4 files changed, 76 insertions, 2 deletions

diff --git a/source/blender/blenkernel/BKE_scene.h b/source/blender/blenkernel/BKE_scene.h
index b31cd1742a2..8e2e37bf39a 100644
--- a/source/blender/blenkernel/BKE_scene.h
+++ b/source/blender/blenkernel/BKE_scene.h
@@ -215,6 +215,10 @@ void        BKE_scene_multiview_videos_dimensions_get(const struct RenderData *r
 int         BKE_scene_multiview_num_videos_get(const struct RenderData *rd);
 
 /* depsgraph */
+void BKE_scene_allocate_depsgraph_hash(struct Scene *scene);
+void BKE_scene_ensure_depsgraph_hash(struct Scene *scene);
+void BKE_scene_free_depsgraph_hash(struct Scene *scene);
+
 struct Depsgraph *BKE_scene_get_depsgraph(struct Scene *scene, struct SceneLayer *scene_layer);
 
 #ifdef __cplusplus
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index c320f3d2a6c..8b53425d343 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -238,6 +238,7 @@ void BKE_scene_copy_data(Main *bmain, Scene *sce_dst, const Scene *sce_src, cons
 
 	sce_dst->ed = NULL;
 	sce_dst->depsgraph_legacy = NULL;
+	sce_dst->depsgraph_hash = NULL;
 	sce_dst->obedit = NULL;
 	sce_dst->fps_info = NULL;
 
@@ -661,7 +662,7 @@ void BKE_scene_free_ex(Scene *sce, const bool do_id_user)
 		sce->toolsettings = NULL;
 	}
 	
-	DEG_scene_graph_free(sce);
+	BKE_scene_free_depsgraph_hash(sce);
 
 	MEM_SAFE_FREE(sce->fps_info);
 
@@ -2401,6 +2402,72 @@ int BKE_scene_multiview_num_videos_get(const RenderData *rd)
 	}
 }
 
+/* Manipulation of depsgraph storage. */
+
+/* This is a key which identifies depsgraph. */
+typedef struct DepsgraphKey {
+	SceneLayer *scene_layer;
+	/* TODO(sergey): Need to include window somehow (same layer might be in a
+	 * different states in different windows).
+	 */
+} DepsgraphKey;
+
+static unsigned int depsgraph_key_hash(const void *key_v)
+{
+	const DepsgraphKey *key = key_v;
+	unsigned int hash = BLI_ghashutil_ptrhash(key->scene_layer);
+	/* TODO(sergey): Include hash from other fields in the key. */
+	return hash;
+}
+
+static bool depsgraph_key_compare(const void *key_a_v, const void *key_b_v)
+{
+	const DepsgraphKey *key_a = key_a_v;
+	const DepsgraphKey *key_b = key_b_v;
+	/* TODO(sergey): Compare rest of  */
+	return !(key_a->scene_layer == key_b->scene_layer);
+}
+
+static void depsgraph_key_free(void *key_v)
+{
+	DepsgraphKey *key = key_v;
+	MEM_freeN(key);
+}
+
+static void depsgraph_key_value_free(void *value)
+{
+	Depsgraph *depsgraph = value;
+	DEG_graph_free(depsgraph);
+}
+
+void BKE_scene_allocate_depsgraph_hash(Scene *scene)
+{
+	scene->depsgraph_hash = BLI_ghash_new(depsgraph_key_hash,
+	                                      depsgraph_key_compare,
+	                                      "Scene Depsgraph Hash");
+}
+
+void BKE_scene_ensure_depsgraph_hash(Scene *scene)
+{
+	if (scene->depsgraph_hash == NULL) {
+		BKE_scene_allocate_depsgraph_hash(scene);
+	}
+}
+
+void BKE_scene_free_depsgraph_hash(Scene *scene)
+{
+	/* TODO(sergey): Keep this for until we get rid of depsgraph_legacy. */
+	DEG_scene_graph_free(scene);
+	if (scene->depsgraph_hash == NULL) {
+		return;
+	}
+	BLI_ghash_free(scene->depsgraph_hash,
+	               depsgraph_key_free,
+	               depsgraph_key_value_free);
+}
+
+/* Query depsgraph for a specific contexts. */
+
 Depsgraph *BKE_scene_get_depsgraph(Scene *scene, SceneLayer *scene_layer)
 {
 	(void) scene_layer;
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index e56218b7c90..c0580660e2b 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -6095,6 +6095,7 @@ static void direct_link_scene(FileData *fd, Scene *sce, Main *bmain)
 	SceneRenderLayer *srl;
 	
 	sce->depsgraph_legacy = NULL;
+	sce->depsgraph_hash = NULL;
 	sce->obedit = NULL;
 	sce->fps_info = NULL;
 	sce->customdata_mask_modal = 0;
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index ec885cb198c..68599a10a3e 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -1655,7 +1655,9 @@ typedef struct Scene {
 	
 	/* none of the dependency graph  vars is mean to be saved */
 	struct Depsgraph *depsgraph_legacy;
-	float pad3;
+	struct GHash *depsgraph_hash;
+	void *pad3;
+	int pad7;
 
 	/* User-Defined KeyingSets */
 	int active_keyingset;			/* index of the active KeyingSet. first KeyingSet has index 1, 'none' active is 0, 'add new' is -1 */