Chapter 6. Video

Table of Contents
SDL_GetVideoSurface -- returns a pointer to the current display surface
SDL_GetVideoInfo -- returns a pointer to information about the video hardware
SDL_VideoDriverName -- Obtain the name of the video driver
SDL_ListModes -- Returns a pointer to an array of available screen dimensions for the given format and video flags
SDL_VideoModeOK -- Check to see if a particular video mode is supported.
SDL_SetVideoMode -- Set up a video mode with the specified width, height and bits-per-pixel.
SDL_UpdateRect -- Makes sure the given area is updated on the given screen.
SDL_UpdateRects -- Makes sure the given list of rectangles is updated on the given screen.
SDL_Flip -- Swaps screen buffers
SDL_SetColors -- Sets a portion of the colormap for the given 8-bit surface.
SDL_SetPalette -- Sets the colors in the palette of an 8-bit surface.
SDL_SetGamma -- Sets the color gamma function for the display
SDL_GetGammaRamp -- Gets the color gamma lookup tables for the display
SDL_SetGammaRamp -- Sets the color gamma lookup tables for the display
SDL_MapRGB -- Map a RGB color value to a pixel format.
SDL_MapRGBA -- Map a RGBA color value to a pixel format.
SDL_GetRGB -- Get RGB values from a pixel in the specified pixel format.
SDL_GetRGBA -- Get RGBA values from a pixel in the specified pixel format.
SDL_CreateRGBSurface -- Create an empty SDL_Surface
SDL_CreateRGBSurfaceFrom -- Create an SDL_Surface from pixel data
SDL_FreeSurface -- Frees (deletes) a SDL_Surface
SDL_LockSurface -- Lock a surface for directly access.
SDL_UnlockSurface -- Unlocks a previously locked surface.
SDL_LoadBMP -- Load a Windows BMP file into an SDL_Surface.
SDL_SaveBMP -- Save an SDL_Surface as a Windows BMP file.
SDL_SetColorKey -- Sets the color key (transparent pixel) in a blittable surface and RLE acceleration.
SDL_SetAlpha -- Adjust the alpha properties of a surface
SDL_SetClipRect -- Sets the clipping rectangle for a surface.
SDL_GetClipRect -- Gets the clipping rectangle for a surface.
SDL_ConvertSurface -- Converts a surface to the same format as another surface.
SDL_BlitSurface -- This performs a fast blit from the source surface to the destination surface.
SDL_FillRect -- This function performs a fast fill of the given rectangle with some color
SDL_DisplayFormat -- Convert a surface to the display format
SDL_DisplayFormatAlpha -- Convert a surface to the display format
SDL_WarpMouse -- Set the position of the mouse cursor.
SDL_CreateCursor -- Creates a new mouse cursor.
SDL_FreeCursor -- Frees a cursor created with SDL_CreateCursor.
SDL_SetCursor -- Set the currently active mouse cursor.
SDL_GetCursor -- Get the currently active mouse cursor.
SDL_ShowCursor -- Toggle whether or not the cursor is shown on the screen.
SDL_GL_LoadLibrary -- Specify an OpenGL library
SDL_GL_GetProcAddress -- Get the address of a GL function
SDL_GL_GetAttribute -- Get the value of a special SDL/OpenGL attribute
SDL_GL_SetAttribute -- Set a special SDL/OpenGL attribute
SDL_GL_SwapBuffers -- Swap OpenGL framebuffers/Update Display
SDL_CreateYUVOverlay -- Create a YUV video overlay
SDL_LockYUVOverlay -- Lock an overlay
SDL_UnlockYUVOverlay -- Unlock an overlay
SDL_DisplayYUVOverlay -- Blit the overlay to the display
SDL_FreeYUVOverlay -- Free a YUV video overlay
SDL_GLattr -- SDL GL Attributes
SDL_Rect -- Defines a rectangular area
SDL_Color -- Format independent color description
SDL_Palette -- Color palette for 8-bit pixel formats
SDL_PixelFormat -- Stores surface format information
SDL_Surface -- Graphical Surface Structure
SDL_VideoInfo -- Video Target information
SDL_Overlay -- YUV video overlay

SDL presents a very simple interface to the display framebuffer. The framebuffer is represented as an offscreen surface to which you can write directly. If you want the screen to show what you have written, call the update function which will guarantee that the desired portion of the screen is updated.

Before you call any of the SDL video functions, you must first call SDL_Init(SDL_INIT_VIDEO), which initializes the video and events in the SDL library. Check the return code, which should be 0, to see if there were any errors in starting up.

If you use both sound and video in your application, you need to call SDL_Init(SDL_INIT_AUDIO | SDL_INIT_VIDEO) before opening the sound device, otherwise under Win32 DirectX, you won't be able to set full-screen display modes.

After you have initialized the library, you can start up the video display in a number of ways. The easiest way is to pick a common screen resolution and depth and just initialize the video, checking for errors. You will probably get what you want, but SDL may be emulating your requested mode and converting the display on update. The best way is to query, for the best video mode closest to the desired one, and then convert your images to that pixel format.

SDL currently supports any bit depth >= 8 bits per pixel. 8 bpp formats are considered 8-bit palettized modes, while 12, 15, 16, 24, and 32 bits per pixel are considered "packed pixel" modes, meaning each pixel contains the RGB color components packed in the bits of the pixel.

After you have initialized your video mode, you can take the surface that was returned, and write to it like any other framebuffer, calling the update routine as you go.

When you have finished your video access and are ready to quit your application, you should call "SDL_Quit()" to shutdown the video and events.