three.js从场景中删除的对象仍在显示

时间:2019-05-24 04:41:47

标签: javascript html three.js

我正在尝试在three.js中将某些文本显示为sprite,并希望将其与对象一起移动。因此,我使用画布创建用于映射SpriteMaterial的纹理,然后从中创建sprite。然后,当我移动对象时删除精灵,并添加一个带有更新文本的新精灵。但是问题是,即使删除后,删除的精灵仍会显示。我也想知道是否有更好的方法来执行我想做的事情。这是我创建精灵的代码:

function makeTextSprite(theMessage, theParameters) {
    if (theParameters === undefined) theParameters = {
    };

    var fontface = theParameters.hasOwnProperty("fontface") ?
       theParameters["fontface"] : "Arial";

    var fontsize = theParameters.hasOwnProperty("fontsize") ?
       theParameters["fontsize"] : 18;

    var borderThickness = theParameters.hasOwnProperty("borderThickness") ?
       theParameters["borderThickness"] : 4;

    var borderColor = theParameters.hasOwnProperty("borderColor") ?
       theParameters["borderColor"] : {
          r: 0, g: 0, b: 0, a: 1.0
       };

    var backgroundColor = theParameters.hasOwnProperty("backgroundColor") ?
       theParameters["backgroundColor"] : {
          r: 255, g: 255, b: 255, a: 1.0
       };

    var canvas = document.createElement('canvas');
    var context = canvas.getContext('2d');
    context.font = "Bold " + fontsize + "px " + fontface;

    // get size data (height depends only on font size)
    var metrics = context.measureText(theMessage);
    var textWidth = metrics.width;

    // background color
    context.fillStyle = "rgba(" + backgroundColor.r + "," + backgroundColor.g + ","
                           + backgroundColor.b + "," + backgroundColor.a + ")";
    // border color
    context.strokeStyle = "rgba(" + borderColor.r + "," + borderColor.g + ","
                           + borderColor.b + "," + borderColor.a + ")";

    context.lineWidth = borderThickness;


    // text color
    context.fillStyle = "rgba(255, 0, 0, 1.0)";

    context.fillText(theMessage, borderThickness, fontsize + borderThickness);

    // canvas contents will be used for a texture
    var texture = new THREE.Texture(canvas)
    texture.needsUpdate = true;

    var spriteMaterial = new THREE.SpriteMaterial(
          {
             map: texture, useScreenCoordinates: true
          });
    var sprite = new THREE.Sprite(spriteMaterial);
    sprite.scale.set(100, 50, 1.0);
    return sprite;
 }

这是我的代码,用于更新精灵的文本和位置: 函数setCoordinatePosition()

{
    if(scene.getObjectByName('text')!=undefined)
    {
        scene.remove("text");
    }

    var sliderValue = document.getElementById("slider").getElementsByTagName("input")[0].value;
    var coordinate_info = "(" + (vx/100)*sliderValue + ", " + (vy/100)*sliderValue + ", " + (vz/100)*sliderValue + ")";  
    text = makeTextSprite(coordinate_info,{ fontsize: 50, borderColor: { r: 0, g: 0, b: 0, a: 1.0 }, backgroundColor: { r: 255, g: 255, b: 255, a: 0.8 } , borderThickness: 5});
    text.name = "text";
    scene.add(text);
    text.position.set(sphere.position.x,sphere.position.y,sphere.position.z);

    text.position.y += 5;
    render();
}

这是我得到的结果: enter image description here

我希望红色文本显示黄色球的坐标并遵循它。

1 个答案:

答案 0 :(得分:0)

Scene.remove需要引用对象,而不是名称

pi@raspberrypi:~ $ sudo apt-get install python-pip Reading package lists... Done Building dependency tree Reading state information... Done python-pip is already the newest version (9.0.1-2+rpt2). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

代替

scene.remove(scene.getObjectByName('text'));

场景是Object3D的一个实例,因此它使用this方法

如果要实现的目的是将文本与球体一起移动,则可以使用this方法将文本简单地添加为球体的子级。您还必须调整相对位置。

scene.remove("text");