Fix #33113: cycles not rendering motion blur correct with dying particles.

There were a bunch of other issues with dupli motion blur and syncing, the problem
being that there was no proper way to detect corresponding duplis between frames
or updates. As a solution, a persistent_id was added to the DupliObject. It's an
extension of the previous index value, with one index for each dupli level. This
can be used to reliably find matching dupli objects between frames. Works with
nested duplis, multiple particle systems, etc.

1 files changed, 64 insertions, 42 deletions

diff --git a/source/blender/blenkernel/intern/anim.c b/source/blender/blenkernel/intern/anim.c
index dffe26bd782..4b0c89f3a7a 100644
--- a/source/blender/blenkernel/intern/anim.c
+++ b/source/blender/blenkernel/intern/anim.c
@@ -76,8 +76,8 @@
 /* --------------------- */
 /* forward declarations */
 
-static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBase *duplilist, float par_space_mat[][4], int par_index,
-                                       int level, short flag);
+static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBase *duplilist, float par_space_mat[][4],
+                                       int persistent_id[MAX_DUPLI_RECUR], int level, int index, short flag);
 
 /* ******************************************************************** */
 /* Animation Visualization */
@@ -706,31 +706,39 @@ int where_on_path(Object *ob, float ctime, float vec[4], float dir[3], float qua
 #define DUPLILIST_FOR_RENDER	2
 #define DUPLILIST_ANIMATED		4
 
-static DupliObject *new_dupli_object(ListBase *lb, Object *ob, float mat[][4], int lay, int index, int par_index, int type, short flag)
+static DupliObject *new_dupli_object(ListBase *lb, Object *ob, float mat[][4], int lay,
+                                     int persistent_id[MAX_DUPLI_RECUR], int level, int index, int type, short flag)
 {
 	DupliObject *dob = MEM_callocN(sizeof(DupliObject), "dupliobject");
-	
+	int i;
+
 	BLI_addtail(lb, dob);
 	dob->ob = ob;
 	copy_m4_m4(dob->mat, mat);
 	copy_m4_m4(dob->omat, ob->obmat);
 	dob->origlay = ob->lay;
-	dob->index = index;
-	dob->particle_index = par_index;
 	dob->type = type;
 	dob->animated = (type == OB_DUPLIGROUP) && (flag & DUPLILIST_ANIMATED);
 	ob->lay = lay;
+
+	/* set persistent id, which is an array with a persistent index for each level
+	 * (particle number, vertex number, ..). by comparing this we can find the same
+	 * dupli object between frames, which is needed for motion blur. last level
+	 * goes first in the array. */
+	dob->persistent_id[0] = index;
+	for(i = 1; i < level; i++)
+		dob->persistent_id[i] = persistent_id[level-1-i];
 	
 	return dob;
 }
 
-static void group_duplilist(ListBase *lb, Scene *scene, Object *ob, int par_index,
+static void group_duplilist(ListBase *lb, Scene *scene, Object *ob, int persistent_id[MAX_DUPLI_RECUR],
                             int level, short flag)
 {
 	DupliObject *dob;
 	Group *group;
 	GroupObject *go;
-	float mat[4][4], tmat[4][4];
+	float mat[4][4], tmat[4][4], id;
 	
 	if (ob->dup_group == NULL) return;
 	group = ob->dup_group;
@@ -750,7 +758,7 @@ static void group_duplilist(ListBase *lb, Scene *scene, Object *ob, int par_inde
 	if (group_is_animated(ob, group))
 		flag |= DUPLILIST_ANIMATED;
 	
-	for (go = group->gobject.first; go; go = go->next) {
+	for (go = group->gobject.first, id = 0; go; go = go->next, id++) {
 		/* note, if you check on layer here, render goes wrong... it still deforms verts and uses parent imat */
 		if (go->ob != ob) {
 			
@@ -764,7 +772,7 @@ static void group_duplilist(ListBase *lb, Scene *scene, Object *ob, int par_inde
 				mult_m4_m4m4(mat, ob->obmat, go->ob->obmat);
 			}
 			
-			dob = new_dupli_object(lb, go->ob, mat, ob->lay, 0, par_index, OB_DUPLIGROUP, flag);
+			dob = new_dupli_object(lb, go->ob, mat, ob->lay, persistent_id, level, id, OB_DUPLIGROUP, flag);
 
 			/* check the group instance and object layers match, also that the object visible flags are ok. */
 			if ((dob->origlay & group->layer) == 0 ||
@@ -779,14 +787,14 @@ static void group_duplilist(ListBase *lb, Scene *scene, Object *ob, int par_inde
 
 			if (go->ob->transflag & OB_DUPLI) {
 				copy_m4_m4(dob->ob->obmat, dob->mat);
-				object_duplilist_recursive(&group->id, scene, go->ob, lb, ob->obmat, par_index, level + 1, flag);
+				object_duplilist_recursive(&group->id, scene, go->ob, lb, ob->obmat, persistent_id, level + 1, id, flag);
 				copy_m4_m4(dob->ob->obmat, dob->omat);
 			}
 		}
 	}
 }
 
