画布和精灵材质 [英] Canvas and SpriteMaterial

问题描述

对不起，如果这是一个菜鸟问题.

Sorry if this is a Noob question.

我一直在尝试使用动态生成的画布元素作为精灵为在three.js 中创建的时间线添加标签.时间线部分渲染得很好，但我很难让画布精灵渲染.这是我用于精灵的内容(从更大场景的上下文中取出):

I've been trying to add labels to a timeline created in three.js using dynamically generated canvas elements as sprites. The timeline part is rendering great, but I am having difficulty getting the canvas sprites to render. This is what i'm using for the sprites (taken out of the context of the larger scene):

var canvas = document.createElement('canvas');
var size = 250;
canvas.width = size;
canvas.height = size;
var context = canvas.getContext('2d');
context.fillStyle = '#990000';
context.textAlign = 'center';
context.font = '24px Arial';
context.fillText("some text", size / 2, size / 2);

var amap = new THREE.Texture(canvas);
amap.needsUpdate = true;

var mat = new THREE.SpriteMaterial({
    map: amap,
    transparent: false,
    useScreenCoordinates: false,
    color: 0x000000
});

var sp = new THREE.Sprite(mat);
scene.add(sp);    

您可以在此处查看更完整的示例代码集:http://jsfiddle.net/rgE2j/2/.

You can see a fuller set of example code here: http://jsfiddle.net/rgE2j/2/.

感谢任何帮助.

谢谢，彼得

推荐答案

好吧，你有几个错误.我将相机移近并进行了一些其他更改，请注意.此外，小提琴使用的是旧版本的库.

Well, you have several mistakes. I moved the camera closer and made some other changes, which are noted. Also, the fiddle was using an old version of the library.

更新小提琴:http://jsfiddle.net/rgE2j/141/

three.js r.54

three.js r.54

var canvas = document.createElement('canvas');
var size = 256; // CHANGED
canvas.width = size;
canvas.height = size;
var context = canvas.getContext('2d');
context.fillStyle = '#ff0000'; // CHANGED
context.textAlign = 'center';
context.font = '24px Arial';
context.fillText("some text", size / 2, size / 2);

var amap = new THREE.Texture(canvas);
amap.needsUpdate = true;

var mat = new THREE.SpriteMaterial({
    map: amap,
    transparent: false,
    useScreenCoordinates: false,
    color: 0xffffff // CHANGED
});

var sp = new THREE.Sprite(mat);
sp.scale.set( 10, 10, 1 ); // CHANGED
scene.add(sp);    

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