);
        var lensFlare = new THREE.LensFlare(textureFlare0, 350, 0.0, THREE.AdditiveBlending, flareColor);

        lensFlare.add(textureFlare3, 60, 0.6, THREE.AdditiveBlending);
        lensFlare.add(textureFlare3, 70, 0.7, THREE.AdditiveBlending);
        lensFlare.add(textureFlare3, 120, 0.9, THREE.AdditiveBlending);
        lensFlare.add(textureFlare3, 70, 1.0, THREE.AdditiveBlending);

        lensFlare.position.copy(spotLight.position);
        scene.add(lensFlare);

        render();

        function render() {
            stats.update();
            // 动画旋转立方体
            cube.rotation.x += controls.rotationSpeed;
            cube.rotation.y += controls.rotationSpeed;
            cube.rotation.z += controls.rotationSpeed;

            // 动画实现球体跳动
            step += controls.bouncingSpeed;
            sphere.position.x = 20 + ( 10 * (Math.cos(step)));
            sphere.position.y = 2 + ( 10 * Math.abs(Math.sin(step)));

            requestAnimationFrame(render);
            renderer.render(scene, camera);
        }

        function initStats() {

            var stats = new Stats();

            stats.setMode(0);

            stats.domElement.style.position = 'absolute';
            stats.domElement.style.left = '0px';
            stats.domElement.style.top = '0px';

            document.getElementById("Stats-output").appendChild(stats.domElement);

            return stats;
        }
    };

    window.onload = init;


</script>
</body>
</html>