diff --git a/src/d_main.cpp b/src/d_main.cpp
index 540b002b31c..f94d158b5ae 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -779,7 +779,10 @@ void D_Display ()
 
 
 	{
-		screen->FrameTime = I_msTime();
+		static uint32_t firstFrame = 0;
+		if (firstFrame == 0)
+			firstFrame = screen->FrameTime;
+		screen->FrameTime = I_msTime() - firstFrame;
 		TexMan.UpdateAnimations(screen->FrameTime);
 		R_UpdateSky(screen->FrameTime);
 		switch (gamestate)