SDL Wiki
(This is the legacy documentation for stable SDL2, the current stable version; SDL3 is the current development version.)


Set an additional alpha value used in blit operations.


int SDL_SetSurfaceAlphaMod(SDL_Surface * surface,
                           Uint8 alpha);

Function Parameters

surface the SDL_Surface structure to update
alpha the alpha value multiplied into blit operations

Return Value

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


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)


This function is available since SDL 2.0.0.


[ edit | delete | history | feedback | raw ]

[ front page | index | search | recent changes | git repo | offline html ]

All wiki content is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0).
Wiki powered by ghwikipp.