On 17 January 2014 22:08, Andrew Chadwick <a.t.chadw...@gmail.com> wrote: > (It has to be in a group because MyPaint does non-isolated rendering > onto its internal background layer. Currently you see black if a layer > erases the background layer... The layer group implementation you see > here uses isolated rendering only, however, and the results of that > are then composited onto the background normally. This is just a > workaround for now, allowing some masking experiments.)
Oops, correction. It's because MyPaint renders with an assumed bg alpha of 1 if the background is turned on, for old speedup reasons. Thus if something like Clear or XOR tries to write (0,0,0,0), the result is (0,0,0,1). Kinda suboptimal really; I should make it only attempt that speedup if the layer stack including the backdrop _logically can never_ create a pixel with alpha<1 when it renders. -- Andrew Chadwick _______________________________________________ CREATE mailing list CREATE@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/create
