/*
 * 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) 2007 by Janne Karhu.
 * All rights reserved.
 * Adaptive time step
 * Classical SPH
 * Copyright 2011-2012 AutoCRC
 */

#ifndef __BKE_PARTICLE_H__
#define __BKE_PARTICLE_H__

/** \file
 * \ingroup bke
 */

#include "BLI_utildefines.h"

#include "DNA_particle_types.h"
#include "DNA_object_types.h"

#include "BKE_customdata.h"

struct ParticleKey;
struct ParticleSettings;
struct ParticleSystem;
struct ParticleSystemModifierData;

struct BVHTreeRay;
struct BVHTreeRayHit;
struct CustomData_MeshMasks;
struct Depsgraph;
struct Depsgraph;
struct EdgeHash;
struct KDTree_3d;
struct LatticeDeformData;
struct LinkNode;
struct MCol;
struct MFace;
struct MTFace;
struct MVert;
struct Main;
struct ModifierData;
struct Object;
struct RNG;
struct Scene;
struct ViewLayer;

#define PARTICLE_COLLISION_MAX_COLLISIONS 10

#define PARTICLE_P \
  ParticleData *pa; \
  int p
#define LOOP_PARTICLES for (p = 0, pa = psys->particles; p < psys->totpart; p++, pa++)
#define LOOP_EXISTING_PARTICLES \
  for (p = 0, pa = psys->particles; p < psys->totpart; p++, pa++) \
    if (!(pa->flag & PARS_UNEXIST))
#define LOOP_SHOWN_PARTICLES \
  for (p = 0, pa = psys->particles; p < psys->totpart; p++, pa++) \
    if (!(pa->flag & (PARS_UNEXIST | PARS_NO_DISP)))
/* OpenMP: Can only advance one variable within loop definition. */
#define LOOP_DYNAMIC_PARTICLES \
  for (p = 0; p < psys->totpart; p++) \
    if ((pa = psys->particles + p)->state.time > 0.0f)

/* fast but sure way to get the modifier*/
#define PARTICLE_PSMD \
  ParticleSystemModifierData *psmd = sim->psmd ? sim->psmd : psys_get_modifier(sim->ob, sim->psys)

/* common stuff that many particle functions need */
typedef struct ParticleSimulationData {
  struct Depsgraph *depsgraph;
  struct Scene *scene;
  struct Object *ob;
  struct ParticleSystem *psys;
  struct ParticleSystemModifierData *psmd;
  struct ListBase *colliders;
  /* Courant number. This is used to implement an adaptive time step. Only the
   * maximum value per time step is important. Only sph_integrate makes use of
   * this at the moment. Other solvers could, too. */
  float courant_num;
  /* Only valid during dynamics_step(). */
  struct RNG *rng;
} ParticleSimulationData;

typedef struct SPHData {
  ParticleSystem *psys[10];
  ParticleData *pa;
  float mass;
  struct EdgeHash *eh;
  float *gravity;
  float hfac;
  /* Average distance to neighbors (other particles in the support domain),
   * for calculating the Courant number (adaptive time step). */
  int pass;
  float element_size;
  float flow[3];

  /* Integrator callbacks. This allows different SPH implementations. */
  void (*force_cb)(void *sphdata_v, ParticleKey *state, float *force, float *impulse);
  void (*density_cb)(void *rangedata_v, int index, const float co[3], float squared_dist);
} SPHData;

typedef struct ParticleTexture {
  float ivel;                                         /* used in reset */
  float time, life, exist, size;                      /* used in init */
  float damp, gravity, field;                         /* used in physics */
  float length, clump, kink_freq, kink_amp, effector; /* used in path caching */
  float rough1, rough2, roughe;                       /* used in path caching */
  float twist;                                        /* used in path caching */
} ParticleTexture;

typedef struct ParticleSeam {
  float v0[3], v1[3];
  float nor[3], dir[3], tan[3];
  float length2;
} ParticleSeam;

typedef struct ParticleCacheKey {
  float co[3];
  float vel[3];
  float rot[4];
  float col[3];
  float time;
  int segments;
} ParticleCacheKey;

typedef struct ParticleThreadContext {
  /* shared */
  struct ParticleSimulationData sim;
  struct Mesh *mesh;
  struct Material *ma;

  /* distribution */
  struct KDTree_3d *tree;

  struct ParticleSeam *seams;
  int totseam;

  float *jit, *jitoff, *weight;
  float maxweight;
  int *index, jitlevel;

  int cfrom, distr;

  struct ParticleData *tpars;

