Add Custom Loop Normals to Data Transfer.

Titles says everything, just two notes:
* We have to actually transfer plain *normals*, not 'compressed' clnors,
  so had to add pre/post process to transfer to make the conversions.
* Also added interpolation and advanced copy/mixing to CD_NORMAL, for same reasons.

1 files changed, 119 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/data_transfer.c b/source/blender/blenkernel/intern/data_transfer.c
index 3704174be6e..5ac7b928d96 100644
--- a/source/blender/blenkernel/intern/data_transfer.c
+++ b/source/blender/blenkernel/intern/data_transfer.c
@@ -47,6 +47,7 @@
 #include "BKE_data_transfer.h"
 #include "BKE_deform.h"
 #include "BKE_DerivedMesh.h"
+#include "BKE_mesh.h"
 #include "BKE_mesh_mapping.h"
 #include "BKE_mesh_remap.h"
 #include "BKE_object.h"
@@ -79,6 +80,9 @@ CustomDataMask BKE_object_data_transfer_dttypes_to_cdmask(const int dtdata_types
 		else if (cddata_type == CD_FAKE_UV) {
 			cddata_mask |= CD_MASK_MTEXPOLY | CD_MASK_MLOOPUV;
 		}
+		else if (cddata_type == CD_FAKE_LNOR) {
+			cddata_mask |= CD_MASK_NORMAL | CD_MASK_CUSTOMLOOPNORMAL;
+		}
 	}
 
 	return cddata_mask;
@@ -143,6 +147,10 @@ bool BKE_object_data_transfer_get_dttypes_capacity(
 				*r_threshold = true;
 				ret = true;
 				break;
+			case DT_TYPE_LNOR:
+				*r_advanced_mixing = true;
+				ret = true;
+				break;
 			case DT_TYPE_SHARP_FACE:
 				*r_threshold = true;
 				ret = true;
@@ -217,6 +225,8 @@ int BKE_object_data_transfer_dttype_to_cdtype(const int dtdata_type)
 
 		case DT_TYPE_VCOL:
 			return CD_MLOOPCOL;
+		case DT_TYPE_LNOR:
+			return CD_FAKE_LNOR;
 
 		default:
 			BLI_assert(0);
@@ -242,6 +252,105 @@ int BKE_object_data_transfer_dttype_to_srcdst_index(const int dtdata_type)
 
