Sanitized the Being/End2D interface so that it can be used to keep the attribute buffer mapped while processing 2D commands.

For this to work the 2D mode has to be properly set and unset at the right places so that no double mapping occurs and no render operation can happen while in 2D mode.

# Conflicts:
#	src/d_main.cpp
#	src/v_video.h

src/d_main.cpp

@@ -734,111 +734,98 @@ void D_Display ()
 		wipe = false;
 	}
 	
+	screen->FrameTime = I_msTimeFS();
+	TexMan.UpdateAnimations(screen->FrameTime);
+	R_UpdateSky(screen->FrameTime);
+	screen->BeginFrame();
+	screen->ClearClipRect();
+	if ((gamestate == GS_LEVEL || gamestate == GS_TITLELEVEL) && gametic != 0)
 	{
-		screen->FrameTime = I_msTimeFS();
-		TexMan.UpdateAnimations(screen->FrameTime);
-		R_UpdateSky(screen->FrameTime);
-		screen->BeginFrame();
-		screen->ClearClipRect();
+		// [ZZ] execute event hook that we just started the frame
+		//E_RenderFrame();
+		//
+		
+		// Check for the presence of dynamic lights at the start of the frame once.
+		if ((gl_lights && vid_rendermode == 4) || (r_dynlights && vid_rendermode != 4))
+		{
+			TThinkerIterator<ADynamicLight> it(STAT_DLIGHT);
+			level.HasDynamicLights = !!it.Next();
+		}
+		else level.HasDynamicLights = false;	// lights are off so effectively we have none.
+		
+		viewsec = screen->RenderView(&players[consoleplayer]);
+		screen->Begin2D();
+		screen->DrawBlend(viewsec);
+		if (automapactive)
+		{
+			AM_Drawer (hud_althud? viewheight : StatusBar->GetTopOfStatusbar());
+		}
+		if (!automapactive || viewactive)
+		{
+			screen->RefreshViewBorder ();
+		}
+		
+		// for timing the statusbar code.
+		//cycle_t stb;
+		//stb.Reset();
+		//stb.Clock();
+		if (hud_althud && viewheight == SCREENHEIGHT && screenblocks > 10)
+		{
+			StatusBar->DrawBottomStuff (HUD_AltHud);
+			if (DrawFSHUD || automapactive) DrawHUD();
+			if (players[consoleplayer].camera && players[consoleplayer].camera->player && !automapactive)
+			{
+				StatusBar->DrawCrosshair();
+			}
+			StatusBar->CallDraw (HUD_AltHud, vp.TicFrac);
+			StatusBar->DrawTopStuff (HUD_AltHud);
+		}
+		else if (viewheight == SCREENHEIGHT && viewactive && screenblocks > 10)
+		{
+			EHudState state = DrawFSHUD ? HUD_Fullscreen : HUD_None;
+			StatusBar->DrawBottomStuff (state);
+			StatusBar->CallDraw (state, vp.TicFrac);
+			StatusBar->DrawTopStuff (state);
+		}
+		else
+		{
+			StatusBar->DrawBottomStuff (HUD_StatusBar);
+			StatusBar->CallDraw (HUD_StatusBar, vp.TicFrac);
+			StatusBar->DrawTopStuff (HUD_StatusBar);
+		}
+		//stb.Unclock();
+		//Printf("Stbar = %f\n", stb.TimeMS());
+	}
+	else
+	{
+		screen->Begin2D();
 		switch (gamestate)
 		{
-		case GS_FULLCONSOLE:
-			screen->Begin2D(false);
-			C_DrawConsole ();
-			M_Drawer ();
-			screen->End2D();
-			screen->Update ();
-			return;
+			case GS_FULLCONSOLE:
+				screen->Begin2D();
+				C_DrawConsole ();
+				M_Drawer ();
+				screen->End2DAndUpdate ();
+				return;
 				
-		case GS_LEVEL:
-		case GS_TITLELEVEL:
-			if (!gametic)
-			{
-				screen->Begin2D(false);
+			case GS_INTERMISSION:
+				WI_Drawer ();
 				break;
-			}
 				
-			// [ZZ] execute event hook that we just started the frame
-			//E_RenderFrame();
-			//
+			case GS_FINALE:
+				F_Drawer ();
+				break;
 				
-			// Check for the presence of dynamic lights at the start of the frame once.
-			if ((gl_lights && vid_rendermode == 4) || (r_dynlights && vid_rendermode != 4))
-			{
-				TThinkerIterator<ADynamicLight> it(STAT_DLIGHT);
-				level.HasDynamicLights = !!it.Next();
-			}
-			else level.HasDynamicLights = false;	// lights are off so effectively we have none.
+			case GS_DEMOSCREEN:
+				D_PageDrawer ();
+				break;
 				