  /* path caching */
  bool editupdate;
  int between, segments, extra_segments;
  int totchild, totparent, parent_pass;

  float cfra;

  float *vg_length, *vg_clump, *vg_kink;
  float *vg_rough1, *vg_rough2, *vg_roughe;
  float *vg_effector;
  float *vg_twist;

  struct CurveMapping *clumpcurve;
  struct CurveMapping *roughcurve;
  struct CurveMapping *twistcurve;
} ParticleThreadContext;

typedef struct ParticleTask {
  ParticleThreadContext *ctx;
  struct RNG *rng, *rng_path;
  int begin, end;
} ParticleTask;

typedef struct ParticleCollisionElement {
  /* pointers to original data */
  float *x[3], *v[3];

  /* values interpolated from original data*/
  float x0[3], x1[3], x2[3], p[3];

  /* results for found intersection point */
  float nor[3], vel[3], uv[2];

  /* count of original data (1-4) */
  int tot;

  /* index of the collision face */
  int index;

  /* flags for inversed normal / particle already inside element at start */
  short inv_nor, inside;
} ParticleCollisionElement;

/** Container for moving data between deflet_particle and particle_intersect_face. */
typedef struct ParticleCollision {
  struct Object *current;
  struct Object *hit;
  struct Object *skip[PARTICLE_COLLISION_MAX_COLLISIONS + 1];
  struct Object *emitter;

  /** Collision modifier for current object. */
  struct CollisionModifierData *md;

  /** Time factor of previous collision, needed for substracting face velocity. */
  float f;
  float fac1, fac2;

  float cfra, old_cfra;

  /** Original length of co2-co1, needed for collision time evaluation. */
  float original_ray_length;

  int skip_count;

  ParticleCollisionElement pce;

  /* total_time is the amount of time in this subframe
   * inv_total_time is the opposite
   * inv_timestep is the inverse of the amount of time in this frame */
  float total_time, inv_total_time, inv_timestep;

  float radius;
  float co1[3], co2[3];
  float ve1[3], ve2[3];

  float acc[3], boid_z;

  int boid;
} ParticleCollision;

typedef struct ParticleDrawData {
  float *vdata, *vd;   /* vertice data */
  float *ndata, *nd;   /* normal data */
  float *cdata, *cd;   /* color data */
  float *vedata, *ved; /* velocity data */
  float *ma_col;
  int totpart, partsize;
  int flag;
  int totpoint, totve;
} ParticleDrawData;

#define PARTICLE_DRAW_DATA_UPDATED 1

#define PSYS_FRAND_COUNT 1024
extern unsigned int PSYS_FRAND_SEED_OFFSET[PSYS_FRAND_COUNT];
extern unsigned int PSYS_FRAND_SEED_MULTIPLIER[PSYS_FRAND_COUNT];
extern float PSYS_FRAND_BASE[PSYS_FRAND_COUNT];

void psys_init_rng(void);

BLI_INLINE float psys_frand(ParticleSystem *psys, unsigned int seed)
{
  /* XXX far from ideal, this simply scrambles particle random numbers a bit
   * to avoid obvious correlations.
   * Can't use previous psys->frand arrays because these require initialization
   * inside psys_check_enabled, which wreaks havoc in multi-threaded depgraph updates.
   */
  unsigned int offset = PSYS_FRAND_SEED_OFFSET[psys->seed % PSYS_FRAND_COUNT];
  unsigned int multiplier = PSYS_FRAND_SEED_MULTIPLIER[psys->seed % PSYS_FRAND_COUNT];
  return PSYS_FRAND_BASE[(offset + seed * multiplier) % PSYS_FRAND_COUNT];
}

BLI_INLINE void psys_frand_vec(ParticleSystem *psys, unsigned int seed, float vec[3])
{
  unsigned int offset = PSYS_FRAND_SEED_OFFSET[psys->seed % PSYS_FRAND_COUNT];
  unsigned int multiplier = PSYS_FRAND_SEED_MULTIPLIER[psys->seed % PSYS_FRAND_COUNT];
  vec[0] = PSYS_FRAND_BASE[(offset + (seed + 0) * multiplier) % PSYS_FRAND_COUNT];
  vec[1] = PSYS_FRAND_BASE[(offset + (seed + 1) * multiplier) % PSYS_FRAND_COUNT];
  vec[2] = PSYS_FRAND_BASE[(offset + (seed + 2) * multiplier) % PSYS_FRAND_COUNT];
}

