lesson16/ObjToJSON.html

<html>
<head>
<script type="text/javascript">
/**
 * This code was adapted from the Apple-developed WebGL demo at
 * https://www.khronos.org/registry/webgl/sdk/demos/webkit/TeapotPerVertex.html
 * Copyright as below.
 */

/*
 * Copyright (C) 2009 Apple Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


function loadObj(url)
{
    var req = new XMLHttpRequest();
    req.onreadystatechange = function () { processLoadObj(req) };
    req.open("GET", url, true);
    req.send(null);
}

function processLoadObj(req)
{
    if (req.readyState == 4) {
        doLoadObj(req.responseText);
    }
}

function doLoadObj(text)
{
    vertexArray = [ ];
    normalArray = [ ];
    textureArray = [ ];
    indexArray = [ ];

    var vertex = [ ];
    var normal = [ ];
    var texture = [ ];
    var facemap = { };
    var index = 0;

    var lines = text.split("\n");
    for (var lineIndex in lines) {
        var line = lines[lineIndex].replace(/[ \t]+/g, " ").replace(/\s\s*$/, "");

        // ignore comments
        if (line[0] == "#")
            continue;

        var array = line.split(" ");
        if (array[0] == "v") {
            // vertex
            vertex.push(parseFloat(array[1]));
            vertex.push(parseFloat(array[2]));
            vertex.push(parseFloat(array[3]));
        }
        else if (array[0] == "vt") {
            // normal
            texture.push(parseFloat(array[1]));
            texture.push(parseFloat(array[2]));
        }
        else if (array[0] == "vn") {
            // normal
            normal.push(parseFloat(array[1]));
            normal.push(parseFloat(array[2]));
            normal.push(parseFloat(array[3]));
        }
        else if (array[0] == "f") {
            // face
            if (array.length != 4) {
                //obj.ctx.console.log("*** Error: face '"+line+"' not handled");
                continue;
            }

            for (var i = 1; i < 4; ++i) {
                if (!(array[i] in facemap)) {
                    // add a new entry to the map and arrays
                    var f = array[i].split("/");
                    var vtx, nor, tex;

                    if (f.length == 1) {
                        vtx = parseInt(f[0]) - 1;
                        nor = vtx;
                        tex = vtx;
                    }
                    else if (f.length = 3) {
                        vtx = parseInt(f[0]) - 1;
                        tex = parseInt(f[1]) - 1;
                        nor = parseInt(f[2]) - 1;
                    }
                    else {
                        //obj.ctx.console.log("*** Error: did not understand face '"+array[i]+"'");
                        return null;
                    }

                    // do the vertices
                    var x = 0;
                    var y = 0;
                    var z = 0;
                    if (vtx * 3 + 2 < vertex.length) {
                        x = vertex[vtx*3];
                        y = vertex[vtx*3+1];
                        z = vertex[vtx*3+2];
                    }
                    vertexArray.push(x);
                    vertexArray.push(y);
                    vertexArray.push(z);

                    // do the textures
                    x = 0;
                    y = 0;
                    if (tex * 2 + 1 < texture.length) {
                        x = texture[tex*2];
                        y = texture[tex*2+1];
                    }
                    textureArray.push(x);
                    textureArray.push(y);

                    // do the normals
                    x = 0;
                    y = 0;
                    z = 1;
                    if (nor * 3 + 2 < normal.length) {
                        x = normal[nor*3];
                        y = normal[nor*3+1];
                        z = normal[nor*3+2];
                    }
                    normalArray.push(x);
                    normalArray.push(y);
                    normalArray.push(z);

                    facemap[array[i]] = index++;
                }

                indexArray.push(facemap[array[i]]);
            }
        }
    }

    result = {};
    result["vertexPositions"] = vertexArray;
    result["vertexNormals"] = normalArray;
    result["vertexTextureCoords"] = textureArray;
    result["indices"] = indexArray;;


    document.write(JSON.stringify(result));

}
</script>
</head>


<body onload="loadObj('macbook.obj');">
</body>

</html>