SDL_SetTextureAlphaMod
Use this function to set an additional alpha value multiplied into render copy operations.
Contents
Syntax
int SDL_SetTextureAlphaMod(SDL_Texture* texture,
Uint8 alpha)
Function Parameters
texture |
the texture to update |
alpha |
the source alpha value multiplied into copy operations |
Return Value
Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.
Code Examples
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Remarks
When a texture is copied, 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 driver; it will return -1 if alpha modulation is unsupported.
You can call SDL_GetRendererInfo to get information about the current renderer. The current renderer has a mask of supported channel modulations which will have SDL_TEXTUREMODULATE_ALPHA set if alpha modulation is supported.
