蝴蝶飞舞（butterfly）

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示例

HTML

.p-summary
  h1 Butterfly
  p
    a(href="https://ykob.github.io/sketch-threejs/sketch/butterfly.html", target="_blank")
      |this source.

canvas(id="canvas-webgl", class="p-canvas-webgl")

CSS

@import url('https://fonts.googleapis.com/css?family=Homenaje');

.p-canvas-webgl {
  position: fixed;
  z-index: 1;
  top: 0; left: 0;
}

.p-summary {
  position: absolute;
  top: 20px; left: 20px;
  z-index: 2;
  color: #111;
  font-family: 'Homenaje', sans-serif;
  h1 {
    margin: 0 0 0.8em;
    font-size: 5px;
    font-weight: 400;
    letter-spacing: 0.05em;
  }
  p {
    margin: 0;
    font-size: 1.1rem;
    letter-spacing: 0.1em;
  }
  a {
    color: #1FFFF;
  }
}

JS

class ConsoleSignature {
  constructor() {
    this.message = `created by yoichi kobayashi`;
    this.url = `http://www.tplh.net`;
    this.show();
  }
  show() {
    if (navigator.userAgent.toLowerCase().indexOf('chrome') > -1) {
      const args = [
        `\n%c ${this.message} %c%c ${this.url} \n\n`,
        'color: #fff; background: #222; padding:3px 0;',
        'padding:3px 1px;',
        'color: #fff; background: #47c; padding:3px 0;',
      ];
      console.log.apply(console, args);
    } else if (window.console) {
      console.log(`${this.message} ${this.url}`);
    }
  }
}

const debounce = (callback, duration) => {
  var timer;
  return function(event) {
    clearTimeout(timer);
    timer = setTimeout(function(){
      callback(event);
    }, duration);
  };
};

const SIZE = 280;

class Butterfly {
  constructor(i, texture) {
    this.uniforms = {
      index: {
        type: 'f',
        value: i
      },
      time: {
        type: 'f',
        value: 0
      },
      size: {
        type: 'f',
        value: SIZE
      },
      texture: {
        type: 't',
        value: texture
      },
    }
    this.physicsRenderer = null;
    this.obj = this.createObj();
  }
  createObj() {
    const geometry = new THREE.PlaneBufferGeometry(SIZE, SIZE / 3, 48, 24);
    const mesh = new THREE.Mesh(
      geometry,
      new THREE.RawShaderMaterial({
        uniforms: this.uniforms,
        vertexShader: `attribute vec3 position;
attribute vec2 uv;

uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
uniform float index;
uniform float time;
uniform float size;

varying vec3 vPosition;
varying vec2 vUv;

void main() {
  float flapTime = radians(sin(time * 6.0 - length(position.xy) / size * 2.6 + index * 2.0) * 45.0 + 30.0);
  float hovering = cos(time * 2.0 + index * 3.0) * size / 16.0;
  vec3 updatePosition = vec3(
    cos(flapTime) * position.x,
    position.y + hovering,
    sin(flapTime) * abs(position.x) + hovering
  );

  vec4 mvPosition = modelViewMatrix * vec4(updatePosition, 1.0);

  vPosition = position;
  vUv = uv;

  gl_Position = projectionMatrix * mvPosition;
}
`,
        fragmentShader: `precision highp float;

uniform float index;
uniform float time;
uniform float size;
uniform sampler2D texture;

varying vec3 vPosition;
varying vec2 vUv;

//
// Description : Array and textureless GLSL 2D/3D/4D simplex
//               noise functions.
//      Author : Ian McEwan, Ashima Arts.
//  Maintainer : ijm
//     Lastmod : 20110822 (ijm)
//     License : Copyright (C) 2011 Ashima Arts. All rights reserved.
//               Distributed under the MIT License. See LICENSE file.
//               https://github.com/ashima/webgl-noise
//

vec3 mod289(vec3 x) {
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec4 mod289(vec4 x) {
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec4 permute(vec4 x) {
     return mod289(((x*34.0)+1.0)*x);
}

vec4 taylorInvSqrt(vec4 r)
{
  return 1.79284291400159 - 0.85373472095314 * r;
}

float snoise3(vec3 v)
  {
  const vec2  C = vec2(1.0/6.0, 1.0/3.0) ;
  const vec4  D = vec4(0.0, 0.5, 1.0, 2.0);

// First corner
  vec3 i  = floor(v + dot(v, C.yyy) );
  vec3 x0 =   v - i + dot(i, C.xxx) ;

// Other corners
  vec3 g = step(x0.yzx, x0.xyz);
  vec3 l = 1.0 - g;
  vec3 i1 = min( g.xyz, l.zxy );
  vec3 i2 = max( g.xyz, l.zxy );

  //   x0 = x0 - 0.0 + 0.0 * C.xxx;
  //   x1 = x0 - i1  + 1.0 * C.xxx;
  //   x2 = x0 - i2  + 2.0 * C.xxx;
  //   x3 = x0 - 1.0 + 3.0 * C.xxx;
  vec3 x1 = x0 - i1 + C.xxx;
  vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
  vec3 x3 = x0 - D.yyy;      // -1.0+3.0*C.x = -0.5 = -D.y

// Permutations
  i = mod289(i);
  vec4 p = permute( permute( permute(
             i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
           + i.y + vec4(0.0, i1.y, i2.y, 1.0 ))
           + i.x + vec4(0.0, i1.x, i2.x, 1.0 ));

