enhancement: Show SDL2 render thread option in the GUI

src/osdep/amiberry.cpp

@@ -2508,6 +2508,17 @@ void set_logfile_enabled(bool enabled)
 	amiberry_options.write_logfile = enabled;
 }
 
+bool get_sdl2_thread_enabled()
+{
+	return amiberry_options.use_sdl2_render_thread;
+}
+
+void set_sdl2_thread_enabled(bool enabled)
+{
+	amiberry_options.use_sdl2_render_thread = enabled;
+	sdl2_thread_changed = true;
+}
+
 // Returns 1 if savedatapath is overridden
 // if force_internal == true, the non-overridden whdbootpath based save-data path will be returned
 int get_savedatapath(char* out, int size, const int force_internal)

src/osdep/amiberry_gfx.cpp

@@ -96,6 +96,7 @@ static int deskhz;
 
 #ifdef AMIBERRY
 bool vsync_changed = false;
+bool sdl2_thread_changed = false;
 #endif
 
 // Check if the requested Amiga resolution can be displayed with the current Screen mode as a direct multiple
@@ -1003,7 +1004,7 @@ int check_prefs_changed_gfx()
 	c |= currprefs.multithreaded_drawing != changed_prefs.multithreaded_drawing ? (512) : 0;
 #endif
 
-	if (display_change_requested || c)
+	if (display_change_requested || c || sdl2_thread_changed)
 	{
 		bool setpause = false;
 		bool dontcapture = false;
@@ -1128,7 +1129,13 @@ int check_prefs_changed_gfx()
 		currprefs.rtgallowscaling = changed_prefs.rtgallowscaling;
 		currprefs.rtgscaleaspectratio = changed_prefs.rtgscaleaspectratio;
 		currprefs.rtgvblankrate = changed_prefs.rtgvblankrate;
-
+
+		if (sdl2_thread_changed)
+		{
+			graphics_leave();
+			graphics_init(true);
+			sdl2_thread_changed = false;
+		}
 		bool unacquired = false;
 		for (int monid = MAX_AMIGAMONITORS - 1; monid >= 0; monid--) {
 			if (!monitors[monid])

src/osdep/amiberry_gfx.h

@@ -147,3 +147,4 @@ void SDL2_toggle_vsync(bool vsync);
 extern void auto_crop_image();
 
 extern SDL_GameControllerButton vkbd_button;
+extern bool sdl2_thread_changed;

src/osdep/gui/Navigation.cpp

@@ -268,7 +268,7 @@ static NavigationMap navMap[] =
 
 	//  active            move left           move right          move up           move down
 	// PanelDisplay
-	{ "cboFullscreen", "Display", "chkHorizontal", "sldBrightness", "cboScreenmode" },
+	{ "cboFullscreen", "Display", "chkHorizontal", "chkSdl2Thread", "cboScreenmode" },
 	{ "cboScreenmode", "Display", "chkVertical", "cboFullscreen", "sldWidth" },
 	{ "sldWidth", "", "", "cboScreenmode", "sldHeight" },
 	{ "sldHeight", "", "", "sldWidth", "chkAutoCrop" },
@@ -285,7 +285,8 @@ static NavigationMap navMap[] =
 	{ "chkFlickerFixer", "Display", "optIDouble", "chkAspect", "chkFrameskip" },
 	{ "chkFrameskip", "Display", "optIDouble2", "chkFlickerFixer", "sldBrightness" },
 	{ "sldRefresh", "", "", "chkFlickerFixer", "sldBrightness" },
-	{ "sldBrightness", "", "", "chkFrameskip", "cboFullscreen" },
+	{ "sldBrightness", "", "", "chkFrameskip", "chkSdl2Thread" },
+	{ "chkSdl2Thread", "Display", "optIDouble2", "sldBrightness", "cboFullscreen" },
 
 	{ "chkHorizontal", "cboScreenmode", "", "optIDouble3", "chkVertical" },
 	{ "chkVertical", "cboScreenmode", "", "chkHorizontal", "optSingle" },

src/osdep/gui/PanelDisplay.cpp

@@ -124,6 +124,8 @@ static gcn::Label* lblBrightness;
 static gcn::Slider* sldBrightness;
 static gcn::Label* lblBrightnessValue;
 
