Implement GLimp_SetScreenParms() for "vid_restart partial"

"vid_restart partial" only changes the window size or its fullscreen
(or windowed) state, without recreating everything.
If that fails (or antialiasing settings have changed), it will fall back
to a full vid_restart (this behavior is different than original
 "vid_restart partial" that probably was implemented in Vanilla Doom3
 but not dhewm3)

This is used for Alt-Enter (which toggles between fullscreen and
windowed state) and when pressing the Apply button in the new Video Menu

neo/framework/Dhewm3SettingsMenu.cpp

@@ -1757,9 +1757,7 @@ static void ApplyVideoSettings()
 	int msaa = ( msaaModeIndex > 0 ) ? ( 1 << msaaModeIndex ) : 0;
 	r_multiSamples.SetInteger( msaa );
 
-	cmdSystem->BufferCommandText( CMD_EXEC_APPEND, "vid_restart\n" );
-	// TODO: if only fullscreen is changed, the following might suffice
-	//cmdSystem->BufferCommandText( CMD_EXEC_APPEND, "vid_restart partial windowed\n" );
+	cmdSystem->BufferCommandText( CMD_EXEC_APPEND, "vid_restart partial\n" );
 }
 
 static void InitVideoOptionsMenu()
@@ -1859,7 +1857,6 @@ static void DrawVideoOptionsMenu()
 	if ( !VideoHasApplyableChanges() ) {
 		ImGui::BeginDisabled();
 		ImGui::Button( "Apply" );
-		// TODO: the tooltips backgrounds are transparent (due to this being disabled), which sucks
 		AddTooltip( "No changes were made, so there's nothing to apply" );
 		ImGui::SameLine();
 		ImGui::Button( "Reset" );

neo/renderer/RenderSystem_init.cpp

@@ -1961,12 +1961,6 @@ void R_VidRestart_f( const idCmdArgs &args ) {
 		return;
 	}
 
-	// DG: notify the game DLL about the reloadImages and vid_restart commands
-	if(gameCallbacks.reloadImagesCB != NULL)
-	{
-		gameCallbacks.reloadImagesCB(gameCallbacks.reloadImagesUserArg, args);
-	}
-
 	bool full = true;
 	bool forceWindow = false;
 	for ( int i = 1 ; i < args.Argc() ; i++ ) {
@@ -1980,6 +1974,38 @@ void R_VidRestart_f( const idCmdArgs &args ) {
 		}
 	}
 
+	// DG: in partial mode, try to just resize the window (and make it fullscreen or windowed)
+	//     instead of doing a full vid_restart. Still falls back to a full vid_restart
+	//     in case this doesn't work (for example because MSAA settings have changed)
+	if ( !full ) {
+		int wantedWidth=0, wantedHeight=0;
+		if ( !R_GetModeInfo( &wantedWidth, &wantedHeight, r_mode.GetInteger() ) ) {
+			common->Warning( "vid_restart: R_GetModeInfo() failed?!\n" );
+		} else {
+			glimpParms_t	parms;
+			parms.width = wantedWidth;
+			parms.height = wantedHeight;
+
+			parms.fullScreen = ( forceWindow ) ? false : r_fullscreen.GetBool();
+			parms.displayHz = r_displayRefresh.GetInteger();
+			// "vid_restart partial windowed" is used in case of errors to return to windowed mode
+			// before things explode more. in that case just keep whatever MSAA setting is active
+			parms.multiSamples = forceWindow ? -1 : r_multiSamples.GetInteger();
+			parms.stereo = false;
+
+			if ( GLimp_SetScreenParms( parms ) ) {
+				common->Printf( "'vid_restart partial' succeeded in changing resolution and/or fullscreen mode" );
+				return;
+			}
+		}
+	}
+
+	// DG: notify the game DLL about the reloadImages and (non-partial) vid_restart commands
+	if(gameCallbacks.reloadImagesCB != NULL)
+	{
+		gameCallbacks.reloadImagesCB(gameCallbacks.reloadImagesUserArg, args);
+	}
+
 	// this could take a while, so give them the cursor back ASAP
 	Sys_GrabMouseCursor( false );
 
@@ -1998,37 +2024,24 @@ void R_VidRestart_f( const idCmdArgs &args ) {
 
 	// sound and input are tied to the window we are about to destroy
 
-	if ( full ) {
-		// free all of our texture numbers
-		soundSystem->ShutdownHW();
-		Sys_ShutdownInput();
-		globalImages->PurgeAllImages();
-		// free the context and close the window
-		GLimp_Shutdown();
-		glConfig.isInitialized = false;
+	// free all of our texture numbers
+	soundSystem->ShutdownHW();
+	Sys_ShutdownInput();
+	globalImages->PurgeAllImages();
+	// free the context and close the window
+	GLimp_Shutdown();
+	glConfig.isInitialized = false;
 
-		// create the new context and vertex cache
-		bool latch = cvarSystem->GetCVarBool( "r_fullscreen" );
-		if ( forceWindow ) {
-			cvarSystem->SetCVarBool( "r_fullscreen", false );
-		}
-		R_InitOpenGL();
-		cvarSystem->SetCVarBool( "r_fullscreen", latch );
-
-		// regenerate all images
-		globalImages->ReloadAllImages();
-	} else {
-		glimpParms_t	parms;
-		parms.width = glConfig.winWidth;   // DG: HighDPI adjustment: explicitly use window size
-		parms.height = glConfig.winHeight;
-		parms.fullScreen = ( forceWindow ) ? false : r_fullscreen.GetBool();
-		parms.displayHz = r_displayRefresh.GetInteger();
-		parms.multiSamples = r_multiSamples.GetInteger();
-		parms.stereo = false;
-		GLimp_SetScreenParms( parms );
+	// create the new context and vertex cache
+	bool latch = cvarSystem->GetCVarBool( "r_fullscreen" );
+	if ( forceWindow ) {
+		cvarSystem->SetCVarBool( "r_fullscreen", false );
 	}
+	R_InitOpenGL();
+	cvarSystem->SetCVarBool( "r_fullscreen", latch );
 
