webgl_buffergeometry_lines_indexed

对应 three.js 示例地址。

仅需关注 init 函数的内容，其他部分都是示例小程序所使用的描述配置。

example.jstypings.d.ts

import * as THREE from "three";

/** @type {import("@minisheeep/mp-three-examples").OfficialExampleInfo} */
const exampleInfo = {
  name: "webgl_buffergeometry_lines_indexed",
  useLoaders: [],
  info: [
    [
      {
        tag: "a",
        link: "https://threejs.org",
        content: "three.js"
      },
      {
        tag: "text",
        content: "webgl - buffergeometry - lines - indexed"
      }
    ]
  ],
  init: ({ window, canvas, GUI, Stats, needToDispose, useFrame }) => {
    let stats;
    let camera, scene, renderer;
    let parent_node;
    init();
    function init() {
      camera = new THREE.PerspectiveCamera(27, window.innerWidth / window.innerHeight, 1, 1e4);
      camera.position.z = 9e3;
      scene = new THREE.Scene();
      const geometry = new THREE.BufferGeometry();
      const material = new THREE.LineBasicMaterial({ vertexColors: true });
      const indices = [];
      const positions = [];
      const colors = [];
      let next_positions_index = 0;
      const iteration_count = 4;
      const rangle = 60 * Math.PI / 180;
      function add_vertex(v) {
        positions.push(v.x, v.y, v.z);
        colors.push(Math.random() * 0.5 + 0.5, Math.random() * 0.5 + 0.5, 1);
        return next_positions_index++;
      }
      function snowflake_iteration(p0, p4, depth) {
        if (--depth < 0) {
          const i = next_positions_index - 1;
          add_vertex(p4);
          indices.push(i, i + 1);
          return;
        }
        const v = p4.clone().sub(p0);
        const v_tier = v.clone().multiplyScalar(1 / 3);
        const p1 = p0.clone().add(v_tier);
        const angle = Math.atan2(v.y, v.x) + rangle;
        const length = v_tier.length();
        const p2 = p1.clone();
        p2.x += Math.cos(angle) * length;
        p2.y += Math.sin(angle) * length;
        const p3 = p0.clone().add(v_tier).add(v_tier);
        snowflake_iteration(p0, p1, depth);
        snowflake_iteration(p1, p2, depth);
        snowflake_iteration(p2, p3, depth);
        snowflake_iteration(p3, p4, depth);
      }
      function snowflake(points, loop, x_offset) {
        for (let iteration = 0; iteration != iteration_count; iteration++) {
          add_vertex(points[0]);
          for (let p_index = 0, p_count = points.length - 1; p_index != p_count; p_index++) {
            snowflake_iteration(points[p_index], points[p_index + 1], iteration);
          }
          if (loop) snowflake_iteration(points[points.length - 1], points[0], iteration);
          for (let p_index = 0, p_count = points.length; p_index != p_count; p_index++) {
            points[p_index].x += x_offset;
          }
        }
      }
      let y = 0;
      snowflake([new THREE.Vector3(0, y, 0), new THREE.Vector3(500, y, 0)], false, 600);
      y += 600;
      snowflake(
        [
          new THREE.Vector3(0, y, 0),
          new THREE.Vector3(250, y + 400, 0),
          new THREE.Vector3(500, y, 0)
        ],
        true,
        600
      );
      y += 600;
      snowflake(
        [
          new THREE.Vector3(0, y, 0),
          new THREE.Vector3(500, y, 0),
          new THREE.Vector3(500, y + 500, 0),
          new THREE.Vector3(0, y + 500, 0)
        ],
        true,
        600
      );
      y += 1e3;
      snowflake(
        [
          new THREE.Vector3(250, y, 0),
          new THREE.Vector3(500, y, 0),
          new THREE.Vector3(250, y, 0),
          new THREE.Vector3(250, y + 250, 0),
          new THREE.Vector3(250, y, 0),
          new THREE.Vector3(0, y, 0),
          new THREE.Vector3(250, y, 0),
          new THREE.Vector3(250, y - 250, 0),
          new THREE.Vector3(250, y, 0)
        ],
        false,
        600
      );
      geometry.setIndex(indices);
      geometry.setAttribute("position", new THREE.Float32BufferAttribute(positions, 3));
      geometry.setAttribute("color", new THREE.Float32BufferAttribute(colors, 3));
      geometry.computeBoundingSphere();
      const lineSegments = new THREE.LineSegments(geometry, material);
      lineSegments.position.x -= 1200;
      lineSegments.position.y -= 1200;
      parent_node = new THREE.Object3D();
      parent_node.add(lineSegments);
      scene.add(parent_node);
      renderer = new THREE.WebGLRenderer({ canvas });
      renderer.setPixelRatio(window.devicePixelRatio);
      renderer.setSize(window.innerWidth, window.innerHeight);
      renderer.setAnimationLoop(animate);
      stats = new Stats(renderer);
      window.addEventListener("resize", onWindowResize);
      needToDispose(renderer, scene);
    }
    function onWindowResize() {
      camera.aspect = window.innerWidth / window.innerHeight;
      camera.updateProjectionMatrix();
      renderer.setSize(window.innerWidth, window.innerHeight);
    }
    function animate() {
      const time = Date.now() * 1e-3;
      parent_node.rotation.z = time * 0.5;
      renderer.render(scene, camera);
      stats.update();
    }
  }
};
export {
  exampleInfo as default
};

