Fix (unreported) looptri array not being recalculated in ccgDM and emDM

In ccgDM and emDM, looptri array recalculation was being handled
directly by `*DM_getLoopTriArray` (`getLoopTriArray` callback), while
`*DM_recalcLoopTri` (`recalcLoopTri` callback) was doing nothing.

This results in the array not being recalculated when other functions
that depend on the array data called the recalc function.

This moves all the recalculation code to `*DM_recalcLoopTri` and makes
`*DM_getLoopTriArray` call that.

This commit also makes a minor change to the `getNumLoopTri` function,
so that it returns the correct number without having to recalculate the
looptri array.

Reviewed By: mont29

Differential Revision: https://developer.blender.org/D2375

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index ae18f5289d4..1f937d837b4 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -230,7 +230,9 @@ static MPoly *dm_dupPolyArray(DerivedMesh *dm)
 
 static int dm_getNumLoopTri(DerivedMesh *dm)
 {
-	return dm->looptris.num;
+	const int numlooptris = poly_to_tri_count(dm->getNumPolys(dm), dm->getNumLoops(dm));
+	BLI_assert(ELEM(dm->looptris.num, 0, numlooptris));
+	return numlooptris;
 }
 
 static CustomData *dm_getVertCData(DerivedMesh *dm)