SDL_SetAlpha – Adjust the alpha properties of a surface Synopsis#include "SDL.h" int SDL_SetAlpha(SDL_Surface *surface, Uint32 flag, Uint8 alpha); DescriptionNote: This function and the semantics of SDL alpha blending have changed since version 1.1.4. Up until version 1.1.5, an alpha value of 0 was considered opaque and a value of 255 was considered transparent. This has…
SDL_SemWaitTimeout – Lock a semaphore, but only wait up to a specified maximum time. Synopsis#include "SDL.h" #include "SDL_thread.h" int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout); DescriptionSDL_SemWaitTimeout() is a varient of SDL_SemWait with a maximum timeout value. If the value of the semaphore pointed to by sem is positive (greater than zero) it will atomically decrement the semaphore…
SDL_SemWait – Lock a semaphore and suspend the thread if the semaphore value is zero. Synopsis#include "SDL.h" #include "SDL_thread.h" int SDL_SemWait(SDL_sem *sem); DescriptionSDL_SemWait() suspends the calling thread until either the semaphore pointed to by sem has a positive value, the call is interrupted by a signal or error. If the call is successful it will…
SDL_SemValue – Return the current value of a semaphore. Synopsis#include "SDL.h" #include "SDL/SDL_thread.h" Uint32 SDL_SemValue(SDL_sem *sem); DescriptionSDL_SemValue() returns the current semaphore value from the semaphore pointed to by sem. Return ValueReturns current value of the semaphore. Examples sem_value = SDL_SemValue(my_sem);See AlsoSDL_CreateSemaphore, SDL_DestroySemaphore, SDL_SemWait, SDL_SemTryWait, SDL_SemWaitTimeout, SDL_SemPost
SDL_SemTryWait – Attempt to lock a semaphore but don’t suspend the thread. Synopsis#include "SDL.h" #include "SDL_thread.h" int SDL_SemTryWait(SDL_sem *sem); DescriptionSDL_SemTryWait is a non-blocking varient of SDL_SemWait. If the value of the semaphore pointed to by sem is positive it will atomically decrement the semaphore value and return 0, otherwise it will return SDL_MUTEX_TIMEOUT instead of…
SDL_SemPost – Unlock a semaphore. Synopsis#include "SDL.h" #include "SDL_thread.h" int SDL_SemPost(SDL_sem *sem); DescriptionSDL_SemPost unlocks the semaphore pointed to by sem and atomically increments the semaphores value. Threads that were blocking on the semaphore may be scheduled after this call succeeds. SDL_SemPost should be called after a semaphore is locked by a successful call to SDL_SemWait,…
SDL_Rect – Defines a rectangular area Structure Definitiontypedef struct{ Sint16 x, y; Uint16 w, h; } SDL_Rect;Structure Datax, y Position of the upper-left corner of the rectangle w, h The width and height of the rectangleDescriptionA SDL_Rect defines a rectangular area of pixels. It is used by SDL_BlitSurface to define blitting regions and by several…
SDL_FunctionName – Short description of function Synopsis#include "SDL.h" return typeSDL_FunctionName(parameter); DescriptionFull description Examplesexamples here See AlsoSDL_AnotherFunction
SDL_QuitSubSystem – Shut down a subsystem Synopsis#include "SDL.h" void SDL_QuitSubSystem(Uint32 flags); DescriptionSDL_QuitSubSystem allows you to shut down a subsystem that has been previously initialized by SDL_Init or SDL_InitSubSystem. The flags tells SDL_QuitSubSystem which subsystems to shut down, it uses the same values that are passed to SDL_Init. See AlsoSDL_Quit, SDL_Init, SDL_InitSubSystem
SDL_QuitEvent – Quit requested event Structure Definitiontypedef struct{ Uint8 type } SDL_QuitEvent;Structure Datatype SDL_QUITDescriptionSDL_QuitEvent is a member of the SDL_Event union and is used whan an event of type SDL_QUIT is reported. As can be seen, the SDL_QuitEvent structure serves no useful purpose. The event itself, on the other hand, is very important. If you…
SDL_Quit – Shut down SDL Synopsis#include "SDL.h" void SDL_Quit(void); DescriptionSDL_Quit shuts down all SDL subsystems and frees the resources allocated to them. This should always be called before you exit. For the sake of simplicity you can set SDL_Quit as your atexit call, like: SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO); atexit(SDL_Quit); . .Note: While using atexit maybe be fine for…
SDL_PushEvent – Pushes an event onto the event queue Synopsis#include "SDL.h" int SDL_PushEvent(SDL_Event *event); DescriptionThe event queue can actually be used as a two way communication channel. Not only can events be read from the queue, but the user can also push their own events onto it. event is a pointer to the event structure…
SDL_PumpEvents – Pumps the event loop, gathering events from the input devices. Synopsis#include "SDL.h" void SDL_PumpEvents(void); DescriptionPumps the event loop, gathering events from the input devices. SDL_PumpEvents gathers all the pending input information from devices and places it on the event queue. Without calls to SDL_PumpEvents no events would ever be placed on the queue….
