BKE: Add 'mesh remap' code.

This is the (big!) core of mesh transfer data, it defines a set of structures
to represent a mapping of mesh elements (verts, edges, polys of loops) between
two arbitrary meshes, and code to compute such mappings.

No similarity is required between source and destination meshes (though results
when using complete different meshes are rather unlikely to be useful!).

This code is not bound to data transfer, it is defined to be as generic as possible,
and easy to reuse or extend as needs arise.

Several methods of mapping generation are defined for each element type,
we probably will have to adjust that in future (remove useless ones, add
new ones...).

For loops, you can also define islands (for UVs e.g.) so that loops of a same
destination polygon do not 'spread' across several source islands.

Heavily reviewed and enhanced by Campbell, thanks a lot!

1 files changed, 171 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_mesh_remap.h b/source/blender/blenkernel/BKE_mesh_remap.h
new file mode 100644
index 00000000000..e1f37a63ff0
--- /dev/null
+++ b/source/blender/blenkernel/BKE_mesh_remap.h
@@ -0,0 +1,171 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#ifndef __BKE_MESH_REMAP_H__
+#define __BKE_MESH_REMAP_H__
+
+/** \file BKE_mesh_remap.h
+ *  \ingroup bke
+ */
+
+struct CustomData;
+struct DerivedMesh;
+struct MVert;
+struct MeshElemMap;
+struct MemArena;
+
+/* Generic ways to map some geometry elements from a source mesh to a dest one. */
+
+typedef struct MeshPairRemapItem {
+	int    sources_num;
+	int   *indices_src;     /* NULL if no source found. */
+	float *weights_src;     /* NULL if no source found, else, always normalized! */
+	/* UNUSED (at the moment)*/
+	// float  hit_dist;     /* FLT_MAX if irrelevant or no source found. */
+	int    island;          /* For loops only. */
+} MeshPairRemapItem;
+
+/* All mapping computing func return this. */
+typedef struct MeshPairRemap {
+	int                items_num;
+	MeshPairRemapItem *items;  /* array, one item per dest element. */
+
+	struct MemArena *mem;  /* memory arena, internal use only. */
+} MeshPairRemap;
+
+/* Helpers! */
+void BKE_mesh_remap_init(MeshPairRemap *map, const int items_num);
+void BKE_mesh_remap_free(MeshPairRemap *map);
+
+void BKE_mesh_remap_item_define_invalid(MeshPairRemap *map, const int index);
+
+/* TODO:
+ * Add other 'from/to' mapping sources, like e.g. using an UVMap, etc.
+ *     http://blenderartists.org/forum/showthread.php?346458-Move-Vertices-to-the-location-of-the-Reference-Mesh-based-on-the-UV-Position
+ * We could also use similar topology mappings inside a same mesh
+ * (cf. Campbell's 'select face islands from similar topology' wip work).
+ * Also, users will have to check, whether we can get rid of some modes here, not sure all will be useful!
+ */
+enum {
+	MREMAP_USE_VERT                      = 1 << 4,
+	MREMAP_USE_EDGE                      = 1 << 5,
+	MREMAP_USE_LOOP                      = 1 << 6,
+	MREMAP_USE_POLY                      = 1 << 7,
+
+	MREMAP_USE_NEAREST                   = 1 << 8,
+	MREMAP_USE_NORPROJ                   = 1 << 9,
+	MREMAP_USE_INTERP                    = 1 << 10,
+	MREMAP_USE_NORMAL                    = 1 << 11,
+
+	/* ***** Target's vertices ***** */
+	MREMAP_MODE_VERT                     = 1 << 24,
+	/* Nearest source vert. */
+	MREMAP_MODE_VERT_NEAREST             = MREMAP_MODE_VERT | MREMAP_USE_VERT | MREMAP_USE_NEAREST,
+
+	/* Nearest vertex of nearest edge. */
+	MREMAP_MODE_VERT_EDGE_NEAREST        = MREMAP_MODE_VERT | MREMAP_USE_EDGE | MREMAP_USE_NEAREST,
+	/* This one uses two verts of selected edge (weighted interpolation). */
+	/* Nearest point on nearest edge. */
+	MREMAP_MODE_VERT_EDGEINTERP_NEAREST  = MREMAP_MODE_VERT | MREMAP_USE_EDGE | MREMAP_USE_NEAREST | MREMAP_USE_INTERP,
+
+	/* Nearest vertex of nearest poly. */
+	MREMAP_MODE_VERT_POLY_NEAREST        = MREMAP_MODE_VERT | MREMAP_USE_POLY | MREMAP_USE_NEAREST,
+	/* Those two use all verts of selected poly (weighted interpolation). */
+	/* Nearest point on nearest poly. */
+	MREMAP_MODE_VERT_POLYINTERP_NEAREST  = MREMAP_MODE_VERT | MREMAP_USE_POLY | MREMAP_USE_NEAREST | MREMAP_USE_INTERP,
+	/* Point on nearest face hit by ray from target vertex's normal. */
+	MREMAP_MODE_VERT_POLYINTERP_VNORPROJ = MREMAP_MODE_VERT | MREMAP_USE_POLY | MREMAP_USE_NORPROJ | MREMAP_USE_INTERP,
+
+	/* ***** Target's edges ***** */
+	MREMAP_MODE_EDGE                     = 1 << 25,
+
+	/* Source edge which both vertices are nearest of dest ones. */