// Gradients: 7x7 points over a square, mapped onto an octahedron.
// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
  float n_ = 0.142857142857; // 1.0/7.0
  vec3  ns = n_ * D.wyz - D.xzx;

  vec4 j = p - 49.0 * floor(p * ns.z * ns.z);  //  mod(p,7*7)

  vec4 x_ = floor(j * ns.z);
  vec4 y_ = floor(j - 7.0 * x_ );    // mod(j,N)

  vec4 x = x_ *ns.x + ns.yyyy;
  vec4 y = y_ *ns.x + ns.yyyy;
  vec4 h = 1.0 - abs(x) - abs(y);

  vec4 b0 = vec4( x.xy, y.xy );
  vec4 b1 = vec4( x.zw, y.zw );

  //vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0;
  //vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0;
  vec4 s0 = floor(b0)*2.0 + 1.0;
  vec4 s1 = floor(b1)*2.0 + 1.0;
  vec4 sh = -step(h, vec4(0.0));

  vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
  vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;

  vec3 p0 = vec3(a0.xy,h.x);
  vec3 p1 = vec3(a0.zw,h.y);
  vec3 p2 = vec3(a1.xy,h.z);
  vec3 p3 = vec3(a1.zw,h.w);

//Normalise gradients
  vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
  p0 *= norm.x;
  p1 *= norm.y;
  p2 *= norm.z;
  p3 *= norm.w;

// Mix final noise value
  vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
  m = m * m;
  return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1),
                                dot(p2,x2), dot(p3,x3) ) );
  }

vec3 convertHsvToRgb(vec3 c) {
  vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
  vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
  return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

void main() {
  vec4 texColor = texture2D(texture, vUv);

  float noise = snoise3(vPosition / vec3(size * 0.25) + vec3(0.0, 0.0, time));
  vec3 hsv = vec3(1.0 + noise * 0.2 + index * 0.7, 0.4, 1.0);
  vec3 rgb = convertHsvToRgb(hsv);

  gl_FragColor = vec4(rgb, 1.0) * texColor;
}`,
        depthWrite: false,
        side: THREE.DoubleSide,
        transparent: true
      })
    );
    mesh.rotation.set(-45 * Math.PI / 180, 0, 0);
    return mesh;
  }
  render(renderer, time) {
    this.uniforms.time.value += time;
    this.obj.position.z = (this.obj.position.z > -900) ? this.obj.position.z - 4 : 900;
  }
}

const resolution = {
  x: 0,
  y: 0
};
const canvas = document.getElementById('canvas-webgl');
const renderer = new THREE.WebGLRenderer({
  antialias: false,
  canvas: canvas,
});
const scene = new THREE.Scene();
const camera = new THREE.OrthographicCamera(-1, 1, 1, -1, 1, 10000);
const clock = new THREE.Clock();
const loader = new THREE.TextureLoader();

const vectorTouchStart = new THREE.Vector2();
const vectorTouchMove = new THREE.Vector2();
const vectorTouchEnd = new THREE.Vector2();

const CAMERA_SIZE_X = 640;
const CAMERA_SIZE_Y = 480;

const BUTTERFLY_NUM = 7;
const butterflies = [];

const resizeCamera = () => {
  const x = Math.min((resolution.x / resolution.y) / (CAMERA_SIZE_X / CAMERA_SIZE_Y), 1.0) * CAMERA_SIZE_X;
  const y = Math.min((resolution.y / resolution.x) / (CAMERA_SIZE_Y / CAMERA_SIZE_X), 1.0) * CAMERA_SIZE_Y;
  camera.left   = x * -0.5;
  camera.right  = x *  0.5;
  camera.top    = y *  0.5;
  camera.bottom = y * -0.5;
  camera.updateProjectionMatrix();
};
const resizeWindow = () => {
  resolution.x = window.innerWidth;
  resolution.y = window.innerHeight;
  canvas.width = resolution.x;
  canvas.height = resolution.y;
  resizeCamera();
  renderer.setSize(resolution.x, resolution.y);
}
const render = () => {
  const time = clock.getDelta();
  for (var i = 0; i < butterflies.length; i++) {
    butterflies[i].render(renderer, time);
  }
  renderer.render(scene, camera);
}
const renderLoop = () => {
  render();
  requestAnimationFrame(renderLoop);
}
const on = () => {
  window.addEventListener('resize', debounce(resizeWindow), 1000);
}

const init = () => {
  resizeWindow();
  on();

  renderer.setClearColor(0x1FFFF, 1.0);
  camera.position.set(250, 500, 1000);
  camera.lookAt(new THREE.Vector3());

  loader.crossOrigin = 'anonymous';  
  loader.load('http://ykob.github.io/sketch-threejs/img/sketch/butterfly/tex.png', (texture) => {
    texture.magFilter = THREE.NearestFilter;
    texture.minFilter = THREE.NearestFilter;

    for (var i = 0; i < BUTTERFLY_NUM; i++) {
      butterflies[i] = new Butterfly(i, texture);
      butterflies[i].obj.position.set(((i + 1) % 3 - 1) * i * 50, 0, 1800 / BUTTERFLY_NUM * i);
      scene.add(butterflies[i].obj);
    }
    renderLoop();
  });
}
init();

new ConsoleSignature();