Set an additional alpha value multiplied into render copy operations.
Defined in SDL_render.h
| texture | the texture to update |
| alpha | the source alpha value multiplied into copy operations |
Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.
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 / 255)
Alpha modulation is not always supported by the renderer; it will return -1 if alpha modulation is not supported.
This function is available since SDL 2.0.0.