Threejs系列：物体

本文介绍Threejs中物体(geometory)相关内容

threejs中常见几何体包括：平面体、立方体、圆、锥体、柱体、圆环、四面、八面、十二面缓冲、挤压缓冲体、形状缓冲几何体、圆环扭结、管道体等等

1. 空间的中的物体由一个个三维的点构成

• 直接给点

const geometry = new THREE.BufferGeometry();
const vertices = new Float32Array( [
    -1.0, -1.0,  1.0, // v0
    1.0, -1.0,  1.0, // v1
    1.0,  1.0,  1.0, // v2

     1.0,  1.0,  1.0, // v3
    -1.0,  1.0,  1.0, // v4
    -1.0, -1.0,  1.0  // v5
] );

geometry.setAttribute( 'position', new THREE.BufferAttribute( vertices, 3 ) );

• 索引给点

  const geometry = new THREE.BufferGeometry();
  const vertices = new Float32Array( [
      -1.0, -1.0,  1.0, // v0
      1.0, -1.0,  1.0, // v1
      1.0,  1.0,  1.0, // v2
  
      //  1.0,  1.0,  1.0, // v3
      -1.0,  1.0,  1.0, // v4
      // -1.0, -1.0,  1.0  // v5
  ] );
  
  geometry.setAttribute( 'position', new THREE.BufferAttribute( vertices, 3 ) );
  const indexs = new Uint16Array(
  [
      0, 1,2,2, 3, 0
  ]
  )
  geometry.index = new THREE.BufferAttribute(indexs, 1)