###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!) # SDL_SetTextureAlphaModFloat Set an additional alpha value multiplied into render copy operations. ## Header File Defined in [](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_render.h) ## Syntax ```c bool SDL_SetTextureAlphaModFloat(SDL_Texture *texture, float alpha); ``` ## Function Parameters | | | | | ---------------------------- | ----------- | ------------------------------------------------------- | | [SDL_Texture](SDL_Texture) * | **texture** | the texture to update. | | float | **alpha** | the source alpha value multiplied into copy operations. | ## Return Value (bool) Returns true on success or false on failure; call [SDL_GetError](SDL_GetError)() for more information. ## Remarks When this texture is rendered, during the copy operation the source alpha value is modulated by this alpha value according to the following formula: `srcA = srcA * alpha` Alpha modulation is not always supported by the renderer; it will return false if alpha modulation is not supported. ## Thread Safety You may only call this function from the main thread. ## Version This function is available since SDL 3.1.3. ## See Also - [SDL_GetTextureAlphaModFloat](SDL_GetTextureAlphaModFloat) - [SDL_SetTextureAlphaMod](SDL_SetTextureAlphaMod) - [SDL_SetTextureColorModFloat](SDL_SetTextureColorModFloat) ---- [CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryRender](CategoryRender)