3D-Viewer: mark flag as initialized

Fixes https://gitlab.com/kicad/code/kicad/issues/6331

3d-viewer/3d_rendering/3d_render_ogl_legacy/clayer_triangles.cpp

@@ -224,7 +224,6 @@ void CLAYER_TRIANGLES::AddToMiddleContourns( const std::vector< SFVEC2F > &aCont
             if( aThroughHoles && aThroughHoles->IntersectAny( RAYSEG2D( v0, v1 ) ) )
                 continue;
             else
-            //if( aThroughHoles && aThroughHoles->IntersectAny( RAYSEG2D( v0, v1 ) ) )
             {
                 std::lock_guard<std::mutex> lock( m_middle_layer_lock );
                 m_layer_middle_contourns_quads->AddQuad( SFVEC3F( v0.x, v0.y, zTop ),

3d-viewer/3d_rendering/3d_render_raytracing/accelerators/ccontainer2d.cpp

@@ -276,12 +276,13 @@ void CBVHCONTAINER2D::BuildBVH()
     if( m_isInitialized )
         destroy();
 
+    m_isInitialized = true;
+
     if( m_objects.empty() )
     {
         return;
     }
 
-    m_isInitialized = true;
     m_Tree = new BVH_CONTAINER_NODE_2D;
 
     m_elements_to_delete.push_back( m_Tree );