 /* ********** */
 
+/* Generic pre/post processing, only used by custom loop normals currently. */
+
+static void data_transfer_dtdata_type_preprocess(
+        Object *UNUSED(ob_src), Object *UNUSED(ob_dst), DerivedMesh *dm_src, DerivedMesh *dm_dst, Mesh *me_dst,
+        const int dtdata_type, const bool dirty_nors_dst, const bool use_split_nors_src, const float split_angle_src)
+{
+	if (dtdata_type == DT_TYPE_LNOR) {
+		/* Compute custom normals into regular loop normals, which will be used for the transfer. */
+		MVert *verts_dst = dm_dst ? dm_dst->getVertArray(dm_dst) : me_dst->mvert;
+		const int num_verts_dst = dm_dst ? dm_dst->getNumVerts(dm_dst) : me_dst->totvert;
+		MEdge *edges_dst = dm_dst ? dm_dst->getEdgeArray(dm_dst) : me_dst->medge;
+		const int num_edges_dst = dm_dst ? dm_dst->getNumEdges(dm_dst) : me_dst->totedge;
+		MPoly *polys_dst = dm_dst ? dm_dst->getPolyArray(dm_dst) : me_dst->mpoly;
+		const int num_polys_dst = dm_dst ? dm_dst->getNumPolys(dm_dst) : me_dst->totpoly;
+		MLoop *loops_dst = dm_dst ? dm_dst->getLoopArray(dm_dst) : me_dst->mloop;
+		const int num_loops_dst = dm_dst ? dm_dst->getNumLoops(dm_dst) : me_dst->totloop;
+		CustomData *pdata_dst = dm_dst ? dm_dst->getPolyDataLayout(dm_dst) : &me_dst->pdata;
+		CustomData *ldata_dst = dm_dst ? dm_dst->getLoopDataLayout(dm_dst) : &me_dst->ldata;
+
+		const bool use_split_nors_dst = (me_dst->flag & ME_AUTOSMOOTH) != 0;
+		const float split_angle_dst = me_dst->smoothresh;
+
+		dm_src->calcLoopNormals(dm_src, use_split_nors_src, split_angle_src);
+
+		if (dm_dst) {
+			dm_dst->calcLoopNormals(dm_dst, use_split_nors_dst, split_angle_dst);
+		}
+		else {
+			float (*poly_nors_dst)[3];
+			float (*loop_nors_dst)[3];
+			short (*custom_nors_dst)[2] = CustomData_get_layer(ldata_dst, CD_CUSTOMLOOPNORMAL);
+
+			/* Cache poly nors into a temp CDLayer. */
+			poly_nors_dst = CustomData_get_layer(pdata_dst, CD_NORMAL);
+			if (dirty_nors_dst || !poly_nors_dst) {
+				if (!poly_nors_dst) {
+					poly_nors_dst = CustomData_add_layer(pdata_dst, CD_NORMAL, CD_CALLOC, NULL, num_polys_dst);
+					CustomData_set_layer_flag(pdata_dst, CD_NORMAL, CD_FLAG_TEMPORARY);
+				}
+				BKE_mesh_calc_normals_poly(verts_dst, num_verts_dst, loops_dst, polys_dst,
+				                           num_loops_dst, num_polys_dst, poly_nors_dst, true);
+			}
+			/* Cache loop nors into a temp CDLayer. */
+			loop_nors_dst = CustomData_get_layer(ldata_dst, CD_NORMAL);
+			if (dirty_nors_dst || loop_nors_dst) {
+				if (!loop_nors_dst) {
+					loop_nors_dst = CustomData_add_layer(ldata_dst, CD_NORMAL, CD_CALLOC, NULL, num_loops_dst);
+					CustomData_set_layer_flag(ldata_dst, CD_NORMAL, CD_FLAG_TEMPORARY);
+				}
+				BKE_mesh_normals_loop_split(verts_dst, num_verts_dst, edges_dst, num_edges_dst,
+				                            loops_dst, loop_nors_dst, num_loops_dst,
+				                            polys_dst, (const float (*)[3])poly_nors_dst, num_polys_dst,
+				                            use_split_nors_dst, split_angle_dst, NULL, custom_nors_dst, NULL);
+			}
+		}
+	}
+}
+
+static void data_transfer_dtdata_type_postprocess(
+        Object *UNUSED(ob_src), Object *UNUSED(ob_dst), DerivedMesh *UNUSED(dm_src), DerivedMesh *dm_dst, Mesh *me_dst,
+        const int dtdata_type, const bool changed)
+{
+	if (dtdata_type == DT_TYPE_LNOR) {
+		/* Bake edited destination loop normals into custom normals again. */
+		MVert *verts_dst = dm_dst ? dm_dst->getVertArray(dm_dst) : me_dst->mvert;
+		const int num_verts_dst = dm_dst ? dm_dst->getNumVerts(dm_dst) : me_dst->totvert;
+		MEdge *edges_dst = dm_dst ? dm_dst->getEdgeArray(dm_dst) : me_dst->medge;
+		const int num_edges_dst = dm_dst ? dm_dst->getNumEdges(dm_dst) : me_dst->totedge;
+		MPoly *polys_dst = dm_dst ? dm_dst->getPolyArray(dm_dst) : me_dst->mpoly;
+		const int num_polys_dst = dm_dst ? dm_dst->getNumPolys(dm_dst) : me_dst->totpoly;
+		MLoop *loops_dst = dm_dst ? dm_dst->getLoopArray(dm_dst) : me_dst->mloop;
+		const int num_loops_dst = dm_dst ? dm_dst->getNumLoops(dm_dst) : me_dst->totloop;
+		CustomData *pdata_dst = dm_dst ? dm_dst->getPolyDataLayout(dm_dst) : &me_dst->pdata;
+		CustomData *ldata_dst = dm_dst ? dm_dst->getLoopDataLayout(dm_dst) : &me_dst->ldata;
+
+		const float (*poly_nors_dst)[3] = CustomData_get_layer(pdata_dst, CD_NORMAL);
+		float (*loop_nors_dst)[3] = CustomData_get_layer(ldata_dst, CD_NORMAL);
+		short (*custom_nors_dst)[2] = CustomData_get_layer(ldata_dst, CD_CUSTOMLOOPNORMAL);
+
+		BLI_assert(poly_nors_dst);
+
+		if (!changed) {
+			return;
+		}
+
+		if (!custom_nors_dst) {
+			custom_nors_dst = CustomData_add_layer(ldata_dst, CD_CUSTOMLOOPNORMAL, CD_CALLOC, NULL, num_loops_dst);
+		}
+
+		/* Note loop_nors_dst contains our custom normals as transferred from source... */
+		BKE_mesh_normals_loop_custom_set(verts_dst, num_verts_dst, edges_dst, num_edges_dst,
+		                                 loops_dst, loop_nors_dst, num_loops_dst,
+		                                 polys_dst, poly_nors_dst, num_polys_dst,
+		                                 custom_nors_dst);
+	}
+}
+
+/* ********** */
+
 static MeshRemapIslandsCalc data_transfer_get_loop_islands_generator(const int cddata_type)
 {
 	switch (cddata_type) {
@@ -805,6 +914,10 @@ static bool data_transfer_layersmapping_generate(
 		if (cddata_type == CD_FAKE_UV) {
 			cddata_type = CD_MLOOPUV;
 		}
+		else if (cddata_type == CD_FAKE_LNOR) {
+			/* Preprocess should have generated it, Postprocess will convert it back to CD_CUSTOMLOOPNORMAL. */
+			cddata_type = CD_NORMAL;
+		}
 
 		if (!(cddata_type & CD_FAKE)) {
 			cd_src = dm_src->getLoopDataLayout(dm_src);
@@ -1023,6 +1136,10 @@ bool BKE_object_data_transfer_dm(
 			continue;
 		}
 
+		data_transfer_dtdata_type_preprocess(ob_src, ob_dst, dm_src, dm_dst, me_dst,
+		                                     dtdata_type, dirty_nors_dst,
+		                                     (me_src->flag & ME_AUTOSMOOTH) != 0, me_src->smoothresh);
+
 		cddata_type = BKE_object_data_transfer_dttype_to_cdtype(dtdata_type);
 
 		fromto_idx = BKE_object_data_transfer_dttype_to_srcdst_index(dtdata_type);
@@ -1217,6 +1334,8 @@ bool BKE_object_data_transfer_dm(
 				BLI_freelistN(&lay_map);
 			}
 		}
+
+		data_transfer_dtdata_type_postprocess(ob_src, ob_dst, dm_src, dm_dst, me_dst, dtdata_type, changed);
 	}
 
 	for (i = 0; i < DATAMAX; i++) {