webgl_materials_cubemap_render_to_mipmaps

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.js

import * as THREE from "three";
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls.js";

/** @type {import("@minisheeep/mp-three-examples").OfficialExampleInfo} */
const exampleInfo = {
  name: "webgl_materials_cubemap_render_to_mipmaps",
  useLoaders: [],
  info: [
    [
      { tag: "a", link: "https://threejs.org", content: "three.js" },
      { tag: "text", content: "- rendering to cubemap mip levels demo." }
    ],
    [
      { tag: "text", content: "Left: original cubemap" },
      { tag: "text", content: "Right: generated cubemap" }
    ]
  ],
  init: ({ window, canvas, GUI, Stats, needToDispose, useFrame }) => {
    let camera, scene, renderer;
    const CubemapFilterShader = {
      name: "CubemapFilterShader",
      uniforms: {
        cubeTexture: { value: null },
        mipIndex: { value: 0 }
      },
      vertexShader: (
        /* glsl */
        `

					varying vec3 vWorldDirection;

					#include <common>

					void main() {
						vWorldDirection = transformDirection(position, modelMatrix);
						#include <begin_vertex>
						#include <project_vertex>
						gl_Position.z = gl_Position.w; // set z to camera.far
					}

					`
      ),
      fragmentShader: (
        /* glsl */
        `

					uniform samplerCube cubeTexture;
					varying vec3 vWorldDirection;

					uniform float mipIndex;

					#include <common>

					void main() {
						vec3 cubeCoordinates = normalize(vWorldDirection);

						// Colorize mip levels
						vec4 color = vec4(1.0, 0.0, 0.0, 1.0);
						if (mipIndex == 0.0) color.rgb = vec3(1.0, 1.0, 1.0);
						else if (mipIndex == 1.0) color.rgb = vec3(0.0, 0.0, 1.0);
						else if (mipIndex == 2.0) color.rgb = vec3(0.0, 1.0, 1.0);
						else if (mipIndex == 3.0) color.rgb = vec3(0.0, 1.0, 0.0);
						else if (mipIndex == 4.0) color.rgb = vec3(1.0, 1.0, 0.0);

						gl_FragColor = textureCube(cubeTexture, cubeCoordinates, 0.0) * color;
					}

					`
      )
    };
    init();
    async function loadCubeTexture(urls) {
      return new Promise(function(resolve) {
        new THREE.CubeTextureLoader().load(urls, function(cubeTexture) {
          resolve(cubeTexture);
        });
      });
    }
    function allocateCubemapRenderTarget(cubeMapSize) {
      const params = {
        magFilter: THREE.LinearFilter,
        minFilter: THREE.LinearMipMapLinearFilter,
        generateMipmaps: false,
        type: THREE.HalfFloatType,
        format: THREE.RGBAFormat,
        colorSpace: THREE.LinearSRGBColorSpace,
        depthBuffer: false
      };
      const rt = new THREE.WebGLCubeRenderTarget(cubeMapSize, params);
      const mipLevels = Math.log(cubeMapSize) * Math.LOG2E + 1;
      for (let i = 0; i < mipLevels; i++) rt.texture.mipmaps.push({});
      rt.texture.mapping = THREE.CubeReflectionMapping;
      return rt;
    }
    function renderToCubeTexture(cubeMapRenderTarget, sourceCubeTexture) {
      const geometry = new THREE.BoxGeometry(5, 5, 5);
      const material = new THREE.ShaderMaterial({
        name: CubemapFilterShader.name,
        uniforms: THREE.UniformsUtils.clone(CubemapFilterShader.uniforms),
        vertexShader: CubemapFilterShader.vertexShader,
        fragmentShader: CubemapFilterShader.fragmentShader,
        side: THREE.BackSide,
        blending: THREE.NoBlending
      });
      material.uniforms.cubeTexture.value = sourceCubeTexture;
      const mesh = new THREE.Mesh(geometry, material);
      const cubeCamera = new THREE.CubeCamera(1, 10, cubeMapRenderTarget);
      const mipmapCount = Math.floor(
        Math.log2(Math.max(cubeMapRenderTarget.width, cubeMapRenderTarget.height))
      );
      for (let mipmap = 0; mipmap < mipmapCount; mipmap++) {
        material.uniforms.mipIndex.value = mipmap;
        material.needsUpdate = true;
        cubeMapRenderTarget.viewport.set(
          0,
          0,
          cubeMapRenderTarget.width >> mipmap,
          cubeMapRenderTarget.height >> mipmap
        );
        cubeCamera.activeMipmapLevel = mipmap;
        cubeCamera.update(renderer, mesh);
      }
      mesh.geometry.dispose();
      mesh.material.dispose();
    }
    function init() {
      renderer = new THREE.WebGLRenderer({ antialias: true, canvas });
      renderer.setPixelRatio(window.devicePixelRatio);
      renderer.setSize(window.innerWidth, window.innerHeight);
      renderer.setAnimationLoop(animate);
      scene = new THREE.Scene();
      camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 1e4);
      camera.position.z = 500;
      const controls = new OrbitControls(camera, renderer.domElement);
      controls.minPolarAngle = Math.PI / 4;
      controls.maxPolarAngle = Math.PI / 1.5;
      window.addEventListener("resize", onWindowResize);
      const r = "textures/cube/Park3Med/";
      const urls = [
        r + "px.jpg",
        r + "nx.jpg",
        r + "py.jpg",
        r + "ny.jpg",
        r + "pz.jpg",
        r + "nz.jpg"
      ];
      loadCubeTexture(urls).then((cubeTexture) => {
        const cubeMapRenderTarget = allocateCubemapRenderTarget(512);
        renderToCubeTexture(cubeMapRenderTarget, cubeTexture);
        const sphere = new THREE.SphereGeometry(100, 128, 128);
        let material = new THREE.MeshBasicMaterial({ color: 16777215, envMap: cubeTexture });
        let mesh = new THREE.Mesh(sphere, material);
        mesh.position.set(-100, 0, 0);
        scene.add(mesh);
        material = material.clone();
        material.envMap = cubeMapRenderTarget.texture;
        mesh = new THREE.Mesh(sphere, material);
        mesh.position.set(100, 0, 0);
        scene.add(mesh);
      });
      needToDispose(renderer, scene);
    }
    function onWindowResize() {
      camera.aspect = window.innerWidth / window.innerHeight;
      camera.updateProjectionMatrix();
      renderer.setSize(window.innerWidth, window.innerHeight);
    }
    function animate() {
      renderer.render(scene, camera);
    }
  }
};
export {
  exampleInfo as default
};

typings.d.ts

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;