内置几何体

此笔记记录于DISCOVER three.js，大多数为其中的摘要，少数为笔者自己的理解

目录

效果

Material.flatShading属性

const material = new MeshStandardMaterial({
color: 'red',
flatShading: true,
});

左边: flatShading 禁用。右边: flatShading 启用。

Train.js

import { Group, MathUtils } from 'three';

import { createMeshes } from './meshes.js';

const wheelSpeed = MathUtils.degToRad(24);

class Train extends Group {
  constructor() {
    super();

    this.meshes = createMeshes();

    this.add(
      this.meshes.nose,
      this.meshes.cabin,
      this.meshes.chimney,
      this.meshes.smallWheelRear,
      this.meshes.smallWheelCenter,
      this.meshes.smallWheelFront,
      this.meshes.bigWheel,
    );
  }

  tick(delta) {
    this.meshes.bigWheel.rotation.y += wheelSpeed * delta;
    this.meshes.smallWheelRear.rotation.y += wheelSpeed * delta;
    this.meshes.smallWheelCenter.rotation.y += wheelSpeed * delta;
    this.meshes.smallWheelFront.rotation.y += wheelSpeed * delta;
  }
}

export { Train };

• Train类继承自Group
• 注意super()的使用。这意味着Train类现在具有Group的所有常规功能。

geometries.js

import { BoxBufferGeometry, CylinderBufferGeometry } from 'three';

function createGeometries() {
  const cabin = new BoxBufferGeometry(2, 2.25, 1.5);

  const nose = new CylinderBufferGeometry(0.75, 0.75, 3, 12);

  // we can reuse a single cylinder geometry for all 4 wheels
  const wheel = new CylinderBufferGeometry(0.4, 0.4, 1.75, 16);

  // different values for the top and bottom radius creates a cone shape
  const chimney = new CylinderBufferGeometry(0.3, 0.1, 0.5);

  return {
    cabin,
    nose,
    wheel,
    chimney,
  };
}

export { createGeometries };

materials.js

import { MeshStandardMaterial } from 'three';

function createMaterials() {
  const body = new MeshStandardMaterial({
    color: 'firebrick',
    flatShading: true,
  });

  const detail = new MeshStandardMaterial({
    color: 'darkslategray',
    flatShading: true,
  });

  return { body, detail };
}

export { createMaterials };

meshes.js

import { Mesh } from 'three';

import { createGeometries } from './geometries.js';
import { createMaterials } from './materials.js';

function createMeshes() {
  const geometries = createGeometries();
  const materials = createMaterials();

  const cabin = new Mesh(geometries.cabin, materials.body);
  cabin.position.set(1.5, 1.4, 0);

  const chimney = new Mesh(geometries.chimney, materials.detail);
  chimney.position.set(-2, 1.9, 0);

  const nose = new Mesh(geometries.nose, materials.body);
  nose.position.set(-1, 1, 0);
  nose.rotation.z = Math.PI / 2;

  const smallWheelRear = new Mesh(geometries.wheel, materials.detail);
  smallWheelRear.position.y = 0.5;
  smallWheelRear.rotation.x = Math.PI / 2;

  const smallWheelCenter = smallWheelRear.clone();
  smallWheelCenter.position.x = -1;

  const smallWheelFront = smallWheelRear.clone();
  smallWheelFront.position.x = -2;

  const bigWheel = smallWheelRear.clone();
  bigWheel.position.set(1.5, 0.9, 0);
  bigWheel.scale.set(2, 1.25, 2);

  return {
    nose,
    cabin,
    chimney,
    smallWheelRear,
    smallWheelCenter,
    smallWheelFront,
    bigWheel,
  };
}

export { createMeshes };

World.js 中使用

import { createCamera } from './components/camera.js';
import {
  createAxesHelper,
  createGridHelper,
} from './components/helpers.js';
import { createLights } from './components/lights.js';
import { createScene } from './components/scene.js';
import { Train } from './components/Train/Train.js'; 

import { createControls } from './systems/controls.js';
import { createRenderer } from './systems/renderer.js';
import { Resizer } from './systems/Resizer.js';
import { Loop } from './systems/Loop.js';

let camera;
let renderer;
let scene;
let loop;

class World {
  constructor(container) {
    camera = createCamera();
    renderer = createRenderer();
    scene = createScene();
    loop = new Loop(camera, scene, renderer);
    container.append(renderer.domElement);

    const controls = createControls(camera, renderer.domElement);
    const { ambientLight, mainLight } = createLights();
    const train = new Train(); 

    loop.updatables.push(controls, train); 
    scene.add(ambientLight, mainLight, train); 

    const resizer = new Resizer(container, camera, renderer);

    scene.add(createAxesHelper(), createGridHelper());
  }

  render() {
    renderer.render(scene, camera);
  }

  start() {
    loop.start();
  }

  stop() {
    loop.stop();
  }
}

export { World };