Section 3: library functions
SDL_SetPalette – Sets the colors in the palette of an 8-bit surface. Synopsis#include "SDL.h" int SDL_SetPalette(SDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors); DescriptionSets a portion of the palette for the given 8-bit surface. Palettized (8-bit) screen surfaces with the SDL_HWPALETTE flag have two palettes, a logical palette that is used for mapping…
SDL_SetModState – Set the current key modifier state Synopsis#include "SDL.h" void SDL_SetModState(SDLMod modstate); DescriptionThe inverse of SDL_GetModState, SDL_SetModState allows you to impose modifier key states on your application. Simply pass your desired modifier states into modstate. This value my be a logical OR’d combination of the following: typedef enum { KMOD_NONE = 0x0000, KMOD_LSHIFT= 0x0001,…
SDL_SetGammaRamp – Sets the color gamma lookup tables for the display Synopsis#include "SDL.h" int SDL_SetGammaRamp(Uint16 *redtable, Uint16 *greentable, Uint16 *bluetable); DescriptionSets the gamma lookup tables for the display for each color component. Each table is an array of 256 Uint16 values, representing a mapping between the input and output for that channel. The input is…
SDL_SetGamma – Sets the color gamma function for the display Synopsis#include "SDL.h" int SDL_SetGamma(float redgamma, float greengamma, float bluegamma); DescriptionSets the "gamma function" for the display of each color component. Gamma controls the brightness/contrast of colors displayed on the screen. A gamma value of 1.0 is identity (i.e., no adjustment is made). This function adjusts…
SDL_SetEventFilter – Sets up a filter to process all events before they are posted to the event queue. Synopsis#include "SDL.h" void SDL_SetEventFilter(SDL_EventFilter filter); DescriptionThis function sets up a filter to process all events before they are posted to the event queue. This is a very powerful and flexible feature. The filter is prototyped as: typedef…
SDL_SetCursor – Set the currently active mouse cursor. Synopsis#include "SDL.h" void SDL_SetCursor(SDL_Cursor *cursor); DescriptionSets the currently active cursor to the specified one. If the cursor is currently visible, the change will be immediately represented on the display. See AlsoSDL_GetCursor, SDL_CreateCursor, SDL_ShowCursor
SDL_SetColors – Sets a portion of the colormap for the given 8-bit surface. Synopsis#include "SDL.h" int SDL_SetColors(SDL_Surface *surface, SDL_Color *colors, int firstcolor, int ncolors); DescriptionSets a portion of the colormap for the given 8-bit surface. When surface is the surface associated with the current display, the display colormap will be updated with the requested colors….
SDL_SetColorKey – Sets the color key (transparent pixel) in a blittable surface and RLE acceleration. Synopsis#include "SDL.h" int SDL_SetColorKey(SDL_Surface *surface, Uint32 flag, Uint32 key); Description Sets the color key (transparent pixel) in a blittable surface and enables or disables RLE blit acceleration. RLE acceleration can substantially speed up blitting of images with large horizontal runs of transparent pixels…
SDL_SetClipRect – Sets the clipping rectangle for a surface. Synopsis#include "SDL.h" void SDL_SetClipRect(SDL_Surface *surface, SDL_Rect *rect); DescriptionSets the clipping rectangle for a surface. When this surface is the destination of a blit, only the area within the clip rectangle will be drawn into. The rectangle pointed to by rect will be clipped to the edges…
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…