/* particle.c
 *
 *
 * $Id$
 *
 * ***** 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) 2007 by Janne Karhu.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenkernel/intern/particle.c
 *  \ingroup bke
 */


#include <stdlib.h>
#include <math.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_curve_types.h"
#include "DNA_group_types.h"
#include "DNA_key_types.h"
#include "DNA_material_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_particle_types.h"
#include "DNA_smoke_types.h"
#include "DNA_scene_types.h"

#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BLI_utildefines.h"
#include "BLI_kdtree.h"
#include "BLI_rand.h"
#include "BLI_threads.h"

#include "BKE_anim.h"
#include "BKE_animsys.h"

#include "BKE_boids.h"
#include "BKE_cloth.h"
#include "BKE_effect.h"
#include "BKE_global.h"
#include "BKE_group.h"
#include "BKE_main.h"
#include "BKE_lattice.h"

#include "BKE_displist.h"
#include "BKE_particle.h"
#include "BKE_object.h"
#include "BKE_material.h"
#include "BKE_key.h"
#include "BKE_library.h"
#include "BKE_depsgraph.h"
#include "BKE_modifier.h"
#include "BKE_mesh.h"
#include "BKE_cdderivedmesh.h"
#include "BKE_pointcache.h"

#include "RE_render_ext.h"

static void get_child_modifier_parameters(ParticleSettings *part, ParticleThreadContext *ctx,
				ChildParticle *cpa, short cpa_from, int cpa_num, float *cpa_fuv, float *orco, ParticleTexture *ptex);
static void do_child_modifiers(ParticleSimulationData *sim,
				ParticleTexture *ptex, ParticleKey *par, float *par_rot, ChildParticle *cpa,
				float *orco, float mat[4][4], ParticleKey *state, float t);

/* few helpers for countall etc. */
int count_particles(ParticleSystem *psys){
	ParticleSettings *part=psys->part;
	PARTICLE_P;
	int tot=0;

	LOOP_SHOWN_PARTICLES {
		if(pa->alive == PARS_UNBORN && (part->flag & PART_UNBORN)==0);
		else if(pa->alive == PARS_DEAD && (part->flag & PART_DIED)==0);
		else tot++;
	}
	return tot;
}
int count_particles_mod(ParticleSystem *psys, int totgr, int cur){
	ParticleSettings *part=psys->part;
	PARTICLE_P;
	int tot=0;

	LOOP_SHOWN_PARTICLES {
		if(pa->alive == PARS_UNBORN && (part->flag & PART_UNBORN)==0);
		else if(pa->alive == PARS_DEAD && (part->flag & PART_DIED)==0);
		else if(p%totgr==cur) tot++;
	}
	return tot;
}
/* we allocate path cache memory in chunks instead of a big continguous
 * chunk, windows' memory allocater fails to find big blocks of memory often */

#define PATH_CACHE_BUF_SIZE 1024

static ParticleCacheKey **psys_alloc_path_cache_buffers(ListBase *bufs, int tot, int steps)
{
	LinkData *buf;
	ParticleCacheKey **cache;
	int i, totkey, totbufkey;

	tot= MAX2(tot, 1);
	totkey = 0;
	cache = MEM_callocN(tot*sizeof(void*), "PathCacheArray");

	while(totkey < tot) {
		totbufkey= MIN2(tot-totkey, PATH_CACHE_BUF_SIZE);
		buf= MEM_callocN(sizeof(LinkData), "PathCacheLinkData");
		buf->data= MEM_callocN(sizeof(ParticleCacheKey)*totbufkey*steps, "ParticleCacheKey");

		for(i=0; i<totbufkey; i++)
			cache[totkey+i] = ((ParticleCacheKey*)buf->data) + i*steps;

		totkey += totbufkey;
		BLI_addtail(bufs, buf);
	}

	return cache;
}

static void psys_free_path_cache_buffers(ParticleCacheKey **cache, ListBase *bufs)
{
	LinkData *buf;

	if(cache)
		MEM_freeN(cache);

	for(buf= bufs->first; buf; buf=buf->next)
		MEM_freeN(buf->data);
	BLI_freelistN(bufs);
}

/************************************************/
/*			Getting stuff						*/
/************************************************/
/* get object's active particle system safely */
ParticleSystem *psys_get_current(Object *ob)
{
	ParticleSystem *psys;
	if(ob==NULL) return NULL;

	for(psys=ob->particlesystem.first; psys; psys=psys->next){
		if(psys->flag & PSYS_CURRENT)
			return psys;
	}
	
	return NULL;
}
short psys_get_current_num(Object *ob)
{
	ParticleSystem *psys;
	short i;

	if(ob==NULL) return 0;

	for(psys=ob->particlesystem.first, i=0; psys; psys=psys->next, i++)
		if(psys->flag & PSYS_CURRENT)
			return i;
	
	return i;
}
void psys_set_current_num(Object *ob, int index)
{
	ParticleSystem *psys;
	short i;

	if(ob==NULL) return;

	for(psys=ob->particlesystem.first, i=0; psys; psys=psys->next, i++) {
		if(i == index)
			psys->flag |= PSYS_CURRENT;
		else
			psys->flag &= ~PSYS_CURRENT;
	}
}
Object *psys_find_object(Scene *scene, ParticleSystem *psys)
{
	Base *base;
	ParticleSystem *tpsys;

	for(base = scene->base.first; base; base = base->next) {
		for(tpsys = base->object->particlesystem.first; psys; psys=psys->next) {
			if(tpsys == psys)
				return base->object;
		}
	}

	return NULL;
}
Object *psys_get_lattice(ParticleSimulationData *sim)
{
	Object *lattice=NULL;
	
	if(psys_in_edit_mode(sim->scene, sim->psys)==0){

		ModifierData *md = (ModifierData*)psys_get_modifier(sim->ob, sim->psys);

		for(; md; md=md->next){
			if(md->type==eModifierType_Lattice){
				LatticeModifierData *lmd = (LatticeModifierData *)md;
				lattice=lmd->object;
				break;
			}
		}
		if(lattice)
			init_latt_deform(lattice, NULL);
	}

	return lattice;
}
void psys_disable_all(Object *ob)
{
	ParticleSystem *psys=ob->particlesystem.first;

	for(; psys; psys=psys->next)
		psys->flag |= PSYS_DISABLED;
}
void psys_enable_all(Object *ob)
{
	ParticleSystem *psys=ob->particlesystem.first;

	for(; psys; psys=psys->next)
		psys->flag &= ~PSYS_DISABLED;
}
int psys_in_edit_mode(Scene *scene, ParticleSystem *psys)
{
	return (scene->basact && (scene->basact->object->mode & OB_MODE_PARTICLE_EDIT) && psys==psys_get_current((scene->basact)->object) && (psys->edit || psys->pointcache->edit) && !psys->renderdata);
}
static void psys_create_frand(ParticleSystem *psys)
{
	int i;
	float *rand = psys->frand = MEM_callocN(PSYS_FRAND_COUNT * sizeof(float), "particle randoms");

	BLI_srandom(psys->seed);

	for(i=0; i<1024; i++, rand++)
		*rand = BLI_frand();
}
int psys_check_enabled(Object *ob, ParticleSystem *psys)
{
	ParticleSystemModifierData *psmd;

	if(psys->flag & PSYS_DISABLED || psys->flag & PSYS_DELETE || !psys->part)
		return 0;

	psmd= psys_get_modifier(ob, psys);
	if(psys->renderdata || G.rendering) {
		if(!(psmd->modifier.mode & eModifierMode_Render))
			return 0;
	}
	else if(!(psmd->modifier.mode & eModifierMode_Realtime))
		return 0;

