function warp_to {
    parameter timestamp.
    
    KUNIVERSE:TIMEWARP:WARPTO(timestamp).  // TODO: improve.
    // wait until TIME >= timestamp. // TODO
}

function warp_for {
    parameter seconds.
    return warp_to(TIME:SECONDS + seconds).
}


function stage_when_ready {
    wait until STAGE:READY.
    print "STAGING".
    STAGE.
}


function isp_sum {
    local sum is 0.
    list ENGINES in engines_list.
    for engine in engines_list {
        if engine:STAGE = STAGE:NUMBER set sum to sum + engine:VACUUMISP.
    }
    return sum.
}


function any_flameout {
    list ENGINES in engines_list.
    for engine in engines_list {
        if engine:FLAMEOUT return true.
    }
    return false.
}


function round_towards_zero {
    parameter n.
    
    if n < 0 return CEILING(n).
    return FLOOR(n).
}


function orbital_velocity {
    // Calculate the required velocity to acheive orbit at the provided altitude.
    // https://en.wikipedia.org/wiki/Orbital_speed#Mean_orbital_speed
    // http://www.orbiterwiki.org/wiki/Front_Cover_Equations
    parameter altitude.
    
    return SQRT(BODY:MU / (BODY:RADIUS + altitude)).  // BODY:MU = CONSTANT:G * BODY:MASS
}



function unlock_control {
    // Ensure that the throttle will be 0 when execution stops
    set SHIP:CONTROL:PILOTMAINTHROTTLE to 0.
    
    // Ensure that the player is not locked out of control.
    set SHIP:CONTROL:NEUTRALIZE to true.
    unlock STEERING.
    unlock THROTTLE.
}


function disable_engine_gimbal {
    // Disable engine gimbal when engine is off
    on (THROTTLE = 0) {
        list ENGINES in engines_list.
        for engine in engines_list {
            if engine:HASGIMBAL set engine:GIMBAL:LOCK to (not THROTTLE).
        }
        return true.  // preserve trigger
    }
}