Yup. screen = A+B-AB, where AB term represents the if intersection of the subpixel geometry.
But in the case where you have two mattes where you know the correlation == -1, (which denotes no overlap in the subpixel geometry), adding mattes reduces to a simple A+B. An example of no overlap in the subpixel geometry would be the alpha rasterization of two adjacent triangles in a mesh. So to summarize, if the subpixel geometry has a correlation of 0, the math for combining alphas is A+B-AB. If the correlation is -1, the math is A+B. And for perfectly correlated subpixel geometry? Sounds like a good white-board project for this weekend... Surely there's some paper from 1985 that has worked this all out? :) -- Jeremy On Thu, Jul 12, 2012 at 9:05 PM, Troy Sobotka <[email protected]> wrote: > And the inevitable question: What is the canonical compositing formula > for correlated then? Simple add? > _______________________________________________ Oiio-dev mailing list [email protected] http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org