	/* perhaps not the perfect place, but we have to be sure the rands are there before usage */
	if(!psys->frand)
		psys_create_frand(psys);
	else if(psys->recalc & PSYS_RECALC_RESET) {
		MEM_freeN(psys->frand);
		psys_create_frand(psys);
	}
	
	return 1;
}

int psys_check_edited(ParticleSystem *psys)
{
	if(psys->part && psys->part->type==PART_HAIR)
		return (psys->flag & PSYS_EDITED || (psys->edit && psys->edit->edited));
	else
		return (psys->pointcache->edit && psys->pointcache->edit->edited);
}

void psys_check_group_weights(ParticleSettings *part)
{
	ParticleDupliWeight *dw, *tdw;
	GroupObject *go;
	int current = 0;

	if(part->ren_as == PART_DRAW_GR && part->dup_group && part->dup_group->gobject.first) {
		/* first remove all weights that don't have an object in the group */
		dw = part->dupliweights.first;
		while(dw) {
			if(!object_in_group(dw->ob, part->dup_group)) {
				tdw = dw->next;
				BLI_freelinkN(&part->dupliweights, dw);
				dw = tdw;
			}
			else
				dw = dw->next;
		}

		/* then add objects in the group to new list */
		go = part->dup_group->gobject.first;
		while(go) {
			dw = part->dupliweights.first;
			while(dw && dw->ob != go->ob)
				dw = dw->next;
			
			if(!dw) {
				dw = MEM_callocN(sizeof(ParticleDupliWeight), "ParticleDupliWeight");
				dw->ob = go->ob;
				dw->count = 1;
				BLI_addtail(&part->dupliweights, dw);
			}

			go = go->next;	
		}

		dw = part->dupliweights.first;
		for(; dw; dw=dw->next) {
			if(dw->flag & PART_DUPLIW_CURRENT) {
				current = 1;
				break;
			}
		}

		if(!current) {
			dw = part->dupliweights.first;
			if(dw)
				dw->flag |= PART_DUPLIW_CURRENT;
		}
	}
	else {
		BLI_freelistN(&part->dupliweights);
	}
}
int psys_uses_gravity(ParticleSimulationData *sim)
{
	return sim->scene->physics_settings.flag & PHYS_GLOBAL_GRAVITY && sim->psys->part && sim->psys->part->effector_weights->global_gravity != 0.0f;
}
/************************************************/
/*			Freeing stuff						*/
/************************************************/
static void fluid_free_settings(SPHFluidSettings *fluid)
{
	if(fluid)
		MEM_freeN(fluid); 
}

void psys_free_settings(ParticleSettings *part)
{
	MTex *mtex;
	int a;
	BKE_free_animdata(&part->id);
	free_partdeflect(part->pd);
	free_partdeflect(part->pd2);

	if(part->effector_weights)
		MEM_freeN(part->effector_weights);

	BLI_freelistN(&part->dupliweights);

	boid_free_settings(part->boids);
	fluid_free_settings(part->fluid);

	for(a=0; a<MAX_MTEX; a++) {
		mtex= part->mtex[a];
		if(mtex && mtex->tex) mtex->tex->id.us--;
		if(mtex) MEM_freeN(mtex);
	}
}

void free_hair(Object *UNUSED(ob), ParticleSystem *psys, int dynamics)
{
	PARTICLE_P;

	LOOP_PARTICLES {
		if(pa->hair)
			MEM_freeN(pa->hair);
		pa->hair = NULL;
		pa->totkey = 0;
	}

	psys->flag &= ~PSYS_HAIR_DONE;

	if(psys->clmd) {
		if(dynamics) {
			BKE_ptcache_free_list(&psys->ptcaches);
			psys->clmd->point_cache = psys->pointcache = NULL;
			psys->clmd->ptcaches.first = psys->clmd->ptcaches.last = NULL;

			modifier_free((ModifierData*)psys->clmd);
			
			psys->clmd = NULL;
			psys->pointcache = BKE_ptcache_add(&psys->ptcaches);
		}
		else {
			cloth_free_modifier(psys->clmd);
		}
	}

	if(psys->hair_in_dm)
		psys->hair_in_dm->release(psys->hair_in_dm);
	psys->hair_in_dm = NULL;

	if(psys->hair_out_dm)
		psys->hair_out_dm->release(psys->hair_out_dm);
	psys->hair_out_dm = NULL;
}
void free_keyed_keys(ParticleSystem *psys)
{
	PARTICLE_P;

	if(psys->part->type == PART_HAIR)
		return;

	if(psys->particles && psys->particles->keys) {
		MEM_freeN(psys->particles->keys);

		LOOP_PARTICLES {
			if(pa->keys) {
				pa->keys= NULL;
				pa->totkey= 0;
			}
		}
	}
}
static void free_child_path_cache(ParticleSystem *psys)
{
	psys_free_path_cache_buffers(psys->childcache, &psys->childcachebufs);
	psys->childcache = NULL;
	psys->totchildcache = 0;
}
void psys_free_path_cache(ParticleSystem *psys, PTCacheEdit *edit)
{
	if(edit) {
		psys_free_path_cache_buffers(edit->pathcache, &edit->pathcachebufs);
		edit->pathcache= NULL;
		edit->totcached= 0;
	}
	if(psys) {
		psys_free_path_cache_buffers(psys->pathcache, &psys->pathcachebufs);
		psys->pathcache= NULL;
		psys->totcached= 0;

		free_child_path_cache(psys);
	}
}
void psys_free_children(ParticleSystem *psys)
{
	if(psys->child) {
		MEM_freeN(psys->child);
		psys->child= NULL;
		psys->totchild=0;
	}

	free_child_path_cache(psys);
}
void psys_free_particles(ParticleSystem *psys)
{
	PARTICLE_P;

	if(psys->particles) {
		if(psys->part->type==PART_HAIR) {
			LOOP_PARTICLES {
				if(pa->hair)
					MEM_freeN(pa->hair);
			}
		}
		
		if(psys->particles->keys)
			MEM_freeN(psys->particles->keys);
		
		if(psys->particles->boid)
			MEM_freeN(psys->particles->boid);

		MEM_freeN(psys->particles);
		psys->particles= NULL;
		psys->totpart= 0;
	}
}
void psys_free_pdd(ParticleSystem *psys)
{
	if(psys->pdd) {
		if(psys->pdd->cdata)
			MEM_freeN(psys->pdd->cdata);
		psys->pdd->cdata = NULL;

		if(psys->pdd->vdata)
			MEM_freeN(psys->pdd->vdata);
		psys->pdd->vdata = NULL;

		if(psys->pdd->ndata)
			MEM_freeN(psys->pdd->ndata);
		psys->pdd->ndata = NULL;

		if(psys->pdd->vedata)
			MEM_freeN(psys->pdd->vedata);
		psys->pdd->vedata = NULL;

		psys->pdd->totpoint = 0;
		psys->pdd->tot_vec_size = 0;
	}
}
/* free everything */
void psys_free(Object *ob, ParticleSystem * psys)
{	
	if(psys){
		int nr = 0;
		ParticleSystem * tpsys;
		
		psys_free_path_cache(psys, NULL);

		free_hair(ob, psys, 1);

		psys_free_particles(psys);

		if(psys->edit && psys->free_edit)
			psys->free_edit(psys->edit);

		if(psys->child){
			MEM_freeN(psys->child);
			psys->child = NULL;
			psys->totchild = 0;
		}
		
		// check if we are last non-visible particle system
		for(tpsys=ob->particlesystem.first; tpsys; tpsys=tpsys->next){
			if(tpsys->part)
			{
				if(ELEM(tpsys->part->ren_as,PART_DRAW_OB,PART_DRAW_GR))
				{
					nr++;
					break;
				}
			}
		}
		// clear do-not-draw-flag
		if(!nr)
			ob->transflag &= ~OB_DUPLIPARTS;

		if(psys->part){
			psys->part->id.us--;		
			psys->part=NULL;
		}

		BKE_ptcache_free_list(&psys->ptcaches);
		psys->pointcache = NULL;
		
