Question

I am trying to write a OBJMesh model reader and I’ve got the OBJMesh class setted up, but when I try to retrieve the stored data in the array by creating the OBJMesh object and call the get function, it doesn’t do it.

Here’s the code

OBJMesh.js

function OBJMesh(file)
{
    this.modelVertex = [];
    this.modelColor = [];
    this.init = false;

    var rawFile = new XMLHttpRequest();
    rawFile.open("GET", file, true);

    var objmesh = this;
    rawFile.onreadystatechange = function ()
    {

        if(rawFile.readyState == 4)
        {
            if(rawFile.status === 200 || rawFile.status === 0)
            {
                var allText = rawFile.responseText;
                var lines = allText.split("\n");


                for(var i = 0; i < lines.length; i ++)
                {
                    var lineData = lines[i];
                    var lineString = lineData.split(" ");

                    if(lineString[0] === "v")
                    {

                        var x = parseFloat(lineString[1]);
                        var y = parseFloat(lineString[2]);
                        var z = parseFloat(lineString[3]);

                        objmesh.modelVertex.push(x);
                        objmesh.modelVertex.push(y);
                        objmesh.modelVertex.push(z);

                        objmesh.modelColor.push(0.0);
                        objmesh.modelColor.push(0.0);
                        objmesh.modelColor.push(0.0);
                        objmesh.modelColor.push(1.0);

                        //document.getElementById("textSection").innerHTML = objmesh.modelVertex[0];
                    }
                }
            }
        }
        objmesh.init = true;
    }

    rawFile.send();
}

OBJMesh.prototype.getModelVertex = function ()
{
    return this.modelVertex;
};

OBJMesh.prototype.getModelColor = function ()
{
    return this.modelColor;
};

OBJMesh.prototype.getInit = function ()
{
    return this.init;
};

main.js

var cubeModel;

function main()
{
    cubeModel = new OBJMesh("file:///Users/DannyChen/Desktop/3DHTMLGame/cube.obj");

    while(cubeModel.getInit() === false)
    {
        //wait for it
    }

    var cubeVertex = cubeModel.getModelVertex();

    document.getElementById("textSection").innerHTML = cubeVertex[0];

}

it just keeps printing out “undefined”. Why’s that? and how can I fix it??

Answer 1

but it seems that onreadystatechange is an async-Call so,

this.init = true;

will be set before the function onreadystatechange is called.

May be you could set at the end of the onreadystatechange function

objmesh.init = true;

i hope this helps