calculateTangents(vs, tc, ind) {
        var i = 0;
        var tangents = [];
        for (i = 0; i < vs.length / 3; i++)
            tangents[i] = [0, 0, 0];

        var a = [0, 0, 0], b = [0, 0, 0];
        var triTangent = [0, 0, 0];

        for (i = 0; i < ind.length; i += 3) {
            var i0 = ind[i];
            var i1 = ind[i + 1];
            var i2 = ind[i + 2];

            var pos0 = [vs[i0 * 3], vs[i0 * 3 + 1], vs[i0 * 3 + 2]];
            var pos1 = [vs[i1 * 3], vs[i1 * 3 + 1], vs[i1 * 3 + 2]];
            var pos2 = [vs[i2 * 3], vs[i2 * 3 + 1], vs[i2 * 3 + 2]];

            var tex0 = [tc[i0 * 2], tc[i0 * 2 + 1]];
            var tex1 = [tc[i1 * 2], tc[i1 * 2 + 1]];
            var tex2 = [tc[i2 * 2], tc[i2 * 2 + 1]];

            vec3.subtract(a, pos1, pos0);
            vec3.subtract(b, pos2, pos0);

            var c2c1t = tex1[0] - tex0[0];
            var c2c1b = tex1[1] - tex0[1];
            var c3c1t = tex2[0] - tex0[0];
            var c3c1b = tex2[0] - tex0[1];

            triTangent = [c3c1b * a[0] - c2c1b * b[0], c3c1b * a[1] - c2c1b * b[1], c3c1b * a[2] - c2c1b * b[2]];

            vec3.add(tangents[i0], tangents[i0], triTangent);
            vec3.add(tangents[i1], tangents[i1], triTangent);
            vec3.add(tangents[i2], tangents[i2], triTangent);
        }

        // Normalize tangents
        var ts = [];
        for (i = 0; i < tangents.length; i++) {
            var tan = tangents[i];
            vec3.normalize(tan, tan);
            ts.push(tan[0]);
            ts.push(tan[1]);
            ts.push(tan[2]);
        }

        return ts;
    }