perf: stop resetting mouse to center each frame

this is actually quite expensive on Windows. 5% of the frame
can be used up by this over time due to weird process initialization,
calling into WoW64, etc.

this may have regressions. i tried testing as much as possible but
vgui is a strange beast.

Author: mastercoms

src/engine/sys_mainwind.cpp

@@ -301,6 +301,9 @@ void CGame::AppActivate( bool fActive )
 			ClearIOStates();
 
 			UpdateMaterialSystemConfig();
+
+			// Once we return, let VGUI know it needs to relock.
+			vgui::surface()->UnlockCursor();
 		}
 		else
 		{

src/game/client/in_mouse.cpp

@@ -138,8 +138,8 @@ void CInput::ActivateMouse (void)
 		}
 		m_fMouseActive = true;
 
-		ResetMouse();
 #if !defined( PLATFORM_WINDOWS )
+		ResetMouse();
 		int dx, dy;
 		engine->GetMouseDelta( dx, dy, true );
 #endif
@@ -174,9 +174,10 @@ void CInput::DeactivateMouse (void)
 		}
 		m_fMouseActive = false;
 		vgui::surface()->SetCursor( vgui::dc_arrow );
-#if !defined( PLATFORM_WINDOWS )
 		// now put the mouse back in the middle of the screen
 		ResetMouse();
+#ifdef PLATFORM_WINDOWS
+		::ClipCursor(NULL);
 #endif
 
 		// Clear accumulated error, too
@@ -686,8 +687,10 @@ void CInput::MouseMove( CUserCmd *cmd )
 		// Add mouse X/Y movement to cmd
 		ApplyMouse( viewangles, cmd, mouse_x, mouse_y );
 
+#if !defined( PLATFORM_WINDOWS )
 		// Re-center the mouse.
 		ResetMouse();
+#endif
 	}
 
 	// Store out the new viewangles.

src/game/client/tf/vgui/tf_matchmaking_dashboard.cpp

@@ -314,10 +314,10 @@ void CTFMatchmakingPopup::OnTick()
 			m_bActive = false;
 			OnExit();
 		}
-	}
 
-	SetMouseInputEnabled( ShouldBeActve() );
-	SetKeyBoardInputEnabled( false ); // Never
+		SetMouseInputEnabled( bShouldBeActive );
+		SetKeyBoardInputEnabled( false ); // Never
+	}
 }
 
 

src/vguimatsurface/MatSystemSurface.cpp

@@ -4108,6 +4108,8 @@ void CMatSystemSurface::CalculateMouseVisible()
 	int c = surface()->GetPopupCount();
 
 	VPANEL modalSubTree = input()->GetModalSubTree();
+	VPanel* p = nullptr;
+
 	if ( modalSubTree )
 	{
 		for (i = 0 ; i < c ; i++ )
@@ -4118,7 +4120,7 @@ void CMatSystemSurface::CalculateMouseVisible()
 				continue;
 
 			bool isVisible=pop->IsVisible();
-			VPanel *p= pop->GetParent();
+			p= pop->GetParent();
 
 			while (p && isVisible)
 			{
@@ -4148,7 +4150,7 @@ void CMatSystemSurface::CalculateMouseVisible()
 			VPanel *pop = (VPanel *)surface()->GetPopup(i) ;
 
 			bool isVisible=pop->IsVisible();
-			VPanel *p= pop->GetParent();
+			p= pop->GetParent();
 
 			while (p && isVisible)
 			{
@@ -4185,6 +4187,27 @@ void CMatSystemSurface::CalculateMouseVisible()
 	}
 	else
 	{
+#ifdef PLATFORM_WINDOWS
+		if (!IsCursorLocked() && p)
+		{
+			VPanel* contextPanel = p;
+			while (contextPanel->GetParent() && !contextPanel->Plat())
+			{
+				contextPanel = contextPanel->GetParent();
+			}
+			int absThis[4];
+			contextPanel->GetAbsPos(absThis[0], absThis[1]);
+			contextPanel->GetSize(absThis[2], absThis[3]);
+			absThis[2] += absThis[0];
+			absThis[3] += absThis[1];
+			RECT rect;
+			rect.left = absThis[0];
+			rect.top = absThis[1];
+			rect.right = absThis[2];
+			rect.bottom = absThis[3];
+			::ClipCursor(&rect);
+		}
+#endif
 		SetCursor(vgui::dc_none);
 		LockCursor();
 	}