/* ----------- functions needed outside particlesystem ---------------- */
/* particle.c */
int count_particles(struct ParticleSystem *psys);
int count_particles_mod(struct ParticleSystem *psys, int totgr, int cur);

int psys_get_child_number(struct Scene *scene,
                          struct ParticleSystem *psys,
                          const bool use_render_params);
int psys_get_tot_child(struct Scene *scene,
                       struct ParticleSystem *psys,
                       const bool use_render_params);

struct ParticleSystem *psys_get_current(struct Object *ob);
/* for rna */
short psys_get_current_num(struct Object *ob);
void psys_set_current_num(Object *ob, int index);
/* UNUSED */
// struct Object *psys_find_object(struct Scene *scene, struct ParticleSystem *psys);

struct LatticeDeformData *psys_create_lattice_deform_data(struct ParticleSimulationData *sim);

/* For a given evaluated particle system get its original.
 *
 * If this input is an original particle system already, the return value is the
 * same as the input. */
struct ParticleSystem *psys_orig_get(struct ParticleSystem *psys);

/* For a given original object and its particle system, get evaluated particle
 * system within a given dependency graph. */
struct ParticleSystem *psys_eval_get(struct Depsgraph *depsgraph,
                                     struct Object *object,
                                     struct ParticleSystem *psys);

bool psys_in_edit_mode(struct Depsgraph *depsgraph, const struct ParticleSystem *psys);
bool psys_check_enabled(struct Object *ob,
                        struct ParticleSystem *psys,
                        const bool use_render_params);
bool psys_check_edited(struct ParticleSystem *psys);

void psys_find_group_weights(struct ParticleSettings *part);
void psys_check_group_weights(struct ParticleSettings *part);
int psys_uses_gravity(struct ParticleSimulationData *sim);
void BKE_particlesettings_fluid_default_settings(struct ParticleSettings *part);

/* free */
void BKE_particlesettings_free(struct ParticleSettings *part);
void psys_free_path_cache(struct ParticleSystem *psys, struct PTCacheEdit *edit);
void psys_free(struct Object *ob, struct ParticleSystem *psys);

/* Copy. */
void psys_copy_particles(struct ParticleSystem *psys_dst, struct ParticleSystem *psys_src);

bool psys_render_simplify_params(struct ParticleSystem *psys,
                                 struct ChildParticle *cpa,
                                 float *params);

void psys_interpolate_uvs(const struct MTFace *tface, int quad, const float w[4], float uvco[2]);
void psys_interpolate_mcol(const struct MCol *mcol, int quad, const float w[4], struct MCol *mc);

void copy_particle_key(struct ParticleKey *to, struct ParticleKey *from, int time);

void psys_emitter_customdata_mask(struct ParticleSystem *psys,
                                  struct CustomData_MeshMasks *r_cddata_masks);
void psys_particle_on_emitter(struct ParticleSystemModifierData *psmd,
                              int distr,
                              int index,
                              int index_dmcache,
                              float fuv[4],
                              float foffset,
                              float vec[3],
                              float nor[3],
                              float utan[3],
                              float vtan[3],
                              float orco[3]);
struct ParticleSystemModifierData *psys_get_modifier(struct Object *ob,
                                                     struct ParticleSystem *psys);

struct ModifierData *object_add_particle_system(struct Main *bmain,
                                                struct Scene *scene,
                                                struct Object *ob,
                                                const char *name);
void object_remove_particle_system(struct Main *bmain, struct Scene *scene, struct Object *ob);
struct ParticleSettings *BKE_particlesettings_add(struct Main *bmain, const char *name);
void BKE_particlesettings_copy_data(struct Main *bmain,
                                    struct ParticleSettings *part_dst,
                                    const struct ParticleSettings *part_src,
                                    const int flag);
struct ParticleSettings *BKE_particlesettings_copy(struct Main *bmain,
                                                   const struct ParticleSettings *part);
void BKE_particlesettings_make_local(struct Main *bmain,
                                     struct ParticleSettings *part,
                                     const bool lib_local);

void psys_reset(struct ParticleSystem *psys, int mode);

void psys_find_parents(struct ParticleSimulationData *sim, const bool use_render_params);

void psys_unique_name(struct Object *object, struct ParticleSystem *psys, const char *defname);

