sdlSetSurfaceAlphaMod function

bool sdlSetSurfaceAlphaMod(
  1. Pointer<SdlSurface> surface,
  2. int alpha
)

Set an additional alpha value used in blit operations.

When this surface is blitted, during the blit operation the source alpha value is modulated by this alpha value according to the following formula:

srcA = srcA * (alpha / 255)

\param surface the SDL_Surface structure to update. \param alpha the alpha value multiplied into blit operations. \returns true on success or false on failure; call SDL_GetError() for more information.

\since This function is available since SDL 3.1.3.

\sa SDL_GetSurfaceAlphaMod \sa SDL_SetSurfaceColorMod

extern SDL_DECLSPEC bool SDLCALL SDL_SetSurfaceAlphaMod(SDL_Surface *surface, Uint8 alpha)

Implementation

bool sdlSetSurfaceAlphaMod(Pointer<SdlSurface> surface, int alpha) {
  final sdlSetSurfaceAlphaModLookupFunction = libSdl3.lookupFunction<
      Uint8 Function(Pointer<SdlSurface> surface, Uint8 alpha),
      int Function(
          Pointer<SdlSurface> surface, int alpha)>('SDL_SetSurfaceAlphaMod');
  return sdlSetSurfaceAlphaModLookupFunction(surface, alpha) == 1;
}