-			viewsec = screen->RenderView(&players[consoleplayer]);
-			screen->Begin2D(false);
-			screen->DrawBlend(viewsec);
-			// returns with 2S mode set.
-			if (automapactive)
-			{
-				AM_Drawer (hud_althud? viewheight : StatusBar->GetTopOfStatusbar());
-			}
-			if (!automapactive || viewactive)
-			{
-				screen->RefreshViewBorder ();
-			}
-
-			// for timing the statusbar code.
-			//cycle_t stb;
-			//stb.Reset();
-			//stb.Clock();
-			if (hud_althud && viewheight == SCREENHEIGHT && screenblocks > 10)
-			{
-				StatusBar->DrawBottomStuff (HUD_AltHud);
-				if (DrawFSHUD || automapactive) DrawHUD();
-				if (players[consoleplayer].camera && players[consoleplayer].camera->player && !automapactive)
-				{
-					StatusBar->DrawCrosshair();
-				}
-				StatusBar->CallDraw (HUD_AltHud, vp.TicFrac);
-				StatusBar->DrawTopStuff (HUD_AltHud);
-			}
-			else 
-			if (viewheight == SCREENHEIGHT && viewactive && screenblocks > 10)
-			{
-				EHudState state = DrawFSHUD ? HUD_Fullscreen : HUD_None;
-				StatusBar->DrawBottomStuff (state);
-				StatusBar->CallDraw (state, vp.TicFrac);
-				StatusBar->DrawTopStuff (state);
-			}
-			else
-			{
-				StatusBar->DrawBottomStuff (HUD_StatusBar);
-				StatusBar->CallDraw (HUD_StatusBar, vp.TicFrac);
-				StatusBar->DrawTopStuff (HUD_StatusBar);
-			}
-			//stb.Unclock();
-			//Printf("Stbar = %f\n", stb.TimeMS());
-			CT_Drawer ();
-			break;
-
-		case GS_INTERMISSION:
-			screen->Begin2D(false);
-			WI_Drawer ();
-			CT_Drawer ();
-			break;
-
-		case GS_FINALE:
-			screen->Begin2D(false);
-			F_Drawer ();
-			CT_Drawer ();
-			break;
-
-		case GS_DEMOSCREEN:
-			screen->Begin2D(false);
-			D_PageDrawer ();
-			CT_Drawer ();
-			break;
-
-		default:
-			break;
+			default:
+				break;
 		}
 	}
+	CT_Drawer ();
+
 	// draw pause pic
 	if ((paused || pauseext) && menuactive == MENU_Off)
 	{
@@ -887,7 +874,7 @@ void D_Display ()
 		C_DrawConsole ();	// draw console
 		M_Drawer ();			// menu is drawn even on top of everything
 		FStat::PrintStat ();
-		screen->Update ();		// page flip or blit buffer
+		screen->End2DAndUpdate ();
 	}
 	else
 	{
@@ -897,6 +884,7 @@ void D_Display ()
 
 		GSnd->SetSfxPaused(true, 1);
 		I_FreezeTime(true);
+		screen->End2D();
 		screen->WipeEndScreen ();
 
 		wipestart = I_msTime();
@@ -912,16 +900,16 @@ void D_Display ()
 			} while (diff < 1);
 			wipestart = nowtime;
 			done = screen->WipeDo (1);
+			screen->Begin2D();
 			C_DrawConsole ();	// console and
 			M_Drawer ();			// menu are drawn even on top of wipes
-			screen->Update ();		// page flip or blit buffer
+			screen->End2DAndUpdate ();
 			NetUpdate ();			// [RH] not sure this is needed anymore
 		} while (!done);
 		screen->WipeCleanup();
 		I_FreezeTime(false);
 		GSnd->SetSfxPaused(false, 1);
 	}
-	screen->End2D();
 	cycles.Unclock();
 	FrameCycles = cycles;
 }

src/gl/system/gl_framebuffer.cpp

@@ -151,7 +151,6 @@ void OpenGLFrameBuffer::Update()
 	twoD.Reset();
 	Flush3D.Reset();
 
-	DrawRateStuff();
 	Flush3D.Clock();
 	GLRenderer->Flush();
 	Flush3D.Unclock();

src/gl/system/gl_framebuffer.h

@@ -20,7 +20,7 @@ public:
 	~OpenGLFrameBuffer();
 
 	void InitializeState();
-	void Update();
+	void Update() override;
 
 	// Color correction
 	void SetGamma();

src/v_video.h

@@ -441,11 +441,18 @@ public:
     virtual IUniformBuffer *CreateUniformBuffer(size_t size, bool staticuse = false) { return nullptr; }
 	virtual IShaderProgram *CreateShaderProgram() { return nullptr; }
 
-	// Begin 2D drawing operations.
-	// Returns true if hardware-accelerated 2D has been entered, false if not.
-	void Begin2D(bool copy3d) { isIn2D = true; }
+	// Begin/End 2D drawing operations.
+	void Begin2D() { isIn2D = true; }
 	void End2D() { isIn2D = false; }
 
+	void End2DAndUpdate()
+	{
+		DrawRateStuff();
+		End2D();
+		Update();
+	}
+
+
 	// Returns true if Begin2D has been called and 2D drawing is now active
 	bool HasBegun2D() { return isIn2D; }