Fix T44183 particles in linked group offset from object

A nice bug combining all the broken features of blender:
Particles, duplis and multiple scene dependencies.

Fortunately this was solvable: Basically, we need to
make sure derivedmesh for dupli instance is generated before
obmat is overriden. This also makes sense, since no instance
has "true" obmat apart from original. Lazy initialization of
derivedmesh just does not work here (or it -does- work but first
use should be before instance drawing).

Fingers crossed nothing else breaks after this...

5 files changed, 14 insertions, 5 deletions

diff --git a/source/blender/blenkernel/BKE_anim.h b/source/blender/blenkernel/BKE_anim.h
index e2b9c66780b..584f0da323a 100644
--- a/source/blender/blenkernel/BKE_anim.h
+++ b/source/blender/blenkernel/BKE_anim.h
@@ -80,7 +80,7 @@ typedef struct DupliApplyData {
 	DupliExtraData *extra;
 } DupliApplyData;
 
-DupliApplyData *duplilist_apply(struct Object *ob, struct ListBase *duplilist);
+DupliApplyData *duplilist_apply(struct Object *ob, struct Scene *scene, struct ListBase *duplilist);
 void duplilist_restore(struct ListBase *duplilist, DupliApplyData *apply_data);
 void duplilist_free_apply_data(DupliApplyData *apply_data);
 
diff --git a/source/blender/blenkernel/intern/object_dupli.c b/source/blender/blenkernel/intern/object_dupli.c
index c77f65f69e1..8abe4bdbb97 100644
--- a/source/blender/blenkernel/intern/object_dupli.c
+++ b/source/blender/blenkernel/intern/object_dupli.c
@@ -1237,7 +1237,7 @@ int count_duplilist(Object *ob)
 	return 1;
 }
 
-DupliApplyData *duplilist_apply(Object *ob, ListBase *duplilist)
+DupliApplyData *duplilist_apply(Object *ob, Scene *scene, ListBase *duplilist)
 {
 	DupliApplyData *apply_data = NULL;
 	int num_objects = BLI_listbase_count(duplilist);
@@ -1253,6 +1253,13 @@ DupliApplyData *duplilist_apply(Object *ob, ListBase *duplilist)
 		for (dob = duplilist->first, i = 0; dob; dob = dob->next, ++i) {
 			/* copy obmat from duplis */
 			copy_m4_m4(apply_data->extra[i].obmat, dob->ob->obmat);
+
+			/* make sure derivedmesh is calculated once, before drawing */
+			if (scene && !(dob->ob->transflag & OB_DUPLICALCDERIVED) && dob->ob->type == OB_MESH) {
+				mesh_get_derived_final(scene, dob->ob, scene->customdata_mask);
+				dob->ob->transflag |= OB_DUPLICALCDERIVED;
+			}
+
 			copy_m4_m4(dob->ob->obmat, dob->mat);
 			
 			/* copy layers from the main duplicator object */
@@ -1273,6 +1280,7 @@ void duplilist_restore(ListBase *duplilist, DupliApplyData *apply_data)
 	 */
 	for (dob = duplilist->last, i = apply_data->num_objects - 1; dob; dob = dob->prev, --i) {
 		copy_m4_m4(dob->ob->obmat, apply_data->extra[i].obmat);
+		dob->ob->transflag &= ~OB_DUPLICALCDERIVED;
 		
 		dob->ob->lay = apply_data->extra[i].lay;
 	}
diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index e51993ce91f..8600c1190d4 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -55,6 +55,7 @@
 #include "BKE_camera.h"
 #include "BKE_context.h"
 #include "BKE_customdata.h"
+#include "BKE_DerivedMesh.h"
 #include "BKE_image.h"
 #include "BKE_key.h"
 #include "BKE_main.h"
@@ -2051,7 +2052,7 @@ static void draw_dupli_objects_color(
 	lb = object_duplilist(G.main->eval_ctx, scene, base->object);
 	// BLI_listbase_sort(lb, dupli_ob_sort); /* might be nice to have if we have a dupli list with mixed objects. */
 
-	apply_data = duplilist_apply(base->object, lb);
+	apply_data = duplilist_apply(base->object, scene, lb);
 
 	dob = dupli_step(lb->first);
 	if (dob) dob_next = dupli_step(dob->next);
diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index 702d9acfb58..286461f1b69 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -397,7 +397,7 @@ enum {
 	OB_DUPLIVERTS       = 1 << 4,
 	OB_DUPLIROT         = 1 << 5,
 	OB_DUPLINOSPEED     = 1 << 6,
-/*	OB_POWERTRACK       = 1 << 7,*/ /*UNUSED*/
+	OB_DUPLICALCDERIVED = 1 << 7, /* runtime, calculate derivedmesh for dupli before it's used */
 	OB_DUPLIGROUP       = 1 << 8,
 	OB_DUPLIFACES       = 1 << 9,
 	OB_DUPLIFACES_SCALE = 1 << 10,
diff --git a/source/blender/render/intern/source/convertblender.c b/source/blender/render/intern/source/convertblender.c
index e900d29aa19..8c9bebe7ff9 100644
--- a/source/blender/render/intern/source/convertblender.c
+++ b/source/blender/render/intern/source/convertblender.c
@@ -5002,7 +5002,7 @@ static void database_init_objects(Render *re, unsigned int renderlay, int nolamp
 				 * system need to have render settings set for dupli particles */
 				dupli_render_particle_set(re, ob, timeoffset, 0, 1);
 				duplilist = object_duplilist(re->eval_ctx, re->scene, ob);
-				duplilist_apply_data = duplilist_apply(ob, duplilist);
+				duplilist_apply_data = duplilist_apply(ob, NULL, duplilist);
 				dupli_render_particle_set(re, ob, timeoffset, 0, 0);
 
 				for (dob= duplilist->first, i = 0; dob; dob= dob->next, ++i) {