function Node(position, rotation, geometry)

 {

     this.pos = position;

     this.rot = rotation;

     this.geometry = geometry;

     this.children = [];

 }

 Node.prototype.update = function(time)

 {

     // this.right = [1, 0, 0];

     // this.up = [0, 1, 0];

     // this.target = [0, 0, -1];

     // var x = vec3.dot([1, 0, 0], this.pos);

     // var y = vec3.dot([0, 1, 0], this.pos);

     // var z = vec3.dot([0, 0, -1], this.pos);

     // this.matrix = mat4.create([this.right[0], this.up[0], -this.target[0], 0,

     //  			       this.right[1], this.up[1], -this.target[1], 0,

     //  			       this.right[2], this.up[2], -this.target[2], 0,

     //  			       -x, -y, z, 1]); 

     for (var id in this.children) this.children[id].update(time);

 }

 function CubeVbo(size, context, texture)

 {

     var gl = context.gl;

     this.texture = texture;

     this.useTexture = texture;

     this.size = size || 1;    

     this.positionBuffer = gl.createBuffer();

     gl.bindBuffer(gl.ARRAY_BUFFER, this.positionBuffer);

     var vertices = [

 	     // Front face

             -1.0, -1.0,  1.0,

              1.0, -1.0,  1.0,

              1.0,  1.0,  1.0,

             -1.0,  1.0,  1.0,

             // Back face

             -1.0, -1.0, -1.0,

             -1.0,  1.0, -1.0,

              1.0,  1.0, -1.0,

              1.0, -1.0, -1.0,

             // Top face

             -1.0,  1.0, -1.0,

             -1.0,  1.0,  1.0,

              1.0,  1.0,  1.0,

              1.0,  1.0, -1.0,

             // Bottom face

             -1.0, -1.0, -1.0,

              1.0, -1.0, -1.0,

              1.0, -1.0,  1.0,

             -1.0, -1.0,  1.0,

             // Right face

              1.0, -1.0, -1.0,

              1.0,  1.0, -1.0,

              1.0,  1.0,  1.0,

              1.0, -1.0,  1.0,

             // Left face

             -1.0, -1.0, -1.0,

             -1.0, -1.0,  1.0,

             -1.0,  1.0,  1.0,

             -1.0,  1.0, -1.0];

     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);

     this.positionBuffer.itemSize = 3;

     this.positionBuffer.numItems = 24;

     this.normalBuffer = gl.createBuffer();

     gl.bindBuffer(gl.ARRAY_BUFFER, this.normalBuffer);

     var normals = [// font face

 		   0.0, 0.0, 1.0,

 		   0.0, 0.0, 1.0,

 		   0.0, 0.0, 1.0,

 		   0.0, 0.0, 1.0,

 		   // back face

 		   0.0, 0.0, -1.0,

 		   0.0, 0.0, -1.0,

 		   0.0, 0.0, -1.0,

 		   0.0, 0.0, -1.0,

 		   // top face

 		   0.0, 1.0, 0.0,

 		   0.0, 1.0, 0.0,

 		   0.0, 1.0, 0.0, 

 		   0.0, 1.0, 0.0,

 		   // bottom face

 		   0.0, -1.0, 0.0,

 		   0.0, -1.0, 0.0,

 		   0.0, -1.0, 0.0,

 		   0.0, -1.0, 0.0,

 		   // right face

 		   1.0, 0.0, 0.0,

 		   1.0, 0.0, 0.0,

 		   1.0, 0.0, 0.0,

 		   1.0, 0.0, 0.0,

 		   // left face

 		   -1.0, 0.0, 0.0,

 		   -1.0, 0.0, 0.0,

 		   -1.0, 0.0, 0.0,

 		   -1.0, 0.0, 0.0];

     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(normals), gl.STATIC_DRAW);

     this.normalBuffer.itemSize = 3;

     this.normalBuffer.numItems = 24;

     //if (this.texture)

     //{

 	this.textureCoordBuffer = gl.createBuffer();

 	gl.bindBuffer(gl.ARRAY_BUFFER, this.textureCoordBuffer);

 	var textureCoords = [// front face

 	    0.0, 0.0,

 	    1.0, 0.0,

 	    1.0, 1.0,

 	    0.0, 1.0,

 	    //back face

 	    1.0, 0.0,

 	    1.0, 1.0,

 	    0.0, 1.0,

 	    0.0, 0.0,

 	    // top face

 	    0.0, 1.0,

 	    0.0, 0.0,

 	    1.0, 0.0,

 	    1.0, 1.0,

 	    // bottom face

 	    1.0, 1.0,

 	    0.0, 1.0,

 	    0.0, 0.0,

 	    1.0, 0.0,

 	    // right face

 	    1.0, 0.0, 

 	    1.0, 1.0,

 	    0.0, 1.0,

 	    0.0, 0.0,

 	    // left face

 	    0.0, 0.0,

 	    1.0, 0.0,

 	    1.0, 1.0,

 	    0.0, 1.0];

 	gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(textureCoords), gl.STATIC_DRAW);

 	this.textureCoordBuffer.itemSize = 2;

 	this.textureCoordBuffer.numItems = 24;

     //}

     this.colourBuffer = gl.createBuffer();

     gl.bindBuffer(gl.ARRAY_BUFFER, this.colourBuffer);

     var alpha = 1.0;

     var uni = [1.0, 1.0, 1.0, alpha];

     var colours = [[0.0, 0.0, 0.0, alpha],

 		   [0.0, 0.0, 0.0, alpha],

 		   [0.0, 0.0, 0.0, alpha],

 		   [0.0, 0.0, 0.0, alpha],

 		   [0.0, 0.0, 0.0, alpha],

 		   [0.0, 0.0, 0.0, alpha]];

     var unpackedColours = [];

     for (var i in colours)

     {

 	var colour = uni;//colours[i];

 	for (var j = 0; j < 4; j++)

 	{

 	    unpackedColours = unpackedColours.concat(colour);

 	}

 	//colours = colours.concat([0.5, 0.5, 1.0, 1.0]);

     }

     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(unpackedColours), gl.STATIC_DRAW);

     this.colourBuffer.itemSize = 4;

     this.colourBuffer.numItems = 24;

     this.indexBuffer = gl.createBuffer();

     gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, this.indexBuffer);

     var indices = [0, 1, 2, 0, 2, 3,

 		   4, 5, 6, 4, 6, 7,

 		   8, 9, 10, 8, 10, 11,

 		   12, 13, 14, 12, 14, 15,

 		   16, 17, 18, 16, 18, 19,

 		   20, 21, 22, 20, 22, 23];

     gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(indices), gl.STATIC_DRAW);

     this.indexBuffer.itemSize = 1;

     this.indexBuffer.numItems = 36;

 }

 var id = 0;

 function Cube(vbo)

 {

     this.id = id++;

     this.vbo = vbo;

 }