Moved if section to the top

Signed-off-by: Sergey Pereslavtsev <pereslav@amazon.com>

Gems/PhysX/Code/Editor/DebugDraw.cpp

@@ -687,12 +687,6 @@ namespace PhysX
             [[maybe_unused]] const AZ::Vector3& colliderScale,
             [[maybe_unused]] const bool forceUniformScaling) const
         {
-            const int numColumns = heightfieldShapeConfig.GetNumColumns();
-            const int numRows = heightfieldShapeConfig.GetNumRows();
-
-            const float minXBounds = -(numColumns * heightfieldShapeConfig.GetGridResolution().GetX()) / 2.0f;
-            const float minYBounds = -(numRows * heightfieldShapeConfig.GetGridResolution().GetY()) / 2.0f;
-
             auto heights = heightfieldShapeConfig.GetSamples();
 
             if (heights.empty())
@@ -700,6 +694,12 @@ namespace PhysX
                 return;
             }
 
+            const int numColumns = heightfieldShapeConfig.GetNumColumns();
+            const int numRows = heightfieldShapeConfig.GetNumRows();
+
+            const float minXBounds = -(numColumns * heightfieldShapeConfig.GetGridResolution().GetX()) / 2.0f;
+            const float minYBounds = -(numRows * heightfieldShapeConfig.GetGridResolution().GetY()) / 2.0f;
+
             for (int xIndex = 0; xIndex < numColumns - 1; xIndex++)
             {
                 for (int yIndex = 0; yIndex < numRows - 1; yIndex++)