/*
 * 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.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

#ifndef __BKE_DERIVEDMESH_H__
#define __BKE_DERIVEDMESH_H__

/** \file \ingroup bke
 *
 * Basic design of the DerivedMesh system:
 *
 * DerivedMesh is a common set of interfaces for mesh systems.
 *
 * There are three main mesh data structures in Blender:
 * #Mesh, #CDDerivedMesh and #BMesh.
 *
 * These, and a few others, all implement DerivedMesh interfaces,
 * which contains unified drawing interfaces, a few utility interfaces,
 * and a bunch of read-only interfaces intended mostly for conversion from
 * one format to another.
 *
 * All Mesh structures in blender make use of CustomData, which is used to store
 * per-element attributes and interpolate them (e.g. uvs, vcols, vgroups, etc).
 *
 * Mesh is the "serialized" structure, used for storing object-mode mesh data
 * and also for saving stuff to disk.  It's interfaces are also what DerivedMesh
 * uses to communicate with.
 *
 * CDDM is a little mesh library, that uses Mesh data structures in the backend.
 * It's mostly used for modifiers, and has the advantages of not taking much
 * resources.
 *
 * BMesh is a full-on brep, used for editmode, some modifiers, etc.  It's much
 * more capable (if memory-intensive) then CDDM.
 *
 * DerivedMesh is somewhat hackish.  Many places assumes that a DerivedMesh is
 * a CDDM (most of the time by simply copying it and converting it to one).
 * CDDM is the original structure for modifiers, but has since been superseded
 * by BMesh, at least for the foreseeable future.
 */

/*
 * Note: This structure is read-only, for all practical purposes.
 *       At some point in the future, we may want to consider
 *       creating a replacement structure that implements a proper
 *       abstract mesh kernel interface.  Or, we can leave this
 *       as it is and stick with using BMesh and CDDM.
 */

#include "DNA_defs.h"
#include "DNA_customdata_types.h"
#include "DNA_meshdata_types.h"

#include "BLI_compiler_attrs.h"

#include "BKE_customdata.h"
#include "BKE_bvhutils.h"

struct BMEditMesh;
struct CCGElem;
struct CCGKey;
struct Depsgraph;
struct MEdge;
struct MFace;
struct MLoopNorSpaceArray;
struct MVert;
struct Mesh;
struct ModifierData;
struct Object;
struct PBVH;
struct Scene;

/* number of sub-elements each mesh element has (for interpolation) */
// #define SUB_ELEMS_VERT 0 /* UNUSED */
#define SUB_ELEMS_EDGE 2
#define SUB_ELEMS_FACE 50

/*
 * Note: all mface interfaces now officially operate on tessellated data.
 *       Also, the mface origindex layer indexes mpolys, not mfaces.
 */

typedef struct DMCoNo {
	float co[3];
	float no[3];
} DMCoNo;

/* keep in sync with MFace/MPoly types */
typedef struct DMFlagMat {
	short mat_nr;
	char flag;
} DMFlagMat;

typedef enum DerivedMeshType {
	DM_TYPE_CDDM,
	DM_TYPE_CCGDM
} DerivedMeshType;

typedef enum DMForeachFlag {
	DM_FOREACH_NOP = 0,
	DM_FOREACH_USE_NORMAL = (1 << 0),  /* foreachMappedVert, foreachMappedLoop, foreachMappedFaceCenter */
} DMForeachFlag;

typedef enum DMDirtyFlag {
	/* dm has valid tessellated faces, but tessellated CDDATA need to be updated. */
	DM_DIRTY_TESS_CDLAYERS = 1 << 0,

	/* check this with modifier dependsOnNormals callback to see if normals need recalculation */
	DM_DIRTY_NORMALS = 1 << 1,
}  DMDirtyFlag;

typedef struct DerivedMesh DerivedMesh;
struct DerivedMesh {
	/** Private DerivedMesh data, only for internal DerivedMesh use */
	CustomData vertData, edgeData, faceData, loopData, polyData;
	int numVertData, numEdgeData, numTessFaceData, numLoopData, numPolyData;
	int needsFree; /* checked on ->release, is set to 0 for cached results */
	int deformedOnly; /* set by modifier stack if only deformed from original */
	BVHCache *bvhCache;
	DerivedMeshType type;
	DMDirtyFlag dirty;
	int totmat; /* total materials. Will be valid only before object drawing. */
	struct Material **mat; /* material array. Will be valid only before object drawing */