-
+	// regenerate all images
+	globalImages->ReloadAllImages();
 
 	// make sure the regeneration doesn't use anything no longer valid
 	tr.viewCount++;

neo/sys/events.cpp

@@ -1190,7 +1190,7 @@ sysEvent_t Sys_GetEvent() {
 		case SDL_KEYDOWN:
 			if (ev.key.keysym.sym == SDLK_RETURN && (ev.key.keysym.mod & KMOD_ALT) > 0) {
 				cvarSystem->SetCVarBool("r_fullscreen", !renderSystem->IsFullScreen());
-				PushConsoleEvent("vid_restart");
+				PushConsoleEvent("vid_restart partial");
 				return res_none;
 			}
 

neo/sys/glimp.cpp

@@ -608,8 +608,94 @@ GLimp_SetScreenParms
 ===================
 */
 bool GLimp_SetScreenParms(glimpParms_t parms) {
-	common->DPrintf("TODO: GLimp_ActivateContext\n");
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	int curMultiSamples = 0;
+	if ( SDL_GL_GetAttribute( SDL_GL_MULTISAMPLEBUFFERS, &curMultiSamples ) == 0 && curMultiSamples > 0 ) {
+		if ( SDL_GL_GetAttribute( SDL_GL_MULTISAMPLESAMPLES, &curMultiSamples ) != 0 ) {
+			curMultiSamples = 0; // SDL_GL_GetAttribute() call failed, assume no MSAA
+		}
+	} else {
+		curMultiSamples = 0; // SDL_GL_GetAttribute() call failed, assume no MSAA
+	}
+
+	if( parms.multiSamples != -1 && parms.multiSamples != curMultiSamples ) {
+		// if MSAA settings have changed, we really need a vid_restart
+		return false;
+	}
+
+	Uint32 winFlags = SDL_GetWindowFlags( window );
+	bool isFullscreen = (winFlags & SDL_WINDOW_FULLSCREEN) != 0;
+	bool isFullscreenDesktop = (winFlags & SDL_WINDOW_FULLSCREEN_DESKTOP) == SDL_WINDOW_FULLSCREEN_DESKTOP;
+
+	bool wantFullscreenDesktop = parms.fullScreen && r_fullscreenDesktop.GetBool();
+
+	// TODO: parms.displayHz ?
+
+	if ( isFullscreenDesktop && wantFullscreenDesktop ) {
+		return true; // nothing to do (resolution is not configurable in that mode)
+	}
+
+	if ( !parms.fullScreen ) { // we want windowed mode
+		if ( isFullscreen && SDL_SetWindowFullscreen( window, 0 ) != 0 ) {
+			common->Warning( "GLimp_SetScreenParms(): Couldn't switch to windowed mode, SDL error: %s\n", SDL_GetError() );
+			return false;
+		}
+		SDL_RestoreWindow( window ); // make sure we're not maximized, then setting the size wouldn't work
+		SDL_SetWindowSize( window, parms.width, parms.height );
+	} else { // we want some kind of fullscreen mode
+
+		// it's probably safest to first switch to windowed mode
+		if ( isFullscreen ) {
+			SDL_SetWindowFullscreen( window, 0 );
+		}
+
+		if ( wantFullscreenDesktop ) {
+			if ( SDL_SetWindowFullscreen( window, SDL_WINDOW_FULLSCREEN_DESKTOP ) != 0 ) {
+				common->Warning( "GLimp_SetScreenParms(): Couldn't switch to fullscreen desktop mode, SDL error: %s\n", SDL_GetError() );
+				return false;
+			}
+		} else { // want real fullscreen
+			SDL_DisplayMode wanted_mode = {};
+
+			wanted_mode.w = parms.width;
+			wanted_mode.h = parms.height;
+
+			// TODO: refresh rate? parms.displayHz should probably try to get most similar mode before trying to set it?
+
+			if ( SDL_SetWindowDisplayMode( window, &wanted_mode ) != 0 )
+			{
+				common->Warning("GLimp_SetScreenParms(): Can't set fullscreen resolution to %ix%i: %s\n", wanted_mode.w, wanted_mode.h, SDL_GetError());
+				return false;
+			}
+
+			/* The SDL doku says, that SDL_SetWindowSize() shouldn't be
+			   used on fullscreen windows. But at least in my test with
+			   SDL 2.0.9 the subsequent SDL_GetWindowDisplayMode() fails
+			   if I don't call it. */
+			SDL_SetWindowSize( window, wanted_mode.w, wanted_mode.h );
+
+			SDL_DisplayMode real_mode = {};
+			if ( SDL_GetWindowDisplayMode( window, &real_mode ) != 0 )
+			{
+				common->Warning( "GLimp_SetScreenParms(): Can't get display mode: %s\n", SDL_GetError() );
+				return false; // trying other color depth etc is unlikely to help with this issue
+			}
+
+			if ( (real_mode.w != wanted_mode.w) || (real_mode.h != wanted_mode.h) )
+			{
+				common->Warning( "GLimp_SetScreenParms(): Still in wrong display mode: %ix%i instead of %ix%i\n",
+				                 real_mode.w, real_mode.h, wanted_mode.w, wanted_mode.h );
+
+				return false;
+			}
+		}
+	}
+
 	return true;
+
+#else // SDL1.2 - I don't feel like implementing this for old SDL, just do a full vid_restart, like before
+	return false;
+#endif
 }
 
 /*