文字

在3D扩展中显示文字也很简单，通过layer的createText方法创建一个文字纹理，然后将它应用到对应的元素上。不过注意的是，显示的宽高比要和文字纹理的宽高比保持一致，以免文字变形。

const {Scene} = spritejs;
const {Plane, shaders} = spritejs.ext3d;
const container = document.getElementById('container');
const scene = new Scene({
  container,
  displayRatio: 2,
});
const layer = scene.layer3d('fglayer', {
  camera: {
    fov: 35,
  },
});
layer.camera.attributes.pos = [2, 2, 3];
layer.camera.lookAt([0, 1.5, 0]);
const texture = layer.createText('你好 SpriteJS 3D', {
  font: '48px Arial',
  fillColor: 'red',
});
const program = layer.createProgram({
  ...shaders.NORMAL_TEXTURE,
  texture,
  cullFace: null,
});
const label = new Plane(program, {
  width: 1,
  height: texture.image.height / texture.image.width,
});
label.animate([
  {rotateY: 0},
  {rotateY: 360},
], {
  duration: 20000,
  iterations: Infinity,
});
layer.append(label);
layer.setOrbit();