Name
sdl.SetTextureAlphaMod -- set texture alpha modulation
Synopsis
r = sdl.SetTextureAlphaMod(tex, alpha)
Function
Use this function to set an additional alpha value multiplied into render copy operations. 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)

Note that alpha modulation is not always supported by the renderer; it will return -1 if alpha modulation is not supported.

The tex argument must simply be the identifier of a hardware brush.

Inputs
tex
identifier of hardware brush
alpha
the source alpha value multiplied into copy operations (ranging from 0 to 255)
Results
r
0 on success or a negative error code on failure

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