From 2e7b90421617a40aa0ef9d6e9d41dc6efefba61f Mon Sep 17 00:00:00 2001
From: annabunches <annabunches@gmail.com>
Date: Wed, 11 Aug 2021 05:04:21 -0400
Subject: [PATCH] Modify launch code to be smoother.

---
 lib/launch_rocket.ks | 39 +++++++++++----------------------------
 prog/rocket.ks       |  8 +++-----
 2 files changed, 14 insertions(+), 33 deletions(-)

diff --git a/lib/launch_rocket.ks b/lib/launch_rocket.ks
index 2ef3b62..885eb18 100644
--- a/lib/launch_rocket.ks
+++ b/lib/launch_rocket.ks
@@ -1,15 +1,14 @@
 runoncepath("lib/throttle").
 runoncepath("lib/navigation").
-runoncepath("lib/node").
 
-// Calculate the vector at which to ascend.
-// This is basically prograde plus some anti-rotation logic and a lower bound.
-function getAscentVector {
-  parameter minPitch.
-  // face prograde, but hold a solid eastern heading and don't
+// Calculate the direction to lock during ascent.
+function getAscentDir {
+  parameter leadAngle is 5.
+  parameter minPitch is 5.
+  // face just beneath prograde, but hold a solid eastern heading and don't
   // rotate the ship
-  local newHeading is lookdirup(SHIP:SRFPROGRADE:FOREVECTOR,
-    heading(90, 0, 270):TOPVECTOR).
+  local newHeading is lookdirup(SHIP:SRFPROGRADE:FOREVECTOR, heading(90, 0, 270):TOPVECTOR).
+  set newHeading to angleaxis(leadAngle, newHeading:TOPVECTOR)*newHeading.
   if getPitch(newHeading:FOREVECTOR) < minPitch {
     set newHeading to heading(90, minPitch, 270).
   }
@@ -26,7 +25,7 @@ function Launch {
   parameter APOAPSIS_TARGET is 80000.
   parameter ATMO_TWR is 1.6.
   parameter GRAVITY_TURN_START is 8000.
-  parameter GRAVITY_PITCH is 75.
+  parameter LEAD_ANGLE is 5.
 //  parameter INITIAL_PITCH is 85.
   parameter MINIMUM_PITCH is 5.
 
@@ -51,7 +50,7 @@ function Launch {
     return true.
   }
 
-  // Hold throttle to maintain 1.5 TWR.
+  // Hold throttle to maintain target TWR.
   // We do *not* use a PID Loop here because we can
   // calculate the correct value discretely.
   lock THROTTLE to ThrottleToTWR(ATMO_TWR).
@@ -61,26 +60,10 @@ function Launch {
   lock STEERING to heading(90,90,270).
   stage.
 
-  // wait until SHIP:ALTITUDE > 200.
-  // print "Vectoring away from launchpad.".
-  // lock STEERING to heading(90, INITIAL_PITCH, 270).
   wait until SHIP:ALTITUDE > GRAVITY_TURN_START.
 
-  print "Pitching for gravity turn.".
-  // Pitch over...
-  lock STEERING to heading(90, GRAVITY_PITCH, 270).
-  // Wait until we have rotated to (approximately) that pitch...
-  wait until vectorangle(
-    SHIP:FACING:FOREVECTOR,
-    STEERINGMANAGER:TARGET:FOREVECTOR)
-    < 0.5.
-
-  // then wait until Prograde catches up (or passes us).
-  local targetPitch is GetPitch(STEERINGMANAGER:TARGET:FOREVECTOR).
-  wait until GetPitch(SHIP:SRFPROGRADE:FOREVECTOR) <= targetPitch.
-
-  print "Locking to prograde, letting gravity do the hard work.".
-  lock STEERING to getAscentVector(MINIMUM_PITCH).
+  print "Turning gravity...".
+  lock STEERING to getAscentDir(LEAD_ANGLE, MINIMUM_PITCH).
   wait until SHIP:ALTITUDE > 32000. // todo: if we have a pressure sensor we can use it to decide when to kick the throttle up instead, neat solution for e.g. Duna and Eve.
 
   lock THROTTLE to 1.0.
diff --git a/prog/rocket.ks b/prog/rocket.ks
index ddbc077..a692d06 100644
--- a/prog/rocket.ks
+++ b/prog/rocket.ks
@@ -80,10 +80,9 @@ MakeMenu(
   List(
     List("Target Apoapsis", "SCALAR", "80000"),
     List("Atmo TWR", "SCALAR", "1.8"),
-    // List("Initial Pitch", "SCALAR", "85"),
-    List("Minimum Pitch", "SCALAR", "5"),
     List("Gravity Turn Alt", "SCALAR", "8000"),
-    List("Gravity Turn Pitch", "SCALAR", "75")
+    List("Lead Angle", "SCALAR", "5"),
+    List("Minimum Pitch", "SCALAR", "5")
   ),
   "Execute",
   {
@@ -92,8 +91,7 @@ MakeMenu(
       options["Target Apoapsis"]:TEXT:ToNumber(),
       options["Atmo TWR"]:TEXT:ToNumber(),
       options["Gravity Turn Alt"]:TEXT:ToNumber(),
-      options["Gravity Turn Pitch"]:TEXT:ToNumber(),
-      // options["Initial Pitch"]:TEXT:ToNumber(),
+      options["Lead Angle"]:TEXT:ToNumber(),
       options["Minimum Pitch"]:TEXT:ToNumber()
     ).
   }