import { Loader, TypedArray } from 'three';
/**
 * 官网示例的多端使用封装把版本
 * */
export interface OfficialExampleInfo extends MiniProgramMeta {
  /*** 示例名称（保持和官网一致）*/
  name: string;
  /** main */
  init: (context: LoadContext) => void;
}

export interface LoadContext {
  //为了减少官方代码的改动，实际上等同于 canvas
  window: EventTarget & { innerWidth: number; innerHeight: number; devicePixelRatio: number };
  /** HTMLCanvasElement */
  canvas: any;
  /** https://www.npmjs.com/package/lil-gui */
  GUI: any;
  /**
   * https://www.npmjs.com/package/stats.js
   * 也可以使用其他受支持的版本
   * */
  Stats: any;
  /** 收集需要 dispose 的对象（官方示例没有处理这部分）*/
  needToDispose: (...objs: any[]) => void | ((fromFn: () => any[]) => void);

  /**基于 raq 的通用封装 */
  useFrame(animateFunc: (/** ms */ delta: number) => void): { cancel: () => void };

  /** 显示加载模态框 */
  requestLoading(text?: string): Promise<void>;

  /** 隐藏加载模态框*/
  cancelLoading(): void;

  /** 保存文件的通用封装*/
  saveFile(
    fileName: string,
    data: ArrayBuffer | TypedArray | DataView | string
  ): Promise<string | null>;

  /** 示例使用 DracoDecoder 时的资源路径 */
  DecoderPath: {
    GLTF: string;
    STANDARD: string;
  };

  /** 为资源路径拼上 CDN 前缀 */
  withCDNPrefix(path: string): string;

  /**
   * 在小程序中应使用 import { VideoTexture } from '@minisheep/three-platform-adapter/override/jsm/textures/VideoTexture.js';
   * 正常情况（web） 可直接使用 THREE.VideoTexture
   * */
  getVideoTexture(videoOptions: VideoOptions): Promise<[{ isVideoTexture: true }, video: any]>;

  /**
   * 在小程序中应使用 import { CameraTexture } from '@minisheep/three-platform-adapter/override/jsm/textures/CameraTexture.js';
   * 正常情况（web） 可参考示例 webgl_materials_video_webcam
   * */
  getCameraTexture(): { isVideoTexture: true };

  /** 用于动态修改 info 中的占位符*/
  bindInfoText(template: `$${string}$`, initValue?: string): { value: string };

  /** 分屏控件对应的事件回调 */
  onSlideStart(handle: () => void): void;
  /** 分屏控件对应的事件回调 */
  onSlideEnd(handle: () => void): void;
  /** 分屏控件对应的事件回调 */
  onSlideChange(handle: (offset: number, boxSize: number) => void): void;
}

export type VideoOptions = {
  src: string;
  /** 相当于 HTMLVideoElement 的 naturalWidth (小程序中获取不到)*/
  width: number;
  /** 相当于 HTMLVideoElement 的 naturalHeight (小程序中获取不到)*/
  height: number;
  loop?: boolean;
  autoplay?: boolean;
  muted?: boolean;
};

/** 示例小程序中使用的一些配置 */
export interface MiniProgramMeta {
  /** 用于统计加载相关信息 */
  useLoaders: Loader[];
  /** 通用 info */
  info: TagItem[][];
  /** 特殊 info */
  infoPanel?: {
    left?: [string, string][];
    right?: [string, string][];
  };
  /** 分屏控件配置 */
  needSlider?: {
    /** 方向 */
    direction?: 'horizontal' | 'vertical';
    /** 初始偏移 0-100 */
    initPosition?: number;
  };
  /** 操作摇杆控件 */
  needArrowControls?: boolean;
  /** 默认需要的画布类型 */
  canvasType?: '2d' | 'webgl' | 'webgl2';
  /** 为保持效果一致所需要的画布样式 */
  canvasStyle?: {
    bgColor?: string;
    width?: number | string;
    height?: number | string;
  };
  /** 部分示例需要在加载前进行一些提示 */
  initAfterConfirm?: {
    /**
     * 提示类型
     * @default 'default'
     * */
    type?: 'warning' | 'default';
    text: string[];
  };
}

export interface BaseTag<T extends string> {
  tag: T;
  content: string;
}

export interface ATag extends BaseTag<'a'> {
  link: string;
}

export type TextTag = BaseTag<'text'>;

export type TagItem = TextTag | ATag;

webgl_buffergeometry_lines_indexed ​

webgl_buffergeometry_lines_indexed