modifier stack: lazy initialize normals

many modifiers were calculating normals, when those normals were ignored by the next modifier.
now flag normals as dirty and recalculate for modifiers that set use `dependsOnNormals()` callback.

Quick test on mesh with 12 modifiers (mostly build type), calculated normals 6 times, now it only runs once - so this will give some speedup too.

15 files changed, 19 insertions, 27 deletions

diff --git a/source/blender/modifiers/intern/MOD_array.c b/source/blender/modifiers/intern/MOD_array.c
index a1fdae5792c..902afd2ed41 100644
--- a/source/blender/modifiers/intern/MOD_array.c
+++ b/source/blender/modifiers/intern/MOD_array.c
@@ -565,11 +565,7 @@ static DerivedMesh *arrayModifier_doArray(ArrayModifierData *amd,
 
 	if ((amd->offset_type & MOD_ARR_OFF_OBJ) && (amd->offset_ob)) {
 		/* Update normals in case offset object has rotation. */
-		
-		/* BMESH_TODO: check if normal recalc needed under any other
-		 * conditions? */
-
-		CDDM_calc_normals(result);
+		result->dirty |= DM_DIRTY_NORMALS;
 	}
 
 	BM_mesh_free(bm);
@@ -591,9 +587,6 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 
 	result = arrayModifier_doArray(amd, md->scene, ob, dm, 0);
 
-	//if (result != dm)
-	//	CDDM_calc_normals_mapping(result);
-
 	return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_bevel.c b/source/blender/modifiers/intern/MOD_bevel.c
index 7cd10491c89..cbb0e05aa4a 100644
--- a/source/blender/modifiers/intern/MOD_bevel.c
+++ b/source/blender/modifiers/intern/MOD_bevel.c
@@ -171,7 +171,7 @@ static DerivedMesh *applyModifier(ModifierData *md, struct Object *ob,
 	           bm->ftoolflagpool == NULL);  /* make sure we never alloc'd these */
 	BM_mesh_free(bm);
 
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
@@ -208,7 +208,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *UNUSED(ob),
 
 	/* until we allow for dirty normal flag, always calc,
 	 * note: calculating on the CDDM is faster then the BMesh equivalent */
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_boolean_util.c b/source/blender/modifiers/intern/MOD_boolean_util.c
index ed5bb1d3f4d..75a05633507 100644
--- a/source/blender/modifiers/intern/MOD_boolean_util.c
+++ b/source/blender/modifiers/intern/MOD_boolean_util.c
@@ -485,7 +485,7 @@ static DerivedMesh *ConvertCSGDescriptorsToDerivedMesh(
 	DM_ensure_tessface(result);
 #endif
 
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_edgesplit.c b/source/blender/modifiers/intern/MOD_edgesplit.c
index 94e7475e9b3..0c50d4d3323 100644
--- a/source/blender/modifiers/intern/MOD_edgesplit.c
+++ b/source/blender/modifiers/intern/MOD_edgesplit.c
@@ -136,7 +136,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob, DerivedMesh *der
 	result = edgesplitModifier_do(emd, ob, derivedData);
 
 	if (result != derivedData)
-		CDDM_calc_normals(result);
+		result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_explode.c b/source/blender/modifiers/intern/MOD_explode.c
index f0eb113e46f..c8899bac450 100644
--- a/source/blender/modifiers/intern/MOD_explode.c
+++ b/source/blender/modifiers/intern/MOD_explode.c
@@ -971,7 +971,7 @@ static DerivedMesh *explodeMesh(ExplodeModifierData *emd,
 	/* finalization */
 	CDDM_calc_edges_tessface(explode);
 	CDDM_tessfaces_to_faces(explode);
-	CDDM_calc_normals(explode);
+	explode->dirty |= DM_DIRTY_NORMALS;
 
 	if (psmd->psys->lattice) {
 		end_latt_deform(psmd->psys->lattice);
diff --git a/source/blender/modifiers/intern/MOD_mask.c b/source/blender/modifiers/intern/MOD_mask.c
index 46a590e24e9..0d302fed3e6 100644
--- a/source/blender/modifiers/intern/MOD_mask.c
+++ b/source/blender/modifiers/intern/MOD_mask.c
@@ -384,7 +384,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 
 	/* why is this needed? - campbell */
 	/* recalculate normals */
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 	
 	/* free hashes */
 	BLI_ghash_free(vertHash, NULL, NULL);
diff --git a/source/blender/modifiers/intern/MOD_mirror.c b/source/blender/modifiers/intern/MOD_mirror.c
index b85ca2c1532..2e7b7c7ab7d 100644
--- a/source/blender/modifiers/intern/MOD_mirror.c
+++ b/source/blender/modifiers/intern/MOD_mirror.c
@@ -330,7 +330,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 	result = mirrorModifier__doMirror(mmd, ob, derivedData);
 
 	if (result != derivedData)
-		CDDM_calc_normals(result);
+		result->dirty |= DM_DIRTY_NORMALS;
 	
