Convert drivetrain mode from a bool to a number

This lets us support more than 2 drivetrain controller types in
perparation for splines.

Change-Id: I943d6073e6c5facae7223cc6111551a57b039a04
diff --git a/frc971/control_loops/drivetrain/drivetrain.cc b/frc971/control_loops/drivetrain/drivetrain.cc
index 523c9b3..62f31fa 100644
--- a/frc971/control_loops/drivetrain/drivetrain.cc
+++ b/frc971/control_loops/drivetrain/drivetrain.cc
@@ -242,9 +242,9 @@
 
   dt_openloop_.SetPosition(position, left_gear_, right_gear_);
 
-  bool control_loop_driving = false;
+  int controller_type = 0;
   if (goal) {
-    control_loop_driving = goal->control_loop_driving;
+    controller_type = goal->controller_type;
 
     dt_closedloop_.SetGoal(*goal);
     dt_openloop_.SetGoal(*goal);
@@ -252,13 +252,15 @@
 
   dt_openloop_.Update();
 
-  if (control_loop_driving) {
-    dt_closedloop_.Update(output != NULL);
-    dt_closedloop_.SetOutput(output);
-  } else {
-    dt_openloop_.SetOutput(output);
-    // TODO(austin): Set profile to current spot.
-    dt_closedloop_.Update(false);
+  dt_closedloop_.Update(output != NULL && controller_type == 1);
+
+  switch (controller_type) {
+    case 0:
+      dt_openloop_.SetOutput(output);
+      break;
+    case 1:
+      dt_closedloop_.SetOutput(output);
+      break;
   }
 
   // The output should now contain the shift request.
diff --git a/frc971/control_loops/drivetrain/drivetrain.q b/frc971/control_loops/drivetrain/drivetrain.q
index ed659c3..7fb859d 100644
--- a/frc971/control_loops/drivetrain/drivetrain.q
+++ b/frc971/control_loops/drivetrain/drivetrain.q
@@ -55,8 +55,11 @@
     // True to activate quickturn.
     bool quickturn;
 
-    // True to have the closed-loop controller take over.
-    bool control_loop_driving;
+    // Type of controller in charge of the drivetrain.
+    //  0: polydrive
+    //  1: motion profiled position drive (statespace)
+    //  2: spline follower.
+    uint8_t controller_type;
 
     // Position goals for each drivetrain side (in meters) when the
     // closed-loop controller is active.
diff --git a/frc971/control_loops/drivetrain/drivetrain_lib_test.cc b/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
index f6d5aa2..49022f6 100644
--- a/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
+++ b/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
@@ -261,7 +261,7 @@
 // Tests that the drivetrain converges on a goal.
 TEST_F(DrivetrainTest, ConvergesCorrectly) {
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(true)
+      .controller_type(1)
       .left_goal(-1.0)
       .right_goal(1.0)
       .Send();
@@ -273,7 +273,7 @@
 // voltage offset/disturbance.
 TEST_F(DrivetrainTest, ConvergesWithVoltageError) {
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(true)
+      .controller_type(1)
       .left_goal(-1.0)
       .right_goal(1.0)
       .Send();
@@ -286,7 +286,7 @@
 // Tests that it survives disabling.
 TEST_F(DrivetrainTest, SurvivesDisabling) {
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(true)
+      .controller_type(1)
       .left_goal(-1.0)
       .right_goal(1.0)
       .Send();
@@ -322,7 +322,7 @@
 // This used to not work due to a U-capping bug.
 TEST_F(DrivetrainTest, DriveStraightForward) {
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(true)
+      .controller_type(1)
       .left_goal(4.0)
       .right_goal(4.0)
       .Send();
@@ -341,7 +341,7 @@
 // This used to fail in simulation due to libcdd issues with U-capping.
 TEST_F(DrivetrainTest, DriveAlmostStraightForward) {
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(true)
+      .controller_type(1)
       .left_goal(4.0)
       .right_goal(3.9)
       .Send();
@@ -385,7 +385,7 @@
   {
     ::aos::ScopedMessagePtr<::frc971::control_loops::DrivetrainQueue::Goal>
         goal = my_drivetrain_queue_.goal.MakeMessage();
-    goal->control_loop_driving = true;
+    goal->controller_type = 1;
     goal->left_goal = 4.0;
     goal->right_goal = 4.0;
     goal->left_velocity_goal = 0.0;
@@ -416,7 +416,7 @@
   {
     ::aos::ScopedMessagePtr<::frc971::control_loops::DrivetrainQueue::Goal>
         goal = my_drivetrain_queue_.goal.MakeMessage();
-    goal->control_loop_driving = true;
+    goal->controller_type = 1;
     goal->left_goal = -1.0;
     goal->right_goal = 1.0;
     goal->left_velocity_goal = 0.0;
@@ -447,7 +447,7 @@
   {
     ::aos::ScopedMessagePtr<::frc971::control_loops::DrivetrainQueue::Goal>
         goal = my_drivetrain_queue_.goal.MakeMessage();
-    goal->control_loop_driving = true;
+    goal->controller_type = 1;
     goal->left_goal = 5.0;
     goal->right_goal = 4.0;
     goal->left_velocity_goal = 0.0;
@@ -471,7 +471,7 @@
 // drive profiles nicely.
 TEST_F(DrivetrainTest, OpenLoopThenClosed) {
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(false)
+      .controller_type(0)
       .wheel(0.0)
       .throttle(1.0)
       .highgear(true)
@@ -481,7 +481,7 @@
   RunForTime(chrono::seconds(1));
 
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(false)
+      .controller_type(0)
       .wheel(0.0)
       .throttle(-0.3)
       .highgear(true)
@@ -491,7 +491,7 @@
   RunForTime(chrono::seconds(1));
 
   my_drivetrain_queue_.goal.MakeWithBuilder()
-      .control_loop_driving(false)
+      .controller_type(0)
       .wheel(0.0)
       .throttle(0.0)
       .highgear(true)
@@ -503,7 +503,7 @@
   {
     ::aos::ScopedMessagePtr<::frc971::control_loops::DrivetrainQueue::Goal>
         goal = my_drivetrain_queue_.goal.MakeMessage();
-    goal->control_loop_driving = true;
+    goal->controller_type = 1;
     goal->left_goal = 5.0;
     goal->right_goal = 4.0;
     goal->left_velocity_goal = 0.0;