#pragma section-numbers off
#pragma disable-camelcase

= SDL_SetSurfaceAlphaMod =
Use this function to set an additional alpha value used in blit operations.

<<TableOfContents()>>

== Syntax ==
{{{#!highlight cpp
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.

== Code Examples ==
{{{#!highlight cpp
You can add your code example here
}}}

== Remarks ==
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)`

== Related Functions ==
 .[[SDL_GetSurfaceAlphaMod]]
 .[[SDL_SetSurfaceColorMod]]

----
[[CategoryAPI]], [[CategorySurface]]