Hi, On Tue, Jan 17, 2012 at 10:09 AM, Lukas Tönne <[email protected]> wrote: > Troy Sobotka has asked me in IRC if it would be feasible to clamp > alpha values output in the render layers node. > > The problem is that AA filtering leads to alpha values with both a<0 > and a>1, which usually requires the artist to add additional math > nodes to clamp those values to 0..1 range. While Brecht's alleged > opinion (correct me if i'm wrong) is that this is not a problem since > compositing should be done with full samples, it is apparently a nasty > workflow.
My opinion is not that's a not a problem, but that it's not a bug so should not be in the bug tracker. > So here's a patch that adds a "clamp alpha" option to render layers > node. The button for this setting is located in the node editor side > bar, instead of the node itself to avoid clutter (case of "set once, > don't touch again"). It is enabled by default for new nodes, but > disabled for old files (backward & forward compatible). I think clamping alpha to a valid range way can always be done, no option is needed. However, it needs to be done on any render output, not in a compositing node. For example saving directly to EXR without nodes enabled or doing full sample re-compositing also needs this, so the clamping code should elsewhere. Also note that both the combined and color passes have an alpha channel, so ideally both would be clamped. Brecht. _______________________________________________ Bf-committers mailing list [email protected] http://lists.blender.org/mailman/listinfo/bf-committers
