SDL_SetWindowOpacity - Man Page

#include <SDL3/SDL_video.h>

bool SDL_SetWindowOpacity(SDL_Window *window, float opacity);

The parameter opacity will be clamped internally between 0.0f (transparent) and 1.0f (opaque).

This function also returns false if setting the opacity isn't supported.

window

the window which will be made transparent or opaque.

opacity

the opacity value (0.0f - transparent, 1.0f - opaque).

for more information.

This function should only be called on the main thread.

This function is available since SDL 3.2.0.

SDL_GetWindowOpacity(3)

SDL_GetWindowOpacity(3).