/*
 * ***** 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.
 *
 * The Original Code is Copyright (C) Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */
#ifndef __BKE_SHRINKWRAP_H__
#define __BKE_SHRINKWRAP_H__

/** \file BKE_shrinkwrap.h
 *  \ingroup bke
 */

/* mesh util */

//TODO: move this somewhere else
#include "BKE_customdata.h"
struct DerivedMesh;
struct Object;
struct DerivedMesh *object_get_derived_final(struct Object *ob, bool for_render);


/* SpaceTransform stuff */
/*
 * TODO: move this somewhere else
 *
 * this structs encapsulates all needed data to convert between 2 coordinate spaces
 * (where conversion can be represented by a matrix multiplication)
 *
 * This is used to reduce the number of arguments to pass to functions that need to perform
 * this kind of operation and make it easier for the coder, as he/she doenst needs to recode
 * the matrix calculation.
 *
 * A SpaceTransform is initialized using:
 *   SPACE_TRANSFORM_SETUP( &data,  ob1, ob2 )
 *
 * After that the following calls can be used:
 *   space_transform_apply (&data, co); //converts a coordinate in ob1 coords space to the corresponding ob2 coords
 *   space_transform_invert(&data, co); //converts a coordinate in ob2 coords space to the corresponding ob1 coords
 *
 *	//Same Concept as space_transform_apply and space_transform_invert, but no is normalized after conversion
 *   space_transform_apply_normal (&data, &no);
 *   space_transform_invert_normal(&data, &no);
 *
 */
struct Object;

typedef struct SpaceTransform {
	float local2target[4][4];
	float target2local[4][4];

} SpaceTransform;

void space_transform_from_matrixs(struct SpaceTransform *data, float local[4][4], float target[4][4]);
void space_transform_apply(const struct SpaceTransform *data, float co[3]);
void space_transform_invert(const struct SpaceTransform *data, float co[3]);

#define SPACE_TRANSFORM_SETUP(data, local, target) space_transform_from_matrixs(data, (local)->obmat, (target)->obmat)

/* Shrinkwrap stuff */
#include "BKE_bvhutils.h"

/*
 * Shrinkwrap is composed by a set of functions and options that define the type of shrink.
 *
 * 3 modes are available:
 *    - Nearest vertex
 *	  - Nearest surface
 *    - Normal projection
 *
 * ShrinkwrapCalcData encapsulates all needed data for shrinkwrap functions.
 * (So that you don't have to pass an enormous amount of arguments to functions)
 */

struct Object;
struct Scene;
struct DerivedMesh;
struct MVert;
struct MDeformVert;
struct ShrinkwrapModifierData;
struct MDeformVert;
struct BVHTree;


typedef struct ShrinkwrapCalcData {
	ShrinkwrapModifierData *smd;    //shrinkwrap modifier data

	struct Object *ob;              //object we are applying shrinkwrap to

	struct MVert *vert;             //Array of verts being projected (to fetch normals or other data)
	float (*vertexCos)[3];          //vertexs being shrinkwraped
	int numVerts;

	struct MDeformVert *dvert;      //Pointer to mdeform array
	int vgroup;                     //Vertex group num

	struct DerivedMesh *target;     //mesh we are shrinking to
	SpaceTransform local2target;    //transform to move between local and target space

	float keepDist;                 //Distance to keep above target surface (units are in local space)

} ShrinkwrapCalcData;

void shrinkwrapModifier_deform(struct ShrinkwrapModifierData *smd, struct Object *ob, struct DerivedMesh *dm,
                               float (*vertexCos)[3], int numVerts, bool for_render);

/*
 * This function casts a ray in the given BVHTree.. but it takes into consideration the space_transform, that is:
 *
 * if transf was configured with "SPACE_TRANSFORM_SETUP( &transf,  ob1, ob2 )"
 * then the input (vert, dir, BVHTreeRayHit) must be defined in ob1 coordinates space
 * and the BVHTree must be built in ob2 coordinate space.
 *
 * Thus it provides an easy way to cast the same ray across several trees
 * (where each tree was built on its own coords space)
 */
bool BKE_shrinkwrap_project_normal(
        char options, const float vert[3], const float dir[3],
        const SpaceTransform *transf, BVHTree *tree, BVHTreeRayHit *hit,
        BVHTree_RayCastCallback callback, void *userdata);

/*
 * NULL initializers to local data
 */
#define NULL_ShrinkwrapCalcData {NULL, }
#define NULL_BVHTreeFromMesh    {NULL, }
#define NULL_BVHTreeRayHit      {NULL, }
#define NULL_BVHTreeNearest     {0, }

#endif  /* __BKE_SHRINKWRAP_H__ */
