Plask OBJ Loader

obj.js

// Based on Dean McNamee's OBJ loader
// Modified to output triangles with texture coords

function loadOBJ(filename){
    var filedata = fs.readFileSync(filename, 'utf8');

    var lines = filedata.split('\n');

    var tris = [ ];
    var v = [ null, ];  // Verts, indexed from 1, so put in a filler.
    var vt = [ null, ];  // Texture Coords, indexed from 1, so put in a filler.
    var vn = [ null, ];  // Normals, indexed from 1, so put in a filler.

    function splitFaceIndices(str) {
        var pieces = str.split('/');
        var obj = { v:  parseInt(pieces[0]),
                    vt: parseInt(pieces[1]),
                    vn: parseInt(pieces[2]) };
        return obj;
    }

    for (var k = 0, kl = lines.length; k < kl; ++k) {
        var line = lines[k].trim();
        if (line.length === 0 || line.substr(0, 1) === "#")
            continue;

        var pieces = line.split(/\s+/);
        switch (pieces[0]) {
            case 'v':
                v.push({ x: parseFloat(pieces[1]),
                         y: parseFloat(pieces[2]),
                         z: parseFloat(pieces[3]) });
                break;
            case 'vn':
                vn.push({ x: parseFloat(pieces[1]),
                          y: parseFloat(pieces[2]),
                          z: parseFloat(pieces[3]) });
                break;
            case 'vt':
                vt.push({ x: parseFloat(pieces[1]),
                          y: parseFloat(pieces[2]) });
                break;  // Ignore texture coordinates.
            case 'f':
                var inds1 = splitFaceIndices(pieces[1]);
                var indsi1 = splitFaceIndices(pieces[2]);
                // We triangle all faces.  This keeps the vertes ordering, always
                // creating a triangle from the first vertex together with the next
                // and previous vertex (indsi and indsi1).
                for (var i = 3, il = pieces.length; i < il; ++i) {
                    var indsi = splitFaceIndices(pieces[i]);
                    tris.push([
                        { v:  new plask.Vec3(v[inds1.v].x, v[inds1.v].y, v[inds1.v].z),
                          vn: new plask.Vec3(vn[inds1.vn].x, vn[inds1.vn].y, vn[inds1.vn].z),
                          vt: new plask.Vec2(vt[inds1.vt].x, vt[inds1.vt].y) },
                        { v:  new plask.Vec3(v[indsi1.v].x, v[indsi1.v].y, v[indsi1.v].z),
                          vn: new plask.Vec3(vn[indsi1.vn].x, vn[indsi1.vn].y, vn[indsi1.vn].z),
                          vt: new plask.Vec2(vt[indsi1.vt].x, vt[indsi1.vt].y) },
                        { v:  new plask.Vec3(v[indsi.v].x, v[indsi.v].y, v[indsi.v].z),
                          vn: new plask.Vec3(vn[indsi.vn].x, vn[indsi.vn].y, vn[indsi.vn].z),
                          vt: new plask.Vec2(vt[indsi.vt].x, vt[indsi.vt].y) }
                    ]);
                    indsi1 = indsi;
                }
                break;
            default:
                console.log('Unknown command: ' + pieces[0]);
                break;
        }
    }

    return tris;
}