1 files changed, 24 insertions, 12 deletions

diff --git a/source/blender/makesdna/DNA_simulation_types.h b/source/blender/makesdna/DNA_simulation_types.h
index 5bb0e50e089..afc59b422c5 100644
--- a/source/blender/makesdna/DNA_simulation_types.h
+++ b/source/blender/makesdna/DNA_simulation_types.h
@@ -30,16 +30,21 @@ typedef struct Simulation {
 
   struct bNodeTree *nodetree;
 
-  int flag;
+  uint32_t flag;
+
+  /** This is the frame in scene time, that the states correspond to. */
   float current_frame;
+
+  /** Time since the start of the simulation in simulation time (which might differ from scene
+   * time). */
   float current_simulation_time;
   char _pad[4];
 
   /** List containing SimulationState objects. */
   struct ListBase states;
 
-  /** List containing PersistentDataHandleItem objects. */
-  struct ListBase persistent_data_handles;
+  /** List containing SimulationDependency objects. */
+  struct ListBase dependencies;
 } Simulation;
 
 typedef struct SimulationState {
@@ -54,8 +59,8 @@ typedef struct ParticleSimulationState {
   SimulationState head;
 
   /** Contains the state of the particles at time Simulation->current_frame. */
-  int tot_particles;
-  int next_particle_id;
+  int32_t tot_particles;
+  int32_t next_particle_id;
   struct CustomData attributes;
 } ParticleSimulationState;
 
@@ -66,20 +71,27 @@ typedef struct ParticleMeshEmitterSimulationState {
   char _pad[4];
 } ParticleMeshEmitterSimulationState;
 
-/** Stores a mapping between an integer handle and a corresponding ID data block. */
-typedef struct PersistentDataHandleItem {
-  struct PersistentDataHandleItem *next;
-  struct PersistentDataHandleItem *prev;
+/** Stores a reference to data that the simulation depends on. This is partially derived from the
+ * simulation node tree. */
+typedef struct SimulationDependency {
+  struct SimulationDependency *next;
+  struct SimulationDependency *prev;
   struct ID *id;
-  int handle;
-  char _pad[4];
-} PersistentDataHandleItem;
+  int32_t handle;
+  uint32_t flag;
+} SimulationDependency;
 
 /* Simulation.flag */
 enum {
   SIM_DS_EXPAND = (1 << 0),
 };
 
+/* SimulationDependency.flag */
+enum {
+  SIM_DEPENDS_ON_TRANSFORM = (1 << 0),
+  SIM_DEPENDS_ON_GEOMETRY = (1 << 1),
+};
+
 #define SIM_TYPE_NAME_PARTICLE_SIMULATION "Particle Simulation"
 #define SIM_TYPE_NAME_PARTICLE_MESH_EMITTER "Particle Mesh Emitter"