three.js實現炫酷的3d影院

閱讀本博客能夠獲取到的知識

  • 建立一個3d的空間
  • 粒子效果
  • three.js點擊事件的處理
  • 着色器的初步使用
  • 實現一個光暈效果

1.建立一個3d的空間

能夠想象一下咱們在房間內,房間是一個立方體,若是你有生活品味,可能會在房間內貼上壁紙,three.js能夠很方便的建立一個立方體,而且給它的周圍貼上紋理,讓照相機在立方體之中,照相機能夠360旋轉,就模擬了一個真實的場景。git

轉換爲代碼:

const path = 'assets/image/'
    const format = '.jpg'
    const urls = [
      `${path}px${format}`, `${path}nx${format}`,
      `${path}py${format}`, `${path}ny${format}`,
      `${path}pz${format}`, `${path}nz${format}`
    ]
    const materials = []
    urls.forEach(url => {
      const textureLoader = new TextureLoader()
      textureLoader.setCrossOrigin(this.crossOrigin)
      const texture = textureLoader.load(url)
      materials.push(new MeshBasicMaterial({
        map: texture,
        overdraw: true,
        side: BackSide
      }))
    })
    const cube = new Mesh(new CubeGeometry(9000, 9000, 9000), new MeshFaceMaterial(materials))
    this.scene.add(cube)
複製代碼
  • CubeGeometry建立一個超大的立方體
  • MeshFaceMaterial給立方體貼上文理,因爲視角是在立方體內部,因此side:BackSide

2.粒子效果

一個3d模型是由點,線,面組成的,能夠遍歷模型的每個點,把每個點轉換爲幾何模型,而且給它貼上文理,拷貝每個點的位置,用這些幾何模型從新構成一個只有點的模型,這就是粒子效果的基本原理。github

this.points = new Group()
    const vertices = []
    let point
    const texture = new TextureLoader().load('assets/image/dot.png')
    geometry.vertices.forEach((o, i) => {
      // 記錄每一個點的位置
      vertices.push(o.clone())
      const _geometry = new Geometry()
     // 拿到當前點的位置
      const pos = vertices[i]
      _geometry.vertices.push(new Vector3())
      const color = new Color()
      color.r = Math.abs(Math.random() * 10)
      color.g = Math.abs(Math.random() * 10)
      color.b = Math.abs(Math.random() * 10)
      const material = new PointsMaterial({
        color,
        size: Math.random() * 4 + 2,
        map: texture,
        blending: AddEquation,
        depthTest: false,
        transparent: true
      })
      point = new Points(_geometry, material)
      point.position.copy(pos)
      this.points.add(point)
    })
    return this.points
複製代碼
  • new Group建立一個羣,能夠說是粒子的集合
  • 經過point.position.copy(pos)設置粒子和位置,座標和模型中對應點的位置相同

3.點擊事件的處理

three.js的點擊事件須要藉助光線投射器(Raycaster),爲了方便理解,請先看一張圖:數組

image

Raycaster發射一個射線,intersectObject監測射線命中的物體bash

this.raycaster = new Raycaster()

// 把你要監聽點擊事件的物體用數組儲存起來
this.seats.push(seat)

onTouchStart(event) {
    event.preventDefault()
    event.clientX = event.touches[0].clientX;
    event.clientY = event.touches[0].clientY;
    this.onClick(event)
  }

  onClick(event) {
    const mouse = new Vector2()
    mouse.x = ( event.clientX / this.renderer.domElement.clientWidth ) * 2 - 1
    mouse.y = - ( event.clientY / this.renderer.domElement.clientHeight ) * 2 + 1;
    this.raycaster.setFromCamera(mouse, this.camera)
   // 檢測命中的座位
    const intersects = this.raycaster.intersectObjects(this.seats)
    if (intersects.length > 0) {
        intersects[0].object.material = new MeshLambertMaterial({
            color: 0xff0000
        })
    }
  }
  
複製代碼
  • intersects.length > 0 表示射線命中了某個幾何體
  • 偷懶只實現了移動端的點擊實現,若是想看pc怎麼實現,請看thee.js官網

4.着色器的初步使用

着色器分爲頂點着色器和片元着色器,用GLSL語言編寫,是一種和GPU溝通的的語言,這裏只講如何使用dom

const vertext = `
   void main()
    {
    gl_Position = projectionMatrix * modelViewMatrix * vec4(position,1.0);
    }
  `

const fragment = `
    uniform vec2 resolution;
    uniform float time;

    vec2 rand(vec2 pos)
    {
    return fract( 0.00005 * (pow(pos+2.0, pos.yx + 1.0) * 22222.0));
    }
    vec2 rand2(vec2 pos)
    {
    return rand(rand(pos));
    }

    float softnoise(vec2 pos, float scale)
    {
    vec2 smplpos = pos * scale;
    float c0 = rand2((floor(smplpos) + vec2(0.0, 0.0)) / scale).x;
    float c1 = rand2((floor(smplpos) + vec2(1.0, 0.0)) / scale).x;
    float c2 = rand2((floor(smplpos) + vec2(0.0, 1.0)) / scale).x;
    float c3 = rand2((floor(smplpos) + vec2(1.0, 1.0)) / scale).x;

    vec2 a = fract(smplpos);
    return mix(
    mix(c0, c1, smoothstep(0.0, 1.0, a.x)),
    mix(c2, c3, smoothstep(0.0, 1.0, a.x)),
    smoothstep(0.0, 1.0, a.y));
    }

    void main(void)
    {
    vec2 pos = gl_FragCoord.xy / resolution.y;
    pos.x += time * 0.1;
    float color = 0.0;
    float s = 1.0;
    for(int i = 0; i < 8; i++)
    {
    color += softnoise(pos+vec2(i)*0.02, s * 4.0) / s / 2.0;
    s *= 2.0;
    }
    gl_FragColor = vec4(color);
    }
  `
// 設置物體的質材爲着色器質材
 let material = new ShaderMaterial({
        uniforms: uniforms,
        vertexShader: vertext,
        fragmentShader: fragment,
        transparent: true,
      })

複製代碼

5.光暈效果

因爲是模擬電影院,我想作一個投影儀,模擬投影儀射出的光線。ide

// 光暈效果必須設置alpha = true
 const renderer = this.renderer = new WebGLRenderer({alpha: true, antialias: true})

 let textureFlare = new TextureLoader().load('assets/image/lensflare0.png')
      let textureFlare3 = new TextureLoader().load('assets/image/lensflare3.png')
      let flareColor = new Color(0xffffff)
      let lensFlare = new LensFlare(textureFlare, 150, 0.0 , AdditiveBlending, flareColor)
      lensFlare.add(textureFlare3, 60, 0.6, AdditiveBlending);
      lensFlare.add(textureFlare3, 70, 0.7, AdditiveBlending);
      lensFlare.add(textureFlare3, 120, 0.9, AdditiveBlending);
      lensFlare.add(textureFlare3, 70, 1.0, AdditiveBlending);
      lensFlare.position.set(0, 150, -85)
複製代碼
  • 主要的光線仍是靠lensflare0.png模擬
  • textureFlare3設置光暈的範圍

後記:

入門教程ui

原博客地址this

原創不易,辛苦各位大大點個starurl

源碼地址spa

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