	/**
	 * \warning Typical access is done via #getLoopTriArray, #getNumLoopTri.
	 */
	struct {
		/* WARNING! swapping between array (ready-to-be-used data) and array_wip (where data is actually computed)
		 *          shall always be protected by same lock as one used for looptris computing. */
		struct MLoopTri *array, *array_wip;
		int num;
		int num_alloc;
	} looptris;

	/* use for converting to BMesh which doesn't store bevel weight and edge crease by default */
	char cd_flag;

	short tangent_mask; /* which tangent layers are calculated */

	/** Calculate vert and face normals */
	void (*calcNormals)(DerivedMesh *dm);

	/** Calculate loop (split) normals */
	void (*calcLoopNormals)(DerivedMesh *dm, const bool use_split_normals, const float split_angle);

	/** Calculate loop (split) normals, and returns split loop normal spacearr. */
	void (*calcLoopNormalsSpaceArray)(DerivedMesh *dm, const bool use_split_normals, const float split_angle,
	                                  struct MLoopNorSpaceArray *r_lnors_spacearr);

	void (*calcLoopTangents)(
	        DerivedMesh *dm, bool calc_active_tangent,
	        const char (*tangent_names)[MAX_NAME], int tangent_names_count);

	/** Recalculates mesh tessellation */
	void (*recalcTessellation)(DerivedMesh *dm);

	/** Loop tessellation cache (WARNING! Only call inside threading-protected code!) */
	void (*recalcLoopTri)(DerivedMesh *dm);
	/** accessor functions */
	const struct MLoopTri *(*getLoopTriArray)(DerivedMesh * dm);
	int (*getNumLoopTri)(DerivedMesh *dm);

	/* Misc. Queries */

	/* Also called in Editmode */
	int (*getNumVerts)(DerivedMesh *dm);
	int (*getNumEdges)(DerivedMesh *dm);
	int (*getNumTessFaces)(DerivedMesh *dm);
	int (*getNumLoops)(DerivedMesh *dm);
	int (*getNumPolys)(DerivedMesh *dm);

	/** Copy a single vert/edge/tessellated face from the derived mesh into
	 * ``*r_{vert/edge/face}``. note that the current implementation
	 * of this function can be quite slow, iterating over all
	 * elements (editmesh)
	 */
	void (*getVert)(DerivedMesh *dm, int index, struct MVert *r_vert);
	void (*getEdge)(DerivedMesh *dm, int index, struct MEdge *r_edge);
	void (*getTessFace)(DerivedMesh *dm, int index, struct MFace *r_face);

	/** Return a pointer to the entire array of verts/edges/face from the
	 * derived mesh. if such an array does not exist yet, it will be created,
	 * and freed on the next ->release(). consider using getVert/Edge/Face if
	 * you are only interested in a few verts/edges/faces.
	 */
	struct MVert *(*getVertArray)(DerivedMesh * dm);
	struct MEdge *(*getEdgeArray)(DerivedMesh * dm);
	struct MFace *(*getTessFaceArray)(DerivedMesh * dm);
	struct MLoop *(*getLoopArray)(DerivedMesh * dm);
	struct MPoly *(*getPolyArray)(DerivedMesh * dm);

	/** Copy all verts/edges/faces from the derived mesh into
	 * *{vert/edge/face}_r (must point to a buffer large enough)
	 */
	void (*copyVertArray)(DerivedMesh *dm, struct MVert *r_vert);
	void (*copyEdgeArray)(DerivedMesh *dm, struct MEdge *r_edge);
	void (*copyTessFaceArray)(DerivedMesh *dm, struct MFace *r_face);
	void (*copyLoopArray)(DerivedMesh *dm, struct MLoop *r_loop);
	void (*copyPolyArray)(DerivedMesh *dm, struct MPoly *r_poly);

	/** Return a copy of all verts/edges/faces from the derived mesh
	 * it is the caller's responsibility to free the returned pointer
	 */
	struct MVert *(*dupVertArray)(DerivedMesh * dm);
	struct MEdge *(*dupEdgeArray)(DerivedMesh * dm);
	struct MFace *(*dupTessFaceArray)(DerivedMesh * dm);
	struct MLoop *(*dupLoopArray)(DerivedMesh * dm);
	struct MPoly *(*dupPolyArray)(DerivedMesh * dm);

