系列博文-Three.js入门指南(张雯莉)-网格 setInterval方法 requestAnimationFrame方法 使用stat.js记录FPS

时间：2023-03-08 21:22:03

第6章 动画

在本章之前，所有画面都是静止的，本章将介绍如果使用Three.js进行动态画面的渲染。此外，将会介绍一个Three.js作者写的另外一个库，用来观测每秒帧数（FPS）。

CSS3动画那么强，requestAnimationFrame还有毛线用？

window.requestAnimationFrame  MDN

小球下落例子

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>我随便写写的HTML小Demo合集</title>

    <link rel="stylesheet" href="css/bootstrap.css">

    <link rel="stylesheet" href="css/main.css">

</head>

<body onload="init()">

<button>hehe</button>

    <canvas id="mainCanvas" width="400px" height="300px" ></canvas>

</body>

    <script src="lib/jquery.js"></script>

    <script src="lib/bootstrap.js"></script>

    <script src="lib/underscore.js"></script>

    <script src="lib/backbone.js"></script>

    <script src="js/main.js"></script>

    <script src="lib/three.js"></script>

    <script src="lib/stat.js"></script>

    <script>

var requestAnimationFrame = window.requestAnimationFrame

        || window.mozRequestAnimationFrame

        || window.webkitRequestAnimationFrame

        || window.msRequestAnimationFrame;

window.requestAnimationFrame = requestAnimationFrame;

var scene = null;

var camera = null;

var renderer = null;

var id = null;

var stat = null;

var ballMesh = null;

var ballRadius = 0.5;

var isMoving = false;

var maxHeight = 5;

var v = 0;

var a = -0.01;

function init() {

    stat = new Stats();

    stat.domElement.style.position = 'absolute';

    stat.domElement.style.right = '0px';

    stat.domElement.style.top = '0px';

    document.body.appendChild(stat.domElement);

    renderer = new THREE.WebGLRenderer({

        canvas: document.getElementById('mainCanvas')});

    scene = new THREE.Scene();

    camera = new THREE.OrthographicCamera(-5, 5, 3.75, -3.75, 0.1, 100);

    camera.position.set(5, 10, 20);

    camera.lookAt(new THREE.Vector3(0, 3, 0));

    scene.add(camera);

    // ball

    ballMesh = new THREE.Mesh(new THREE.SphereGeometry(ballRadius, 16, 8),

        new THREE.MeshLambertMaterial({

            color: 0xffff00

    }));

    ballMesh.position.y = ballRadius;

    scene.add(ballMesh);

    // plane

    var texture = THREE.ImageUtils.loadTexture('../img/chess.png', {}, function() {

        renderer.render(scene, camera);

    });

    texture.wrapS = texture.wrapT = THREE.RepeatWrapping;

    texture.repeat.set(4, 4);

    var plane = new THREE.Mesh(new THREE.PlaneGeometry(5, 5),

            new THREE.MeshLambertMaterial({map: texture}));

    plane.rotation.x = -Math.PI / 2;

    scene.add(plane);

    var light = new THREE.DirectionalLight(0xffffff);

    light.position.set(10, 10, 15);

    scene.add(light);

    id = requestAnimationFrame(draw);

}

function draw() {

    stat.begin();

    if (isMoving) {

        ballMesh.position.y += v;

        v += a;

 if (ballMesh.position.y <= ballRadius) {

            // hit plane

            v = -v * 0.9;

        }

        if (Math.abs(v) < 0.001) {

            // stop moving

            isMoving = false;

            ballMesh.position.y = ballRadius;

        }

    }

    renderer.render(scene, camera);

    id = requestAnimationFrame(draw);

    stat.end();

}

function stop() {

    if (id !== null) {

        cancelAnimationFrame(id);

        id = null;

    }

}

function drop() {

    isMoving = true;

    ballMesh.position.y = maxHeight;

    v = 0;

}

$("button").click(drop);

    </script>