+	MREMAP_MODE_EDGE_VERT_NEAREST        = MREMAP_MODE_EDGE | MREMAP_USE_VERT | MREMAP_USE_NEAREST,
+
+	/* Nearest source edge (using mid-point). */
+	MREMAP_MODE_EDGE_NEAREST             = MREMAP_MODE_EDGE | MREMAP_USE_EDGE | MREMAP_USE_NEAREST,
+
+	/* Nearest edge of nearest poly (using mid-point). */
+	MREMAP_MODE_EDGE_POLY_NEAREST        = MREMAP_MODE_EDGE | MREMAP_USE_POLY | MREMAP_USE_NEAREST,
+
+	/* Cast a set of rays from along dest edge, interpolating its vertices' normals, and use hit source edges. */
+	MREMAP_MODE_EDGE_EDGEINTERP_VNORPROJ = MREMAP_MODE_EDGE | MREMAP_USE_VERT | MREMAP_USE_NORPROJ | MREMAP_USE_INTERP,
+
+	/* ***** Target's loops ***** */
+	/* Note: when islands are given to loop mapping func, all loops from the same destination face will always be mapped
+	 *       to loops of source faces within a same island, regardless of mapping mode. */
+	MREMAP_MODE_LOOP                     = 1 << 26,
+
+	/* Best normal-matching loop from nearest vert. */
+	MREMAP_MODE_LOOP_NEAREST_LOOPNOR     = MREMAP_MODE_LOOP | MREMAP_USE_LOOP | MREMAP_USE_VERT | MREMAP_USE_NEAREST | MREMAP_USE_NORMAL,
+	/* Loop from best normal-matching poly from nearest vert. */
+	MREMAP_MODE_LOOP_NEAREST_POLYNOR     = MREMAP_MODE_LOOP | MREMAP_USE_POLY | MREMAP_USE_VERT | MREMAP_USE_NEAREST | MREMAP_USE_NORMAL,
+
+	/* Loop from nearest vertex of nearest poly. */
+	MREMAP_MODE_LOOP_POLY_NEAREST        = MREMAP_MODE_LOOP | MREMAP_USE_POLY | MREMAP_USE_NEAREST,
+	/* Those two use all verts of selected poly (weighted interpolation). */
+	/* Nearest point on nearest poly. */
+	MREMAP_MODE_LOOP_POLYINTERP_NEAREST  = MREMAP_MODE_LOOP | MREMAP_USE_POLY | MREMAP_USE_NEAREST | MREMAP_USE_INTERP,
+	/* Point on nearest face hit by ray from target loop's normal. */
+	MREMAP_MODE_LOOP_POLYINTERP_LNORPROJ = MREMAP_MODE_LOOP | MREMAP_USE_POLY | MREMAP_USE_NORPROJ | MREMAP_USE_INTERP,
+
+	/* ***** Target's polygons ***** */
+	MREMAP_MODE_POLY                     = 1 << 27,
+
+	/* Nearest source poly. */
+	MREMAP_MODE_POLY_NEAREST             = MREMAP_MODE_POLY | MREMAP_USE_POLY | MREMAP_USE_NEAREST,
+	/* Source poly from best normal-matching dest poly. */
+	MREMAP_MODE_POLY_NOR                 = MREMAP_MODE_POLY | MREMAP_USE_POLY | MREMAP_USE_NORMAL,
+
+	/* Project dest poly onto source mesh using its normal, and use interpolation of all intersecting source polys. */
+	MREMAP_MODE_POLY_POLYINTERP_PNORPROJ = MREMAP_MODE_POLY | MREMAP_USE_POLY | MREMAP_USE_NORPROJ | MREMAP_USE_INTERP,
+
+	/* ***** Same topology, applies to all four elements types. ***** */
+	MREMAP_MODE_TOPOLOGY                 = MREMAP_MODE_VERT | MREMAP_MODE_EDGE | MREMAP_MODE_LOOP | MREMAP_MODE_POLY,
+};
+
+/* TODO add mesh2mesh versions (we'll need mesh versions of bvhtree funcs too, though!). */
+
+void BKE_mesh_remap_calc_verts_from_dm(
+        const int mode, const struct SpaceTransform *space_transform, const float max_dist, const float ray_radius,
+        const struct MVert *verts_dst, const int numverts_dst, const bool dirty_nors_dst,
+        struct DerivedMesh *dm_src, MeshPairRemap *r_map);
+
+void BKE_mesh_remap_calc_edges_from_dm(
+        const int mode, const struct SpaceTransform *space_transform, const float max_dist, const float ray_radius,
+        const struct MVert *verts_dst, const int numverts_dst, const struct MEdge *edges_dst, const int numedges_dst,
+        const bool dirty_nors_dst, struct DerivedMesh *dm_src, MeshPairRemap *r_map);
+
+void BKE_mesh_remap_calc_loops_from_dm(
+        const int mode, const struct SpaceTransform *space_transform, const float max_dist, const float ray_radius,
+        struct MVert *verts_dst, const int numverts_dst, struct MEdge *edges_dst, const int numedges_dst,
+        struct MLoop *loops_dst, const int numloops_dst, struct MPoly *polys_dst, const int numpolys_dst,
+        struct CustomData *ldata_dst, struct CustomData *pdata_dst,
+        const float split_angle_dst, const bool dirty_nors_dst,
+        struct DerivedMesh *dm_src,
+        MeshRemapIslandsCalc gen_islands_src, const float islands_precision_src, struct MeshPairRemap *r_map);
+
+void BKE_mesh_remap_calc_polys_from_dm(
+        const int mode, const struct SpaceTransform *space_transform, const float max_dist, const float ray_radius,
+        struct MVert *verts_dst, const int numverts_dst, struct MLoop *loops_dst, const int numloops_dst,
+        struct MPoly *polys_dst, const int numpolys_dst, struct CustomData *pdata_dst, const bool dirty_nors_dst,
+        struct DerivedMesh *dm_src, struct MeshPairRemap *r_map);
+
+#endif  /* __BKE_MESH_REMAP_H__ */