Lots of changes everywhere.

lib/control.ks

@@ -4,10 +4,11 @@
 // set externally when they should return.
 
 
+// Helicopter-style point stability control.
 // Hover, ascend, or descend at a fixed rate.
 // Adjusts the throttle to control ascent or descent.
 // Adjusts pitch and roll to maintain zero lateral velocity.
-function Stabilize {
+function PointStabilizeH {
   parameter vertSpeed is 0.0.
 
   set done to false.

lib/stabilize_rocket.ks

@@ -0,0 +1,98 @@
+// Provides stabilization functions, including Hover.
+
+
+// Stabilizes a rocket relative to the surface, with optional vertical
+// velocity. Do not include both this and helicopter_stabilize.ks in one
+// program.
+function Hover {
+  parameter vertSpeed is 0.0.
+
+  set done to false.
+  SAS off.
+
+  lock THROTTLE to 0.0.
+
+  if SHIP:SENSORS:PRES = 0 {
+    // In a vacuum, perform a more efficient vacuum maneuver.
+    // This will call hoverAtmo after initial stabilization, to make sure
+    // we don't flip upside down.
+    hoverVac(vertSpeed).
+  } else {
+    hoverAtmo(vertSpeed).
+  }
+
+  set SHIP:CONTROL:PILOTMAINTHROTTLE to THROTTLE.
+  unlock THROTTLE.
+  unlock STEERING.
+  SAS on.
+  print "Stabilized operation ended. Returning control to pilot.".
+  set done to false.
+}
+
+function hoverAtmo {
+  parameter vertSpeed.
+
+  local headingV is V(0,0,0).
+  lock headingV to VectorExcl(SHIP:UP:FOREVECTOR, SHIP:SRFRETROGRADE).
+
+  // set up PID controllers
+  local pitchPID is PIDLoop(5, 0.1, 0.01, 0, 90).
+  set pitchPID:SETPOINT to 0.
+
+  local throttlePID is PIDLoop(0.1, 0.1, 0.001, 0, 1).
+  set throttlePID:SETPOINT to vertSpeed.
+
+  // we use the inverse of GROUNDSPEED because pitch and acceleration are
+  // inversely proportional here.
+  local newPitch is 0.0.
+  lock newPitch to pitchPID:Update(TIME:SECONDS, -SHIP:GROUNDSPEED).
+  lock STEERING to AngleAxis(-newPitch, SHIP:FACING:STARVECTOR) * headingV.
+  lock THROTTLE to throttlePID:Update(TIME:SECONDS, SHIP:VERTICALSPEED).
+  wait until done.
+}
+
+function hoverVac {
+  parameter vertSpeed.
+  // TODO: implement me!
+  hoverAtmo(vertSpeed).
+}
+
+// Convenience function for landing operations. Hover over a point with a negative velocity, shutting down on landing.
+function Land {
+  set done to false.
+  when SHIP:STATUS = "LANDED" then {
+    set done to true.
+  }
+  Hover(-0.5).
+  set SHIP:CONTROL:PILOTMAINTHROTTLE to 0.0.
+  set done to false.
+}
+
+// Rocket-style point stability control.
+// Hover, ascend, or descend at a fixed rate.
+// Adjusts the throttle to control target vertical speed.
+// Uses retrograde lock to cancel horizontal velocity.
+// TODO: how does this work
+// function PointStabilizeR {
+//   parameter vertSpeed is 0.0.
+
+//   set done to false.
+//   SAS off.
+
+//   lock STEERING to SHIP:RETROGRADE.
+//   wait until VectorAngle(
+//     SHIP:FACING:FOREVECTOR,
+//     SHIP:SRFRETROGRADE:FOREVECTOR) < 0.05.
+
+//   local throttlePID is PIDLoop(0.1, 0.001, 0.001, 0, 1).
+//   set throttlePID:SETPOINT to vertSpeed.
+//   lock THROTTLE to throttlePID:Update(TIME:SECONDS, SHIP:VERTICALSPEED).
+//   wait until done.
+
+//   set SHIP:CONTROL:PILOTMAINTHROTTLE to THROTTLE.
+//   unlock THROTTLE.
+//   unlock STEERING.
+//   SAS on.
+//   set done to false.
+//   print "Stabilized operation ended. Returning control to pilot.".
+// }

lib/throttle.ks

@@ -1,4 +1,5 @@
-// Functions for calculating thrust values.
+// Functions for calculating values related to throttle and thrust.
+
 @lazyglobal off.
 
 // point gravity for TWR calculations.