SDL 显示YUV，RGB， BMP

This is a list of API changes in SDL's version history. Version 1.0: 1.2.14: Added cast macros for correct usage with C++: SDL_reinterpret_cast(type, expression) SDL_static_cast(type, expression) Added SDL_VIDEO_FULLSCREEN_DISPLAY as a preferred synonym for SDL_VIDEO_FULLSCREEN_HEAD on X11. Added SDL_DISABLE_LOCK_KEYS environment variable to enable normal up/down events for Caps-Lock and Num-Lock keys. 1.2.13: Added SDL_BUTTON_X1 and SDL_BUTTON_X2 constants. 1.2.12: Added SDL_VIDEO_ALLOW_SCREENSAVER to override SDL's disabling of the screensaver on Mac OS X and X11. 1.2.10: If SDL_OpenAudio() is passed zero for the desired format fields, the following environment variables will be used to fill them in: SDL_AUDIO_FREQUENCY SDL_AUDIO_FORMAT SDL_AUDIO_CHANNELS SDL_AUDIO_SAMPLES If an environment variable is not specified, it will be set to a reasonable default value. Added support for the SDL_VIDEO_FULLSCREEN_HEAD environment variable, currently supported on X11 Xinerama configurations. Added SDL_GL_SWAP_CONTROL to wait for vsync in OpenGL applications. Added SDL_GL_ACCELERATED_VISUAL to guarantee hardware acceleration. Added current_w and current_h to the SDL_VideoInfo structure, which is set to the desktop resolution during video intialization, and then set to the current resolution when a video mode is set. SDL_SetVideoMode() now accepts 0 for width or height and will use the current video mode (or the desktop mode if no mode has been set.) Added SDL_GetKeyRepeat() Added SDL_config.h, with defaults for various build environments. 1.2.7: Added CPU feature detection functions to SDL_cpuinfo.h: SDL_HasRDTSC(), SDL_HasMMX(), SDL_Has3DNow(), SDL_HasSSE(), SDL_HasAltiVec() Added function to create RWops from const memory: SDL_RWFromConstMem() 1.2.6: Added SDL_LoadObject(), SDL_LoadFunction(), and SDL_UnloadObject() Added SDL_GL_MULTISAMPLEBUFFERS and SDL_GL_MULTISAMPLESAMPLES for FSAA 1.2.5: Added SDL_BUTTON_WHEELUP (4) and SDL_BUTTON_WHEELDOWN (5) Added SDL_GL_STEREO for stereoscopic OpenGL contexts 1.2.0: Added SDL_VIDEOEXPOSE event to signal that the screen needs to be redrawn. This is currently only delivered to OpenGL windows on X11, though it may be delivered in the future when the video memory is lost under DirectX. 1.1.8: You can pass SDL_NOFRAME to SDL_VideoMode() to create a window that has no title bar or frame decoration. Fullscreen video modes automatically have this flag set. Added a function to query the clipping rectangle for a surface: void SDL_GetClipRect(SDL_Surface *surface, SDL_Rect *rect) Added a function to query the current event filter: SDL_EventFilter SDL_GetEventFilter(void) If you pass -1 to SDL_ShowCursor(), it won't change the current cursor visibility state, but will still return it. SDL_LockSurface() and SDL_UnlockSurface() are recursive, meaning you can nest them as deep as you want, as long as each lock call has a matching unlock call. The surface remains locked until the last matching unlock call. Note that you may not blit to or from a locked surface. 1.1.7: The SDL_SetGammaRamp() and SDL_GetGammaRamp() functions now take arrays of Uint16 values instead of Uint8 values. For the most part, you can just take your old values and shift them up 8 bits to get new correct values for your gamma ramps. You can pass SDL_RLEACCEL in flags passed to SDL_ConvertSurface() and SDL will try to RLE accelerate colorkey and alpha blits in the resulting surface. 1.1.6: Added a function to return the thread ID of a specific thread: Uint32 SDL_GetThreadID(SDL_Thread *thread) If 'thread' is NULL, this function returns the id for this thread. 