/*
 * ***** 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): Daniel Genrich
 *
 * ***** END GPL LICENSE BLOCK *****
 */
#ifndef __BKE_CLOTH_H__
#define __BKE_CLOTH_H__

/** \file BKE_cloth.h
 *  \ingroup bke
 *  \author Daniel Genrich
 */

#include <float.h>
#include "BLI_math_inline.h"

struct Object;
struct Scene;
struct MFace;
struct DerivedMesh;
struct ClothModifierData;
struct CollisionModifierData;

#define DO_INLINE MALWAYS_INLINE

/* goal defines */
#define SOFTGOALSNAP  0.999f

/* This is approximately the smallest number that can be
 * represented by a float, given its precision. */
#define ALMOST_ZERO		FLT_EPSILON

/* Bits to or into the ClothVertex.flags. */
typedef enum eClothVertexFlag {
	CLOTH_VERT_FLAG_PINNED      = 1,
	CLOTH_VERT_FLAG_NOSELFCOLL  = 2, /* vertex NOT used for self collisions */
} eClothVertexFlag;

typedef struct ClothHairData {
	float loc[3];
	float rot[3][3];
	float rest_target[3]; /* rest target direction for each segment */
	float radius;
	float bending_stiffness;
} ClothHairData;

typedef struct ClothSolverResult {
	int status;
	
	int max_iterations, min_iterations;
	float avg_iterations;
	float max_error, min_error, avg_error;
} ClothSolverResult;

/**
 * This structure describes a cloth object against which the
 * simulation can run.
 *
 * The m and n members of this structure represent the assumed
 * rectangular ordered grid for which the original paper is written.
 * At some point they need to disappear and we need to determine out
 * own connectivity of the mesh based on the actual edges in the mesh.
 *
 */
typedef struct Cloth {
	struct ClothVertex	*verts;			/* The vertices that represent this cloth. */
	struct	LinkNode	*springs;		/* The springs connecting the mesh. */
	unsigned int		numsprings;		/* The count of springs. */
	unsigned int		mvert_num;		/* The number of verts == m * n. */
	unsigned int		tri_num;
	unsigned char 		old_solver_type;	/* unused, only 1 solver here */
	unsigned char 		pad2;
	short 			pad3;
	struct BVHTree		*bvhtree;			/* collision tree for this cloth object */
	struct BVHTree 		*bvhselftree;			/* collision tree for this cloth object */
	struct MVertTri		*tri;
	struct Implicit_Data	*implicit; 		/* our implicit solver connects to this pointer */
	struct EdgeSet	 	*edgeset; 		/* used for selfcollisions */
	int last_frame, pad4;
} Cloth;

/**
 * The definition of a cloth vertex.
 */
typedef struct ClothVertex {
	int	flags;		/* General flags per vertex.		*/
	float	v[3];		/* The velocity of the point.		*/
	float	xconst[3];	/* constrained position			*/
	float	x[3];		/* The current position of this vertex.	*/
	float 	xold[3];	/* The previous position of this vertex.*/
	float	tx[3];		/* temporary position */
	float 	txold[3];	/* temporary old position */
	float 	tv[3];		/* temporary "velocity", mostly used as tv = tx-txold */
	float 	mass;		/* mass / weight of the vertex		*/
	float 	goal;		/* goal, from SB			*/
	float	impulse[3];	/* used in collision.c */
	float	xrest[3];   /* rest position of the vertex */
	unsigned int impulse_count; /* same as above */
	float 	avg_spring_len; /* average length of connected springs */
	float 	struct_stiff;
	float	bend_stiff;
	float 	shear_stiff;
	int 	spring_count; /* how many springs attached? */
	float	shrink_factor; /* how much to shrink this cloth */
}
ClothVertex;

