Merge topic '17265-reslicemapper-render' into release

fd6b906b 17265: Fix OpenGL2 vtkImageResliceMapper OOB issue

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !4076

Rendering/OpenGL2/vtkOpenGLImageSliceMapper.cxx

@@ -465,6 +465,10 @@ void vtkOpenGLImageSliceMapper::RenderPolygon(
       polyTCoords->Modified();
     }
   }
+  else // no polygon to render
+  {
+    return;
+  }
 
   if (textured)
   {
@@ -596,6 +600,10 @@ void vtkOpenGLImageSliceMapper::RenderBackground(
       dy0 = dy1;
     }
   }
+  else // no polygon to render
+  {
+    return;
+  }
 
   polyPoints->GetData()->Modified();
   tris->Modified();