1.1.5: The YUV overlay structure has been changed to use an array of pitches and pixels representing the planes of a YUV image, to better enable hardware acceleration. The YV12 and IYUV formats each have three planes, corresponding to the Y, U, and V portions of the image, while packed pixel YUV formats just have one plane. For palettized mode (8bpp), the screen colormap is now split in a physical and a logical palette. The physical palette determines what colours the screen pixels will get when displayed, and the logical palette controls the mapping from blits to/from the screen. A new function, SDL_SetPalette() has been added to change logical and physical palettes separately. SDL_SetColors() works just as before, and is equivalent to calling SDL_SetPalette() with a flag argument of (SDL_LOGPAL|SDL_PHYSPAL). SDL_BlitSurface() no longer modifies the source rectangle, only the destination rectangle. The width/height members of the destination rectangle are ignored, only the position is used. The old source clipping function SDL_SetClipping() has been replaced with a more useful function to set the destination clipping rectangle: SDL_bool SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect) Added a function to see what subsystems have been initialized: Uint32 SDL_WasInit(Uint32 flags) The Big Alpha Flip: SDL now treats alpha as opacity like everybody else, and not as transparency: A new cpp symbol: SDL_ALPHA_OPAQUE is defined as 255 A new cpp symbol: SDL_ALPHA_TRANSPARENT is defined as 0 Values between 0 and 255 vary from fully transparent to fully opaque. New functions: SDL_DisplayFormatAlpha() Returns a surface converted to a format with alpha-channel that can be blit efficiently to the screen. (In other words, like SDL_DisplayFormat() but the resulting surface has an alpha channel.) This is useful for surfaces with alpha. SDL_MapRGBA() Works as SDL_MapRGB() but takes an additional alpha parameter. SDL_GetRGBA() Works as SDL_GetRGB() but also returns the alpha value (SDL_ALPHA_OPAQUE for formats without an alpha channel) Both SDL_GetRGB() and SDL_GetRGBA() now always return values in the [0..255] interval. Previously, SDL_GetRGB() would return (0xf8, 0xfc, 0xf8) for a completely white pixel in RGB565 format. (N.B.: This is broken for bit fields < 3 bits.) SDL_MapRGB() returns pixels in which the alpha channel is set opaque. SDL_SetAlpha() can now be used for both setting the per-surface alpha, using the new way of thinking of alpha, and also to enable and disable per-pixel alpha blending for surfaces with an alpha channel: To disable alpha blending: SDL_SetAlpha(surface, 0, 0); To re-enable alpha blending: SDL_SetAlpha(surface, SDL_SRCALPHA, 0); Surfaces with an alpha channel have blending enabled by default. SDL_SetAlpha() now accepts SDL_RLEACCEL as a flag, which requests RLE acceleration of blits, just as like with SDL_SetColorKey(). This flag can be set for both surfaces with an alpha channel and surfaces with an alpha value set by SDL_SetAlpha(). As always, RLE surfaces must be locked before pixel access is allowed, and unlocked before any other SDL operations are done on it. The blit semantics for surfaces with and without alpha and colorkey have now been defined: RGBA->RGB: SDL_SRCALPHA set: alpha-blend (using alpha-channel). SDL_SRCCOLORKEY ignored. SDL_SRCALPHA not set: copy RGB. if SDL_SRCCOLORKEY set, only copy the pixels matching the RGB values of the source colour key, ignoring alpha in the comparison. RGB->RGBA: SDL_SRCALPHA set: alpha-blend (using the source per-surface alpha value); set destination alpha to opaque. SDL_SRCALPHA not set: copy RGB, set destination alpha to opaque. both: if SDL_SRCCOLORKEY set, only copy the pixels matching the source colour key. RGBA->RGBA: SDL_SRCALPHA set: alpha-blend (using the source alpha channel) the RGB values; leave destination alpha untouched. [Note: is th