feat: technique overhaul

particle-track-and-trace/src/layers/Layer.cpp

@@ -1,5 +1,6 @@
 #include "Layer.h"
 #include <vtkRenderWindow.h>
+#include <vtkCamera.h>
 #include <vtkRenderWindowInteractor.h>
 
 using std::string;
@@ -16,7 +17,10 @@ void Layer::addObservers(vtkSmartPointer<vtkRenderWindowInteractor> interactor)
     // By default, do nothing
 }
 
+void Layer::removeObservers(vtkSmartPointer<vtkRenderWindowInteractor> interactor) {
+    // By default, do nothing
+}
 
-void Layer::setCamera(vtkCamera *camera) {
-  this->getLayer()->SetActiveCamera(camera);
+void Layer::setCamera(vtkSmartPointer<vtkCamera> cam) {
+  this->getLayer()->SetActiveCamera(cam.GetPointer());
 }