Handle zSpaceCoreCompat libraries not found

We do not search for zSpaceCoreCompatibility dynamic libraries during configuration anymore.
These being searched and loaded only at runtime, ParaView will not crash anymore if they are not found.

Rendering/ZSpace/vtkZSpaceCoreCompatibilitySDKManager.cxx

@@ -56,6 +56,10 @@ vtkZSpaceCoreCompatibilitySDKManager::vtkZSpaceCoreCompatibilitySDKManager()
 //------------------------------------------------------------------------------
 vtkZSpaceCoreCompatibilitySDKManager::~vtkZSpaceCoreCompatibilitySDKManager()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
   ZCCompatError error;
 
   error = this->EntryPts.zccompatShutDown(this->ZSpaceContext);
@@ -126,6 +130,8 @@ void vtkZSpaceCoreCompatibilitySDKManager::InitializeZSpace()
     return;
   }
 
+  this->Initialized = true;
+
   ZCCompatError error;
 
   // Initialize the zSpace SDK. This MUST be called before
@@ -231,6 +237,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::InitializeZSpace()
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::UpdateViewport()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   if (!this->RenderWindow)
   {
     vtkErrorMacro("No render window has been set to the zSpace SDK manager !");
@@ -265,6 +276,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::UpdateViewport()
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::UpdateTrackers()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   ZCCompatError error;
 
   // Update the zSpace SDK. This updates both tracking information
@@ -303,6 +319,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::UpdateTrackers()
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::UpdateViewAndProjectionMatrix()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   ZCCompatError error;
 
   // Update the view matrix for each eye
@@ -346,6 +367,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::UpdateViewAndProjectionMatrix()
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::UpdateButtonState()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   ZSBool isButtonPressed;
 
   for (int buttonId = vtkZSpaceSDKManager::MiddleButton;
@@ -366,6 +392,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::UpdateButtonState()
 void vtkZSpaceCoreCompatibilitySDKManager::CalculateFrustumFit(
   const double bounds[6], double position[3], double viewUp[3])
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   ZCCompatError error;
 
   vtkBoundingBox bBox;
@@ -453,6 +484,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::CalculateFrustumFit(
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::BeginFrame()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   ZCCompatError error = this->EntryPts.zccompatBeginFrame(this->ZSpaceContext);
   ZSPACE_CHECK_ERROR(zccompatBeginFrame, error);
 }
@@ -460,6 +496,11 @@ void vtkZSpaceCoreCompatibilitySDKManager::BeginFrame()
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::EndFrame()
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
+
   ZCCompatError error = this->EntryPts.zccompatEndFrame(this->ZSpaceContext);
   ZSPACE_CHECK_ERROR(zccompatEndFrame, error);
 }
@@ -467,6 +508,10 @@ void vtkZSpaceCoreCompatibilitySDKManager::EndFrame()
 //------------------------------------------------------------------------------
 void vtkZSpaceCoreCompatibilitySDKManager::SetRenderWindow(vtkRenderWindow* renderWindow)
 {
+  if (!this->Initialized)
+  {
+    return;
+  }
   // Give the application window handle to the zSpace Core Compatibilty API.
   HWND hWnd = static_cast<HWND>(renderWindow->GetGenericWindowId());
   ZCCompatError error =

Rendering/ZSpace/vtkZSpaceCoreCompatibilitySDKManager.h

@@ -151,6 +151,12 @@ protected:
    */
   void ConvertZSpaceMatrixToVTKMatrix(ZSMatrix4 zSpaceMatrix, vtkMatrix4x4* vtkMatrix);
 
+  /**
+   * Set to true if zSpaceCoreCompatibility dynamic libraries are found upon
+   * vtkZSpaceCoreCompatibilitySDKManager instantiation (see InitializeZSpace()).
+   */
+  bool Initialized = false;
+
 private:
   vtkZSpaceCoreCompatibilitySDKManager(const vtkZSpaceCoreCompatibilitySDKManager&) = delete;
   void operator=(const vtkZSpaceCoreCompatibilitySDKManager&) = delete;