		BLI_freelistN(&psys->targets);

		BLI_bvhtree_free(psys->bvhtree);
		BLI_kdtree_free(psys->tree);
 
		if(psys->fluid_springs)
			MEM_freeN(psys->fluid_springs);

		pdEndEffectors(&psys->effectors);

		if(psys->frand)
			MEM_freeN(psys->frand);

		if(psys->pdd) {
			psys_free_pdd(psys);
			MEM_freeN(psys->pdd);
		}

		MEM_freeN(psys);
	}
}

/************************************************/
/*			Rendering							*/
/************************************************/
/* these functions move away particle data and bring it back after
 * rendering, to make different render settings possible without
 * removing the previous data. this should be solved properly once */

typedef struct ParticleRenderElem {
	int curchild, totchild, reduce;
	float lambda, t, scalemin, scalemax;
} ParticleRenderElem;

typedef struct ParticleRenderData {
	ChildParticle *child;
	ParticleCacheKey **pathcache;
	ParticleCacheKey **childcache;
	ListBase pathcachebufs, childcachebufs;
	int totchild, totcached, totchildcache;
	DerivedMesh *dm;
	int totdmvert, totdmedge, totdmface;

	float mat[4][4];
	float viewmat[4][4], winmat[4][4];
	int winx, winy;

	int dosimplify;
	int timeoffset;
	ParticleRenderElem *elems;
	int *origindex;
} ParticleRenderData;

static float psys_render_viewport_falloff(double rate, float dist, float width)
{
	return pow(rate, dist/width);
}

static float psys_render_projected_area(ParticleSystem *psys, float *center, float area, double vprate, float *viewport)
{
	ParticleRenderData *data= psys->renderdata;
	float co[4], view[3], ortho1[3], ortho2[3], w, dx, dy, radius;
	
	/* transform to view space */
	VECCOPY(co, center);
	co[3]= 1.0f;
	mul_m4_v4(data->viewmat, co);
	
	/* compute two vectors orthogonal to view vector */
	normalize_v3_v3(view, co);
	ortho_basis_v3v3_v3( ortho1, ortho2,view);

	/* compute on screen minification */
	w= co[2]*data->winmat[2][3] + data->winmat[3][3];
	dx= data->winx*ortho2[0]*data->winmat[0][0];
	dy= data->winy*ortho2[1]*data->winmat[1][1];
	w= sqrt(dx*dx + dy*dy)/w;

	/* w squared because we are working with area */
	area= area*w*w;

	/* viewport of the screen test */

	/* project point on screen */
	mul_m4_v4(data->winmat, co);
	if(co[3] != 0.0f) {
		co[0]= 0.5f*data->winx*(1.0f + co[0]/co[3]);
		co[1]= 0.5f*data->winy*(1.0f + co[1]/co[3]);
	}

	/* screen space radius */
	radius= sqrt(area/(float)M_PI);

	/* make smaller using fallof once over screen edge */
	*viewport= 1.0f;

	if(co[0]+radius < 0.0f)
		*viewport *= psys_render_viewport_falloff(vprate, -(co[0]+radius), data->winx);
	else if(co[0]-radius > data->winx)
		*viewport *= psys_render_viewport_falloff(vprate, (co[0]-radius) - data->winx, data->winx);

	if(co[1]+radius < 0.0f)
		*viewport *= psys_render_viewport_falloff(vprate, -(co[1]+radius), data->winy);
	else if(co[1]-radius > data->winy)
		*viewport *= psys_render_viewport_falloff(vprate, (co[1]-radius) - data->winy, data->winy);
	
	return area;
}

void psys_render_set(Object *ob, ParticleSystem *psys, float viewmat[][4], float winmat[][4], int winx, int winy, int timeoffset)
{
	ParticleRenderData*data;
	ParticleSystemModifierData *psmd= psys_get_modifier(ob, psys);

	if(!G.rendering)
		return;
	if(psys->renderdata)
		return;

	data= MEM_callocN(sizeof(ParticleRenderData), "ParticleRenderData");

	data->child= psys->child;
	data->totchild= psys->totchild;
	data->pathcache= psys->pathcache;
	data->pathcachebufs.first = psys->pathcachebufs.first;
	data->pathcachebufs.last = psys->pathcachebufs.last;
	data->totcached= psys->totcached;
	data->childcache= psys->childcache;
	data->childcachebufs.first = psys->childcachebufs.first;
	data->childcachebufs.last = psys->childcachebufs.last;
	data->totchildcache= psys->totchildcache;

	if(psmd->dm)
		data->dm= CDDM_copy(psmd->dm);
	data->totdmvert= psmd->totdmvert;
	data->totdmedge= psmd->totdmedge;
	data->totdmface= psmd->totdmface;

	psys->child= NULL;
	psys->pathcache= NULL;
	psys->childcache= NULL;
	psys->totchild= psys->totcached= psys->totchildcache= 0;
	psys->pathcachebufs.first = psys->pathcachebufs.last = NULL;
	psys->childcachebufs.first = psys->childcachebufs.last = NULL;

	copy_m4_m4(data->winmat, winmat);
	mul_m4_m4m4(data->viewmat, ob->obmat, viewmat);
	mul_m4_m4m4(data->mat, data->viewmat, winmat);
	data->winx= winx;
	data->winy= winy;

	data->timeoffset= timeoffset;

	psys->renderdata= data;

	/* Hair can and has to be recalculated if everything isn't displayed. */
	if(psys->part->disp != 100 && psys->part->type == PART_HAIR)
		psys->recalc |= PSYS_RECALC_RESET;
}

void psys_render_restore(Object *ob, ParticleSystem *psys)
{
	ParticleRenderData*data;
	ParticleSystemModifierData *psmd= psys_get_modifier(ob, psys);

	data= psys->renderdata;
	if(!data)
		return;
	
	if(data->elems)
		MEM_freeN(data->elems);

	if(psmd->dm) {
		psmd->dm->needsFree= 1;
		psmd->dm->release(psmd->dm);
	}

	psys_free_path_cache(psys, NULL);

	if(psys->child){
		MEM_freeN(psys->child);
		psys->child= 0;
		psys->totchild= 0;
	}

	psys->child= data->child;
	psys->totchild= data->totchild;
	psys->pathcache= data->pathcache;
	psys->pathcachebufs.first = data->pathcachebufs.first;
	psys->pathcachebufs.last = data->pathcachebufs.last;
	psys->totcached= data->totcached;
	psys->childcache= data->childcache;
	psys->childcachebufs.first = data->childcachebufs.first;
	psys->childcachebufs.last = data->childcachebufs.last;
	psys->totchildcache= data->totchildcache;

	psmd->dm= data->dm;
	psmd->totdmvert= data->totdmvert;
	psmd->totdmedge= data->totdmedge;
	psmd->totdmface= data->totdmface;
	psmd->flag &= ~eParticleSystemFlag_psys_updated;

	if(psmd->dm)
		psys_calc_dmcache(ob, psmd->dm, psys);

