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HTML

              
                <!-- 
Mousemove / TouchSwipe
Click / Tap to add stars / density

Boötes /boʊˈoʊtiːz/ 
One of the 48 constellations described by the 2nd century astronomer Ptolemy, Boötes is now one of the 88 modern constellations. It contains the fourth brightest star in the night sky, the orange-hued Arcturus. Boötes is home to many other bright stars, including eight above the fourth magnitude and an additional 21 above the fifth magnitude, making a total of 29 stars. 
!-->

<canvas id="canv"></canvas>


              
            
!

CSS

              
                html {
  height: 100%;
  background-image: radial-gradient(ellipse farthest-corner at center top, hsla(230, 100%, 15%, 1) 0%, hsla(231, 90%, 1%, 1) 100%);
  cursor: move;
}

body {
  width: 100%;
  margin: 0;
  overflow: hidden;
}
              
            
!

JS

              
                var num = 200;
var w = window.innerWidth;
var h = window.innerHeight;
var max = 100;
var _x = 0;
var _y = 0;
var _z = 150;
var dtr = function(d) {
  return d * Math.PI / 180;
};

var rnd = function() {
  return Math.sin(Math.floor(Math.random() * 360) * Math.PI / 180);
};
var dist = function(p1, p2, p3) {
  return Math.sqrt(Math.pow(p2.x - p1.x, 2) + Math.pow(p2.y - p1.y, 2) + Math.pow(p2.z - p1.z, 2));
};

var cam = {
  obj: { x: _x,y: _y, z: _z},
  dest: {x: 0, y: 0,z: 1},
  dist: {x: 0,y: 0,z: 200},
  ang: {cplane: 0,splane: 0,ctheta: 0,stheta: 0},
  zoom: 1,
  disp: {x: w / 2,y: h / 2,z: 0},
  upd: function() {
    cam.dist.x = cam.dest.x - cam.obj.x;
    cam.dist.y = cam.dest.y - cam.obj.y;
    cam.dist.z = cam.dest.z - cam.obj.z;
    cam.ang.cplane = -cam.dist.z / Math.sqrt(cam.dist.x * cam.dist.x + cam.dist.z * cam.dist.z);
    cam.ang.splane = cam.dist.x / Math.sqrt(cam.dist.x * cam.dist.x + cam.dist.z * cam.dist.z);
    cam.ang.ctheta = Math.sqrt(cam.dist.x * cam.dist.x + cam.dist.z * cam.dist.z) / Math.sqrt(cam.dist.x * cam.dist.x + cam.dist.y * cam.dist.y + cam.dist.z * cam.dist.z);
    cam.ang.stheta = -cam.dist.y / Math.sqrt(cam.dist.x * cam.dist.x + cam.dist.y * cam.dist.y + cam.dist.z * cam.dist.z);
  }
};

var trans = {
  parts: {
    sz: function(p, sz) {
      return {
        x: p.x * sz.x,
        y: p.y * sz.y,
        z: p.z * sz.z
      };
    },
    rot: {
      x: function(p, rot) {
        return {
          x: p.x,
          y: p.y * Math.cos(dtr(rot.x)) - p.z * Math.sin(dtr(rot.x)),
          z: p.y * Math.sin(dtr(rot.x)) + p.z * Math.cos(dtr(rot.x))
        };
      },
      y: function(p, rot) {
        return {
          x: p.x * Math.cos(dtr(rot.y)) + p.z * Math.sin(dtr(rot.y)),
          y: p.y,
          z: -p.x * Math.sin(dtr(rot.y)) + p.z * Math.cos(dtr(rot.y))
        };
      },
      z: function(p, rot) {
        return {
          x: p.x * Math.cos(dtr(rot.z)) - p.y * Math.sin(dtr(rot.z)),
          y: p.x * Math.sin(dtr(rot.z)) + p.y * Math.cos(dtr(rot.z)),
          z: p.z
        };
      }
    },
    pos: function(p, pos) {
      return {
        x: p.x + pos.x,
        y: p.y + pos.y,
        z: p.z + pos.z
      };
    }
  },
  pov: {
    plane: function(p) {
      return {
        x: p.x * cam.ang.cplane + p.z * cam.ang.splane,
        y: p.y,
        z: p.x * -cam.ang.splane + p.z * cam.ang.cplane
      };
    },
    theta: function(p) {
      return {
        x: p.x,
        y: p.y * cam.ang.ctheta - p.z * cam.ang.stheta,
        z: p.y * cam.ang.stheta + p.z * cam.ang.ctheta
      };
    },
    set: function(p) {
      return {
        x: p.x - cam.obj.x,
        y: p.y - cam.obj.y,
        z: p.z - cam.obj.z
      };
    }
  },
  persp: function(p) {
    return {
      x: p.x * cam.dist.z / p.z * cam.zoom,
      y: p.y * cam.dist.z / p.z * cam.zoom,
      z: p.z * cam.zoom,
      p: cam.dist.z / p.z
    };
  },
  disp: function(p, disp) {
    return {
      x: p.x + disp.x,
      y: -p.y + disp.y,
      z: p.z + disp.z,
      p: p.p
    };
  },
  steps: function(_obj_, sz, rot, pos, disp) {
    var _args = trans.parts.sz(_obj_, sz);
    _args = trans.parts.rot.x(_args, rot);
    _args = trans.parts.rot.y(_args, rot);
    _args = trans.parts.rot.z(_args, rot);
    _args = trans.parts.pos(_args, pos);
    _args = trans.pov.plane(_args);
    _args = trans.pov.theta(_args);
    _args = trans.pov.set(_args);
    _args = trans.persp(_args);
    _args = trans.disp(_args, disp);
    return _args;
  }
};