SDL_PollEvent – Polls for currently pending events. Synopsis#include "SDL.h" int SDL_PollEvent(SDL_Event *event); DescriptionPolls for currently pending events, and returns 1 if there are any pending events, or 0 if there are none available. If event is not NULL, the next event is removed from the queue and stored in that area. ExamplesSDL_Event event; /* Event…
SDL_PixelFormat – Stores surface format information Structure Definitiontypedef struct SDL_PixelFormat { SDL_Palette *palette; Uint8 BitsPerPixel; Uint8 BytesPerPixel; Uint8 Rloss, Gloss, Bloss, Aloss; Uint8 Rshift, Gshift, Bshift, Ashift; Uint32 Rmask, Gmask, Bmask, Amask; Uint32 colorkey; Uint8 alpha; } SDL_PixelFormat;Structure Datapalette Pointer to the palette, or NULL if the BitsPerPixel>8 BitsPerPixel The number of bits used to…
SDL_PeepEvents – Checks the event queue for messages and optionally returns them. Synopsis#include "SDL.h" int SDL_PeepEvents(SDL_Event *events, int numevents, SDL_eventaction action, Uint32 mask); DescriptionChecks the event queue for messages and optionally returns them. If action is SDL_ADDEVENT, up to numevents events will be added to the back of the event queue. If action is SDL_PEEKEVENT,…
SDL_PauseAudio – Pauses and unpauses the audio callback processing Synopsis#include "SDL.h" void SDL_PauseAudio(int pause_on); DescriptionThis function pauses and unpauses the audio callback processing. It should be called with pause_on=0 after opening the audio device to start playing sound. This is so you can safely initialize data for your callback function after opening the audio device….
SDL_Palette – Color palette for 8-bit pixel formats Structure Definitiontypedef struct{ int ncolors; SDL_Color *colors; } SDL_Palette;Structure Datancolors Number of colors used in this palette colors Pointer to SDL_Color structures that make up the palette.DescriptionEach pixel in an 8-bit surface is an index into the colors field of the SDL_Palette structure store in SDL_PixelFormat. A…
SDL_Overlay – YUV video overlay Structure Definitiontypedef struct{ Uint32 format; int w, h; int planes; Uint16 *pitches; Uint8 **pixels; Uint32 hw_overlay:1; } SDL_Overlay;Structure Dataformat Overlay format (see below) w, h Width and height of overlay planes Number of planes in the overlay. Usually either 1 or 3 pitches An array of pitches, one for each…
SDL_OpenAudio – Opens the audio device with the desired parameters. Synopsis#include "SDL.h" int SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained); DescriptionThis function opens the audio device with the desired parameters, and returns 0 if successful, placing the actual hardware parameters in the structure pointed to by obtained. If obtained is NULL, the audio data passed to the callback…