win32: add ability to disable each gpu, for speedup by halting render of useless screens

desmume/src/GPU.cpp

@@ -3062,6 +3062,14 @@ void GPU_ligne(NDS_Screen * screen, u16 l)
 		gpu->refreshAffineStartRegs(-1,-1);
 	}
 
+	//blacken the screen if it is turned off by the user
+	if(!CommonSettings.showGpu.screens[gpu->core])
+	{
+		u8 * dst =  GPU_tempScreen + (screen->offset + l) * 512;
+		memset(dst,0,512);
+		return;
+	}
+
 	//cache some parameters which are assumed to be stable throughout the rendering of the entire line
 	gpu->currLine = (u8)l;
 	u16 mosaic_control = T1ReadWord((u8 *)&gpu->dispx_st->dispx_MISC.MOSAIC, 0);

desmume/src/NDSSystem.h

@@ -389,6 +389,14 @@ extern struct TCommonSettings {
 	//this is the user's choice of manual backup type, for cases when the autodetection can't be trusted
 	int manualBackupType;
 
+	struct _ShowGpu {
+		_ShowGpu() : main(true), sub(true) {}
+		union {
+			struct { bool main,sub; };
+			bool screens[2];
+		};
+	} showGpu;
+
 } CommonSettings;
 
 extern char ROMserial[20];

desmume/src/gfx3d.cpp

@@ -1510,10 +1510,12 @@ void gfx3d_VBlankEndSignal(bool skipFrame)
 	if(!drawPending) return;
 
 	drawPending = FALSE;
-	gpu3D->NDS_3D_Render();
+
+	if(CommonSettings.showGpu.main)
+		gpu3D->NDS_3D_Render();
 
 	//if the null 3d core is chosen, then we need to clear out the 3d buffers to keep old data from being rendered
-	if(gpu3D == &gpu3DNull)
+	if(gpu3D == &gpu3DNull || !CommonSettings.showGpu.main)
 	{
 		memset(gfx3d_convertedScreen,0,sizeof(gfx3d_convertedScreen));
 		memset(gfx3d_convertedScreen,0,sizeof(gfx3d_convertedAlpha));

desmume/src/windows/main.cpp

@@ -1639,6 +1639,9 @@ int _main()
 	ShowMicrophone = GetPrivateProfileInt("Display","Display Microphone", 0, IniName);
 	ScreenGap = GetPrivateProfileInt("Display", "ScreenGap", 0, IniName);
 	FrameLimit = GetPrivateProfileInt("FrameLimit", "FrameLimit", 1, IniName);
+	CommonSettings.showGpu.main = GetPrivateProfileInt("Display", "MainGpu", 1, IniName) != 0;
+	CommonSettings.showGpu.sub = GetPrivateProfileInt("Display", "SubGpu", 1, IniName) != 0;
+
 	
 	//Get Ram-Watch values
 	RWSaveWindowPos = GetPrivateProfileInt("RamWatch", "SaveWindowPos", 0, IniName);
@@ -2674,6 +2677,9 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM
 			MainWindow->checkMenu(IDC_FRAMESKIP8, MF_BYCOMMAND | (!autoframeskipenab && frameskiprate==8) ? MF_CHECKED:MF_UNCHECKED);
 			MainWindow->checkMenu(IDC_FRAMESKIP9, MF_BYCOMMAND | (!autoframeskipenab && frameskiprate==9) ? MF_CHECKED:MF_UNCHECKED);
 
+			MainWindow->checkMenu(IDM_MGPU, MF_BYCOMMAND | CommonSettings.showGpu.main ? MF_CHECKED:MF_UNCHECKED);
+			MainWindow->checkMenu(IDM_SGPU, MF_BYCOMMAND | CommonSettings.showGpu.sub ? MF_CHECKED:MF_UNCHECKED);
+
 			//Language selection
 
 			//Save type
@@ -3180,6 +3186,16 @@ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM
 			return 0;
 			//========================================================== Tools end
 
+		case IDM_MGPU:
+			CommonSettings.showGpu.main = !CommonSettings.showGpu.main;
+			WritePrivateProfileInt("Display","MainGpu",CommonSettings.showGpu.main?1:0,IniName);
+			return 0;
+
+		case IDM_SGPU:
+			CommonSettings.showGpu.sub = !CommonSettings.showGpu.sub;
+			WritePrivateProfileInt("Display","SubGpu",CommonSettings.showGpu.sub?1:0,IniName);
+			return 0;
+
 		case IDM_MBG0 : 
 			if(MainScreen.gpu->dispBG[0])
 			{

desmume/src/windows/resource.h

@@ -97,6 +97,8 @@
 #define IDC_LANGENGLISH                         210
 #define IDC_LANGFRENCH                          211
 #define IDC_LANGDANISH                          212
+#define IDM_MGPU                                213
+#define IDM_SGPU                                214
 #define IDC_8_BIT                               302
 #define IDC_16_BIT                              303
 #define IDC_32_BIT                              304

desmume/src/windows/resources.rc

@@ -359,11 +359,13 @@ MENU_PRINCIPAL MENU
         MENUITEM SEPARATOR
         POPUP "&View Layers"
         {
+            MENUITEM "Main GPU", IDM_MGPU, CHECKED
             MENUITEM "Main BG 0", IDM_MBG0, CHECKED
             MENUITEM "Main BG 1", IDM_MBG1, CHECKED
             MENUITEM "Main BG 2", IDM_MBG2, CHECKED
             MENUITEM "Main BG 3", IDM_MBG3, CHECKED
             MENUITEM SEPARATOR
+            MENUITEM "Sub GPU", IDM_SGPU, CHECKED
             MENUITEM "Sub BG 0", IDM_SBG0, CHECKED
             MENUITEM "Sub BG 1", IDM_SBG1, CHECKED
             MENUITEM "Sub BG 2", IDM_SBG2, CHECKED