-static void frames_duplilist(ListBase *lb, Scene *scene, Object *ob, int par_index, int level, short flag)
+static void frames_duplilist(ListBase *lb, Scene *scene, Object *ob, int persistent_id[MAX_DUPLI_RECUR], int level, short flag)
 {
 	extern int enable_cu_speed; /* object.c */
 	Object copyob;
@@ -834,7 +842,7 @@ static void frames_duplilist(ListBase *lb, Scene *scene, Object *ob, int par_ind
 			BKE_animsys_evaluate_animdata(scene, &ob->id, ob->adt, (float)scene->r.cfra, ADT_RECALC_ANIM); /* ob-eval will do drivers, so we don't need to do them */
 			BKE_object_where_is_calc_time(scene, ob, (float)scene->r.cfra);
 			
-			dob = new_dupli_object(lb, ob, ob->obmat, ob->lay, scene->r.cfra, par_index, OB_DUPLIFRAMES, flag);
+			dob = new_dupli_object(lb, ob, ob->obmat, ob->lay, persistent_id, level, scene->r.cfra, OB_DUPLIFRAMES, flag);
 			copy_m4_m4(dob->omat, copyob.obmat);
 		}
 	}
@@ -865,7 +873,7 @@ typedef struct VertexDupliData {
 	Scene *scene;
 	Object *ob, *par;
 	float (*orco)[3];
-	int par_index;
+	int *persistent_id;
 } VertexDupliData;
 
 /* ------------- */
@@ -902,7 +910,7 @@ static void vertex_dupli__mapFunc(void *userData, int index, const float co[3],
 
 	origlay = vdd->ob->lay;
 	
-	dob = new_dupli_object(vdd->lb, vdd->ob, obmat, vdd->par->lay, index, vdd->par_index, OB_DUPLIVERTS, vdd->flag);
+	dob = new_dupli_object(vdd->lb, vdd->ob, obmat, vdd->par->lay, vdd->persistent_id, vdd->level, index, OB_DUPLIVERTS, vdd->flag);
 
 	/* restore the original layer so that each dupli will have proper dob->origlay */
 	vdd->ob->lay = origlay;
@@ -914,12 +922,12 @@ static void vertex_dupli__mapFunc(void *userData, int index, const float co[3],
 		float tmpmat[4][4];
 		copy_m4_m4(tmpmat, vdd->ob->obmat);
 		copy_m4_m4(vdd->ob->obmat, obmat); /* pretend we are really this mat */
-		object_duplilist_recursive((ID *)vdd->id, vdd->scene, vdd->ob, vdd->lb, obmat, vdd->par_index, vdd->level + 1, vdd->flag);
+		object_duplilist_recursive((ID *)vdd->id, vdd->scene, vdd->ob, vdd->lb, obmat, vdd->persistent_id, vdd->level + 1, index, vdd->flag);
 		copy_m4_m4(vdd->ob->obmat, tmpmat);
 	}
 }
 
-static void vertex_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, float par_space_mat[][4], int par_index,
+static void vertex_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, float par_space_mat[][4], int persistent_id[MAX_DUPLI_RECUR],
                              int level, short flag)
 {
 	Object *ob, *ob_iter;
@@ -1004,7 +1012,7 @@ static void vertex_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, fl
 					vdd.scene = scene;
 					vdd.par = par;
 					copy_m4_m4(vdd.pmat, pmat);
-					vdd.par_index = par_index;
+					vdd.persistent_id = persistent_id;
 					
 					/* mballs have a different dupli handling */
 					if (ob->type != OB_MBALL) ob->flag |= OB_DONE;  /* doesnt render */
@@ -1043,7 +1051,7 @@ static void vertex_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, fl
 	dm->release(dm);
 }
 
-static void face_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, float par_space_mat[][4], int par_index,
+static void face_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, float par_space_mat[][4], int persistent_id[MAX_DUPLI_RECUR],
                            int level, short flag)
 {
 	Object *ob, *ob_iter;
@@ -1186,7 +1194,7 @@ static void face_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, floa
 						copy_m4_m4(tmat, obmat);
 						mul_m4_m4m3(obmat, tmat, mat);
 						
-						dob = new_dupli_object(lb, ob, obmat, par->lay, a, par_index, OB_DUPLIFACES, (flag & DUPLILIST_ANIMATED));
+						dob = new_dupli_object(lb, ob, obmat, par->lay, persistent_id, level, a, OB_DUPLIFACES, (flag & DUPLILIST_ANIMATED));
 						if (flag & DUPLILIST_FOR_RENDER) {
 							w = 1.0f / (float)mp->totloop;
 
