GUI: Do not allocate the Screen dynamically, it's always used (#442)

At least according to Isilkors analysis, this should fix the crash.

src/C4Game.cpp

@@ -327,12 +327,7 @@ bool C4Game::PreInit()
 		{ LogFatal(LoadResStr("IDS_ERR_NOGFXSYS")); return false; }
 
 	// load GUI
-	if (!pGUI)
-	{
-		int32_t iGuiResX = Config.Graphics.ResX;
-		int32_t iGuiResY = Config.Graphics.ResY;
-		pGUI = new C4GUIScreen(0, 0, iGuiResX, iGuiResY);
-	}
+	pGUI->Init(0, 0, Config.Graphics.ResX, Config.Graphics.ResY);
 
 	fPreinited = true;
 
@@ -561,8 +556,8 @@ void C4Game::Clear()
 	C4AulProfiler::Abort();
 
 	// exit gui
-	if (pGUI) { delete pGUI; pGUI=NULL; }
-
+	pGUI->Clear();
+	
 	// next mission (shoud have been transferred to C4Application now if next mission was desired)
 	NextMission.Clear(); NextMissionText.Clear(); NextMissionDesc.Clear();
 
@@ -1584,7 +1579,6 @@ void C4Game::Default()
 	TransferZones.Default();
 	GroupSet.Default();
 	pParentGroup=NULL;
-	pGUI=NULL;
 	pScenarioSections=pCurrentScenarioSection=NULL;
 	*CurrentScenarioSection=0;
 	pGlobalEffects=NULL;

src/gui/C4Gui.cpp

@@ -530,10 +530,18 @@ namespace C4GUI
 		}
 	}
 
-	Screen::Screen(int32_t tx, int32_t ty, int32_t twdt, int32_t thgt) : Window(), Mouse(tx+twdt/2, ty+thgt/2), pContext(NULL), fExclusive(true), pGamePadOpener(NULL), fZoom(1.0f)
+	Screen::Screen() : Window(), Mouse(0, 0), pContext(NULL), fExclusive(true), pGamePadOpener(NULL), fZoom(1.0f)
 	{
 		// no dialog active
 		pActiveDlg = NULL;
+		// set static var
+		pScreen = this;
+	}
+
+	void Screen::Init(int32_t tx, int32_t ty, int32_t twdt, int32_t thgt)
+	{
+		Mouse.x = tx+twdt/2;
+		Mouse.y = ty+thgt/2;
 		// calculate zoom
 		float fZoomX = float(Config.Graphics.ResX) / twdt;
 		float fZoomY = float(Config.Graphics.ResY) / thgt;
@@ -541,23 +549,25 @@ namespace C4GUI
 		// set size - calcs client area as well
 		SetBounds(C4Rect(tx,ty,twdt,thgt));
 		SetPreferredDlgRect(C4Rect(0,0,twdt,thgt));
-		// set static var
-		pScreen = this;
 		// GamePad
 		if (Application.pGamePadControl && Config.Controls.GamepadGuiControl)
 			pGamePadOpener = new C4GamePadOpener(0);
 	}
 
-	Screen::~Screen()
+	void Screen::Clear()
 	{
 		// dtor: Close context menu
 		AbortContext(false);
-		// clear singleton
-		if (this == pScreen) pScreen = NULL;
 		// GamePad
 		if (pGamePadOpener) delete pGamePadOpener;
 	}
 
+	Screen::~Screen()
+	{
+		// clear singleton
+		if (this == pScreen) pScreen = NULL;
+	}
+
 	void Screen::ElementPosChanged(Element *pOfElement)
 	{
 		// redraw fullscreen BG if dlgs are dragged around in shared mode
@@ -1050,6 +1060,7 @@ namespace C4GUI
 		}
 	}
 
+	Screen TheScreen;
 
 // --------------------------------------------------
 // ComponentAligner
@@ -1186,4 +1197,4 @@ namespace C4GUI
 
 } // end of namespace
 
-C4GUIScreen *pGUI;
+C4GUIScreen *pGUI = &C4GUI::TheScreen;

src/gui/C4Gui.h

@@ -2512,8 +2512,11 @@ namespace C4GUI
 
 		Dialog *GetTopDialog(); // get topmost dlg
 	public:
-		Screen(int32_t tx, int32_t ty, int32_t twdt, int32_t thgt); // ctor
-		~Screen(); // dtor
+		Screen();
+		~Screen();
+
+		void Init(int32_t tx, int32_t ty, int32_t twdt, int32_t thgt);
+		void Clear();
 
 		void Render(bool fDoBG);                 // render to lpDDraw
 		void RenderMouse(C4TargetFacet &cgo);        // draw mouse only
@@ -2727,6 +2730,7 @@ namespace C4GUI
 	inline void MouseMove(int32_t iButton, int32_t iX, int32_t iY, DWORD dwKeyParam, class C4Viewport *pVP) // pVP specified for console mode viewports only
 	{ Screen *s=Screen::GetScreenS(); if(s) s->MouseMove(iButton, iX, iY, dwKeyParam, pVP); }
 
+	extern Screen TheScreen;
 } // end of namespace
 
 typedef C4GUI::Screen C4GUIScreen;