Fix terrain wireframe refresh.

If a terrain layer spawner went outside the world bounds, the debug wireframe wouldn't update correctly because the heights were outside the wireframe sector AABBs.  Adjusted the logic to account for this.

Signed-off-by: Mike Balfour <82224783+mbalfour-amzn@users.noreply.github.com>

Gems/Terrain/Code/Source/Components/TerrainWorldDebuggerComponent.cpp

@@ -218,6 +218,12 @@ namespace Terrain
         AzFramework::Terrain::TerrainDataRequestBus::BroadcastResult(
             queryResolution, &AzFramework::Terrain::TerrainDataRequests::GetTerrainHeightQueryResolution);
 
+        // Take the dirty region and adjust the Z values to the world min/max so that even if the dirty region falls outside the current
+        // world bounds, we still update the wireframe accordingly.
+        AZ::Aabb dirtyRegion2D = AZ::Aabb::CreateFromMinMaxValues(
+            dirtyRegion.GetMin().GetX(), dirtyRegion.GetMin().GetY(), worldBounds.GetMin().GetZ(),
+            dirtyRegion.GetMax().GetX(), dirtyRegion.GetMax().GetY(), worldBounds.GetMax().GetZ());
+
         // Calculate the world size of each sector.  Note that this size actually ends at the last point, not the last square.
         // So for example, the sector size for 3 points will go from (*--*--*) even though it will be used to draw (*--*--*--).
         const float xSectorSize = (queryResolution.GetX() * SectorSizeInGridPoints);
@@ -230,7 +236,7 @@ namespace Terrain
 
         // If we haven't cached anything before, or if the world bounds has changed, clear our cache structure and repopulate it
         // with WireframeSector entries with the proper AABB sizes.
-        if (!m_wireframeBounds.IsValid() || !dirtyRegion.IsValid() || !m_wireframeBounds.IsClose(worldBounds))
+        if (!m_wireframeBounds.IsValid() || !dirtyRegion2D.IsValid() || !m_wireframeBounds.IsClose(worldBounds))
         {
             m_wireframeBounds = worldBounds;
 
@@ -266,7 +272,7 @@ namespace Terrain
         // For each sector, if it overlaps with the dirty region, clear it out and recache the wireframe line data.
         for (auto& sector : m_wireframeSectors)
         {
-            if (dirtyRegion.IsValid() && !dirtyRegion.Overlaps(sector.m_aabb))
+            if (dirtyRegion2D.IsValid() && !dirtyRegion2D.Overlaps(sector.m_aabb))
             {
                 continue;
             }