	MEM_freeN(data);
	psys->renderdata= NULL;
}

int psys_render_simplify_distribution(ParticleThreadContext *ctx, int tot)
{
	DerivedMesh *dm= ctx->dm;
	Mesh *me= (Mesh*)(ctx->sim.ob->data);
	MFace *mf, *mface;
	MVert *mvert;
	ParticleRenderData *data;
	ParticleRenderElem *elems, *elem;
	ParticleSettings *part= ctx->sim.psys->part;
	float *facearea, (*facecenter)[3], size[3], fac, powrate, scaleclamp;
	float co1[3], co2[3], co3[3], co4[3], lambda, arearatio, t, area, viewport;
	double vprate;
	int *origindex, *facetotvert;
	int a, b, totorigface, totface, newtot, skipped;

	if(part->ren_as!=PART_DRAW_PATH || !(part->draw & PART_DRAW_REN_STRAND))
		return tot;
	if(!ctx->sim.psys->renderdata)
		return tot;

	data= ctx->sim.psys->renderdata;
	if(data->timeoffset)
		return 0;
	if(!(part->simplify_flag & PART_SIMPLIFY_ENABLE))
		return tot;

	mvert= dm->getVertArray(dm);
	mface= dm->getFaceArray(dm);
	origindex= dm->getFaceDataArray(dm, CD_ORIGINDEX);
	totface= dm->getNumFaces(dm);
	totorigface= me->totface;

	if(totface == 0 || totorigface == 0)
		return tot;

	facearea= MEM_callocN(sizeof(float)*totorigface, "SimplifyFaceArea");
	facecenter= MEM_callocN(sizeof(float[3])*totorigface, "SimplifyFaceCenter");
	facetotvert= MEM_callocN(sizeof(int)*totorigface, "SimplifyFaceArea");
	elems= MEM_callocN(sizeof(ParticleRenderElem)*totorigface, "SimplifyFaceElem");

	if(data->elems)
		MEM_freeN(data->elems);

	data->dosimplify= 1;
	data->elems= elems;
	data->origindex= origindex;

	/* compute number of children per original face */
	for(a=0; a<tot; a++) {
		b= (origindex)? origindex[ctx->index[a]]: ctx->index[a];
		if(b != -1)
			elems[b].totchild++;
	}

	/* compute areas and centers of original faces */
	for(mf=mface, a=0; a<totface; a++, mf++) {
		b= (origindex)? origindex[a]: a;

		if(b != -1) {
			VECCOPY(co1, mvert[mf->v1].co);
			VECCOPY(co2, mvert[mf->v2].co);
			VECCOPY(co3, mvert[mf->v3].co);

			VECADD(facecenter[b], facecenter[b], co1);
			VECADD(facecenter[b], facecenter[b], co2);
			VECADD(facecenter[b], facecenter[b], co3);

			if(mf->v4) {
				VECCOPY(co4, mvert[mf->v4].co);
				VECADD(facecenter[b], facecenter[b], co4);
				facearea[b] += area_quad_v3(co1, co2, co3, co4);
				facetotvert[b] += 4;
			}
			else {
				facearea[b] += area_tri_v3(co1, co2, co3);
				facetotvert[b] += 3;
			}
		}
	}

	for(a=0; a<totorigface; a++)
		if(facetotvert[a] > 0)
			mul_v3_fl(facecenter[a], 1.0f/facetotvert[a]);

	/* for conversion from BU area / pixel area to reference screen size */
	mesh_get_texspace(me, 0, 0, size);
	fac= ((size[0] + size[1] + size[2])/3.0f)/part->simplify_refsize;
	fac= fac*fac;

	powrate= log(0.5f)/log(part->simplify_rate*0.5f);
	if(part->simplify_flag & PART_SIMPLIFY_VIEWPORT)
		vprate= pow(1.0f - part->simplify_viewport, 5.0);
	else
		vprate= 1.0;

	/* set simplification parameters per original face */
	for(a=0, elem=elems; a<totorigface; a++, elem++) {
		area = psys_render_projected_area(ctx->sim.psys, facecenter[a], facearea[a], vprate, &viewport);
		arearatio= fac*area/facearea[a];

		if((arearatio < 1.0f || viewport < 1.0f) && elem->totchild) {
			/* lambda is percentage of elements to keep */
			lambda= (arearatio < 1.0f)? powf(arearatio, powrate): 1.0f;
			lambda *= viewport;

			lambda= MAX2(lambda, 1.0f/elem->totchild);

			/* compute transition region */
			t= part->simplify_transition;
			elem->t= (lambda-t < 0.0f)? lambda: (lambda+t > 1.0f)? 1.0f-lambda: t;
			elem->reduce= 1;

			/* scale at end and beginning of the transition region */
			elem->scalemax= (lambda+t < 1.0f)? 1.0f/lambda: 1.0f/(1.0f - elem->t*elem->t/t);
			elem->scalemin= (lambda+t < 1.0f)? 0.0f: elem->scalemax*(1.0f-elem->t/t);

			elem->scalemin= sqrt(elem->scalemin);
			elem->scalemax= sqrt(elem->scalemax);

			/* clamp scaling */
			scaleclamp= MIN2(elem->totchild, 10.0f);
			elem->scalemin= MIN2(scaleclamp, elem->scalemin);
			elem->scalemax= MIN2(scaleclamp, elem->scalemax);

			/* extend lambda to include transition */
			lambda= lambda + elem->t;
			if(lambda > 1.0f)
				lambda= 1.0f;
		}
		else {
			lambda= arearatio;

			elem->scalemax= 1.0f; //sqrt(lambda);
			elem->scalemin= 1.0f; //sqrt(lambda);
			elem->reduce= 0;
		}

		elem->lambda= lambda;
		elem->scalemin= sqrt(elem->scalemin);
		elem->scalemax= sqrt(elem->scalemax);
		elem->curchild= 0;
	}

	MEM_freeN(facearea);
	MEM_freeN(facecenter);
	MEM_freeN(facetotvert);

	/* move indices and set random number skipping */
	ctx->skip= MEM_callocN(sizeof(int)*tot, "SimplificationSkip");

	skipped= 0;
	for(a=0, newtot=0; a<tot; a++) {
		b= (origindex)? origindex[ctx->index[a]]: ctx->index[a];
		if(b != -1) {
			if(elems[b].curchild++ < ceil(elems[b].lambda*elems[b].totchild)) {
				ctx->index[newtot]= ctx->index[a];
				ctx->skip[newtot]= skipped;
				skipped= 0;
				newtot++;
			}
			else skipped++;
		}
		else skipped++;
	}

	for(a=0, elem=elems; a<totorigface; a++, elem++)
		elem->curchild= 0;

	return newtot;
}

int psys_render_simplify_params(ParticleSystem *psys, ChildParticle *cpa, float *params)
{
	ParticleRenderData *data;
	ParticleRenderElem *elem;
	float x, w, scale, alpha, lambda, t, scalemin, scalemax;
	int b;

	if(!(psys->renderdata && (psys->part->simplify_flag & PART_SIMPLIFY_ENABLE)))
		return 0;
	
	data= psys->renderdata;
	if(!data->dosimplify)
		return 0;
	
	b= (data->origindex)? data->origindex[cpa->num]: cpa->num;
	if(b == -1)
		return 0;

	elem= &data->elems[b];

	lambda= elem->lambda;
	t= elem->t;
	scalemin= elem->scalemin;
	scalemax= elem->scalemax;

	if(!elem->reduce) {
		scale= scalemin;
		alpha= 1.0f;
	}
	else {
		x= (elem->curchild+0.5f)/elem->totchild;
		if(x < lambda-t) {
			scale= scalemax;
			alpha= 1.0f;
		}
		else if(x >= lambda+t) {
			scale= scalemin;
			alpha= 0.0f;
		}
		else {
			w= (lambda+t - x)/(2.0f*t);
			scale= scalemin + (scalemax - scalemin)*w;
			alpha= w;
		}
	}

	params[0]= scale;
	params[1]= alpha;

	elem->curchild++;

	return 1;
}

/************************************************/
/*			Interpolation						*/
/************************************************/
static float interpolate_particle_value(float v1, float v2, float v3, float v4, float *w, int four)
{
	float value;

	value= w[0]*v1 + w[1]*v2 + w[2]*v3;
	if(four)
		value += w[3]*v4;

