From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Sat, 19 Jan 2013 19:13:51 +0000 (+0100)
Subject: Clamp alpha in MixEffect.
X-Git-Tag: 1.0~162
X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=6a8b7d750dff76dee320ad973a52d4d9720510b9;hp=6a8b7d750dff76dee320ad973a52d4d9720510b9

Clamp alpha in MixEffect.

This struck me suddenly one evening as a fix for the issues with alpha in glow,
and seems to work incredibly well for unsharp mask, too. The rationale is
outlined in the comment in the frag.

I'll probably be adding some tests for GlowEffect to make sure that it keeps
working fine, but visual tests so far look very good. The only issue is that
with destination alpha always being in linear light (as it should be),
programs that don't blend in linear light, like GIMP and ImageMagick,
get somewhat dull-looking results with e.g. glow.
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