can the blend mode of blitting be subtractive?

[MichaelJPCT]

this is not absolutely necessary, but it may provide more flexibility.

[EgonOlsen]

I guess so, but it would require some rewrites, because ATM, it's just a boolean flag that gets passed down the pipeline. I'm not sure, if it's really useful. After all, I even left it out when setting up multi texturing, because I see no purpose whatsoever in subtractive blending. Does this ever look good?

[MichaelJPCT]

it's not about looking good. it should be used only in special case.
when several operations are organized in different ways, different effects are achieved. having more options is always better. one would not know its use until he encounters the case.