38 - three.js 笔记 - EdgesGeometry 几何体边框辅助线

程序员文章站 2022-05-27 13:51:53

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EdgesGeometry在老版本中叫做EdgesHelper但是已经被移除。新版本赋予边框辅助参考线，更加灵活的使用方法，可以改变其材质以及其他属性，EdgesGeometry的作用是可以帮助查看几何体对象的边缘。
示例：EdgesGeometry.html

构造函数

EdgesGeometry( geometry : Geometry, thresholdAngle : Integer )

参数

geometry ：几何体对象
thresholdAngle ：只有当相邻的面法线的角度（在一定程度上）超过这个值时，才会呈现出一条边。默认= 1度

使用步骤

1、首先，需要创建一个几何体，例如此处创建一个立方体

 let cubeGeometry = new THREE.BoxGeometry(50, 50 ,50);

2、然后，将立方体对象传给EdgesGeometry的构造函数，此时就创建了边缘几何体对象，但是还需要创阿建边框材质

let cubeEdges = new THREE.EdgesGeometry(cubeGeometry, 1);

3、创建基础线条材质，并创建线框分段THREE.LineSegments

let edgesMtl =  new THREE.LineBasicMaterial({color: 0xff0000});

// edgesMtl.depthTest = false; 深度测试，若开启则是边框透明的效果
let cubeLine = new THREE.LineSegments(cubeEdges, edgesMtl);

4、最后将创建的线框加入的几何体中

cube.add(cubeLine);
scene.add(cube);

效果

38 - three.js 笔记 - EdgesGeometry 几何体边框辅助线

示例代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>EdgesGeometry 边缘几何</title>
    <style>
        body {
            margin: 0;
            overflow: hidden; /*溢出隐藏*/
        }
    </style>
    <script src="../../libs/build/three-r93.min.js"></script>
    <script src="../../libs/examples/js/controls/OrbitControls.js"></script>
    <script src="../../libs/examples/js/libs/dat.gui.min.js"></script>
    <script src="../../libs/examples/js/libs/stats.min.js"></script>
    <script src="../../libs/examples/js/Detector.js"></script>
    <script src="../../libs/examples/js/utils/SceneUtils.js"></script>
</head>
<body>
<script>

    let stats = initStats();
    let scene, camera, renderer, circle, controls, guiControls;

    /* 场景 */
    function initScene() {

        scene = new THREE.Scene();

    }

    /* 相机 */
    function initCamera() {

        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 10000);
        camera.position.set(0, 10, 200);
        camera.lookAt(new THREE.Vector3(0, 0, 0));

    }

    /* 渲染器 */
    function initRenderer() {

        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setSize(window.innerWidth, window.innerHeight);

        document.body.appendChild(renderer.domElement);

    }

    /* 灯光 */
    function initLight() {

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

        let spotLight = new THREE.SpotLight(0xffffff);
        spotLight.position.set(100, 500, 400);
        scene.add(spotLight);
    }

    /* 控制器 */
    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);
        // 添加惯性
        controls.enableDamping = true;

    }

    /* 调试插件 */
    let gui;
    function initGui() {

        guiControls = new function () {



        };

        gui = new dat.GUI({width:300});


    }

    /* 场景中的内容 */
    let cube;
    function initContent() {

        let cubeGeometry = new THREE.BoxGeometry(50, 50 ,50);
        let material = new THREE.MeshPhongMaterial();
        let edgesMtl =  new THREE.LineBasicMaterial({color: 0xff0000});

        cube = new THREE.Mesh(cubeGeometry, material);
        cube.position.x = -55;

        // THREE.EdgesHelper has been removed. Use THREE.EdgesGeometry instead.
        let cubeEdges = new THREE.EdgesGeometry(cubeGeometry, 1);
        // edgesMtl.depthTest = false;
        let cubeLine = new THREE.LineSegments(cubeEdges, edgesMtl);

        let cylinderGeometry = new THREE.CylinderGeometry(25, 25, 50, 10);
        let cylinder = new THREE.Mesh(cylinderGeometry, material);
        cylinder.position.x = 55;

        let cylinderEdges= new THREE.EdgesGeometry(cylinderGeometry, 1);
        let cylinderLine = new THREE.LineSegments(cylinderEdges, edgesMtl);

        let coneGeometry = new THREE.ConeGeometry(25, 50);
        let cone = new THREE.Mesh(coneGeometry, material);

        let coneEdges = new THREE.EdgesGeometry(coneGeometry, 1);
        let coneLine = new THREE.LineSegments(coneEdges, edgesMtl);

        cube.add(cubeLine);
        cylinder.add(cylinderLine);
        cone.add(coneLine);

        scene.add(cylinder);
        scene.add(cube);
        scene.add(cone);

    }

    /* 性能插件 */
    function initStats() {

        let stats = new Stats();

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

        document.body.appendChild(stats.domElement);

        return stats;
    }

    /* 更新 */
    function update() {

        stats.update();
        controls.update();

    }

    /* 初始化 */
    function init() {

        // 兼容性判断，若不兼容会提示信息
        if (!Detector.webgl) Detector.addGetWebGLMessage();

        initScene();
        initCamera();
        initRenderer();
        initLight();
        initControls();
        initContent();
        initGui();

        window.addEventListener('resize', onWindowResize, false);

    }

    /* 窗口变动触发的方法 */
    function onWindowResize() {

        // 重新设置相机的宽高比
        camera.aspect = window.innerWidth / window.innerHeight;

        // 更新相机投影矩阵
        camera.updateProjectionMatrix();

        // 更新渲染器大小
        renderer.setSize(window.innerWidth, window.innerHeight);

    }

    /* 循环渲染 */
    function animate() {

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

    /* 页面绘制完后加载 */
    window.onload = function () {

        init();
        animate();

    };

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

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