	/** Return a pointer to a single element of vert/edge/face custom data
	 * from the derived mesh (this gives a pointer to the actual data, not
	 * a copy)
	 */
	void *(*getVertData)(DerivedMesh *dm, int index, int type);
	void *(*getEdgeData)(DerivedMesh *dm, int index, int type);
	void *(*getTessFaceData)(DerivedMesh *dm, int index, int type);
	void *(*getPolyData)(DerivedMesh *dm, int index, int type);

	/** Return a pointer to the entire array of vert/edge/face custom data
	 * from the derived mesh (this gives a pointer to the actual data, not
	 * a copy)
	 */
	void *(*getVertDataArray)(DerivedMesh *dm, int type);
	void *(*getEdgeDataArray)(DerivedMesh *dm, int type);
	void *(*getTessFaceDataArray)(DerivedMesh *dm, int type);
	void *(*getLoopDataArray)(DerivedMesh *dm, int type);
	void *(*getPolyDataArray)(DerivedMesh *dm, int type);

	/** Retrieves the base CustomData structures for
	 * verts/edges/tessfaces/loops/facdes*/
	CustomData *(*getVertDataLayout)(DerivedMesh * dm);
	CustomData *(*getEdgeDataLayout)(DerivedMesh * dm);
	CustomData *(*getTessFaceDataLayout)(DerivedMesh * dm);
	CustomData *(*getLoopDataLayout)(DerivedMesh * dm);
	CustomData *(*getPolyDataLayout)(DerivedMesh * dm);

	/** Copies all customdata for an element source into dst at index dest */
	void (*copyFromVertCData)(DerivedMesh *dm, int source, CustomData *dst, int dest);
	void (*copyFromEdgeCData)(DerivedMesh *dm, int source, CustomData *dst, int dest);
	void (*copyFromFaceCData)(DerivedMesh *dm, int source, CustomData *dst, int dest);

	/** Optional grid access for subsurf */
	int (*getNumGrids)(DerivedMesh *dm);
	int (*getGridSize)(DerivedMesh *dm);
	struct CCGElem **(*getGridData)(DerivedMesh * dm);
	int *(*getGridOffset)(DerivedMesh * dm);
	void (*getGridKey)(DerivedMesh *dm, struct CCGKey *key);
	DMFlagMat *(*getGridFlagMats)(DerivedMesh * dm);
	unsigned int **(*getGridHidden)(DerivedMesh * dm);


	/** Iterate over each mapped vertex in the derived mesh, calling the
	 * given function with the original vert and the mapped vert's new
	 * coordinate and normal. For historical reasons the normal can be
	 * passed as a float or short array, only one should be non-NULL.
	 */
	void (*foreachMappedVert)(DerivedMesh *dm,
	                          void (*func)(void *userData, int index, const float co[3],
	                                       const float no_f[3], const short no_s[3]),
	                          void *userData,
	                          DMForeachFlag flag);

	/** Iterate over each mapped edge in the derived mesh, calling the
	 * given function with the original edge and the mapped edge's new
	 * coordinates.
	 */
	void (*foreachMappedEdge)(DerivedMesh *dm,
	                          void (*func)(void *userData, int index,
	                                       const float v0co[3], const float v1co[3]),
	                          void *userData);

	/** Iterate over each mapped loop in the derived mesh, calling the given function
	 * with the original loop index and the mapped loops's new coordinate and normal.
	 */
	void (*foreachMappedLoop)(DerivedMesh *dm,
	                          void (*func)(void *userData, int vertex_index, int face_index,
	                                       const float co[3], const float no[3]),
	                          void *userData,
	                          DMForeachFlag flag);

	/** Iterate over each mapped face in the derived mesh, calling the
	 * given function with the original face and the mapped face's (or
	 * faces') center and normal.
	 */
	void (*foreachMappedFaceCenter)(DerivedMesh *dm,
	                                void (*func)(void *userData, int index,
	                                             const float cent[3], const float no[3]),
	                                void *userData,
	                                DMForeachFlag flag);

	/** Iterate over all vertex points, calling DO_MINMAX with given args.
	 *
	 * Also called in Editmode
	 */
	void (*getMinMax)(DerivedMesh *dm, float r_min[3], float r_max[3]);

	/** Direct Access Operations
	 * - Can be undefined
	 * - Must be defined for modifiers that only deform however */