(function() {
  "use strict";
  var threeD = function(param) {
    this.transIn = {};
    this.transOut = {};
    this.transIn.vtx = (param.vtx);
    this.transIn.sz = (param.sz);
    this.transIn.rot = (param.rot);
    this.transIn.pos = (param.pos);
  };

  threeD.prototype.vupd = function() {
    this.transOut = trans.steps(
      this.transIn.vtx,
      this.transIn.sz,
      this.transIn.rot,
      this.transIn.pos,
      cam.disp
    );
  };

  var Build = function() {
    this.vel = 0.04;
    this.lim = 360;
    this.diff = 200;
    this.initPos = 100;
    this.toX = _x;
    this.toY = _y;
    this.go();
  };

  Build.prototype.go = function() {
    this.canvas = document.getElementById("canv");
    this.canvas.width = window.innerWidth;
    this.canvas.height = window.innerHeight;
    this.$ = canv.getContext("2d");
    this.$.globalCompositeOperation = 'source-over';
    this.varr = [];
    this.dist = [];
    this.calc = [];

    for (var i = 0, len = num; i < len; i++) {
      this.add();
    }

    this.rotObj = {x: 0,y: 0,z: 0};
    this.objSz = {x: w / 5,y: h / 5,z: w / 5};
  };

  Build.prototype.add = function() {
    this.varr.push(new threeD({
      vtx: {x: rnd(),y: rnd(),z: rnd()},
      sz: {x: 0,y: 0,z: 0},
      rot: {x: 20,y: -20,z: 0},
      pos: {
        x: this.diff * Math.sin(360 * Math.random() * Math.PI / 180),
        y: this.diff * Math.sin(360 * Math.random() * Math.PI / 180),
        z: this.diff * Math.sin(360 * Math.random() * Math.PI / 180)
      }
    }));
    this.calc.push({
      x: 360 * Math.random(),
      y: 360 * Math.random(),
      z: 360 * Math.random()
    });
  };

  Build.prototype.upd = function() {
    cam.obj.x += (this.toX - cam.obj.x) * 0.05;
    cam.obj.y += (this.toY - cam.obj.y) * 0.05;
  };

  Build.prototype.draw = function() {
    this.$.clearRect(0, 0, this.canvas.width, this.canvas.height);
    cam.upd();
    this.rotObj.x += 0.1;
    this.rotObj.y += 0.1;
    this.rotObj.z += 0.1;

    for (var i = 0; i < this.varr.length; i++) {
      for (var val in this.calc[i]) {
        if (this.calc[i].hasOwnProperty(val)) {
          this.calc[i][val] += this.vel;
          if (this.calc[i][val] > this.lim) this.calc[i][val] = 0;
        }
      }

      this.varr[i].transIn.pos = {
        x: this.diff * Math.cos(this.calc[i].x * Math.PI / 180),
        y: this.diff * Math.sin(this.calc[i].y * Math.PI / 180),
        z: this.diff * Math.sin(this.calc[i].z * Math.PI / 180)
      };
      this.varr[i].transIn.rot = this.rotObj;
      this.varr[i].transIn.sz = this.objSz;
      this.varr[i].vupd();
      if (this.varr[i].transOut.p < 0) continue;
      var g = this.$.createRadialGradient(this.varr[i].transOut.x, this.varr[i].transOut.y, this.varr[i].transOut.p, this.varr[i].transOut.x, this.varr[i].transOut.y, this.varr[i].transOut.p*2);
      this.$.globalCompositeOperation = 'lighter';
       g.addColorStop(0, 'hsla(255, 255%, 255%, 1)');
        g.addColorStop(.5, 'hsla('+(i+2)+',85%, 40%,1)');
        g.addColorStop(1,'hsla('+(i)+',85%, 40%,.5)');
        this.$.fillStyle = g;
      this.$.beginPath();
      this.$.arc(this.varr[i].transOut.x, this.varr[i].transOut.y, this.varr[i].transOut.p * 2, 0, Math.PI * 2, false);
      this.$.fill();
      this.$.closePath();
    }
  };
  Build.prototype.anim = function() {
    window.requestAnimationFrame = (function() {
      return window.requestAnimationFrame ||
        function(callback, element) {
        window.setTimeout(callback, 1000 / 60);
      };
    })();
    var anim = function() {
      this.upd();
      this.draw();
      window.requestAnimationFrame(anim);
    }.bind(this);
    window.requestAnimationFrame(anim);
  };

  Build.prototype.run = function() {
    this.anim();

    window.addEventListener('mousemove', function(e) {
      this.toX = (e.clientX - this.canvas.width / 2) * -0.8;
      this.toY = (e.clientY - this.canvas.height / 2) * 0.8;
    }.bind(this));
    window.addEventListener('touchmove',function(e){
      e.preventDefault();
      this.toX = (e.touches[0].clientX - this.canvas.width / 2) * -0.8;
      this.toY = (e.touches[0].clientY - this.canvas.height / 2) * 0.8;
    }.bind(this));
    window.addEventListener('mousedown', function(e) {
      for (var i = 0; i < 100; i++) {
        this.add();
      }
    }.bind(this));
    window.addEventListener('touchstart', function(e) {
      e.preventDefault();
      for (var i = 0; i < 100; i++) {
        this.add();
      }
    }.bind(this));
  };
  var app = new Build();
  app.run();
})();
window.addEventListener('resize',function(){
 canvas.width = w = window.innerWidth;
 canvas.height = h = window.innerHeight;
}, false);
              
            
!
999px

Console