	CLAMP(value, 0.f, 1.f);
	
	return value;
}

void psys_interpolate_particle(short type, ParticleKey keys[4], float dt, ParticleKey *result, int velocity)
{
	float t[4];

	if(type<0) {
		interp_cubic_v3( result->co, result->vel,keys[1].co, keys[1].vel, keys[2].co, keys[2].vel, dt);
	}
	else {
		key_curve_position_weights(dt, t, type);

		interp_v3_v3v3v3v3(result->co, keys[0].co, keys[1].co, keys[2].co, keys[3].co, t);

		if(velocity){
			float temp[3];

			if(dt>0.999f){
				key_curve_position_weights(dt-0.001f, t, type);
				interp_v3_v3v3v3v3(temp, keys[0].co, keys[1].co, keys[2].co, keys[3].co, t);
				VECSUB(result->vel, result->co, temp);
			}
			else{
				key_curve_position_weights(dt+0.001f, t, type);
				interp_v3_v3v3v3v3(temp, keys[0].co, keys[1].co, keys[2].co, keys[3].co, t);
				VECSUB(result->vel, temp, result->co);
			}
		}
	}
}



typedef struct ParticleInterpolationData {
	HairKey *hkey[2];

	DerivedMesh *dm;
	MVert *mvert[2];

	int keyed;
	ParticleKey *kkey[2];

	PointCache *cache;
	PTCacheMem *pm;

	PTCacheEditPoint *epoint;
	PTCacheEditKey *ekey[2];

	float birthtime, dietime;
	int bspline;
} ParticleInterpolationData;
/* Assumes pointcache->mem_cache exists, so for disk cached particles call psys_make_temp_pointcache() before use */
/* It uses ParticleInterpolationData->pm to store the current memory cache frame so it's thread safe. */
static void get_pointcache_keys_for_time(Object *UNUSED(ob), PointCache *cache, PTCacheMem **cur, int index, float t, ParticleKey *key1, ParticleKey *key2)
{
	static PTCacheMem *pm = NULL;
	int index1, index2;

	if(index < 0) { /* initialize */
		*cur = cache->mem_cache.first;

		if(*cur)
			*cur = (*cur)->next;
	}
	else {
		if(*cur) {
			while(*cur && (*cur)->next && (float)(*cur)->frame < t)
				*cur = (*cur)->next;

			pm = *cur;

			index2 = BKE_ptcache_mem_index_find(pm, index);
			index1 = BKE_ptcache_mem_index_find(pm->prev, index);

			BKE_ptcache_make_particle_key(key2, index2, pm->data, (float)pm->frame);
			if(index1 < 0)
				copy_particle_key(key1, key2, 1);
			else
				BKE_ptcache_make_particle_key(key1, index1, pm->prev->data, (float)pm->prev->frame);
		}
		else if(cache->mem_cache.first) {
			pm = cache->mem_cache.first;
			index2 = BKE_ptcache_mem_index_find(pm, index);
			BKE_ptcache_make_particle_key(key2, index2, pm->data, (float)pm->frame);
			copy_particle_key(key1, key2, 1);
		}
	}
}
static int get_pointcache_times_for_particle(PointCache *cache, int index, float *start, float *end)
{
	PTCacheMem *pm;
	int ret = 0;

	for(pm=cache->mem_cache.first; pm; pm=pm->next) {
		if(BKE_ptcache_mem_index_find(pm, index) >= 0) {
			*start = pm->frame;
			ret++;
			break;
		}
	}

	for(pm=cache->mem_cache.last; pm; pm=pm->prev) {
		if(BKE_ptcache_mem_index_find(pm, index) >= 0) {
			*end = pm->frame;
			ret++;
			break;
		}
	}

	return ret == 2;
}

float psys_get_dietime_from_cache(PointCache *cache, int index) {
	PTCacheMem *pm;
	int dietime = 10000000; /* some max value so that we can default to pa->time+lifetime */

	for(pm=cache->mem_cache.last; pm; pm=pm->prev) {
		if(BKE_ptcache_mem_index_find(pm, index) >= 0)
			return (float)pm->frame;
	}

	return (float)dietime;
}

static void init_particle_interpolation(Object *ob, ParticleSystem *psys, ParticleData *pa, ParticleInterpolationData *pind)
{

	if(pind->epoint) {
		PTCacheEditPoint *point = pind->epoint;

		pind->ekey[0] = point->keys;
		pind->ekey[1] = point->totkey > 1 ? point->keys + 1 : NULL;

		pind->birthtime = *(point->keys->time);
		pind->dietime = *((point->keys + point->totkey - 1)->time);
	}
	else if(pind->keyed) {
		ParticleKey *key = pa->keys;
		pind->kkey[0] = key;
		pind->kkey[1] = pa->totkey > 1 ? key + 1 : NULL;

		pind->birthtime = key->time;
		pind->dietime = (key + pa->totkey - 1)->time;
	}
	else if(pind->cache) {
		float start=0.0f, end=0.0f;
		get_pointcache_keys_for_time(ob, pind->cache, &pind->pm, -1, 0.0f, NULL, NULL);
		pind->birthtime = pa ? pa->time : pind->cache->startframe;
		pind->dietime = pa ? pa->dietime : pind->cache->endframe;

		if(get_pointcache_times_for_particle(pind->cache, pa - psys->particles, &start, &end)) {
			pind->birthtime = MAX2(pind->birthtime, start);
			pind->dietime = MIN2(pind->dietime, end);
		}
	}
	else {
		HairKey *key = pa->hair;
		pind->hkey[0] = key;
		pind->hkey[1] = key + 1;

		pind->birthtime = key->time;
		pind->dietime = (key + pa->totkey - 1)->time;

		if(pind->dm) {
			pind->mvert[0] = CDDM_get_vert(pind->dm, pa->hair_index);
			pind->mvert[1] = pind->mvert[0] + 1;
		}
	}
}
static void edit_to_particle(ParticleKey *key, PTCacheEditKey *ekey)
{
	VECCOPY(key->co, ekey->co);
	if(ekey->vel) {
		VECCOPY(key->vel, ekey->vel);
	}
	key->time = *(ekey->time);
}
static void hair_to_particle(ParticleKey *key, HairKey *hkey)
{
	VECCOPY(key->co, hkey->co);
	key->time = hkey->time;
}

static void mvert_to_particle(ParticleKey *key, MVert *mvert, HairKey *hkey)
{
	VECCOPY(key->co, mvert->co);
	key->time = hkey->time;
}

static void do_particle_interpolation(ParticleSystem *psys, int p, ParticleData *pa, float t, ParticleInterpolationData *pind, ParticleKey *result)
{
	PTCacheEditPoint *point = pind->epoint;
	ParticleKey keys[4];
	int point_vel = (point && point->keys->vel);
	float real_t, dfra, keytime, invdt = 1.f;

	/* billboards wont fill in all of these, so start cleared */
	memset(keys, 0, sizeof(keys));

	/* interpret timing and find keys */
	if(point) {
		if(result->time < 0.0f)
			real_t = -result->time;
		else
			real_t = *(pind->ekey[0]->time) + t * (*(pind->ekey[0][point->totkey-1].time) - *(pind->ekey[0]->time));

		while(*(pind->ekey[1]->time) < real_t)
			pind->ekey[1]++;

		pind->ekey[0] = pind->ekey[1] - 1;
	}
	else if(pind->keyed) {
		/* we have only one key, so let's use that */
		if(pind->kkey[1]==NULL) {
			copy_particle_key(result, pind->kkey[0], 1);
			return;
		}

		if(result->time < 0.0f)
			real_t = -result->time;
		else
			real_t = pind->kkey[0]->time + t * (pind->kkey[0][pa->totkey-1].time - pind->kkey[0]->time);

		if(psys->part->phystype==PART_PHYS_KEYED && psys->flag & PSYS_KEYED_TIMING) {
			ParticleTarget *pt = psys->targets.first;

			pt=pt->next;

			while(pt && pa->time + pt->time < real_t)
				pt= pt->next;

			if(pt) {
				pt=pt->prev;

				if(pa->time + pt->time + pt->duration > real_t)
					real_t = pa->time + pt->time;
			}
			else
				real_t = pa->time + ((ParticleTarget*)psys->targets.last)->time;
		}

