SDL_LockSurface
Use this function to set up a surface for directly accessing the pixels.
Contents
Syntax
int SDL_LockSurface(SDL_Surface* surface)
Function Parameters
surface |
the SDL_Surface structure to be locked |
Return Value
Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.
Code Examples
/* Make the pixels pointer valid in the surface */
SDL_LockSurface( surface );
/* Surface is locked */
/* Direct pixel access on surface here */
SDL_UnlockSurface( surface );
/* Surface is now unlocked */
Remarks
Between calls to SDL_LockSurface() / SDL_UnlockSurface(), you can write to and read from surface->pixels, using the pixel format stored in surface->format. Once you are done accessing the surface, you should use SDL_UnlockSurface() to release it.
Not all surfaces require locking. If SDL_MUSTLOCK(surface) evaluates to 0, then you can read and write to the surface at any time, and the pixel format of the surface will not change.
