function ortho(out, left, right, bottom, top, near, far) {
    var lr = 1 / (left - right),
        bt = 1 / (bottom - top),
        nf = 1 / (near - far);
    out[0] = -2 * lr;
    out[1] = 0;
    out[2] = 0;
    out[3] = 0;
    out[4] = 0;
    out[5] = -2 * bt;
    out[6] = 0;
    out[7] = 0;
    out[8] = 0;
    out[9] = 0;
    out[10] = 2 * nf;
    out[11] = 0;
    out[12] = (left + right) * lr;
    out[13] = (top + bottom) * bt;
    out[14] = (far + near) * nf;
    out[15] = 1;
    return out;
}
Generates a orthogonal projection matrix with the given bounds

@param {mat4} out mat4 frustum matrix will be written into
@param {number} left Left bound of the frustum
@param {number} right Right bound of the frustum
@param {number} bottom Bottom bound of the frustum
@param {number} top Top bound of the frustum
@param {number} near Near bound of the frustum
@param {number} far Far bound of the frustum
@returns {mat4} out