		CLAMP(real_t, pa->time, pa->dietime);

		while(pind->kkey[1]->time < real_t)
			pind->kkey[1]++;
		
		pind->kkey[0] = pind->kkey[1] - 1;
	}
	else if(pind->cache) {
		if(result->time < 0.0f) /* flag for time in frames */
			real_t = -result->time;
		else
			real_t = pa->time + t * (pa->dietime - pa->time);
	}
	else {
		if(result->time < 0.0f)
			real_t = -result->time;
		else
			real_t = pind->hkey[0]->time + t * (pind->hkey[0][pa->totkey-1].time - pind->hkey[0]->time);

		while(pind->hkey[1]->time < real_t) {
			pind->hkey[1]++;
			pind->mvert[1]++;
		}

		pind->hkey[0] = pind->hkey[1] - 1;
	}

	/* set actual interpolation keys */
	if(point) {
		edit_to_particle(keys + 1, pind->ekey[0]);
		edit_to_particle(keys + 2, pind->ekey[1]);
	}
	else if(pind->dm) {
		pind->mvert[0] = pind->mvert[1] - 1;
		mvert_to_particle(keys + 1, pind->mvert[0], pind->hkey[0]);
		mvert_to_particle(keys + 2, pind->mvert[1], pind->hkey[1]);
	}
	else if(pind->keyed) {
		memcpy(keys + 1, pind->kkey[0], sizeof(ParticleKey));
		memcpy(keys + 2, pind->kkey[1], sizeof(ParticleKey));
	}
	else if(pind->cache) {
		get_pointcache_keys_for_time(NULL, pind->cache, &pind->pm, p, real_t, keys+1, keys+2);
	}
	else {
		hair_to_particle(keys + 1, pind->hkey[0]);
		hair_to_particle(keys + 2, pind->hkey[1]);
	}

	/* set secondary interpolation keys for hair */
	if(!pind->keyed && !pind->cache && !point_vel) {
		if(point) {
			if(pind->ekey[0] != point->keys)
				edit_to_particle(keys, pind->ekey[0] - 1);
			else
				edit_to_particle(keys, pind->ekey[0]);
		}
		else if(pind->dm) {
			if(pind->hkey[0] != pa->hair)
				mvert_to_particle(keys, pind->mvert[0] - 1, pind->hkey[0] - 1);
			else
				mvert_to_particle(keys, pind->mvert[0], pind->hkey[0]);
		}
		else {
			if(pind->hkey[0] != pa->hair)
				hair_to_particle(keys, pind->hkey[0] - 1);
			else
				hair_to_particle(keys, pind->hkey[0]);
		}

		if(point) {
			if(pind->ekey[1] != point->keys + point->totkey - 1)
				edit_to_particle(keys + 3, pind->ekey[1] + 1);
			else
				edit_to_particle(keys + 3, pind->ekey[1]);
		}
		else if(pind->dm) {
			if(pind->hkey[1] != pa->hair + pa->totkey - 1)
				mvert_to_particle(keys + 3, pind->mvert[1] + 1, pind->hkey[1] + 1);
			else
				mvert_to_particle(keys + 3, pind->mvert[1], pind->hkey[1]);
		}
		else {
			if(pind->hkey[1] != pa->hair + pa->totkey - 1)
				hair_to_particle(keys + 3, pind->hkey[1] + 1);
			else
				hair_to_particle(keys + 3, pind->hkey[1]);
		}
	}

	dfra = keys[2].time - keys[1].time;
	keytime = (real_t - keys[1].time) / dfra;

	/* convert velocity to timestep size */
	if(pind->keyed || pind->cache || point_vel){
		invdt = dfra * 0.04f * (psys ? psys->part->timetweak : 1.f);
		mul_v3_fl(keys[1].vel, invdt);
		mul_v3_fl(keys[2].vel, invdt);
		interp_qt_qtqt(result->rot,keys[1].rot,keys[2].rot,keytime);
	}

	/* now we should have in chronologiacl order k1<=k2<=t<=k3<=k4 with keytime between [0,1]->[k2,k3] (k1 & k4 used for cardinal & bspline interpolation)*/
	psys_interpolate_particle((pind->keyed || pind->cache || point_vel) ? -1 /* signal for cubic interpolation */
		: (pind->bspline ? KEY_BSPLINE : KEY_CARDINAL)
		,keys, keytime, result, 1);

	/* the velocity needs to be converted back from cubic interpolation */
	if(pind->keyed || pind->cache || point_vel)
		mul_v3_fl(result->vel, 1.f/invdt);
}
/************************************************/
/*			Particles on a dm					*/
/************************************************/
/* interpolate a location on a face based on face coordinates */
void psys_interpolate_face(MVert *mvert, MFace *mface, MTFace *tface, float (*orcodata)[3], float *w, float *vec, float *nor, float *utan, float *vtan, float *orco,float *ornor){
	float *v1=0, *v2=0, *v3=0, *v4=0;
	float e1[3],e2[3],s1,s2,t1,t2;
	float *uv1, *uv2, *uv3, *uv4;
	float n1[3], n2[3], n3[3], n4[3];
	float tuv[4][2];
	float *o1, *o2, *o3, *o4;

	v1= mvert[mface->v1].co;
	v2= mvert[mface->v2].co;
	v3= mvert[mface->v3].co;

	normal_short_to_float_v3(n1, mvert[mface->v1].no);
	normal_short_to_float_v3(n2, mvert[mface->v2].no);
	normal_short_to_float_v3(n3, mvert[mface->v3].no);

	if(mface->v4) {
		v4= mvert[mface->v4].co;
		normal_short_to_float_v3(n4, mvert[mface->v4].no);
		
		interp_v3_v3v3v3v3(vec, v1, v2, v3, v4, w);

		if(nor){
			if(mface->flag & ME_SMOOTH)
				interp_v3_v3v3v3v3(nor, n1, n2, n3, n4, w);
			else
				normal_quad_v3(nor,v1,v2,v3,v4);
		}
	}
	else {
		interp_v3_v3v3v3(vec, v1, v2, v3, w);

		if(nor){
			if(mface->flag & ME_SMOOTH)
				interp_v3_v3v3v3(nor, n1, n2, n3, w);
			else
				normal_tri_v3(nor,v1,v2,v3);
		}
	}
	
