Depsgraph: cache effector relations, for performance and stability.

To find all effectors in the scene, we need to loop over all objects.
Doing this during depsgraph evaluation caused crashes because not all
objects are guaranteed to be evaluated yet.

To fix this, we now cache the relations as part of the dependency graph
build. As a bonus this also makes evaluation faster for big scenes,
since looping over all objects for each particle system is slow.

Fixes T55156.

1 files changed, 31 insertions, 7 deletions

diff --git a/source/blender/blenkernel/BKE_effect.h b/source/blender/blenkernel/BKE_effect.h
index 379ab3e81b5..a0af34d59e6 100644
--- a/source/blender/blenkernel/BKE_effect.h
+++ b/source/blender/blenkernel/BKE_effect.h
@@ -45,6 +45,7 @@ struct ParticleSimulationData;
 struct ParticleData;
 struct ParticleKey;
 struct Depsgraph;
+struct ViewLayer;
 
 struct EffectorWeights *BKE_add_effector_weights(struct Collection *collection);
 struct PartDeflect *object_add_collision_fields(int type);
@@ -111,13 +112,36 @@ typedef struct EffectorCache {
 	int flag;
 } EffectorCache;
 
-void            free_partdeflect(struct PartDeflect *pd);
-struct ListBase *pdInitEffectors(
-        struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob_src, struct ParticleSystem *psys_src,
-        struct EffectorWeights *weights, bool for_simulation);
-void            pdEndEffectors(struct ListBase **effectors);
-void            pdPrecalculateEffectors(struct Depsgraph *depsgraph, struct ListBase *effectors);
-void            pdDoEffectors(struct ListBase *effectors, struct ListBase *colliders, struct EffectorWeights *weights, struct EffectedPoint *point, float *force, float *impulse);
+typedef struct EffectorRelation {
+	struct EffectorRelation *next, *prev;
+
+	struct Object *ob;
+	struct ParticleSystem *psys;
+	struct PartDeflect *pd;
+} EffectorRelation;
+
+void free_partdeflect(struct PartDeflect *pd);
+
+struct ListBase *BKE_effector_relations_create(
+        struct Depsgraph *depsgraph,
+        struct ViewLayer *view_layer,
+        struct Collection *collection);
+void BKE_effector_relations_free(struct ListBase *lb);
+
+struct ListBase *BKE_effectors_create(
+        struct Depsgraph *depsgraph,
+        struct Scene *scene,
+        struct Object *ob_src,
+        struct ParticleSystem *psys_src,
+        struct EffectorWeights *weights);
+void BKE_effectors_apply(
+        struct ListBase *effectors,
+        struct ListBase *colliders,
+        struct EffectorWeights *weights,
+        struct EffectedPoint *point,
+        float *force,
+        float *impulse);
+void BKE_effectors_free(struct ListBase *lb);
 
 void pd_point_from_particle(struct ParticleSimulationData *sim, struct ParticleData *pa, struct ParticleKey *state, struct EffectedPoint *point);
 void pd_point_from_loc(struct Scene *scene, float *loc, float *vel, int index, struct EffectedPoint *point);