Hello all,
I was experimenting with the learningwebgl tuts and was trying to load a json file and draw it on the screen
I have a json file named cube.json in the directory where i have stored my index.html
the json have been converted from the obj of a plane.
I cant seem to load the json and draw it. I dont knwo where i am doing wrong, please somebody help me

this is the json file

{
"objectName" : ["Plane"],
"texturePath" : ["(null)"],
"vertexPositions" : [1.000000,0.000000,-1.000000,1.000000,0.000000,1.000000,-1.000000,0.000000,1.000000,-1.000000,0.000000,-1.000000],
"vertexTextureCoords" : [],
"indices" : [0,3,2,1],
"texIndices" : []
}


and my index.html is

<html>

<head>
<title>Learning WebGL &mdash; lesson 1</title>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

<script type="text/javascript" src="glMatrix-0.9.5.min.js"></script>

<script id="shader-fs" type="x-shader/x-fragment">
#ifdef GL_ES
precision highp float;
#endif

void main(void) {
gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
}
</script>

<script id="shader-vs" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;

uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;

void main(void) {
gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
}
</script>


<script type="text/javascript">

var gl;
function initGL(canvas) {
try {
gl = canvas.getContext("experimental-webgl");
gl.viewportWidth = canvas.width;
gl.viewportHeight = canvas.height;
} catch (e) {
}
if (!gl) {
alert("Could not initialise WebGL, sorry ");
}
}


function getShader(gl, id) {
var shaderScript = document.getElementById(id);
if (!shaderScript) {
return null;
}

var str = "";
var k = shaderScript.firstChild;
while (k) {
if (k.nodeType == 3) {
str += k.textContent;
}
k = k.nextSibling;
}

var shader;
if (shaderScript.type == "x-shader/x-fragment") {
shader = gl.createShader(gl.FRAGMENT_SHADER);
} else if (shaderScript.type == "x-shader/x-vertex") {
shader = gl.createShader(gl.VERTEX_SHADER);
} else {
return null;
}

gl.shaderSource(shader, str);
gl.compileShader(shader);

if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
alert(gl.getShaderInfoLog(shader));
return null;
}

return shader;
}


var shaderProgram;

function initShaders() {
var fragmentShader = getShader(gl, "shader-fs");
var vertexShader = getShader(gl, "shader-vs");

shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vertexShader);
gl.attachShader(shaderProgram, fragmentShader);
gl.linkProgram(shaderProgram);

if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
alert("Could not initialise shaders");
}

gl.useProgram(shaderProgram);

shaderProgram.vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
gl.enableVertexAttribArray(shaderProgram.vertexPos itionAttribute);

shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
}


var mvMatrix = mat4.create();
var pMatrix = mat4.create();

function setMatrixUniforms() {
gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, pMatrix);
gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, mvMatrix);
}



var triangleVertexPositionBuffer;
var squareVertexPositionBuffer;

function initBuffers() {
triangleVertexPositionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, triangleVertexPositionBuffer);
var vertices = [
0.0, 1.0, 0.0,
-1.0, -1.0, 0.0,
1.0, -1.0, 0.0
];
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
triangleVertexPositionBuffer.itemSize = 3;
triangleVertexPositionBuffer.numItems = 3;

squareVertexPositionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexPositionBuffer);
vertices = [
1.0, 1.0, 0.0,
-1.0, 1.0, 0.0,
1.0, -1.0, 0.0,
-1.0, -1.0, 0.0
];
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
squareVertexPositionBuffer.itemSize = 3;
squareVertexPositionBuffer.numItems = 4;
}

var cubeVertexPositionBuffer;

function handlecube(Data) {
cubeVertexPositionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexPositionBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(Data.vertexPositions), gl.STATIC_DRAW);
cubeVertexPositionBuffer.itemSize = 3;
cubeVertexPositionBuffer.numItems = Data.vertexPositions.length / 3;

document.getElementById("loadingtext").textContent = "";
}


function loadTeapot() {
var request = new XMLHttpRequest();
request.open("GET", "cube.json");
request.onreadystatechange = function () {
if (request.readyState == 4) {
handlecube(JSON.parse(request.responseText));
}
}
request.send();
}

function drawScene() {
gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

mat4.perspective(45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0, pMatrix);

mat4.identity(mvMatrix);

mat4.translate(mvMatrix, [-1.5, 0.0, -7.0]);
gl.bindBuffer(gl.ARRAY_BUFFER, triangleVertexPositionBuffer);
gl.vertexAttribPointer(shaderProgram.vertexPositio nAttribute, triangleVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
setMatrixUniforms();
gl.drawArrays(gl.TRIANGLES, 0, triangleVertexPositionBuffer.numItems);


mat4.translate(mvMatrix, [3.0, 0.0, 0.0]);
gl.bindBuffer(gl.ARRAY_BUFFER, squareVertexPositionBuffer);
gl.vertexAttribPointer(shaderProgram.vertexPositio nAttribute, squareVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
setMatrixUniforms();
gl.drawArrays(gl.TRIANGLE_STRIP, 0, squareVertexPositionBuffer.numItems);

mat4.translate(mvMatrix, [2.0, 0.0, 0.0]);
gl.bindBuffer(gl.ARRAY_BUFFER, cubeVertexPositionBuffer);
gl.vertexAttribPointer(shaderProgram.vertexPositio nAttribute, cubeVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
setMatrixUniforms();
gl.drawArrays(gl.TRIANGLES, cubeVertexPositionBuffer.numItems, gl.UNSIGNED_SHORT, 0);
}



function webGLStart() {
var canvas = document.getElementById("lesson01-canvas");
initGL(canvas);
initShaders();
initBuffers();
loadTeapot();

gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.enable(gl.DEPTH_TEST);

drawScene();
}


</script>


</head>


<body onload="webGLStart();">
&lt;&lt; Back to Lesson 1


<canvas id="lesson01-canvas" style="border: none;" width="500" height="500"></canvas>



&lt;&lt; Back to Lesson 1

</body>

</html>