	/* calculate tangent vectors */
	if(utan && vtan){
		if(tface){
			uv1= tface->uv[0];
			uv2= tface->uv[1];
			uv3= tface->uv[2];
			uv4= tface->uv[3];
		}
		else{
			uv1= tuv[0]; uv2= tuv[1]; uv3= tuv[2]; uv4= tuv[3];
			map_to_sphere( uv1, uv1+1,v1[0], v1[1], v1[2]);
			map_to_sphere( uv2, uv2+1,v2[0], v2[1], v2[2]);
			map_to_sphere( uv3, uv3+1,v3[0], v3[1], v3[2]);
			if(v4)
				map_to_sphere( uv4, uv4+1,v4[0], v4[1], v4[2]);
		}

		if(v4){
			s1= uv3[0] - uv1[0];
			s2= uv4[0] - uv1[0];

			t1= uv3[1] - uv1[1];
			t2= uv4[1] - uv1[1];

			sub_v3_v3v3(e1, v3, v1);
			sub_v3_v3v3(e2, v4, v1);
		}
		else{
			s1= uv2[0] - uv1[0];
			s2= uv3[0] - uv1[0];

			t1= uv2[1] - uv1[1];
			t2= uv3[1] - uv1[1];

			sub_v3_v3v3(e1, v2, v1);
			sub_v3_v3v3(e2, v3, v1);
		}

		vtan[0] = (s1*e2[0] - s2*e1[0]);
		vtan[1] = (s1*e2[1] - s2*e1[1]);
		vtan[2] = (s1*e2[2] - s2*e1[2]);

		utan[0] = (t1*e2[0] - t2*e1[0]);
		utan[1] = (t1*e2[1] - t2*e1[1]);
		utan[2] = (t1*e2[2] - t2*e1[2]);
	}

	if(orco) {
		if(orcodata) {
			o1= orcodata[mface->v1];
			o2= orcodata[mface->v2];
			o3= orcodata[mface->v3];

			if(mface->v4) {
				o4= orcodata[mface->v4];

				interp_v3_v3v3v3v3(orco, o1, o2, o3, o4, w);

				if(ornor)
					normal_quad_v3( ornor,o1, o2, o3, o4);
			}
			else {
				interp_v3_v3v3v3(orco, o1, o2, o3, w);

				if(ornor)
					normal_tri_v3( ornor,o1, o2, o3);
			}
		}
		else {
			VECCOPY(orco, vec);
			if(ornor && nor)
				VECCOPY(ornor, nor);
		}
	}
}
void psys_interpolate_uvs(MTFace *tface, int quad, float *w, float *uvco)
{
	float v10= tface->uv[0][0];
	float v11= tface->uv[0][1];
	float v20= tface->uv[1][0];
	float v21= tface->uv[1][1];
	float v30= tface->uv[2][0];
	float v31= tface->uv[2][1];
	float v40,v41;

	if(quad) {
		v40= tface->uv[3][0];
		v41= tface->uv[3][1];

		uvco[0]= w[0]*v10 + w[1]*v20 + w[2]*v30 + w[3]*v40;
		uvco[1]= w[0]*v11 + w[1]*v21 + w[2]*v31 + w[3]*v41;
	}
	else {
		uvco[0]= w[0]*v10 + w[1]*v20 + w[2]*v30;
		uvco[1]= w[0]*v11 + w[1]*v21 + w[2]*v31;
	}
}

void psys_interpolate_mcol(MCol *mcol, int quad, float *w, MCol *mc)
{
	char *cp, *cp1, *cp2, *cp3, *cp4;

	cp= (char *)mc;
	cp1= (char *)&mcol[0];
	cp2= (char *)&mcol[1];
	cp3= (char *)&mcol[2];
	
	if(quad) {
		cp4= (char *)&mcol[3];

		cp[0]= (int)(w[0]*cp1[0] + w[1]*cp2[0] + w[2]*cp3[0] + w[3]*cp4[0]);
		cp[1]= (int)(w[0]*cp1[1] + w[1]*cp2[1] + w[2]*cp3[1] + w[3]*cp4[1]);
		cp[2]= (int)(w[0]*cp1[2] + w[1]*cp2[2] + w[2]*cp3[2] + w[3]*cp4[2]);
		cp[3]= (int)(w[0]*cp1[3] + w[1]*cp2[3] + w[2]*cp3[3] + w[3]*cp4[3]);
	}
	else {
		cp[0]= (int)(w[0]*cp1[0] + w[1]*cp2[0] + w[2]*cp3[0]);
		cp[1]= (int)(w[0]*cp1[1] + w[1]*cp2[1] + w[2]*cp3[1]);
		cp[2]= (int)(w[0]*cp1[2] + w[1]*cp2[2] + w[2]*cp3[2]);
		cp[3]= (int)(w[0]*cp1[3] + w[1]*cp2[3] + w[2]*cp3[3]);
	}
}

static float psys_interpolate_value_from_verts(DerivedMesh *dm, short from, int index, float *fw, float *values)
{
	if(values==0 || index==-1)
		return 0.0;

	switch(from){
		case PART_FROM_VERT:
			return values[index];
		case PART_FROM_FACE:
		case PART_FROM_VOLUME:
		{
			MFace *mf=dm->getFaceData(dm,index,CD_MFACE);
			return interpolate_particle_value(values[mf->v1],values[mf->v2],values[mf->v3],values[mf->v4],fw,mf->v4);
		}
			
	}
	return 0.0;
}

/* conversion of pa->fw to origspace layer coordinates */
static void psys_w_to_origspace(float *w, float *uv)
{
	uv[0]= w[1] + w[2];
	uv[1]= w[2] + w[3];
}

/* conversion of pa->fw to weights in face from origspace */
static void psys_origspace_to_w(OrigSpaceFace *osface, int quad, float *w, float *neww)
{
	float v[4][3], co[3];

	v[0][0]= osface->uv[0][0]; v[0][1]= osface->uv[0][1]; v[0][2]= 0.0f;
	v[1][0]= osface->uv[1][0]; v[1][1]= osface->uv[1][1]; v[1][2]= 0.0f;
	v[2][0]= osface->uv[2][0]; v[2][1]= osface->uv[2][1]; v[2][2]= 0.0f;

	psys_w_to_origspace(w, co);
	co[2]= 0.0f;
	
	if(quad) {
		v[3][0]= osface->uv[3][0]; v[3][1]= osface->uv[3][1]; v[3][2]= 0.0f;
		interp_weights_poly_v3( neww,v, 4, co);
	}
	else {
		interp_weights_poly_v3( neww,v, 3, co);
		neww[3]= 0.0f;
	}
}

/* find the derived mesh face for a particle, set the mf passed. this is slow
 * and can be optimized but only for many lookups. returns the face index. */
int psys_particle_dm_face_lookup(Object *ob, DerivedMesh *dm, int index, float *fw, struct LinkNode *node)
{
	Mesh *me= (Mesh*)ob->data;
	MFace *mface;
	OrigSpaceFace *osface;
	int *origindex;
	int quad, findex, totface;
	float uv[2], (*faceuv)[2];

	mface = dm->getFaceDataArray(dm, CD_MFACE);
	origindex = dm->getFaceDataArray(dm, CD_ORIGINDEX);
	osface = dm->getFaceDataArray(dm, CD_ORIGSPACE);

	totface = dm->getNumFaces(dm);
	
	if(osface==NULL || origindex==NULL) {
		/* Assume we dont need osface data */
		if (index <totface) {
			//printf("\tNO CD_ORIGSPACE, assuming not needed\n");
			return index;
		} else {
			printf("\tNO CD_ORIGSPACE, error out of range\n");
			return DMCACHE_NOTFOUND;
		}
	}
	else if(index >= me->totface)
		return DMCACHE_NOTFOUND; /* index not in the original mesh */

	psys_w_to_origspace(fw, uv);
	
	if(node) { /* we have a linked list of faces that we use, faster! */
		for(;node; node=node->next) {
			findex= GET_INT_FROM_POINTER(node->link);
			faceuv= osface[findex].uv;
			quad= mface[findex].v4;

			/* check that this intersects - Its possible this misses :/ -
			 * could also check its not between */
			if(quad) {
				if(isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3]))
					return findex;
			}
			else if(isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2]))
				return findex;
		}
	}
	else { /* if we have no node, try every face */
		for(findex=0; findex<totface; findex++) {
			if(origindex[findex] == index) {
				faceuv= osface[findex].uv;
				quad= mface[findex].v4;

