点进来就看炫酷的3D字体！

1.准备工作:字体模型json

可以通过facetype.js将字体包转成typeface.json

facetype.jsgithub链接：https://github.com/gero3/facetype.js
facetype.js官网链接：http://gero3.github.io/facetype.js/

2.加载字体

if (!this.loader) {
            this.loader = new THREE.FontLoader();
          }
          this.loader.load('DIN_Bold.json', (font) => {
         
            //...
            });

3.创建字体并获取字体点面

 //创建字体图形
            let geometry = new THREE.TextGeometry(that.text, {
              font: font,
              size: that.fontSize, //字体大小
              height: that.thickness, //字体厚度
              curveSegments: 3,
              bevelThickness: 2,
              bevelSize: 1,
              bevelEnabled: true
            });
            
             //图形居中
            geometry.center();
            

            //转为缓存图形，方便获取点面等数据
            geometry = new THREE.BufferGeometry().fromGeometry(geometry);
            //三角形面数
            const numFaces = geometry.attributes.position.count / 3;

4.字体形状赋值颜色

 //需要赋值的点颜色数组
            const colors = new Float32Array(numFaces * 3 * 3);
            
         const color = new THREE.Color();


            for (let f = 0; f < numFaces; f++) {
              const index = 9 * f;
              //随机颜色
              color.setRGB(
                Math.random() * 0.5 + 0.5,
                Math.random() * 0.5 + 0.5,
                Math.random() * 0.5 + 0.5
              );
            


              for (let i = 0; i < 3; i++) {
                //给3个点赋值同样的颜色，形成一个颜色的三角形
                colors[index + 3 * i] = color.r;
                colors[index + 3 * i + 1] = color.g;
                colors[index + 3 * i + 2] = color.b;
                
              }
            }
            //设置顶点着色器值
            geometry.setAttribute('aColor', new THREE.BufferAttribute(colors, 3));

5.着色器材质

5.1 顶点着色器

                  attribute vec3 aColor; 
                  varying vec3 vColor;

                  void main() {
                      vColor = aColor; 
                      gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

                  }

5.2 片元着色器

  varying vec3 vColor;
      void main() {
              gl_FragColor =vec4(vColor, 1.0 );


      }

5.3 着色材质

//着色器材质
            const shaderMaterial = new THREE.ShaderMaterial({
              uniforms: {
                amplitude: { value: 0.0 }
              },
              vertexShader: document.getElementById('vertexshader').textContent,
              fragmentShader: document.getElementById('fragmentshader').textContent
            });

6.使用

  var myFont = new MyFont();
      myFont.initThree(document.getElementById('font'));
      myFont.createChart({
        text: '666',//文本
        fontSize: 20,//字体大小
        thickness: 5,//厚度
        distance: 30,//偏移距离
        minDistance: 5,//最小偏移距离 
      });

7.字体每个面的偏移

顶点着色器：normal是three顶点着色器默认值

                  attribute vec3 aColor;  
                  varying vec3 vColor;


                  void main() {
                      vColor = aColor; 
      vec3 newPosition =position+normal*2.0;//每个面偏移                       
        gl_Position = projectionMatrix * modelViewMatrix * vec4( newPosition, 1.0 );
                  }

8.让每个面三角形随机偏移

                   attribute vec3 aColor;
                   attribute vec3 displacement; //偏移值
                   varying vec3 vColor; 


                   void main() {
                       vColor = aColor; 

       vec3 newPosition =position+normal*displacement;//每个面随机偏移
   gl_Position = projectionMatrix * modelViewMatrix * vec4( newPosition, 1.0 );

                   }

设置随机偏移值

   //需要赋值的偏移变量数组
            const displacement = new Float32Array(numFaces * 3 * 3);
      for (let f = 0; f < numFaces; f++) {
              const index = 9 * f;
               
              //随机偏移值
              const d = that.minDistance + that.distance * Math.random();


              for (let i = 0; i < 3; i++) {
               
                //给3个点赋值偏移值，形成对应的三角形
                displacement[index + 3 * i] = d;
                displacement[index + 3 * i + 1] = d + Math.random() * that.minDistance;
                displacement[index + 3 * i + 2] = d + Math.random() * that.minDistance;
              }
            }
            //设置顶点着色器值            
            geometry.setAttribute('displacement', new THREE.BufferAttribute(displacement, 3));

9.随机偏移的三角形汇聚成原来的字体

9.1 偏移

uniform float time;
 attribute vec3 aColor;
                   attribute vec3 displacement; //偏移值
                   varying vec3 vColor; 


                   void main() {
                       vColor = aColor; 


       vec3 newPosition =position+normal*displacement*time;//每个面随机偏移随时间变
   gl_Position = projectionMatrix * modelViewMatrix * vec4( newPosition, 1.0 );

                   }

9.2 汇聚

让偏移值随时间递减到0，汇聚成原来的字体，则时间值递减

 animateAction() {
          if (this.mesh) {
            if (this.time >= 0) {
              this.time += 0.005;
              this.mesh.material.uniforms.time.value = 2.0 - this.time;
              if (this.time >= 2.0) {
                this.time = -1;
              }
            } else {
              this.mesh.material.uniforms.time.value = 0.0;
            }
          }
        }

10.字体面数细化

        import { TessellateModifier } from '../node_modules/three/examples/jsm/modifiers/TessellateModifier.js';
        
         //细化修改器            
            const tessellateModifier = new TessellateModifier(8, 6);
            //修改图形的面数
            geometry = tessellateModifier.modify(geometry);

细化修改器 TessellateModifier( maxEdgeLength=0.1 最大边长, maxIterations = 6 最大遍历次数, maxFaces = Infinity 最大面数 )

可以看到相对于原来的字体，面数增加了，更加精细了！

11.同理可在其他模型形状也可使用该效果


   let geometry = new THREE.CylinderGeometry(that.topRadius, that.bottomRadius, that.height);
          //图形居中
          geometry.center();
          //细化修改器
          const tessellateModifier = new TessellateModifier(8, 6);
          //修改图形的面数
          geometry = tessellateModifier.modify(geometry);

          //转为缓存图形，方便获取点面等数据
          geometry = new THREE.BufferGeometry().fromGeometry(geometry);
          //...