Add Custom Loop Normals.

This is the core code for it, tools (datatransfer and modifier) will come in next commits).
RNA api is already there, though.

See the code for details, but basically, we define, for each 'smooth fan'
(which is a set of adjacent loops around a same vertex that are smooth, i.e. have a single same normal),
a 'loop normal space' (or lnor space), using auto-computed normal and relevant edges, and store
custom normal as two angular factors inside that space. This allows to have custom normals
'following' deformations of the geometry, and to only save two shorts per loop in new clnor CDLayer.

Normal manipulation (editing, mixing, interpolating, etc.) shall always happen with plain 3D vectors normals,
and be converted back into storage format at the end.

Clnor computation has also been threaded (at least for Mesh case, not for BMesh), since the process can
be rather heavy with high poly meshes.

Also, bumping subversion, and fix mess in 2.70 versioning code.

1 files changed, 53 insertions, 5 deletions

diff --git a/source/blender/blenkernel/BKE_mesh.h b/source/blender/blenkernel/BKE_mesh.h
index 3138fd69cc4..224be0f3685 100644
--- a/source/blender/blenkernel/BKE_mesh.h
+++ b/source/blender/blenkernel/BKE_mesh.h
@@ -36,6 +36,9 @@ struct BoundBox;
 struct DispList;
 struct EdgeHash;
 struct ListBase;
+struct LinkNode;
+struct BLI_Stack;
+struct MemArena;
 struct BMEditMesh;
 struct BMesh;
 struct Main;
@@ -174,11 +177,6 @@ void BKE_mesh_calc_normals_tessface(
         struct MVert *mverts, int numVerts,
         struct MFace *mfaces, int numFaces,
         float (*r_faceNors)[3]);
-void BKE_mesh_normals_loop_split(
-        struct MVert *mverts, const int numVerts, struct MEdge *medges, const int numEdges,
-        struct MLoop *mloops, float (*r_loopnors)[3], const int numLoops,
-        struct MPoly *mpolys, float (*polynors)[3], const int numPolys,
-        const bool use_split_normals, float split_angle);
 void BKE_mesh_loop_tangents_ex(
         struct MVert *mverts, const int numVerts, struct MLoop *mloops, float (*r_looptangent)[4], float (*loopnors)[3],
         struct MLoopUV *loopuv, const int numLoops, struct MPoly *mpolys, const int numPolys,
@@ -186,6 +184,56 @@ void BKE_mesh_loop_tangents_ex(
 void BKE_mesh_loop_tangents(
         struct Mesh *mesh, const char *uvmap, float (*r_looptangents)[4], struct ReportList *reports);
 
+/**
+ * References a contiguous loop-fan with normal offset vars.
+ */
+typedef struct MLoopNorSpace {
+	float vec_lnor[3];      /* Automatically computed loop normal. */
+	float vec_ref[3];       /* Reference vector, orthogonal to vec_lnor. */
+	float vec_ortho[3];     /* Third vector, orthogonal to vec_lnor and vec_ref. */
+	float ref_alpha;        /* Reference angle, around vec_ortho, in ]0, pi] range (0.0 marks that space as invalid). */
+	float ref_beta;         /* Reference angle, around vec_lnor, in ]0, 2pi] range (0.0 marks that space as invalid). */
+	struct LinkNode *loops; /* All indices (uint_in_ptr) of loops using this lnor space (i.e. smooth fan of loops). */
+} MLoopNorSpace;
+/**
+ * Collection of #MLoopNorSpace basic storage & pre-allocation.
+ */
+typedef struct MLoopNorSpaceArray {
+	MLoopNorSpace **lspacearr;    /* MLoop aligned array */
+	struct LinkNode *loops_pool;  /* Allocated once, avoids to call BLI_linklist_prepend_arena() for each loop! */
+	struct MemArena *mem;
+} MLoopNorSpaceArray;
+void BKE_lnor_spacearr_init(MLoopNorSpaceArray *lnors_spacearr, const int numLoops);
+void BKE_lnor_spacearr_clear(MLoopNorSpaceArray *lnors_spacearr);
+void BKE_lnor_spacearr_free(MLoopNorSpaceArray *lnors_spacearr);
+MLoopNorSpace *BKE_lnor_space_create(MLoopNorSpaceArray *lnors_spacearr);
+void BKE_lnor_space_define(
+        MLoopNorSpace *lnor_space, const float lnor[3], float vec_ref[3], float vec_other[3],
+        struct BLI_Stack *edge_vectors);
+void BKE_lnor_space_add_loop(
+        MLoopNorSpaceArray *lnors_spacearr, MLoopNorSpace *lnor_space, const int ml_index, const bool add_to_list);
+void BKE_lnor_space_custom_data_to_normal(MLoopNorSpace *lnor_space, const short clnor_data[2], float r_custom_lnor[3]);
+void BKE_lnor_space_custom_normal_to_data(MLoopNorSpace *lnor_space, const float custom_lnor[3], short r_clnor_data[2]);
+
+bool BKE_mesh_has_custom_loop_normals(struct Mesh *me);
+
+void BKE_mesh_normals_loop_split(struct MVert *mverts, const int numVerts, struct MEdge *medges, const int numEdges,
+        struct MLoop *mloops, float (*r_loopnors)[3], const int numLoops,
+        struct MPoly *mpolys, const float (*polynors)[3], const int numPolys,
+        const bool use_split_normals, float split_angle,
+        MLoopNorSpaceArray *r_lnors_spacearr, short (*clnors_data)[2], int *r_loop_to_poly);
+
+void BKE_mesh_normals_loop_custom_set(
+        struct MVert *mverts, const int numVerts, struct MEdge *medges, const int numEdges,
+        struct MLoop *mloops, float (*custom_loopnors)[3], const int numLoops,
+        struct MPoly *mpolys, const float (*polynors)[3], const int numPolys,
+        short (*r_clnors_data)[2]);
+void BKE_mesh_normals_loop_custom_from_vertices_set(
+        struct MVert *mverts, float (*custom_vertnors)[3], const int numVerts,
+        struct MEdge *medges, const int numEdges, struct MLoop *mloops, const int numLoops,
+        struct MPoly *mpolys, const float (*polynors)[3], const int numPolys,
+        short (*r_clnors_data)[2]);
+
 void BKE_mesh_calc_poly_normal(
         struct MPoly *mpoly, struct MLoop *loopstart,
         struct MVert *mvarray, float no[3]);