Question

你好，我有一个疑问：

今天我试着改变画布＆＃39;大小不一致。我希望得到平面的大小，并将其大小放入画布的大小，以使画布适应任何尺寸的平面。

首先，调试程序我看到正在创建第一个画布800x600，这是正确的：

其次我认为它是线性的并且转到加载函数以从本地sotrage获取模型，但是它转到了renderer.setSize（）

然后为第二个画布完成相同的两个步骤：

然后，在第五步和第六步中，我们将模型加载到画布中：

在这里，我向您展示完整的代码，首先是正在讨论的文件，然后是其他重要文件：

InitCanvas.js

// this class handles the load and the canva for a nrrd
// Using programming based on prototype: https://javascript.info/class
// This class should be improved:
//   - Canvas Width and height

InitCanvas = function (IdDiv, Filename) {


    this.IdDiv = IdDiv;
    this.Filename = Filename
}

InitCanvas.prototype = {

    constructor: InitCanvas,

    init: function () {

        this.container = document.getElementById(this.IdDiv);

        // this should be changed.
        debugger;
        this.container.innerHeight = 600;
        this.container.innerWidth = 800;

        //These statenments should be changed to improve the image position
        this.camera = new THREE.PerspectiveCamera(60, this.container.innerWidth / this.container.innerHeight, 0.01, 1e10);
        this.camera.position.z = 300;

        let scene = new THREE.Scene();
        scene.add(this.camera);

        // light

        let dirLight = new THREE.DirectionalLight(0xffffff);
        dirLight.position.set(200, 200, 1000).normalize();

        this.camera.add(dirLight);
        this.camera.add(dirLight.target);


        // read file

        let loader = new THREE.NRRDLoader();
        loader.load(this.Filename, function (volume) {

            //z plane
            let sliceZ = volume.extractSlice('z', Math.floor(volume.RASDimensions[2] / 4));

            debugger;
            this.container.innerWidth = sliceZ.iLength;
            this.container.innerHeight = sliceZ.jLength;

            sliceZ.mesh.material.color.setRGB(0,1,1);


            console.log('Our slice is: ', sliceZ);

            scene.add(sliceZ.mesh);
        }.bind(this));


        this.scene = scene;

        // renderer

        this.renderer = new THREE.WebGLRenderer({alpha: true});
        this.renderer.setPixelRatio(this.container.devicePixelRatio);
        debugger;
        this.renderer.setSize(this.container.innerWidth, this.container.innerHeight);

        // add canvas in container
        this.container.appendChild(this.renderer.domElement);

    },

    animate: function () {

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

}

logic.js

if (!Detector.webgl) Detector.addGetWebGLMessage();

// global variables for this scripts
let OriginalImg,
    SegmentImg;

var mouse = new THREE.Vector2();
var raycaster = new THREE.Raycaster();
var mousePressed = false;
var clickCount = 0;


init();
animate();


// initilize the page
function init() {
    let filename = "models/nrrd/columna01.nrrd"; // change your nrrd file
    let idDiv = 'original';
    OriginalImg = new InitCanvas(idDiv, filename);
    OriginalImg.init();
    console.log(OriginalImg);

    filename = "models/nrrd/columnasegmentado01.nrrd"; // change your nrrd file
    idDiv = 'segment';
    SegmentImg = new InitCanvas(idDiv, filename);
    SegmentImg.init();
}

let originalCanvas = document.getElementById('original');
originalCanvas.addEventListener('mousedown', onDocumentMouseDown, false);
originalCanvas.addEventListener('mouseup', onDocumentMouseUp, false);


function onDocumentMouseDown(event) {
    mousePressed = true;

    clickCount++;

    mouse.x = ( ( event.clientX - OriginalImg.renderer.domElement.offsetLeft ) / OriginalImg.renderer.domElement.clientWidth ) * 2 - 1;
    mouse.y = - ( ( event.clientY - OriginalImg.renderer.domElement.offsetTop ) / OriginalImg.renderer.domElement.clientHeight ) * 2 + 1

    console.log('Mouse x position is: ', mouse.x, 'the click number was: ', clickCount);
    console.log('Mouse Y position is: ', mouse.y);

    raycaster.setFromCamera(mouse.clone(), OriginalImg.camera);
    var objects = raycaster.intersectObjects(OriginalImg.scene.children);

    console.log(objects);
}

function onDocumentMouseUp(event) {
    mousePressed = false
}


function animate() {


    requestAnimationFrame(animate);
    OriginalImg.animate();
    SegmentImg.animate();


}

的index.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>Prototype: three.js without react.js</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
        <link rel="stylesheet" href="css/styles.css">

        <!-- load the libraries and js -->
        <script src="js/libs/three.js"></script>

        <script src="js/Volume.js"></script>
        <script src="js/VolumeSlice.js"></script>
        <script src="js/loaders/NRRDLoader.js"></script>

        <script src="js/Detector.js"></script>
        <script src="js/libs/stats.min.js"></script>
        <script src="js/libs/gunzip.min.js"></script>
        <script src="js/libs/dat.gui.min.js"></script>

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


    </head>

    <body>
        <div id="info">
            <h1>Prototype: three.js without react.js</h1> 
        </div>

        <!-- two canvas -->
        <div class="row">
            <div class="column" id="original">
            </div>

            <div class="column" id="segment">

            </div>
          </div> 

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

    </body>
</html>

styles.css的

body {
    font-family: Monospace;
    margin: 0px;
    overflow: hidden;
}

#info {
    color: rgb(137, 145, 192);
    position: absolute;
    top: 10px;
    width: 100%;
    text-align: center;
    z-index: 5;
    display:block;
}

.column {
    float: left;
    width: 50%;
}

/* Clear floats after the columns */
.row:after {
    content: "";
    display: table;
    clear: both;
}

canvas {
    width: 200px;
    height: 200px;
    margin: 100px;
    padding: 0px;
    position: static; /* fixed or static */
    top: 100px;
    left: 100px;
}

此外，正在使用的其他外部资源是NRRDLoader：

https://github.com/mrdoob/three.js/blob/dev/examples/js/loaders/NRRDLoader.js

Volume.js

https://github.com/mrdoob/three.js/blob/dev/examples/js/Volume.js

VolumeSlice.js

https://github.com/mrdoob/three.js/blob/dev/examples/js/VolumeSlice.js

你能帮我吗？

Answer 1

这是因为当加载程序完成加载文件时，加载侦听器将触发，如果之前放置代码，因为您将回调函数作为参数传递，这并不重要。

这可以帮助您了解正在发生的事情：

假设您有3个朋友，您将发出命令。

你告诉1号朋友去远方取一个球完成它会把你拉到球上并在地板上画一个红点。
你告诉2号朋友去开始围绕它自己的轴2 时间并在地板上涂上一个蓝点
你告诉3号朋友跳2次并在地板上画一个绿点。

在朋友1回来之前，两个朋友已经完成了他们的任务，最后最后一个点涂料将是红色的，但你可能期望它是绿色的，因为它是你给出的最后一条指令。

This link将帮助您更好地了解事件循环的工作原理，this will help you to understand closures and callbacks.

Threejs，为什么渲染setSize函数是在它之前的代码之前执行的？

1 个答案: