javascript - Three.js - 如何预先定位要合并的对象？

Question

我已经成功合并了我的立方体，尽管它们似乎合并在一起并恢复到原来的位置/旋转，忽略声明的定位/旋转

var geometries = [];

cube1.position.set( 0, 0, 0 );
geometries.push( cube1 );

cube2.position.set( 1, 0, 0 );
geometries.push( cube2 );

cube3.position.set( 0, 1, 0 );
geometries.push( cube3 );

const cubes = BufferGeometryUtils.mergeBufferGeometries( geometries );

scene.add( cubes );//All the cubes get merged on 0, 0, 0 - overlapping one another

如何定位立方体以便它们可以合并到它们声明的位置？

Answer 1

这是一个使用 BufferGeometryUtils 和 .applyMatrix4() 的工作示例:

body{
  overflow: hidden;
  margin: 0;
}

<script type="module">
import * as THREE from "https://cdn.skypack.dev/three@0.136.0";
import {
  OrbitControls
} from "https://cdn.skypack.dev/three@0.136.0/examples/jsm/controls/OrbitControls.js";
import * as BufferGeometryUtils from "https://cdn.skypack.dev/three@0.136.0/examples/jsm/utils/BufferGeometryUtils";

let scene = new THREE.Scene();
let camera = new THREE.PerspectiveCamera(60, innerWidth / innerHeight, 1, 1000);
camera.position.setScalar(1).setLength(6);
let renderer = new THREE.WebGLRenderer({
  antialias: true
});
renderer.setSize(innerWidth, innerHeight);
renderer.setClearColor(0x404040);
document.body.appendChild(renderer.domElement);

let controls = new OrbitControls(camera, renderer.domElement);

let light = new THREE.DirectionalLight(0xffffff, 1);
light.position.setScalar(1);
scene.add(light, new THREE.AmbientLight(0xffffff, 0.5));

let boxes = [
  makeBox(2, 0, 0, 0xff0000),
  makeBox(0, 2, 0, 0x00ff00),
  makeBox(0, 0, 2, 0x0000ff)
];
let materials = [];

let g = BufferGeometryUtils.mergeBufferGeometries(boxes.map(b => {
  materials.push(b.material);
  b.updateMatrixWorld(); // needs to be done to be sure that all transformations are applied
  return b.geometry.applyMatrix4(b.matrixWorld);
}), true);

let o = new THREE.Mesh(g, materials);
scene.add(o);

window.addEventListener("resize", onWindowResize);

animate();

function animate() {

  requestAnimationFrame(animate);
  renderer.render(scene, camera);

}

function onWindowResize() {

  camera.aspect = innerWidth / innerHeight;
  camera.updateProjectionMatrix();

  renderer.setSize(innerWidth, innerHeight);

}

function makeBox(x, y, z, color) {
  let g = new THREE.BoxGeometry();
  let m = new THREE.MeshLambertMaterial({
    color: color
  });
  let box = new THREE.Mesh(g, m);
  box.position.set(x, y, z);
  return box;
}

</script>