Initialize Field object before physics engine

- Allows physics engine constructor to access field

Author: virtuald

pyfrc/physics/core.py

@@ -148,6 +148,13 @@ def __init__(self, physics_module):
         self.log_init_errors = True
 
     def _simulationInit(self, robot):
+
+        # reset state first so that the PhysicsEngine constructor can use it
+        self.field = wpilib.Field2d()
+        wpilib.SmartDashboard.putData("Field", self.field)
+
+        self.last_tm = None
+
         # look for a class called PhysicsEngine
         try:
             PhysicsEngine = self.module.PhysicsEngine
@@ -171,12 +178,6 @@ def _simulationInit(self, robot):
             logger.exception("Error creating user's PhysicsEngine object")
             raise PhysicsInitException()
 
-        # reset state
-        self.field = wpilib.Field2d()
-        wpilib.SmartDashboard.putData("Field", self.field)
-
-        self.last_tm = None
-
     def _simulationPeriodic(self):
         now = wpilib.Timer.getFPGATimestamp()
         last_tm = self.last_tm