diff --git a/src/posix/sdl/hardware.cpp b/src/posix/sdl/hardware.cpp
index b46458370..5e7ba4f1e 100644
--- a/src/posix/sdl/hardware.cpp
+++ b/src/posix/sdl/hardware.cpp
@@ -334,8 +334,8 @@ CUSTOM_CVAR(Bool, swtruecolor, true, CVAR_ARCHIVE|CVAR_GLOBALCONFIG|CVAR_NOINITC
 
 CUSTOM_CVAR (Bool, fullscreen, false, CVAR_ARCHIVE|CVAR_GLOBALCONFIG|CVAR_NOINITCALL)
 {
-	NewWidth = screen->GetWidth();
-	NewHeight = screen->GetHeight();
+	NewWidth = screen->VideoWidth;
+	NewHeight = screen->VideoHeight;
 	NewBits = DisplayBits;
 	setmodeneeded = true;
 }