Fix T55645: broken particle Use Count option for instancing objects.

There is now a manual refresh button on the panel to update the list
of objects in case it changes, and it also gets refreshed when changing
the collection or toggling the use count option.

This is a bit more manual but the previous code of refreshing the
list while evaluating the depsgraph was unreliable.

This also fixes it to take properly take into account visibility, and
to work with linked collections for which index writing was missing.

1 files changed, 28 insertions, 15 deletions

diff --git a/source/blender/blenkernel/intern/object_dupli.c b/source/blender/blenkernel/intern/object_dupli.c
index 33b65dbe4a3..e288adaf9ad 100644
--- a/source/blender/blenkernel/intern/object_dupli.c
+++ b/source/blender/blenkernel/intern/object_dupli.c
@@ -836,7 +836,7 @@ static void make_duplis_particle_system(const DupliContext *ctx, ParticleSystem
 	float tmat[4][4], mat[4][4], pamat[4][4], vec[3], size = 0.0;
 	float (*obmat)[4];
 	int a, b, hair = 0;
-	int totpart, totchild, totcollection = 0 /*, pa_num */;
+	int totpart, totchild;
 
 	int no_draw_flag = PARS_UNEXIST;
 
@@ -899,15 +899,26 @@ static void make_duplis_particle_system(const DupliContext *ctx, ParticleSystem
 		}
 
 		RNG *rng = BLI_rng_new_srandom(31415926u + (unsigned int)psys->seed);
-		psys_check_group_weights(part);
 
 		psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);
 
 		/* gather list of objects or single object */
+		int totcollection = 0;
+
 		if (part->ren_as == PART_DRAW_GR) {
 			if (part->draw & PART_DRAW_COUNT_GR) {
-				for (dw = part->dupliweights.first; dw; dw = dw->next)
-					totcollection += dw->count;
+				psys_find_group_weights(part);
+
+				for (dw = part->dupliweights.first; dw; dw = dw->next) {
+					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->dup_group, object, mode)
+					{
+						if (dw->ob == object) {
+							totcollection += dw->count;
+							break;
+						}
+					}
+					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+				}
 			}
 			else {
 				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->dup_group, object, mode)
@@ -923,14 +934,20 @@ static void make_duplis_particle_system(const DupliContext *ctx, ParticleSystem
 			oblist = MEM_callocN((size_t)totcollection * sizeof(Object *), "dupcollection object list");
 			obcopylist = MEM_callocN((size_t)totcollection * sizeof(Object), "dupcollection copy list");
 
-			if (part->draw & PART_DRAW_COUNT_GR && totcollection) {
-				dw = part->dupliweights.first;
-
-				for (a = 0; a < totcollection; dw = dw->next) {
-					for (b = 0; b < dw->count; b++, a++) {
-						oblist[a] = dw->ob;
-						obcopylist[a] = *dw->ob;
+			if (part->draw & PART_DRAW_COUNT_GR) {
+				a = 0;
+				for (dw = part->dupliweights.first; dw; dw = dw->next) {
+					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->dup_group, object, mode)
+					{
+						if (dw->ob == object) {
+							for (b = 0; b < dw->count; b++, a++) {
+								oblist[a] = dw->ob;
+								obcopylist[a] = *dw->ob;
+							}
+							break;
+						}
 					}
+					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
 				}
 			}
 			else {
@@ -940,10 +957,6 @@ static void make_duplis_particle_system(const DupliContext *ctx, ParticleSystem
 					oblist[a] = object;
 					obcopylist[a] = *object;
 					a++;
-
-					if (a >= totcollection) {
-						continue;
-					}
 				}
 				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
 			}