Fixed an OpenGL problem which causes a crash on some systems.

When in OpenGL mode, SDL_GL_SwapBuffers should be used instead of SDL_Flip. And only once per frame.
karadoc · Jan 13, 2024 · 7138594 · 7138594
1 parent 123b37f
commit 7138594
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Showing 3 changed files with 8 additions and 7 deletions.
diff --git a/src/Engine/Screen.cpp b/src/Engine/Screen.cpp
@@ -203,7 +203,7 @@ void Screen::flip()
 
 	if (getWidth() != _baseWidth || getHeight() != _baseHeight || useOpenGL())
 	{
-		Zoom::flipWithZoom(_surface.get(), _screen, _topBlackBand, _bottomBlackBand, _leftBlackBand, _rightBlackBand, &glOutput);
+		Zoom::blitWithZoom(_surface.get(), _screen, _topBlackBand, _bottomBlackBand, _leftBlackBand, _rightBlackBand, &glOutput);
 	}
 	else
 	{
@@ -221,9 +221,11 @@ void Screen::flip()
 		_pushPalette = false;
 	}
 
-
-
-	if (SDL_Flip(_screen) == -1)
+	if (useOpenGL())
+	{
+		SDL_GL_SwapBuffers();
+	}
+	else if (SDL_Flip(_screen) == -1)
 	{
 		throw Exception(SDL_GetError());
 	}

diff --git a/src/Engine/Zoom.cpp b/src/Engine/Zoom.cpp
@@ -665,7 +665,7 @@ bool Zoom::haveSSE2()
  * @param rightBlackBand Size of right black band in pixels (letterboxing).
  * @param glOut OpenGL output.
  */
-void Zoom::flipWithZoom(SDL_Surface *src, SDL_Surface *dst, int topBlackBand, int bottomBlackBand, int leftBlackBand, int rightBlackBand, OpenGL *glOut)
+void Zoom::blitWithZoom(SDL_Surface *src, SDL_Surface *dst, int topBlackBand, int bottomBlackBand, int leftBlackBand, int rightBlackBand, OpenGL *glOut)
 {
 	int dstWidth = dst->w - leftBlackBand - rightBlackBand;
 	int dstHeight = dst->h - topBlackBand - bottomBlackBand;
@@ -677,7 +677,6 @@ void Zoom::flipWithZoom(SDL_Surface *src, SDL_Surface *dst, int topBlackBand, in
 			SDL_BlitSurface(src, 0, glOut->surface.get(), 0); // TODO; this is less than ideal...
 
 			glOut->refresh(glOut->linear, glOut->iwidth, glOut->iheight, dst->w, dst->h, topBlackBand, bottomBlackBand, leftBlackBand, rightBlackBand);
-			SDL_GL_SwapBuffers();
 		}
 #endif
 	}

diff --git a/src/Engine/Zoom.h b/src/Engine/Zoom.h
@@ -29,7 +29,7 @@ class Zoom
 
 	public:
 	/// Flip screen given src and dst; might use software or OpenGL.
-	static void flipWithZoom(SDL_Surface *src, SDL_Surface *dst, int topBlackBand, int bottomBlackBand, int leftBlackBand, int rightBlackBand, OpenGL *glOut);
+	static void blitWithZoom(SDL_Surface *src, SDL_Surface *dst, int topBlackBand, int bottomBlackBand, int leftBlackBand, int rightBlackBand, OpenGL *glOut);
 	/// Copy src to dst, resizing as needed. Please don't use flipx or flipy as the optimized functions ignore these parameters.
 	static int _zoomSurfaceY(SDL_Surface * src, SDL_Surface * dst, int flipx, int flipy);
 	/// Check for SSE2 instructions using CPUID.