Simplify Flip Mode rendering code with SDL_RenderCopyEx

Previously, Flip Mode rendering had to be complicated and allocate
another buffer to call FlipSurfaceVerticle, and it was just a mess.

Instead, why not just do SDL_RenderCopyEx, and let SDL flip the screen
for us? This ends up pretty massively simplifying the rendering code.

desktop_version/src/Graphics.cpp

@@ -3038,41 +3038,14 @@ void Graphics::setcol( int t )
 
 void Graphics::menuoffrender(void)
 {
-	SDL_Rect offsetRect1;
+	const int usethisoffset = lerp(oldmenuoffset, menuoffset);
-	setRect (offsetRect1, 0, 0, backBuffer->w ,backBuffer->h);
+	SDL_Rect offsetRect = {0, usethisoffset, backBuffer->w, backBuffer->h};
 
-	//put the back buffer in the menubuffer
 	BlitSurfaceStandard(backBuffer, NULL, menubuffer, NULL);
-
-
-
-	int usethisoffset = lerp(oldmenuoffset, menuoffset);
-	if(flipmode)
-	{
-		SDL_Surface* tempbufferFlipped = FlipSurfaceVerticle(tempBuffer);
-		//put the stored backbuffer in the backbuffer.
-		ClearSurface(backBuffer);
-		BlitSurfaceStandard(tempbufferFlipped, NULL, backBuffer, NULL);
-		SDL_FreeSurface(tempbufferFlipped);
-		SDL_Rect offsetRect;
-		setRect (offsetRect, 0, -usethisoffset, backBuffer->w ,backBuffer->h);
-		SDL_Surface* temp = FlipSurfaceVerticle(menubuffer);
-		BlitSurfaceStandard(temp,NULL,backBuffer,&offsetRect);
-		SDL_FreeSurface(temp);
-	}
-	else
-	{
-		//put the stored backbuffer in the backbuffer.
 	BlitSurfaceStandard(tempBuffer, NULL, backBuffer, NULL);
+	BlitSurfaceStandard(menubuffer, NULL, backBuffer, &offsetRect);
 
-		SDL_Rect offsetRect;
+	screenbuffer->UpdateScreen(backBuffer, NULL);
-		setRect (offsetRect, 0, usethisoffset, backBuffer->w ,backBuffer->h);
-		BlitSurfaceStandard(menubuffer,NULL,backBuffer,&offsetRect);
-	}
-
-	SDL_Rect rect;
-	setRect(rect, 0, 0, backBuffer->w, backBuffer->h);
-	screenbuffer->UpdateScreen(backBuffer,&rect);
 	ClearSurface(backBuffer);
 }
 
@@ -3192,20 +3165,8 @@ void Graphics::flashlight(void)
 
 void Graphics::screenshake(void)
 {
-	if(flipmode)
+	SDL_Rect shakeRect = {screenshake_x, screenshake_y, backBuffer->w, backBuffer->h};
-	{
+	screenbuffer->UpdateScreen(backBuffer, &shakeRect);
-		SDL_Rect shakeRect;
-		setRect(shakeRect,screenshake_x, screenshake_y, backBuffer->w, backBuffer->h);
-		SDL_Surface* flipBackBuffer = FlipSurfaceVerticle(backBuffer);
-		screenbuffer->UpdateScreen( flipBackBuffer, &shakeRect);
-		SDL_FreeSurface(flipBackBuffer);
-	}
-	else
-	{
-		SDL_Rect shakeRect;
-		setRect(shakeRect,screenshake_x, screenshake_y, backBuffer->w, backBuffer->h);
-		screenbuffer->UpdateScreen( backBuffer, &shakeRect);
-	}
 
 	ClearSurface(backBuffer);
 }
@@ -3218,27 +3179,12 @@ void Graphics::updatescreenshake(void)
 
 void Graphics::render(void)
 {
-	if(screenbuffer == NULL)
+	if (screenbuffer == NULL)
 	{
 		return;
 	}
-	if(flipmode)
+
-	{
+	screenbuffer->UpdateScreen(backBuffer, NULL);
-		SDL_Rect rect;
-		setRect(rect, 0, 0, backBuffer->w, backBuffer->h);
-		SDL_Surface* tempsurface = FlipSurfaceVerticle(backBuffer);
-		if(tempsurface != NULL)
-		{
-			screenbuffer->UpdateScreen( tempsurface, &rect);
-			SDL_FreeSurface(tempsurface);
-		}
-	}
-	else
-	{
-		SDL_Rect rect;
-		setRect(rect, 0, 0, backBuffer->w, backBuffer->h);
-		screenbuffer->UpdateScreen( backBuffer, &rect);
-	}
 }
 
 void Graphics::renderwithscreeneffects(void)

desktop_version/src/Screen.cpp

@@ -306,19 +306,32 @@ const SDL_PixelFormat* Screen::GetFormat(void)
 	return m_screen->format;
 }
 
-void Screen::FlipScreen(void)
+void Screen::FlipScreen(const bool flipmode)
 {
+	SDL_RendererFlip flip_flags;
+	if (flipmode)
+	{
+		flip_flags = SDL_FLIP_VERTICAL;
+	}
+	else
+	{
+		flip_flags = SDL_FLIP_NONE;
+	}
+
 	SDL_UpdateTexture(
 		m_screenTexture,
 		NULL,
 		m_screen->pixels,
 		m_screen->pitch
 	);
-	SDL_RenderCopy(
+	SDL_RenderCopyEx(
 		m_renderer,
 		m_screenTexture,
 		isFiltered ? &filterSubrect : NULL,
-		NULL
+		NULL,
+		0.0,
+		NULL,
+		flip_flags
 	);
 	SDL_RenderPresent(m_renderer);
 	SDL_RenderClear(m_renderer);

desktop_version/src/Screen.h

@@ -20,7 +20,7 @@ public:
 	void GetWindowSize(int* x, int* y);
 
 	void UpdateScreen(SDL_Surface* buffer, SDL_Rect* rect);
-	void FlipScreen(void);
+	void FlipScreen(bool flipmode);
 
 	const SDL_PixelFormat* GetFormat(void);
 

desktop_version/src/main.cpp

@@ -750,7 +750,7 @@ static void inline deltaloop(void)
         {
             implfunc->func();
 
-            gameScreen.FlipScreen();
+            gameScreen.FlipScreen(graphics.flipmode);
         }
     }
 }
@@ -781,7 +781,7 @@ static void unfocused_run(void)
 #undef FLIP
     }
     graphics.render();
-    gameScreen.FlipScreen();
+    gameScreen.FlipScreen(graphics.flipmode);
     //We are minimised, so lets put a bit of a delay to save CPU
 #ifndef __EMSCRIPTEN__
     SDL_Delay(100);