section.js

var GearUVGenerator = {

	generateTopUV: function ( geometry, vertices, indexA, indexB, indexC ) {
    function getUV() {
      var s = 0.3;
      return new THREE.Vector2( 0.5+s*vertices[i*3], 0.5+s*vertices[i*3+1] );
    }


		return [ getUV(indexA), getUV(indexB), getUV(indexC) ];

	},

	generateSideWallUV: function ( geometry, vertices, indexA, indexB, indexC, indexD ) {
			return [
				new THREE.Vector2( 0,0.5 ),
				new THREE.Vector2( 0,0.5 ),
				new THREE.Vector2( 1,0.5 ),
				new THREE.Vector2( 1,0.5 )
			];

	}
};


var boxgeometry = new THREE.BoxBufferGeometry( 1, 1, 1);
var geargeometry;
{
  var shape = new THREE.Shape();
  var s = 1.5;
  var ss = 0.2;
  for (var i=0;i<=Math.PI*2;i+=0.05) {
    var t = s + ss*Math.sin(i*16);
    if (i==0) shape.moveTo(Math.sin(i)*t, Math.cos(i)*t);
    else shape.lineTo(Math.sin(i)*t, Math.cos(i)*t);
  }
  geargeometry = new THREE.ExtrudeGeometry(shape, {
    steps: 1,
    depth: 0.5,
    bevelEnabled: false,
    UVGenerator : GearUVGenerator
  });
}


function Section(forceSection) {
  var section = this;
  this.group = new THREE.Object3D();
  this.tweens = [];

  var tweener = function() {
    var mesh = this;
    var p = {
      x: mesh.position.x,
      y: mesh.position.y,
      z: mesh.position.z,
      rx: mesh.rotation.x,
      ry: mesh.rotation.y,
      rz: mesh.rotation.z,
    };
    var t = new TWEEN.Tween(p);
    t.onUpdate(function(){
      mesh.position.x = p.x;
      mesh.position.y = p.y;
      mesh.position.z = p.z;
      mesh.rotation.x = Math.PI*p.rx*2;
      mesh.rotation.y = Math.PI*p.ry*2;
      mesh.rotation.z = Math.PI*p.rz*2;
    });
    section.tweens.push(t);
    return t;
  };

  this.box = function(x,y,z) {
    var mesh = new THREE.Mesh( boxgeometry, materials.sq );
    mesh.position.x = x;
    mesh.position.y = y;
    mesh.position.z = z;
    this.group.add( mesh );
    mesh.tween = tweener;
    return mesh;
  };
  this.gear = function(x,y,z,r) {
    var mesh = new THREE.Mesh( geargeometry, materials.circ );
    mesh.position.x = x;
    mesh.position.y = y;
    mesh.position.z = z;
    this.group.add( mesh );
    mesh.tween = tweener;
    return mesh;
  };

  this.sectionLength = 4;

  var wallgeometry = new THREE.Geometry();
  var uva = [
    new THREE.Vector2(0, 0),
    new THREE.Vector2(1, 0),
    new THREE.Vector2(1, 1)
  ];
  var uvb = [
    new THREE.Vector2(0, 0),
    new THREE.Vector2(1, 1),
    new THREE.Vector2(0, 1)
  ];
  function pushFace(x,y,z, dx,dy) {
    dx*=0.5;
    dy*=0.5;
    var b = wallgeometry.vertices.length;
    wallgeometry.vertices.push(
      new THREE.Vector3( x-dx, y-dy, z - 0.5 ),
      new THREE.Vector3( x+dx, y+dy, z - 0.5),
      new THREE.Vector3( x+dx, y+dy, z + 0.5 ),
      new THREE.Vector3( x-dx, y-dy, z + 0.5 )
    );
    wallgeometry.vertices.push(
      new THREE.Vector3( x-dx, y-dy, z - 0.5 ),
      new THREE.Vector3( x+dx, y+dy, z - 0.5),
      new THREE.Vector3( x+dx, y+dy, z + 0.5 ),
      new THREE.Vector3( x-dx, y-dy, z + 0.5 )
    );
    wallgeometry.faces.push(
        new THREE.Face3( b+0, b+1, b+2 ),
        new THREE.Face3( b+0, b+2, b+3 ) );
    wallgeometry.faceVertexUvs[0].push(uva, uvb);
  }

  for (var z=0.5;z<this.sectionLength;z+=1) {
    pushFace(-1, 0.5,z, 0,1);
    pushFace(-1,-0.5,z, 0,1);
    pushFace( 1, 0.5,z, 0,-1);
    pushFace( 1,-0.5,z, 0,-1);

    pushFace( 0.5,-1,z, -1,0);
    pushFace(-0.5,-1,z, -1,0);
    pushFace( 0.5, 1,z, 1,0);
    pushFace(-0.5, 1,z, 1,0);
  }
  var mesh = new THREE.Mesh( wallgeometry, materials.sq );
  this.group.add( mesh );

  var r = Math.floor(Math.random()*12);
  if (forceSection!==undefined) r=forceSection;
  var r2 = Math.floor(Math.random()*4);
  var sidex = (r2&1)?1:-1;
  var sidey = (r2&2)?1:-1;
  var rotate = Math.random()>0.5;
  // shift forwards and backwards by 1
  var z = 1.5+Math.floor(Math.random()*3);

  switch (r) {
    case 0: // breathe...
            break;
    case 1: this.box(1.5*sidex, 1.5*sidey, z).tween().to({rz:rotate?0.5:0, x:0.5*sidex, y:0.5*sidey}, 1000);
            break;
    case 2: this.box(0.5*sidex+rotate, 0.5*sidey+!rotate, z).tween().to({x:0.5*sidex, y:0.5*sidey}, 1000);
            break;
    case 3: this.box(0.5*sidex, 0.5*sidey, z);
            break;
    case 4: this.box(1.5*sidex,-0.5,z).tween().to({x:0.5*sidex, ry:rotate?1:0}, 1000);
            this.box(1.5*sidex,0.5,z).tween().to({x:0.5*sidex, ry:rotate?1:0}, 1000);
            break;
    case 5: this.box(0.5,1.5*sidey,z).tween().to({y:0.5*sidex, rx:rotate?1:0}, 1000);
            this.box(-0.5,1.5*sidex,z).tween().to({y:0.5*sidex, rx:rotate?1:0}, 1000);
            break;
    case 6: this.box(0.5*sidex, 0.5*sidey, z);
            this.box(-0.5*sidex, 0.5*sidey, z);
            break;
    case 7: this.box(0.5*sidex, -0.5*sidey, z);
            this.box(-0.5*sidex, 0.5*sidey, z);
            break;
    case 8: this.box(0.5*sidex, 0.5*sidey, z);
            this.box(0.5*sidex, -0.5*sidey, z);
            break;
    case 9: this.box(0.5*sidex, 0.5*sidey, z);
            this.box(-0.5*sidex, 0.5*sidey, z);
            this.box(0.5*sidex, -0.5*sidey, z);
            break;
    case 10: this.gear(sidex, sidey, z).tween().to({rz:100}, 1000*1000);
            break;
    case 11: this.gear(1.5*sidex*rotate, 1.5*sidey*!rotate, z).tween().to({rz:100}, 1000*1000);
            break;
    //
    //this.box(1.5,0.5,3.5).tween().to({x:0.5, ry:1}, 1000);
  }


}

Section.prototype.start = function() {
  this.tweens.forEach(function(t) { t.start(); });
};