Added a way to get a framebuffer interface for a window, and also a way to create a software renderer for an arbitrary surface.

The software renderer has been re-routed to use the framebuffer interface, which makes it possible to have software rendering available even on simple ports.

include/SDL_render.h

@@ -154,12 +154,25 @@ extern DECLSPEC int SDLCALL SDL_GetRenderDriverInfo(int index,
  *  
  *  \return A valid rendering context or NULL if there was an error.
  *  
+ *  \sa SDL_CreateSoftwareRenderer()
  *  \sa SDL_GetRendererInfo()
  *  \sa SDL_DestroyRenderer()
  */
 extern DECLSPEC SDL_Renderer * SDLCALL SDL_CreateRenderer(SDL_Window * window,
                                                int index, Uint32 flags);
 
+/**
+ *  \brief Create a 2D software rendering context for a surface.
+ *  
+ *  \param surface The surface where rendering is done.
+ *  
+ *  \return A valid rendering context or NULL if there was an error.
+ *  
+ *  \sa SDL_CreateRenderer()
+ *  \sa SDL_DestroyRenderer()
+ */
+extern DECLSPEC SDL_Renderer * SDLCALL SDL_CreateSoftwareRenderer(SDL_Surface * surface);
+
 /**
  *  \brief Get information about a rendering context.
  */

include/SDL_video.h

@@ -607,6 +607,40 @@ extern DECLSPEC void SDLCALL SDL_RestoreWindow(SDL_Window * window);
 extern DECLSPEC int SDLCALL SDL_SetWindowFullscreen(SDL_Window * window,
                                                     int fullscreen);
 
+/**
+ *  \brief Get an SDL surface associated with the window.
+ *
+ *  \return A surface in the optimal format for the window, or NULL on error.
+ *
+ *  \note You may not combine this with 3D or the rendering API on this window.
+ *
+ *  \sa SDL_UpdateWindowSurface()
+ *  \sa SDL_UpdateWindowSurfaceRects()
+ */
+extern DECLSPEC SDL_Surface * SDLCALL SDL_GetWindowSurface(SDL_Window * window);
+
+/**
+ *  \brief Copy the window surface to the screen.
+ *
+ *  \return 0 on success, or -1 on error.
+ *
+ *  \sa SDL_GetWindowSurface()
+ *  \sa SDL_UpdateWindowSurfaceRects()
+ */
+extern DECLSPEC int SDLCALL SDL_UpdateWindowSurface(SDL_Window * window);
+
+/**
+ *  \brief Copy a number of rectangles on the window surface to the screen.
+ *
+ *  \return 0 on success, or -1 on error.
+ *
+ *  \sa SDL_GetWindowSurface()
+ *  \sa SDL_UpdateWindowSurfaceRect()
+ */
+extern DECLSPEC int SDLCALL SDL_UpdateWindowSurfaceRects(SDL_Window * window,
+                                                         int numrects,
+                                                         SDL_Rect * rects);
+
 /**
  *  \brief Set a window's input grab mode.
  *