@@ -1209,7 +1217,7 @@ static void face_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, floa
 							float tmpmat[4][4];
 							copy_m4_m4(tmpmat, ob->obmat);
 							copy_m4_m4(ob->obmat, obmat); /* pretend we are really this mat */
-							object_duplilist_recursive((ID *)id, scene, ob, lb, ob->obmat, par_index, level + 1, flag);
+							object_duplilist_recursive((ID *)id, scene, ob, lb, ob->obmat, persistent_id, level + 1, a, flag);
 							copy_m4_m4(ob->obmat, tmpmat);
 						}
 					}
@@ -1229,7 +1237,7 @@ static void face_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, floa
 	dm->release(dm);
 }
 
-static void new_particle_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, float par_space_mat[][4], int UNUSED(par_index), ParticleSystem *psys,
+static void new_particle_duplilist(ListBase *lb, ID *id, Scene *scene, Object *par, float par_space_mat[][4], int persistent_id[MAX_DUPLI_RECUR], ParticleSystem *psys,
                                    int level, short flag)
 {
 	GroupObject *go;
@@ -1244,7 +1252,7 @@ static void new_particle_duplilist(ListBase *lb, ID *id, Scene *scene, Object *p
 	float ctime, pa_time, scale = 1.0f;
 	float tmat[4][4], mat[4][4], pamat[4][4], vec[3], size = 0.0;
 	float (*obmat)[4], (*oldobmat)[4];
-	int a, b, counter, index, hair = 0;
+	int a, b, hair = 0;
 	int totpart, totchild, totgroup = 0 /*, pa_num */;
 
 	int no_draw_flag = PARS_UNEXIST;
@@ -1360,8 +1368,7 @@ static void new_particle_duplilist(ListBase *lb, ID *id, Scene *scene, Object *p
 		else
 			a = totpart;
 
-		index = 0;
-		for (pa = psys->particles, counter = 0; a < totpart + totchild; a++, pa++, counter++) {
+		for (pa = psys->particles; a < totpart + totchild; a++, pa++) {
 			if (a < totpart) {
 				/* handle parent particle */
 				if (pa->flag & no_draw_flag)
@@ -1456,7 +1463,8 @@ static void new_particle_duplilist(ListBase *lb, ID *id, Scene *scene, Object *p
 					else
 						copy_m4_m4(mat, tmat);
 
-					dob = new_dupli_object(lb, go->ob, mat, par->lay, counter, index, OB_DUPLIPARTS, (flag & DUPLILIST_ANIMATED));
+					dob = new_dupli_object(lb, go->ob, mat, par->lay, persistent_id, level, a, OB_DUPLIPARTS, (flag & DUPLILIST_ANIMATED));
+					dob->particle_system = psys;
 					copy_m4_m4(dob->omat, obcopylist[b].obmat);
 					if (flag & DUPLILIST_FOR_RENDER)
 						psys_get_dupli_texture(psys, part, sim.psmd, pa, cpa, dob->uv, dob->orco);
@@ -1516,14 +1524,12 @@ static void new_particle_duplilist(ListBase *lb, ID *id, Scene *scene, Object *p
 				if (part->draw & PART_DRAW_GLOBAL_OB)
 					add_v3_v3v3(mat[3], mat[3], vec);
 
-				dob = new_dupli_object(lb, ob, mat, ob->lay, counter, index, GS(id->name) == ID_GR ? OB_DUPLIGROUP : OB_DUPLIPARTS, (flag & DUPLILIST_ANIMATED));
+				dob = new_dupli_object(lb, ob, mat, ob->lay, persistent_id, level, a, GS(id->name) == ID_GR ? OB_DUPLIGROUP : OB_DUPLIPARTS, (flag & DUPLILIST_ANIMATED));
+				dob->particle_system = psys;
 				copy_m4_m4(dob->omat, oldobmat);
 				if (flag & DUPLILIST_FOR_RENDER)
 					psys_get_dupli_texture(psys, part, sim.psmd, pa, cpa, dob->uv, dob->orco);
 			}
-
-			/* only counts visible particles */
-			index++;
 		}
 
 		/* restore objects since they were changed in BKE_object_where_is_calc_time */
@@ -1570,7 +1576,7 @@ static Object *find_family_object(Object **obar, char *family, char ch)
 }
 
 
-static void font_duplilist(ListBase *lb, Scene *scene, Object *par, int par_index, int level, short flag)
+static void font_duplilist(ListBase *lb, Scene *scene, Object *par, int persistent_id[MAX_DUPLI_RECUR], int level, short flag)
 {
 	Object *ob, *obar[256] = {NULL};
 	Curve *cu;
@@ -1609,7 +1615,7 @@ static void font_duplilist(ListBase *lb, Scene *scene, Object *par, int par_inde
 			copy_m4_m4(obmat, par->obmat);
 			copy_v3_v3(obmat[3], vec);
 			
