SDL_SetSurfaceAlphaMod - Man Page

#include <SDL3/SDL_surface.h>

bool SDL_SetSurfaceAlphaMod(SDL_Surface *surface, Uint8 alpha);

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)

surface

the SDL_Surface structure to update.

alpha

the alpha value multiplied into blit operations.

Returns true on success or false on failure; call SDL_GetError() for more information.

This function can be called on different threads with different surfaces.

This function is available since SDL 3.2.0.

SDL_GetSurfaceAlphaMod(3), SDL_SetSurfaceColorMod(3)

SDL_GetSurfaceAlphaMod(3), SDL_SetSurfaceColorMod(3).