diff --git a/desmume/src/GPU.cpp b/desmume/src/GPU.cpp
index 6514ae346..13f177450 100644
--- a/desmume/src/GPU.cpp
+++ b/desmume/src/GPU.cpp
@@ -578,7 +578,7 @@ FORCEINLINE FASTCALL void GPU::_master_setFinal3dColor(int dstX, int srcX)
 
 	if(WINDOW)
 	{
-		bool windowDraw;
+		bool windowDraw = false;
 		renderline_checkWindows(dstX, windowDraw, windowEffect);
 
 		//we never have anything more to do if the window rejected us