Load Obj

from J3DI.js

function loadTeapot() {
        var request = new XMLHttpRequest();
        request.open("GET", "2.obj");
        hasBeenLoaded = false;
        request.onreadystatechange = function () {
            if (request.readyState == 4 && !hasBeenLoaded) {
                hasBeenLoaded = true;
                var chairObj = doLoadObj(request.responseText);
                handleLoadedTeapot(chairObj);
            }
        }
        request.send();
    }

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

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

        // This is a map which associates a range of indices with a name
        // The name comes from the 'g' tag (of the form "g NAME"). Indices
        // are part of one group until another 'g' tag is seen. If any indices
        // come before a 'g' tag, it is given the group name "_unnamed"
        // 'group' is an object whose property names are the group name and
        // whose value is a 2 element array with [, ]
        var groups = { };
        var currentGroup = [-1, 0];
        groups["_unnamed"] = currentGroup;

        var lines = obj.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] == "g") {
                // new group
                currentGroup = [indexArray.length, 0];
                groups[array[1]] = currentGroup;
            }
            else 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") {
                // texture
                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) {
                    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]]);
                    currentGroup[1]++;
                }
            }
        }
        var model={};
        model.vertexNormals = normalArray;
        model.vertexTextureCoords = textureArray;
        model.vertexPositions = vertexArray;
        model.indices = indexArray;
        return model;
    }