clipka <ano### [at] anonymousorg> wrote:
> Am 27.10.2010 16:47, schrieb Mr:
> There is no sane way for a general fix; even a full redesign of
> POV-Ray's internal maths to operate on non-premultiplied values would
> not be a viable solution, as this would in turn cause problems when
> working with emissive media: Non-premultiplied values can't represent
> light to be /added/ to a fully transparent background.

Would an RGB triplet for Alpha solve this, at least for internal working, and as
an extension, use a file format or compositing/post-processing method that
supports this?
i.e. each pixel has:
- source: (R, G, B)
- alpha: (R, G, B)

Examples (I hope I have this correct):
- red filtering glass would be S(1, 0, 0), A(1, 0, 0)
- green transparent emissive media would be S(0, 1, 0), A(1, 1, 1)
- blue surface that lets a little red light through: S(0, 0, 1), A(0.2, 0, 0)

Such a scheme might unify the rgb(), rgbt(), and rgba() methods of specifying
colour.

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