+static gcn::CheckBox* chkSdl2Thread;
+
 class AmigaScreenActionListener : public gcn::ActionListener
 {
 public:
@@ -237,7 +239,10 @@ class AmigaScreenActionListener : public gcn::ActionListener
 
 		else if (actionEvent.getSource() == chkFilterLowRes)
 			changed_prefs.gfx_lores_mode = chkFilterLowRes->isSelected() ? 1 : 0;
-
+
+		else if (actionEvent.getSource() == chkSdl2Thread)
+			set_sdl2_thread_enabled(chkSdl2Thread->isSelected());
+
 		RefreshPanelDisplay();
 	}
 };
@@ -470,6 +475,10 @@ void InitPanelDisplay(const config_category& category)
 	lblBrightnessValue = new gcn::Label("0.0");
 	lblBrightnessValue->setAlignment(gcn::Graphics::LEFT);
 
+	chkSdl2Thread = new gcn::CheckBox("Use SDL2 multi-threaded rendering");
+	chkSdl2Thread->setId("chkSdl2Thread");
+	chkSdl2Thread->addActionListener(amigaScreenActionListener);
+
 	lblScreenmode = new gcn::Label("Screen mode:");
 	lblScreenmode->setAlignment(gcn::Graphics::RIGHT);
 	cboScreenmode = new gcn::DropDown(&fullscreen_modes_list);
@@ -634,6 +643,9 @@ void InitPanelDisplay(const config_category& category)
 	category.panel->add(lblBrightness, DISTANCE_BORDER, posY);
 	category.panel->add(sldBrightness, lblBrightness->getX() + lblBrightness->getWidth() + DISTANCE_NEXT_X, posY);
 	category.panel->add(lblBrightnessValue, sldBrightness->getX() + sldBrightness->getWidth() + 8, posY);
+	posY += lblBrightness->getHeight() + DISTANCE_NEXT_Y;
+
+	category.panel->add(chkSdl2Thread, DISTANCE_BORDER, posY);
 
 	RefreshPanelDisplay();
 }
@@ -696,6 +708,7 @@ void ExitPanelDisplay()
 	delete lblResolution;
 	delete cboResolution;
 	delete chkFilterLowRes;
+	delete chkSdl2Thread;
 }
 
 void RefreshPanelDisplay()
@@ -773,6 +786,8 @@ void RefreshPanelDisplay()
 	chkAspect->setSelected(changed_prefs.gfx_correct_aspect);
 	chkFilterLowRes->setSelected(changed_prefs.gfx_lores_mode);
 
+	chkSdl2Thread->setSelected(get_sdl2_thread_enabled());
+
 	if (changed_prefs.gfx_apmode[0].gfx_fullscreen == GFX_WINDOW)
 	{
 		cboScreenmode->setSelected(0);
@@ -941,6 +956,9 @@ bool HelpPanelDisplay(std::vector<std::string>& helptext)
 	helptext.emplace_back(" ");
 	helptext.emplace_back("\"Brightness\" - Allows adjustment of the output image brightness, from -200 to 200.");
 	helptext.emplace_back(" ");
+	helptext.emplace_back("\"Use SDL2 multi-threaded rendering\" - Enables multi-threaded drawing using SDL2.");
+	helptext.emplace_back("Provides a performance benefit, however not all systems support it.");
+    helptext.emplace_back("Disable this if you notice problems, like a black screen when starting emulation.");
 	helptext.emplace_back(" ");
 	helptext.emplace_back("\"Line Mode\" - These options define how the Amiga screen is drawn.");
 	helptext.emplace_back(" ");

src/osdep/target.h

@@ -106,6 +106,8 @@ extern int get_savedatapath(char* out, int size, const int force_internal);
 extern void get_whdbootpath(char* out, int size);
 extern void set_whdbootpath(char* newpath);
 
+extern bool get_sdl2_thread_enabled();
+extern void set_sdl2_thread_enabled(bool enabled);
 extern bool get_logfile_enabled();
 extern void set_logfile_enabled(bool enabled);
 extern void get_logfile_path(char* out, int size);