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

3 files changed, 61 insertions, 59 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)
diff --git a/source/blender/blenkernel/intern/editderivedmesh.c b/source/blender/blenkernel/intern/editderivedmesh.c
index 05cf5f6d7bd..e7c0e69b1cb 100644
--- a/source/blender/blenkernel/intern/editderivedmesh.c
+++ b/source/blender/blenkernel/intern/editderivedmesh.c
@@ -621,10 +621,33 @@ static void emDM_recalcTessellation(DerivedMesh *UNUSED(dm))
 	/* do nothing */
 }
 
-static void emDM_recalcLoopTri(DerivedMesh *UNUSED(dm))
+static void emDM_recalcLoopTri(DerivedMesh *dm)
 {
-	/* Nothing to do: emDM tessellation is known,
-	 * allocate and fill in with emDM_getLoopTriArray */
+	EditDerivedBMesh *bmdm = (EditDerivedBMesh *)dm;
+	BMLoop *(*looptris)[3] = bmdm->em->looptris;
+	MLoopTri *mlooptri;
+	const int tottri = bmdm->em->tottri;
+	int i;
+
+	DM_ensure_looptri_data(dm);
+	mlooptri = dm->looptris.array;
+
+	BLI_assert(poly_to_tri_count(dm->numPolyData, dm->numLoopData) == dm->looptris.num);
+	BLI_assert(tottri == dm->looptris.num);
+
+	BM_mesh_elem_index_ensure(bmdm->em->bm, BM_FACE | BM_LOOP);
+
+	for (i = 0; i < tottri; i++) {
+		BMLoop **ltri = looptris[i];
+		MLoopTri *lt = &mlooptri[i];
+
+		ARRAY_SET_ITEMS(
+				lt->tri,
+				BM_elem_index_get(ltri[0]),
+				BM_elem_index_get(ltri[1]),
+				BM_elem_index_get(ltri[2]));
+		lt->poly = BM_elem_index_get(ltri[0]->f);
+	}
 }
 
 static const MLoopTri *emDM_getLoopTriArray(DerivedMesh *dm)
@@ -633,32 +656,9 @@ static const MLoopTri *emDM_getLoopTriArray(DerivedMesh *dm)
 		BLI_assert(poly_to_tri_count(dm->numPolyData, dm->numLoopData) == dm->looptris.num);
 	}
 	else {
-		EditDerivedBMesh *bmdm = (EditDerivedBMesh *)dm;
-		BMLoop *(*looptris)[3] = bmdm->em->looptris;
-		MLoopTri *mlooptri;
-		const int tottri = bmdm->em->tottri;
-		int i;
-
-		DM_ensure_looptri_data(dm);
-		mlooptri = dm->looptris.array;
-
-		BLI_assert(poly_to_tri_count(dm->numPolyData, dm->numLoopData) == dm->looptris.num);
-		BLI_assert(tottri == dm->looptris.num);
-
-		BM_mesh_elem_index_ensure(bmdm->em->bm, BM_FACE | BM_LOOP);
-
-		for (i = 0; i < tottri; i++) {
-			BMLoop **ltri = looptris[i];
-			MLoopTri *lt = &mlooptri[i];
-
-			ARRAY_SET_ITEMS(
-			        lt->tri,
-			        BM_elem_index_get(ltri[0]),
-			        BM_elem_index_get(ltri[1]),
-			        BM_elem_index_get(ltri[2]));
-			lt->poly = BM_elem_index_get(ltri[0]->f);
-		}
+		dm->recalcLoopTri(dm);
 	}
+
 	return dm->looptris.array;
 }
 
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index 6d57c5f09e8..c4665c40ec4 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -4474,46 +4474,46 @@ static void ccgDM_recalcTessellation(DerivedMesh *UNUSED(dm))
 	/* Nothing to do: CCG handles creating its own tessfaces */
 }
 
-static void ccgDM_recalcLoopTri(DerivedMesh *UNUSED(dm))
+static void ccgDM_recalcLoopTri(DerivedMesh *dm)
 {
-	/* Nothing to do: CCG tessellation is known,
-	 * allocate and fill in with ccgDM_getLoopTriArray */
+	BLI_rw_mutex_lock(&loops_cache_rwlock, THREAD_LOCK_WRITE);
+	MLoopTri *mlooptri;
+	const int tottri = dm->numPolyData * 2;
+	int i, poly_index;
+
+	DM_ensure_looptri_data(dm);
+	mlooptri = dm->looptris.array;
+
+	BLI_assert(poly_to_tri_count(dm->numPolyData, dm->numLoopData) == dm->looptris.num);
+	BLI_assert(tottri == dm->looptris.num);
+
+	for (i = 0, poly_index = 0; i < tottri; i += 2, poly_index += 1) {
+		MLoopTri *lt;
+		lt = &mlooptri[i];
+		/* quad is (0, 3, 2, 1) */
+		lt->tri[0] = (poly_index * 4) + 0;
+		lt->tri[1] = (poly_index * 4) + 2;
+		lt->tri[2] = (poly_index * 4) + 3;
+		lt->poly = poly_index;
+
+		lt = &mlooptri[i + 1];
+		lt->tri[0] = (poly_index * 4) + 0;
+		lt->tri[1] = (poly_index * 4) + 1;
+		lt->tri[2] = (poly_index * 4) + 2;
+		lt->poly = poly_index;
+	}
+	BLI_rw_mutex_unlock(&loops_cache_rwlock);
 }
 
 static const MLoopTri *ccgDM_getLoopTriArray(DerivedMesh *dm)
 {
-	BLI_rw_mutex_lock(&loops_cache_rwlock, THREAD_LOCK_WRITE);
 	if (dm->looptris.array) {
 		BLI_assert(poly_to_tri_count(dm->numPolyData, dm->numLoopData) == dm->looptris.num);
 	}
 	else {
-		MLoopTri *mlooptri;
-		const int tottri = dm->numPolyData * 2;
-		int i, poly_index;
-
-		DM_ensure_looptri_data(dm);
-		mlooptri = dm->looptris.array;
-
-		BLI_assert(poly_to_tri_count(dm->numPolyData, dm->numLoopData) == dm->looptris.num);
-		BLI_assert(tottri == dm->looptris.num);
-
-		for (i = 0, poly_index = 0; i < tottri; i += 2, poly_index += 1) {
-			MLoopTri *lt;
-			lt = &mlooptri[i];
-			/* quad is (0, 3, 2, 1) */
-			lt->tri[0] = (poly_index * 4) + 0;
-			lt->tri[1] = (poly_index * 4) + 2;
-			lt->tri[2] = (poly_index * 4) + 3;
-			lt->poly = poly_index;
-
-			lt = &mlooptri[i + 1];
-			lt->tri[0] = (poly_index * 4) + 0;
-			lt->tri[1] = (poly_index * 4) + 1;
-			lt->tri[2] = (poly_index * 4) + 2;
-			lt->poly = poly_index;
-		}
+		dm->recalcLoopTri(dm);
 	}
-	BLI_rw_mutex_unlock(&loops_cache_rwlock);
+
 	return dm->looptris.array;
 }