/**
 * The definition of a spring.
 */
typedef struct ClothSpring {
	int	ij;		/* Pij from the paper, one end of the spring.	*/
	int	kl;		/* Pkl from the paper, one end of the spring.	*/
	int mn;
	float	restlen;	/* The original length of the spring.	*/
	int	type;		/* types defined in BKE_cloth.h ("springType") */
	int	flags; 		/* defined in BKE_cloth.h, e.g. deactivated due to tearing */
	float 	stiffness;	/* stiffness factor from the vertex groups */
	float editrestlen;
	
	/* angular bending spring target and derivatives */
	float target[3];
}
ClothSpring;

// some macro enhancements for vector treatment
#define VECADDADD(v1,v2,v3) 	{*(v1)+= *(v2) + *(v3); *(v1+1)+= *(v2+1) + *(v3+1); *(v1+2)+= *(v2+2) + *(v3+2);}
#define VECSUBADD(v1,v2,v3) 	{*(v1)-= *(v2) + *(v3); *(v1+1)-= *(v2+1) + *(v3+1); *(v1+2)-= *(v2+2) + *(v3+2);}
#define VECADDSUB(v1,v2,v3) 	{*(v1)+= *(v2) - *(v3); *(v1+1)+= *(v2+1) - *(v3+1); *(v1+2)+= *(v2+2) - *(v3+2);}
#define VECSUBADDSS(v1,v2,aS,v3,bS) 	{*(v1)-= *(v2)*aS + *(v3)*bS; *(v1+1)-= *(v2+1)*aS + *(v3+1)*bS; *(v1+2)-= *(v2+2)*aS + *(v3+2)*bS;}
#define VECADDSUBSS(v1,v2,aS,v3,bS) 	{*(v1)+= *(v2)*aS - *(v3)*bS; *(v1+1)+= *(v2+1)*aS - *(v3+1)*bS; *(v1+2)+= *(v2+2)*aS - *(v3+2)*bS;}
#define VECADDSS(v1,v2,aS,v3,bS) 	{*(v1)= *(v2)*aS + *(v3)*bS; *(v1+1)= *(v2+1)*aS + *(v3+1)*bS; *(v1+2)= *(v2+2)*aS + *(v3+2)*bS;}
#define VECADDS(v1,v2,v3,bS) 	{*(v1)= *(v2) + *(v3)*bS; *(v1+1)= *(v2+1) + *(v3+1)*bS; *(v1+2)= *(v2+2) + *(v3+2)*bS;}
#define VECSUBMUL(v1,v2,aS) 	{*(v1)-= *(v2) * aS; *(v1+1)-= *(v2+1) * aS; *(v1+2)-= *(v2+2) * aS;}
#define VECSUBS(v1,v2,v3,bS) 	{*(v1)= *(v2) - *(v3)*bS; *(v1+1)= *(v2+1) - *(v3+1)*bS; *(v1+2)= *(v2+2) - *(v3+2)*bS;}
#define VECSUBSB(v1,v2, v3,bS) 	{*(v1)= (*(v2)- *(v3))*bS; *(v1+1)= (*(v2+1) - *(v3+1))*bS; *(v1+2)= (*(v2+2) - *(v3+2))*bS;}
#define VECMULS(v1,aS) 	{*(v1)*= aS; *(v1+1)*= aS; *(v1+2)*= *aS;}
#define VECADDMUL(v1,v2,aS) 	{*(v1)+= *(v2) * aS; *(v1+1)+= *(v2+1) * aS; *(v1+2)+= *(v2+2) * aS;}

