source/blender/blenkernel/BKE_simulation_state.hh

@@ -153,10 +153,16 @@ struct ModifierSimulationStateAtFrame {
   std::unique_ptr<ModifierSimulationState> state;
 };
 
+enum class CacheState {
+  Valid,
+  Invalid,
+  Baked,
+};
+
 class ModifierSimulationCache {
  private:
   Vector<ModifierSimulationStateAtFrame> states_at_frames_;
-  bool invalid_ = false;
+  CacheState cache_state_ = CacheState::Valid;
 
  public:
   void load_baked_states(StringRefNull meta_dir, StringRefNull bdata_dir);
@@ -208,18 +214,18 @@ class ModifierSimulationCache {
 
   void invalidate()
   {
-    invalid_ = true;
+    cache_state_ = CacheState::Invalid;
   }
 
-  bool is_invalid() const
+  CacheState cache_state() const
   {
-    return invalid_;
+    return cache_state_;
   }
 
   void reset()
   {
     states_at_frames_.clear();
-    invalid_ = false;
+    cache_state_ = CacheState::Valid;
   }
 };
 

source/blender/blenkernel/intern/simulation_state.cc

@@ -39,6 +39,8 @@ void ModifierSimulationCache::load_baked_states(const StringRefNull meta_dir,
         dir_entry.path, bdata_dir, *new_state.state);
     states_at_frames_.append(std::move(new_state));
   }
+
+  cache_state_ = CacheState::Baked;
 }
 
 }  // namespace blender::bke::sim

source/blender/depsgraph/intern/builder/deg_builder_nodes.cc

@@ -911,7 +911,8 @@ void DepsgraphNodeBuilder::build_object_modifiers(Object *object)
           return;
         }
         if (modifier_node->flag & DEPSOP_FLAG_USER_MODIFIED) {
-          if (nmd->simulation_cache) {
+          if (nmd->simulation_cache &&
+              nmd->simulation_cache->cache_state() == bke::sim::CacheState::Valid) {
             nmd->simulation_cache->invalidate();
           }
         }

source/blender/editors/space_action/action_draw.cc

@@ -688,10 +688,21 @@ static void timeline_cache_draw_simulation_nodes(
   GPU_matrix_scale_2f(1.0, height);
 
   float color[4];
-  copy_v4_fl4(color, 0.8, 0.8, 0.2, 1.0);
-  if (cache.is_invalid()) {
-    color[3] = 0.3f;
+  switch (cache.cache_state()) {
+    case blender::bke::sim::CacheState::Invalid: {
+      copy_v4_fl4(color, 0.8, 0.8, 0.2, 0.3);
+      break;
+    }
+    case blender::bke::sim::CacheState::Valid: {
+      copy_v4_fl4(color, 0.8, 0.8, 0.2, 1.0);
+      break;
+    }
+    case blender::bke::sim::CacheState::Baked: {
+      copy_v4_fl4(color, 1.0, 0.6, 0.2, 1.0);
+      break;
+    }
   }
+
   immUniformColor4fv(color);
 
   const int start_frame = scene->r.sfra;

source/blender/modifiers/intern/MOD_nodes.cc

@@ -1209,28 +1209,35 @@ static GeometrySet compute_geometry(const bNodeTree &btree,
     if (nmd_orig->simulation_cache == nullptr) {
       nmd_orig->simulation_cache = MEM_new<blender::bke::sim::ModifierSimulationCache>(__func__);
     }
-    if (nmd_orig->simulation_cache->is_invalid() && current_frame == start_frame) {
-      nmd_orig->simulation_cache->reset();
-    }
     if (current_frame.frame() == 150) {
       nmd_orig->simulation_cache->load_baked_states(
           "/home/jacques/Downloads/blendcache_mesh_deform_sim/Cube_GeometryNodes/meta",
           "/home/jacques/Downloads/blendcache_mesh_deform_sim/Cube_GeometryNodes/bdata");
     }
+    const bke::sim::CacheState last_cache_state = nmd_orig->simulation_cache->cache_state();
+    if (last_cache_state == bke::sim::CacheState::Invalid && current_frame == start_frame) {
+      nmd_orig->simulation_cache->reset();
+    }
     const bke::sim::ModifierSimulationStateAtFrame *prev_sim_state =
         nmd_orig->simulation_cache->try_get_last_state_before_frame(current_frame);
     if (prev_sim_state != nullptr) {
       geo_nodes_modifier_data.prev_simulation_state = prev_sim_state->state.get();
       const float frame_diff = float(current_frame) - float(prev_sim_state->frame);
       geo_nodes_modifier_data.simulation_time_delta = frame_diff / FPS;
-      if (geo_nodes_modifier_data.simulation_time_delta > 1.0f) {
+      if (frame_diff > 1.0f && last_cache_state != bke::sim::CacheState::Baked) {
         nmd_orig->simulation_cache->invalidate();
       }
     }
-    geo_nodes_modifier_data.current_simulation_state_for_write =
-        &nmd_orig->simulation_cache->get_state_at_frame_for_write(current_frame);
-    geo_nodes_modifier_data.current_simulation_state =
-        geo_nodes_modifier_data.current_simulation_state_for_write;
+    if (last_cache_state == bke::sim::CacheState::Baked) {
+      geo_nodes_modifier_data.current_simulation_state =
+          nmd_orig->simulation_cache->get_state_at_exact_frame(current_frame);
+    }
+    else {
+      geo_nodes_modifier_data.current_simulation_state_for_write =
+          &nmd_orig->simulation_cache->get_state_at_frame_for_write(current_frame);
+      geo_nodes_modifier_data.current_simulation_state =
+          geo_nodes_modifier_data.current_simulation_state_for_write;
+    }
   }
   else {
     /* TODO: Should probably only access baked data that is not modified in the original data