Provided by: libsdl3-doc_3.2.8+ds-1_all 

NAME
SDL_SetSurfaceAlphaMod - Set an additional alpha value used in blit operations.
HEADER FILE
Defined in SDL3/SDL_surface.h
SYNOPSIS
#include "SDL3/SDL.h"
bool SDL_SetSurfaceAlphaMod(SDL_Surface *surface, Uint8 alpha);
DESCRIPTION
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)
FUNCTION PARAMETERS
surface
the SDL_Surface
structure to update.
alpha the alpha value multiplied into blit operations.
RETURN VALUE
Returns true on success or false on failure; call
SDL_GetError () for more information.
AVAILABILITY
This function is available since SDL 3.2.0.
SEE ALSO
•(3), SDL_GetSurfaceAlphaMod(3), •(3), SDL_SetSurfaceColorMod(3)
Simple Directmedia Layer SDL 3.2.8 SDL_SetSurfaceAlphaMod(3)