-			new_dupli_object(lb, ob, obmat, par->lay, a, par_index, OB_DUPLIVERTS, flag);
+			new_dupli_object(lb, ob, obmat, par->lay, persistent_id, level, a, OB_DUPLIVERTS, flag);
 		}
 	}
 	
@@ -1618,8 +1624,8 @@ static void font_duplilist(ListBase *lb, Scene *scene, Object *par, int par_inde
 
 /* ------------- */
 
-static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBase *duplilist, float par_space_mat[][4], int par_index,
-                                       int level, short flag)
+static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBase *duplilist, float par_space_mat[][4],
+                                       int persistent_id[MAX_DUPLI_RECUR], int level, int index, short flag)
 {	
 	if ((ob->transflag & OB_DUPLI) == 0)
 		return;
@@ -1636,34 +1642,45 @@ static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBas
 		}
 	}
 
+	/* keep track of persistent id */
+	if(level > 0)
+		persistent_id[level-1] = index;
+
 	if (ob->transflag & OB_DUPLIPARTS) {
 		ParticleSystem *psys = ob->particlesystem.first;
-		for (; psys; psys = psys->next)
-			new_particle_duplilist(duplilist, id, scene, ob, par_space_mat, par_index, psys, level + 1, flag);
+		int psysid = 0;
+
+		/* particle system take up one level in id, the particles another */
+		for (; psys; psys = psys->next, psysid++) {
+			persistent_id[level] = psysid;
+			new_particle_duplilist(duplilist, id, scene, ob, par_space_mat, persistent_id, psys, level + 2, flag);
+		}
+
+		persistent_id[level] = 0;
 	}
 	else if (ob->transflag & OB_DUPLIVERTS) {
 		if (ob->type == OB_MESH) {
-			vertex_duplilist(duplilist, id, scene, ob, par_space_mat, par_index, level + 1, flag);
+			vertex_duplilist(duplilist, id, scene, ob, par_space_mat, persistent_id, level + 1, flag);
 		}
 		else if (ob->type == OB_FONT) {
 			if (GS(id->name) == ID_SCE) { /* TODO - support dupligroups */
-				font_duplilist(duplilist, scene, ob, par_index, level + 1, flag);
+				font_duplilist(duplilist, scene, ob, persistent_id, level + 1, flag);
 			}
 		}
 	}
 	else if (ob->transflag & OB_DUPLIFACES) {
 		if (ob->type == OB_MESH)
-			face_duplilist(duplilist, id, scene, ob, par_space_mat, par_index, level + 1, flag);
+			face_duplilist(duplilist, id, scene, ob, par_space_mat, persistent_id, level + 1, flag);
 	}
 	else if (ob->transflag & OB_DUPLIFRAMES) {
 		if (GS(id->name) == ID_SCE) { /* TODO - support dupligroups */
-			frames_duplilist(duplilist, scene, ob, par_index, level + 1, flag);
+			frames_duplilist(duplilist, scene, ob, persistent_id, level + 1, flag);
 		}
 	}
 	else if (ob->transflag & OB_DUPLIGROUP) {
 		DupliObject *dob;
 		
-		group_duplilist(duplilist, scene, ob, par_index, level + 1, flag); /* now recursive */
+		group_duplilist(duplilist, scene, ob, persistent_id, level + 1, flag); /* now recursive */
 
 		if (level == 0) {
 			for (dob = duplilist->first; dob; dob = dob->next)
@@ -1671,6 +1688,10 @@ static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBas
 					copy_m4_m4(dob->ob->obmat, dob->mat);
 		}
 	}
+
+	/* clear persistent id */
+	if(level > 0)
+		persistent_id[level-1] = 0;
 }
 
 /* Returns a list of DupliObject
@@ -1678,13 +1699,14 @@ static void object_duplilist_recursive(ID *id, Scene *scene, Object *ob, ListBas
 ListBase *object_duplilist_ex(Scene *sce, Object *ob, int update, int for_render)
 {
 	ListBase *duplilist = MEM_mallocN(sizeof(ListBase), "duplilist");
+	int persistent_id[MAX_DUPLI_RECUR] = {0};
 	int flag = 0;
 
 	if (update)     flag |= DUPLILIST_DO_UPDATE;
 	if (for_render) flag |= DUPLILIST_FOR_RENDER;
 
 	duplilist->first = duplilist->last = NULL;
-	object_duplilist_recursive((ID *)sce, sce, ob, duplilist, NULL, 0, 0, flag);
+	object_duplilist_recursive((ID *)sce, sce, ob, duplilist, NULL, persistent_id, 0, 0, flag);
 	return duplilist;
 }