devela::_dep::sdl2::sys

Function SDL_SetSurfaceAlphaMod

pub unsafe extern "C" fn SDL_SetSurfaceAlphaMod(
    surface: *mut SDL_Surface,
    alpha: u8,
) -> i32
Available on crate feature dep_sdl2 only.
Expand description

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