	/** Get vertex location, undefined if index is not valid */
	void (*getVertCo)(DerivedMesh *dm, int index, float r_co[3]);

	/** Fill the array (of length .getNumVerts()) with all vertex locations */
	void (*getVertCos)(DerivedMesh *dm, float (*r_cos)[3]);

	/** Get smooth vertex normal, undefined if index is not valid */
	void (*getVertNo)(DerivedMesh *dm, int index, float r_no[3]);
	void (*getPolyNo)(DerivedMesh *dm, int index, float r_no[3]);

	/** Get a map of vertices to faces
	 */
	const struct MeshElemMap *(*getPolyMap)(struct Object *ob, DerivedMesh *dm);

	/** Get the BVH used for paint modes
	 */
	struct PBVH *(*getPBVH)(struct Object *ob, DerivedMesh *dm);

	/** Release reference to the DerivedMesh. This function decides internally
	 * if the DerivedMesh will be freed, or cached for later use. */
	void (*release)(DerivedMesh *dm);
};

void DM_init_funcs(DerivedMesh *dm);

void DM_init(
        DerivedMesh *dm, DerivedMeshType type, int numVerts, int numEdges,
        int numFaces, int numLoops, int numPolys);

void DM_from_template_ex(
        DerivedMesh *dm, DerivedMesh *source, DerivedMeshType type,
        int numVerts, int numEdges, int numTessFaces,
        int numLoops, int numPolys,
        CustomDataMask mask);
void DM_from_template(
        DerivedMesh *dm, DerivedMesh *source,
        DerivedMeshType type,
        int numVerts, int numEdges, int numFaces,
        int numLoops, int numPolys);

/** utility function to release a DerivedMesh's layers
 * returns 1 if DerivedMesh has to be released by the backend, 0 otherwise
 */
int DM_release(DerivedMesh *dm);

/** utility function to convert a DerivedMesh to a Mesh
 */
void DM_to_mesh(DerivedMesh *dm, struct Mesh *me, struct Object *ob, CustomDataMask mask, bool take_ownership);


void DM_set_only_copy(DerivedMesh *dm, CustomDataMask mask);

/* adds a vertex/edge/face custom data layer to a DerivedMesh, optionally
 * backed by an external data array
 * alloctype defines how the layer is allocated or copied, and how it is
 * freed, see BKE_customdata.h for the different options
 */
void DM_add_vert_layer(
        struct DerivedMesh *dm, int type, eCDAllocType alloctype,
        void *layer);
void DM_add_edge_layer(
        struct DerivedMesh *dm, int type, eCDAllocType alloctype,
        void *layer);
void DM_add_tessface_layer(
        struct DerivedMesh *dm, int type, eCDAllocType alloctype,
        void *layer);
void DM_add_loop_layer(
        DerivedMesh *dm, int type, eCDAllocType alloctype,
        void *layer);
void DM_add_poly_layer(
        struct DerivedMesh *dm, int type, eCDAllocType alloctype,
        void *layer);

/* custom data access functions
 * return pointer to data from first layer which matches type
 * if they return NULL for valid indices, data doesn't exist
 * note these return pointers - any change modifies the internals of the mesh
 */
void *DM_get_vert_data(struct DerivedMesh *dm, int index, int type);
void *DM_get_edge_data(struct DerivedMesh *dm, int index, int type);
void *DM_get_tessface_data(struct DerivedMesh *dm, int index, int type);
void *DM_get_poly_data(struct DerivedMesh *dm, int index, int type);

/* custom data layer access functions
 * return pointer to first data layer which matches type (a flat array)
 * if they return NULL, data doesn't exist
 * note these return pointers - any change modifies the internals of the mesh
 */
void *DM_get_vert_data_layer(struct DerivedMesh *dm, int type);
void *DM_get_edge_data_layer(struct DerivedMesh *dm, int type);
void *DM_get_tessface_data_layer(struct DerivedMesh *dm, int type);
void *DM_get_poly_data_layer(struct DerivedMesh *dm, int type);
void *DM_get_loop_data_layer(struct DerivedMesh *dm, int type);

/* custom data setting functions
 * copy supplied data into first layer of type using layer's copy function
 * (deep copy if appropriate)
 */
void DM_set_vert_data(struct DerivedMesh *dm, int index, int type, void *data);
void DM_set_edge_data(struct DerivedMesh *dm, int index, int type, void *data);
void DM_set_tessface_data(struct DerivedMesh *dm, int index, int type, void *data);