void psys_cache_paths(struct ParticleSimulationData *sim,
                      float cfra,
                      const bool use_render_params);
void psys_cache_edit_paths(struct Depsgraph *depsgraph,
                           struct Scene *scene,
                           struct Object *ob,
                           struct PTCacheEdit *edit,
                           float cfra,
                           const bool use_render_params);
void psys_cache_child_paths(struct ParticleSimulationData *sim,
                            float cfra,
                            const bool editupdate,
                            const bool use_render_params);
int do_guides(struct Depsgraph *depsgraph,
              struct ParticleSettings *part,
              struct ListBase *effectors,
              ParticleKey *state,
              int pa_num,
              float time);
void precalc_guides(struct ParticleSimulationData *sim, struct ListBase *effectors);
float psys_get_timestep(struct ParticleSimulationData *sim);
float psys_get_child_time(struct ParticleSystem *psys,
                          struct ChildParticle *cpa,
                          float cfra,
                          float *birthtime,
                          float *dietime);
float psys_get_child_size(struct ParticleSystem *psys,
                          struct ChildParticle *cpa,
                          float cfra,
                          float *pa_time);
void psys_get_particle_on_path(struct ParticleSimulationData *sim,
                               int pa_num,
                               struct ParticleKey *state,
                               const bool vel);
int psys_get_particle_state(struct ParticleSimulationData *sim,
                            int p,
                            struct ParticleKey *state,
                            int always);

/* child paths */
void BKE_particlesettings_clump_curve_init(struct ParticleSettings *part);
void BKE_particlesettings_rough_curve_init(struct ParticleSettings *part);
void BKE_particlesettings_twist_curve_init(struct ParticleSettings *part);
void psys_apply_child_modifiers(struct ParticleThreadContext *ctx,
                                struct ListBase *modifiers,
                                struct ChildParticle *cpa,
                                struct ParticleTexture *ptex,
                                const float orco[3],
                                float hairmat[4][4],
                                struct ParticleCacheKey *keys,
                                struct ParticleCacheKey *parent_keys,
                                const float parent_orco[3]);

void psys_sph_init(struct ParticleSimulationData *sim, struct SPHData *sphdata);
void psys_sph_finalise(struct SPHData *sphdata);
void psys_sph_density(struct BVHTree *tree, struct SPHData *data, float co[3], float vars[2]);

/* for anim.c */
void psys_get_dupli_texture(struct ParticleSystem *psys,
                            struct ParticleSettings *part,
                            struct ParticleSystemModifierData *psmd,
                            struct ParticleData *pa,
                            struct ChildParticle *cpa,
                            float uv[2],
                            float orco[3]);
void psys_get_dupli_path_transform(struct ParticleSimulationData *sim,
                                   struct ParticleData *pa,
                                   struct ChildParticle *cpa,
                                   struct ParticleCacheKey *cache,
                                   float mat[4][4],
                                   float *scale);

void psys_thread_context_init(struct ParticleThreadContext *ctx,
                              struct ParticleSimulationData *sim);
void psys_thread_context_free(struct ParticleThreadContext *ctx);
void psys_tasks_create(struct ParticleThreadContext *ctx,
                       int startpart,
                       int endpart,
                       struct ParticleTask **r_tasks,
                       int *r_numtasks);
void psys_tasks_free(struct ParticleTask *tasks, int numtasks);

void psys_apply_hair_lattice(struct Depsgraph *depsgraph,
                             struct Scene *scene,
                             struct Object *ob,
                             struct ParticleSystem *psys);

/* particle_system.c */
struct ParticleSystem *psys_get_target_system(struct Object *ob, struct ParticleTarget *pt);
void psys_count_keyed_targets(struct ParticleSimulationData *sim);
void psys_update_particle_tree(struct ParticleSystem *psys, float cfra);
void psys_changed_type(struct Object *ob, struct ParticleSystem *psys);

void psys_make_temp_pointcache(struct Object *ob, struct ParticleSystem *psys);
void psys_get_pointcache_start_end(struct Scene *scene,
                                   ParticleSystem *psys,
                                   int *sfra,
                                   int *efra);

void psys_check_boid_data(struct ParticleSystem *psys);

void psys_get_birth_coords(struct ParticleSimulationData *sim,
                           struct ParticleData *pa,
                           struct ParticleKey *state,
                           float dtime,
                           float cfra);

void particle_system_update(struct Depsgraph *depsgraph,
                            struct Scene *scene,
                            struct Object *ob,
                            struct ParticleSystem *psys,
                            const bool use_render_params);

/* Callback format for performing operations on ID-pointers for particle systems */
typedef void (*ParticleSystemIDFunc)(struct ParticleSystem *psys,
                                     struct ID **idpoin,
                                     void *userdata,
                                     int cb_flag);

void BKE_particlesystem_id_loop(struct ParticleSystem *psys,
                                ParticleSystemIDFunc func,
                                void *userdata);

/* Reset all particle systems in the given object. */
void BKE_particlesystem_reset_all(struct Object *object);

