sdlSetSurfaceAlphaMod function

int 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 0 on success or a negative error code on failure; call SDL_GetError() for more information.

\since This function is available since SDL 2.0.0.

\sa SDL_GetSurfaceAlphaMod \sa SDL_SetSurfaceColorMod

extern DECLSPEC int SDLCALL SDL_SetSurfaceAlphaMod(SDL_Surface * surface, Uint8 alpha)

Implementation

int sdlSetSurfaceAlphaMod(Pointer<SdlSurface> surface, int alpha) {
  final sdlSetSurfaceAlphaModLookupFunction = libSdl2.lookupFunction<
      Int32 Function(Pointer<SdlSurface> surface, Uint8 alpha),
      int Function(
          Pointer<SdlSurface> surface, int alpha)>('SDL_SetSurfaceAlphaMod');
  return sdlSetSurfaceAlphaModLookupFunction(surface, alpha);
}