/* custom data copy functions
 * copy count elements from source_index in source to dest_index in dest
 * these copy all layers for which the CD_FLAG_NOCOPY flag is not set
 */
void DM_copy_vert_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int source_index, int dest_index, int count);
void DM_copy_edge_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int source_index, int dest_index, int count);
void DM_copy_tessface_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int source_index, int dest_index, int count);
void DM_copy_loop_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int source_index, int dest_index, int count);
void DM_copy_poly_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int source_index, int dest_index, int count);

/* custom data free functions
 * free count elements, starting at index
 * they free all layers for which the CD_FLAG_NOCOPY flag is not set
 */
void DM_free_vert_data(struct DerivedMesh *dm, int index, int count);
void DM_free_edge_data(struct DerivedMesh *dm, int index, int count);
void DM_free_tessface_data(struct DerivedMesh *dm, int index, int count);
void DM_free_loop_data(struct DerivedMesh *dm, int index, int count);
void DM_free_poly_data(struct DerivedMesh *dm, int index, int count);

/*sets up mpolys for a DM based on face iterators in source*/
void DM_DupPolys(DerivedMesh *source, DerivedMesh *target);

void DM_ensure_normals(DerivedMesh *dm);

void DM_ensure_looptri_data(DerivedMesh *dm);

void DM_interp_vert_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int *src_indices, float *weights,
        int count, int dest_index);

typedef float EdgeVertWeight[SUB_ELEMS_EDGE][SUB_ELEMS_EDGE];
void DM_interp_edge_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int *src_indices,
        float *weights, EdgeVertWeight *vert_weights,
        int count, int dest_index);

typedef float FaceVertWeight[SUB_ELEMS_FACE][SUB_ELEMS_FACE];
void DM_interp_tessface_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int *src_indices,
        float *weights, FaceVertWeight *vert_weights,
        int count, int dest_index);

void DM_interp_loop_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int *src_indices,
        float *weights, int count, int dest_index);

void DM_interp_poly_data(
        struct DerivedMesh *source, struct DerivedMesh *dest,
        int *src_indices,
        float *weights, int count, int dest_index);


void mesh_get_mapped_verts_coords(struct Mesh *me_eval, float (*r_cos)[3], const int totcos);

DerivedMesh *mesh_create_derived_render(
        struct Depsgraph *depsgraph, struct Scene *scene,
        struct Object *ob, CustomDataMask dataMask);

/* same as above but wont use render settings */
DerivedMesh *mesh_create_derived(struct Mesh *me, float (*vertCos)[3]);

struct Mesh *editbmesh_get_eval_cage(
        struct Depsgraph *depsgraph, struct Scene *scene, struct Object *,
        struct BMEditMesh *em, CustomDataMask dataMask);
struct Mesh *editbmesh_get_eval_cage_from_orig(
        struct Depsgraph *depsgraph, struct Scene *scene, struct Object *,
        struct BMEditMesh *em, CustomDataMask dataMask);
struct Mesh *editbmesh_get_eval_cage_and_final(
        struct Depsgraph *depsgraph, struct Scene *scene, struct Object *,
        struct BMEditMesh *em, CustomDataMask dataMask,
        struct Mesh **r_final);

float (*editbmesh_get_vertex_cos(struct BMEditMesh *em, int *r_numVerts))[3];
bool editbmesh_modifier_is_enabled(struct Scene *scene, struct ModifierData *md, bool has_prev_mesh);
void makeDerivedMesh(
        struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob, struct BMEditMesh *em,
        CustomDataMask dataMask, const bool build_shapekey_layers);

void DM_add_named_tangent_layer_for_uv(
        CustomData *uv_data, CustomData *tan_data, int numLoopData,
        const char *layer_name);

void DM_calc_loop_tangents(
        DerivedMesh *dm, bool calc_active_tangent, const char (*tangent_names)[MAX_NAME],
        int tangent_names_count);

void DM_init_origspace(DerivedMesh *dm);

/* debug only */
#ifndef NDEBUG
char *DM_debug_info(DerivedMesh *dm);
void DM_debug_print(DerivedMesh *dm);
void DM_debug_print_cdlayers(CustomData *cdata);

bool DM_is_valid(DerivedMesh *dm);
#endif

#endif  /* __BKE_DERIVEDMESH_H__ */