BUG: Recompute EndoscopyLogic fields immediately instead of lazily

The logic for when to loadCameraOrientations and recompute EndoscopyLogic
fields was not working in all cases.  The lazy approach to loading and
recomputing could have been modified to fix this, but we did not pursue this
approach because the lazy approach has a flaw: the user interface (e.g. number
of frames available) should be available immediately, not lazily (e.g. only
once the user starts a flythrough).

Modules/Scripted/Endoscopy/Endoscopy.py

@@ -128,7 +128,6 @@ def setupPathUI(self):
         inputCurveSelector.addEnabled = False
         inputCurveSelector.removeEnabled = False
         inputCurveSelector.connect("currentNodeChanged(bool)", self.enableOrDisableCreateButton)
-        inputCurveSelector.connect("currentNodeChanged(vtkMRMLNode*)", self.setInputCurve)
         pathFormLayout.addRow(_("Curve to modify:"), inputCurveSelector)
         self.inputCurveSelector = inputCurveSelector
 
@@ -312,16 +311,15 @@ def setInputCurve(self, newInputCurve):
 
         if self.inputCurve is not None:
             self.removeObserver(self.inputCurve, vtk.vtkCommand.ModifiedEvent, self.onInputCurveModified)
-
         self.inputCurve = newInputCurve
-
         if newInputCurve is not None:
             self.addObserver(self.inputCurve, vtk.vtkCommand.ModifiedEvent, self.onInputCurveModified)
 
         if self.logic is not None:
-            # We are going to have rebuild the EndoscopyLogic later
             self.logic.cleanup()
             self.logic = None
+        cameraOrientations = self.loadCameraOrientations()
+        self.logic = EndoscopyLogic(self.inputCurve, cameraOrientations)
 
         # Update UI
         self.updateWidgetFromMRML()
@@ -347,11 +345,15 @@ def enableOrDisableCreateButton(self):
 
     def onInputCurveModified(self, observer, eventid):
         """If the input curve  was changed we need to repopulate the keyframe UI"""
-        if not self.ignoreInputCurveModified:
-            if self.logic:
-                # We are going to have rebuild the EndoscopyLogic later
-                self.logic.cleanup()
-                self.logic = None
+        if self.ignoreInputCurveModified:
+            return
+        self.ignoreInputCurveModified += 1
+        if self.logic:
+            self.logic.cleanup()
+            self.logic = None
+        cameraOrientations = self.loadCameraOrientations()
+        self.logic = EndoscopyLogic(self.inputCurve, cameraOrientations)
+        self.ignoreInputCurveModified -= 1
 
     def onCreatePathButtonClicked(self):
         """Connected to 'Use this curve'` button.  It allows to:
@@ -360,12 +362,13 @@ def onCreatePathButtonClicked(self):
         - ensure cursor, model and input curve are not visible in the endoscopy view
         - go to start of the path
         """
-        inputCurve = self.inputCurveSelector.currentNode()
+        if self.ignoreInputCurveModified:
+            return
         self.ignoreInputCurveModified += 1
 
-        if self.logic:
-            self.logic.cleanup()
-        self.logic = EndoscopyLogic(inputCurve)
+        inputCurve = self.inputCurveSelector.currentNode()
+
+        self.setInputCurve(inputCurve)
 
         numberOfControlPoints = self.logic.resampledCurve.GetNumberOfControlPoints()
 
@@ -442,12 +445,7 @@ def onSaveOrientationButtonClicked(self):
         cameraOrientations[distanceAlongResampledCurve] = worldOrientation
         self.saveCameraOrientations(cameraOrientations)
 
-        if not self.logic:
-            # Create an entire EndoscopyLogic instance
-            self.logic = EndoscopyLogic(self.inputCurve)
-        else:
-            # Update only the interpolations
-            self.logic.interpolateOrientations()
+        self.logic.interpolateOrientations()
 
         self.flyTo(resampledCurvePointIndex)
 
@@ -469,12 +467,7 @@ def onDeleteOrientationButtonClicked(self):
                 del cameraOrientations[distanceAlongResampledCurve]
         self.saveCameraOrientations(cameraOrientations)
 
-        if not self.logic:
-            # Create an entire EndoscopyLogic instance
-            self.logic = EndoscopyLogic(self.inputCurve)
-        else:
-            # Update only the interpolations
-            self.logic.interpolateOrientations()
+        self.logic.interpolateOrientations()
 
         self.flyTo(resampledCurvePointIndex)
 
@@ -576,9 +569,6 @@ def cameraOrientationsIsCorrectType(self, convertedCameraOrientations):
         )
 
     def flyToNext(self):
-        if self.logic is None:
-            # We invalidated self.logic due to an intervening user modification of the input.  We need it now.
-            self.logic = EndoscopyLogic(self.inputCurve)
         currentStep = int(self.frameSlider.value)
         nextStep = currentStep + self.skip + 1
         if nextStep > self.logic.resampledCurve.GetNumberOfControlPoints() - 2:
@@ -588,10 +578,6 @@ def flyToNext(self):
     def flyTo(self, resampledCurvePointIndex):
         """Apply the resampledCurvePointIndex-th step in the path to the global camera"""
 
-        if self.logic is None:
-            # We invalidated self.logic due to an intervening user modification of the input.  We need it now.
-            self.logic = EndoscopyLogic(self.inputCurve)
-
         if (
             self.logic.resampledCurve is None
             or not 0 <= resampledCurvePointIndex < self.logic.resampledCurve.GetNumberOfControlPoints()
@@ -615,7 +601,8 @@ def flyTo(self, resampledCurvePointIndex):
         )
 
         # Set the cursor matrix
-        self.transform.SetMatrixTransformToParent(worldMatrix4x4)
+        if self.transform:
+            self.transform.SetMatrixTransformToParent(worldMatrix4x4)
 
         # Set the camera & cameraNode
         with slicer.util.NodeModify(self.cameraNode):
@@ -720,8 +707,9 @@ class EndoscopyLogic:
 
     NODE_PATH_CAMERA_ORIENTATIONS_ATTRIBUTE_NAME = "Endoscopy.Path.CameraOrientations"
 
-    def __init__(self, inputCurve, dl=0.5):
+    def __init__(self, inputCurve, cameraOrientations, dl=0.5):
         self.cleanup()
+        self.cameraOrientations = cameraOrientations
         self.dl = dl  # desired world space step size (in mm)
         self.setControlPoints(inputCurve)