/* ----------- functions needed only inside particlesystem ------------ */
/* particle.c */
void psys_disable_all(struct Object *ob);
void psys_enable_all(struct Object *ob);

void free_hair(struct Object *ob, struct ParticleSystem *psys, int dynamics);
void free_keyed_keys(struct ParticleSystem *psys);
void psys_free_particles(struct ParticleSystem *psys);
void psys_free_children(struct ParticleSystem *psys);

void psys_interpolate_particle(
    short type, struct ParticleKey keys[4], float dt, struct ParticleKey *result, bool velocity);
void psys_vec_rot_to_face(struct Mesh *mesh, struct ParticleData *pa, float vec[3]);
void psys_mat_hair_to_object(struct Object *ob,
                             struct Mesh *mesh,
                             short from,
                             struct ParticleData *pa,
                             float hairmat[4][4]);
void psys_mat_hair_to_global(struct Object *ob,
                             struct Mesh *mesh,
                             short from,
                             struct ParticleData *pa,
                             float hairmat[4][4]);
void psys_mat_hair_to_orco(struct Object *ob,
                           struct Mesh *mesh,
                           short from,
                           struct ParticleData *pa,
                           float hairmat[4][4]);

float psys_get_dietime_from_cache(struct PointCache *cache, int index);

void psys_free_pdd(struct ParticleSystem *psys);

float *psys_cache_vgroup(struct Mesh *mesh, struct ParticleSystem *psys, int vgroup);
void psys_get_texture(struct ParticleSimulationData *sim,
                      struct ParticleData *pa,
                      struct ParticleTexture *ptex,
                      int event,
                      float cfra);
void psys_interpolate_face(struct MVert *mvert,
                           struct MFace *mface,
                           struct MTFace *tface,
                           float (*orcodata)[3],
                           float w[4],
                           float vec[3],
                           float nor[3],
                           float utan[3],
                           float vtan[3],
                           float orco[3]);
float psys_particle_value_from_verts(struct Mesh *mesh,
                                     short from,
                                     struct ParticleData *pa,
                                     float *values);
void psys_get_from_key(
    struct ParticleKey *key, float loc[3], float vel[3], float rot[4], float *time);

/* BLI_bvhtree_ray_cast callback */
void BKE_psys_collision_neartest_cb(void *userdata,
                                    int index,
                                    const struct BVHTreeRay *ray,
                                    struct BVHTreeRayHit *hit);
void psys_particle_on_dm(struct Mesh *mesh_final,
                         int from,
                         int index,
                         int index_dmcache,
                         const float fw[4],
                         float foffset,
                         float vec[3],
                         float nor[3],
                         float utan[3],
                         float vtan[3],
                         float orco[3]);

/* particle_system.c */
void distribute_particles(struct ParticleSimulationData *sim, int from);
void initialize_particle(struct ParticleSimulationData *sim, struct ParticleData *pa);
void psys_calc_dmcache(struct Object *ob,
                       struct Mesh *mesh_final,
                       struct Mesh *mesh_original,
                       struct ParticleSystem *psys);
int psys_particle_dm_face_lookup(struct Mesh *mesh_final,
                                 struct Mesh *mesh_original,
                                 int findex,
                                 const float fw[4],
                                 struct LinkNode **poly_nodes);

void reset_particle(struct ParticleSimulationData *sim,
                    struct ParticleData *pa,
                    float dtime,
                    float cfra);

float psys_get_current_display_percentage(struct ParticleSystem *psys,
                                          const bool use_render_params);

/* psys_reset */
#define PSYS_RESET_ALL 1
#define PSYS_RESET_DEPSGRAPH 2
/* #define PSYS_RESET_CHILDREN  3 */ /*UNUSED*/
#define PSYS_RESET_CACHE_MISS 4

/* index_dmcache */
#define DMCACHE_NOTFOUND -1
#define DMCACHE_ISCHILD -2

/* **** Depsgraph evaluation **** */

struct Depsgraph;

void BKE_particle_settings_eval_reset(struct Depsgraph *depsgraph,
                                      struct ParticleSettings *particle_settings);

void BKE_particle_system_eval_init(struct Depsgraph *depsgraph, struct Object *object);

/* Draw Cache */
enum {
  BKE_PARTICLE_BATCH_DIRTY_ALL = 0,
};
void BKE_particle_batch_cache_dirty_tag(struct ParticleSystem *psys, int mode);
void BKE_particle_batch_cache_free(struct ParticleSystem *psys);

extern void (*BKE_particle_batch_cache_dirty_tag_cb)(struct ParticleSystem *psys, int mode);
extern void (*BKE_particle_batch_cache_free_cb)(struct ParticleSystem *psys);

#endif /* __BKE_PARTICLE_H__ */
