diff --git a/public/materialsystem/imaterialsystem.h b/public/materialsystem/imaterialsystem.h
index 9a679a10..16f968a7 100644
--- a/public/materialsystem/imaterialsystem.h
+++ b/public/materialsystem/imaterialsystem.h
@@ -64,7 +64,8 @@ class CPaintMaterial;
 class IPaintMapDataManager;
 class IPaintMapTextureManager;
 class GPUMemoryStats;
-
+struct AspectRatioInfo_t;
+struct CascadedShadowMappingState_t;
 
 //-----------------------------------------------------------------------------
 // The vertex format type