/* SIMULATION FLAGS: goal flags,.. */
/* These are the bits used in SimSettings.flags. */
typedef enum {
	CLOTH_SIMSETTINGS_FLAG_COLLOBJ = ( 1 << 2 ),// object is only collision object, no cloth simulation is done
	CLOTH_SIMSETTINGS_FLAG_GOAL = ( 1 << 3 ), 	// we have goals enabled
	CLOTH_SIMSETTINGS_FLAG_TEARING = ( 1 << 4 ),// true if tearing is enabled
	CLOTH_SIMSETTINGS_FLAG_SCALING = ( 1 << 8 ), /* is advanced scaling active? */
	CLOTH_SIMSETTINGS_FLAG_CCACHE_EDIT = (1 << 12),	/* edit cache in editmode */
	CLOTH_SIMSETTINGS_FLAG_NO_SPRING_COMPRESS = (1 << 13), /* don't allow spring compression */
	CLOTH_SIMSETTINGS_FLAG_SEW = (1 << 14), /* pull ends of loose edges together */
	CLOTH_SIMSETTINGS_FLAG_DYNAMIC_BASEMESH = (1 << 15), /* make simulation respect deformations in the base object */
} CLOTH_SIMSETTINGS_FLAGS;

/* COLLISION FLAGS */
typedef enum {
	CLOTH_COLLSETTINGS_FLAG_ENABLED = ( 1 << 1 ), /* enables cloth - object collisions */
	CLOTH_COLLSETTINGS_FLAG_SELF = ( 1 << 2 ), /* enables selfcollisions */
} CLOTH_COLLISIONSETTINGS_FLAGS;

/* Spring types as defined in the paper.*/
typedef enum {
	CLOTH_SPRING_TYPE_STRUCTURAL  = (1 << 1),
	CLOTH_SPRING_TYPE_SHEAR       = (1 << 2),
	CLOTH_SPRING_TYPE_BENDING     = (1 << 3),
	CLOTH_SPRING_TYPE_GOAL        = (1 << 4),
	CLOTH_SPRING_TYPE_SEWING      = (1 << 5),
	CLOTH_SPRING_TYPE_BENDING_ANG = (1 << 6),
} CLOTH_SPRING_TYPES;

/* SPRING FLAGS */
typedef enum {
	CLOTH_SPRING_FLAG_DEACTIVATE = ( 1 << 1 ),
	CLOTH_SPRING_FLAG_NEEDED = ( 1 << 2 ), // springs has values to be applied
} CLOTH_SPRINGS_FLAGS;


/////////////////////////////////////////////////
// collision.c
////////////////////////////////////////////////

struct CollPair;

typedef struct ColliderContacts {
	struct Object *ob;
	struct CollisionModifierData *collmd;
	
	struct CollPair *collisions;
	int totcollisions;
} ColliderContacts;

// needed for implicit.c
int cloth_bvh_objcollision (struct Object *ob, struct ClothModifierData *clmd, float step, float dt );
int cloth_points_objcollision(struct Object *ob, struct ClothModifierData *clmd, float step, float dt);

void cloth_find_point_contacts(struct Object *ob, struct ClothModifierData *clmd, float step, float dt,
                               ColliderContacts **r_collider_contacts, int *r_totcolliders);
void cloth_free_contacts(ColliderContacts *collider_contacts, int totcolliders);

////////////////////////////////////////////////

/////////////////////////////////////////////////
// cloth.c
////////////////////////////////////////////////

// needed for modifier.c
void cloth_free_modifier_extern (struct ClothModifierData *clmd );
void cloth_free_modifier (struct ClothModifierData *clmd );
void cloth_init (struct ClothModifierData *clmd );
void clothModifier_do (struct ClothModifierData *clmd, struct Scene *scene, struct Object *ob, struct DerivedMesh *dm, float (*vertexCos)[3]);

int cloth_uses_vgroup(struct ClothModifierData *clmd);

// needed for collision.c
void bvhtree_update_from_cloth(struct ClothModifierData *clmd, bool moving);
void bvhselftree_update_from_cloth(struct ClothModifierData *clmd, bool moving);

// needed for button_object.c
void cloth_clear_cache (struct Object *ob, struct ClothModifierData *clmd, float framenr );

void cloth_parallel_transport_hair_frame(float mat[3][3], const float dir_old[3], const float dir_new[3]);

////////////////////////////////////////////////

#endif