fix x-fades (part one)

The data from the lower layer(s) was not faded out because
the reversed gain curve was incorrect because ControlList:add()
inserts anchor points.

a call to reverse_curve() for a linear fade produced:
 INPUT: [when,val]  {[0.0, 0.0], [300.0, 1.0]}
 OUTPUT: (reversed) {[0.0, 0.0], [0.0, 1.0], [1.0, 0,0], [300.0, 0.0]}

solution: use fast_simple_add() instead.

git-svn-id: svn://localhost/ardour2/branches/3.0@13572 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 3 insertions, 4 deletions

diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 577f12c78e..a02eb3720b 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -82,9 +82,8 @@ static void
 reverse_curve (boost::shared_ptr<Evoral::ControlList> dst, boost::shared_ptr<const Evoral::ControlList> src)
 {
 	size_t len = src->back()->when;
-	
-	for (Evoral::ControlList::const_iterator it = src->begin(); it!=src->end(); it++) {
-		dst->add (len - (*it)->when, (*it)->value);
+	for (Evoral::ControlList::const_reverse_iterator it = src->rbegin(); it!=src->rend(); it++) {
+		dst->fast_simple_add (len - (*it)->when, (*it)->value);
 	}
 }
 
@@ -141,7 +140,7 @@ merge_curves (boost::shared_ptr<Evoral::ControlList> dst,
 		interp += v2 * ( (double)count / (double)size );
 
 		interp = dB_to_coefficient(interp);
-		dst->add ( (*c1)->when, interp );
+		dst->fast_simple_add ( (*c1)->when, interp );
 		c1++;
 		count++;
 	}