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_ocean.c b/source/blender/modifiers/intern/MOD_ocean.c
index 34c89fc6ee3..125d4bc3789 100644
--- a/source/blender/modifiers/intern/MOD_ocean.c
+++ b/source/blender/modifiers/intern/MOD_ocean.c
@@ -386,6 +386,8 @@ static DerivedMesh *generate_ocean_geometry(OceanModifierData *omd)
 		}
 	}
 
+	result->dirty |= DM_DIRTY_NORMALS;
+
 	return result;
 }
 
@@ -543,7 +545,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 	result = doOcean(md, ob, derivedData, 0);
 
 	if (result != derivedData)
-		CDDM_calc_normals(result);
+		result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_particleinstance.c b/source/blender/modifiers/intern/MOD_particleinstance.c
index 2c942b38286..b0de27b7292 100644
--- a/source/blender/modifiers/intern/MOD_particleinstance.c
+++ b/source/blender/modifiers/intern/MOD_particleinstance.c
@@ -391,7 +391,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 	if (size)
 		MEM_freeN(size);
 
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_remesh.c b/source/blender/modifiers/intern/MOD_remesh.c
index 746cad10a01..c8fdbc535bc 100644
--- a/source/blender/modifiers/intern/MOD_remesh.c
+++ b/source/blender/modifiers/intern/MOD_remesh.c
@@ -202,7 +202,7 @@ static DerivedMesh *applyModifier(ModifierData *md,
 	}
 
 	CDDM_calc_edges(result);
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 	return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_screw.c b/source/blender/modifiers/intern/MOD_screw.c
index bbafa8c939e..475d294abd6 100644
--- a/source/blender/modifiers/intern/MOD_screw.c
+++ b/source/blender/modifiers/intern/MOD_screw.c
@@ -897,8 +897,7 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
 #endif
 
 	if ((ltmd->flag & MOD_SCREW_NORMAL_CALC) == 0) {
-		/* BMESH_TODO, we only need to get vertex normals here, this is way overkill */
-		CDDM_calc_normals(result);
+		result->dirty |= DM_DIRTY_NORMALS;
 	}
 
 	return result;
diff --git a/source/blender/modifiers/intern/MOD_skin.c b/source/blender/modifiers/intern/MOD_skin.c
index ad58aac1746..6c2bd25f0a5 100644
--- a/source/blender/modifiers/intern/MOD_skin.c
+++ b/source/blender/modifiers/intern/MOD_skin.c
@@ -1805,7 +1805,7 @@ static DerivedMesh *base_skin(DerivedMesh *origdm,
 	BM_mesh_free(bm);
 
 	CDDM_calc_edges(result);
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 
 	skin_set_orig_indices(result);
 
diff --git a/source/blender/modifiers/intern/MOD_solidify.c b/source/blender/modifiers/intern/MOD_solidify.c
index c54ed26d47e..ef7f0050bb1 100644
--- a/source/blender/modifiers/intern/MOD_solidify.c
+++ b/source/blender/modifiers/intern/MOD_solidify.c
@@ -820,7 +820,7 @@ static DerivedMesh *applyModifier(
 
 	/* must recalculate normals with vgroups since they can displace unevenly [#26888] */
 	if (dvert) {
-		CDDM_calc_normals(result);
+		result->dirty |= DM_DIRTY_NORMALS;
 	}
 
 	if (numFaces == 0 && numEdges != 0) {
diff --git a/source/blender/modifiers/intern/MOD_triangulate.c b/source/blender/modifiers/intern/MOD_triangulate.c
index 59973fe77a8..fd0bc218bc4 100644
--- a/source/blender/modifiers/intern/MOD_triangulate.c
+++ b/source/blender/modifiers/intern/MOD_triangulate.c
@@ -54,7 +54,7 @@ static DerivedMesh *triangulate_dm(DerivedMesh *dm, const int flag)
 	for (i = 0; i < total_edges; i++, me++)
 		me->flag |= ME_EDGEDRAW | ME_EDGERENDER;
 
-	CDDM_calc_normals(result);
+	result->dirty |= DM_DIRTY_NORMALS;
 
 	return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_util.c b/source/blender/modifiers/intern/MOD_util.c
index 1084023fcf0..c3748ce0265 100644
--- a/source/blender/modifiers/intern/MOD_util.c
+++ b/source/blender/modifiers/intern/MOD_util.c
@@ -184,11 +184,9 @@ DerivedMesh *get_cddm(Object *ob, struct BMEditMesh *em, DerivedMesh *dm, float
 	else {
 		dm = CDDM_copy(dm);
 		CDDM_apply_vert_coords(dm, vertexCos);
+		dm->dirty |= DM_DIRTY_NORMALS;
 	}
 
-	if (dm)
-		CDDM_calc_normals(dm);
-	
 	return dm;
 }
 
@@ -204,7 +202,7 @@ DerivedMesh *get_dm(Object *ob, struct BMEditMesh *em, DerivedMesh *dm, float (*
 
 		if (vertexCos) {
 			CDDM_apply_vert_coords(dm, vertexCos);
-			//CDDM_calc_normals(dm);
+			dm->dirty |= DM_DIRTY_NORMALS;
 		}
 		
 		if (orco)