				/* check that this intersects - Its possible this misses :/ -
				 * could also check its not between */
				if(quad) {
					if(isect_point_quad_v2(uv, faceuv[0], faceuv[1], faceuv[2], faceuv[3]))
						return findex;
				}
				else if(isect_point_tri_v2(uv, faceuv[0], faceuv[1], faceuv[2]))
					return findex;
			}
		}
	}

	return DMCACHE_NOTFOUND;
}

static int psys_map_index_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache, float *fw, float UNUSED(foffset), int *mapindex, float *mapfw)
{
	if(index < 0)
		return 0;

	if (dm->deformedOnly || index_dmcache == DMCACHE_ISCHILD) {
		/* for meshes that are either only defined or for child particles, the
		 * index and fw do not require any mapping, so we can directly use it */
		if(from == PART_FROM_VERT) {
			if(index >= dm->getNumVerts(dm))
				return 0;

			*mapindex = index;
		}
		else  { /* FROM_FACE/FROM_VOLUME */
			if(index >= dm->getNumFaces(dm))
				return 0;

			*mapindex = index;
			QUATCOPY(mapfw, fw);
		}
	} else {
		/* for other meshes that have been modified, we try to map the particle
		 * to their new location, which means a different index, and for faces
		 * also a new face interpolation weights */
		if(from == PART_FROM_VERT) {
			if (index_dmcache == DMCACHE_NOTFOUND || index_dmcache > dm->getNumVerts(dm))
				return 0;

			*mapindex = index_dmcache;
		}
		else  { /* FROM_FACE/FROM_VOLUME */
			/* find a face on the derived mesh that uses this face */
			MFace *mface;
			OrigSpaceFace *osface;
			int i;

			i = index_dmcache;

			if(i== DMCACHE_NOTFOUND || i >= dm->getNumFaces(dm))
				return 0;

			*mapindex = i;

			/* modify the original weights to become
			 * weights for the derived mesh face */
			osface= dm->getFaceDataArray(dm, CD_ORIGSPACE);
			mface= dm->getFaceData(dm, i, CD_MFACE);

			if(osface == NULL)
				mapfw[0]= mapfw[1]= mapfw[2]= mapfw[3]= 0.0f;
			else
				psys_origspace_to_w(&osface[i], mface->v4, fw, mapfw);
		}
	}

	return 1;
}

/* interprets particle data to get a point on a mesh in object space */
void psys_particle_on_dm(DerivedMesh *dm, int from, int index, int index_dmcache, float *fw, float foffset, float *vec, float *nor, float *utan, float *vtan, float *orco, float *ornor)
{
	float tmpnor[3], mapfw[4];
	float (*orcodata)[3];
	int mapindex;

	if(!psys_map_index_on_dm(dm, from, index, index_dmcache, fw, foffset, &mapindex, mapfw)) {
		if(vec) { vec[0]=vec[1]=vec[2]=0.0; }
		if(nor) { nor[0]=nor[1]=0.0; nor[2]=1.0; }
		if(orco) { orco[0]=orco[1]=orco[2]=0.0; }
		if(ornor) { ornor[0]=ornor[1]=0.0; ornor[2]=1.0; }
		if(utan) { utan[0]=utan[1]=utan[2]=0.0; }
		if(vtan) { vtan[0]=vtan[1]=vtan[2]=0.0; }

		return;
	}

	orcodata= dm->getVertDataArray(dm, CD_ORCO);

	if(from == PART_FROM_VERT) {
		dm->getVertCo(dm,mapindex,vec);

		if(nor) {
			dm->getVertNo(dm,mapindex,nor);
			normalize_v3(nor);
		}

		if(orco)
			VECCOPY(orco, orcodata[mapindex])

		if(ornor) {
			dm->getVertNo(dm,mapindex,nor);
			normalize_v3(nor);
		}

		if(utan && vtan) {
			utan[0]= utan[1]= utan[2]= 0.0f;
			vtan[0]= vtan[1]= vtan[2]= 0.0f;
		}
	}
	else { /* PART_FROM_FACE / PART_FROM_VOLUME */
		MFace *mface;
		MTFace *mtface;
		MVert *mvert;

		mface=dm->getFaceData(dm,mapindex,CD_MFACE);
		mvert=dm->getVertDataArray(dm,CD_MVERT);
		mtface=CustomData_get_layer(&dm->faceData,CD_MTFACE);

		if(mtface)
			mtface += mapindex;

		if(from==PART_FROM_VOLUME) {
			psys_interpolate_face(mvert,mface,mtface,orcodata,mapfw,vec,tmpnor,utan,vtan,orco,ornor);
			if(nor)
				VECCOPY(nor,tmpnor);

			normalize_v3(tmpnor);
			mul_v3_fl(tmpnor,-foffset);
			VECADD(vec,vec,tmpnor);
		}
		else
			psys_interpolate_face(mvert,mface,mtface,orcodata,mapfw,vec,nor,utan,vtan,orco,ornor);
	}
}

float psys_particle_value_from_verts(DerivedMesh *dm, short from, ParticleData *pa, float *values)
{
	float mapfw[4];
	int mapindex;

	if(!psys_map_index_on_dm(dm, from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, &mapindex, mapfw))
		return 0.0f;
	
	return psys_interpolate_value_from_verts(dm, from, mapindex, mapfw, values);
}

ParticleSystemModifierData *psys_get_modifier(Object *ob, ParticleSystem *psys)
{
	ModifierData *md;
	ParticleSystemModifierData *psmd;

	for(md=ob->modifiers.first; md; md=md->next){
		if(md->type==eModifierType_ParticleSystem){
			psmd= (ParticleSystemModifierData*) md;
			if(psmd->psys==psys){
				return psmd;
			}
		}
	}
	return NULL;
}
/************************************************/
/*			Particles on a shape				*/
/************************************************/
/* ready for future use */
static void psys_particle_on_shape(int UNUSED(distr), int UNUSED(index), float *UNUSED(fuv), float *vec, float *nor, float *utan, float *vtan, float *orco, float *ornor)
{
	/* TODO */
	float zerovec[3]={0.0f,0.0f,0.0f};
	if(vec){
		VECCOPY(vec,zerovec);
	}
	if(nor){
		VECCOPY(nor,zerovec);
	}
	if(utan){
		VECCOPY(utan,zerovec);
	}
	if(vtan){
		VECCOPY(vtan,zerovec);
	}
	if(orco){
		VECCOPY(orco,zerovec);
	}
	if(ornor){
		VECCOPY(ornor,zerovec);
	}
}
/************************************************/
/*			Particles on emitter				*/
/************************************************/
void psys_particle_on_emitter(ParticleSystemModifierData *psmd, int from, int index, int index_dmcache, float *fuv, float foffset, float *vec, float *nor, float *utan, float *vtan, float *orco, float *ornor){
	if(psmd){
		if(psmd->psys->part->distr==PART_DISTR_GRID && psmd->psys->part->from != PART_FROM_VERT){
			if(vec)
				copy_v3_v3(vec,fuv);

			if(orco)
				copy_v3_v3(orco, fuv);
			return;
		}
		/* we cant use the num_dmcache */
		psys_particle_on_dm(psmd->dm,from,index,index_dmcache,fuv,foffset,vec,nor,utan,vtan,orco,ornor);
	}
	else
		psys_particle_on_shape(from,index,fuv,vec,nor,utan,vtan,orco,ornor);

}
/************************************************/
/*			Path Cache							*/
/************************************************/
static float vert_weight(MDeformVert *dvert, int group)
{
	MDeformWeight *dw;
	int i;
	
	if(dvert) {
		dw= dvert->dw;
		for(i= dvert->totweight; i>0; i--, dw++) {
			if(dw->def_nr == group) return dw->weight;
			if(i==1) break; /*otherwise dw will point to somewhere it shouldn't*/
		}
	}
	return 0.0;
}

static void do_kink(ParticleKey *state, ParticleKey *par, float *par_rot, float time, float freq, float shape, float amplitude, float flat, short type, short axis, float obmat[][4], int smooth_start)
{
	float kink[3]={1.f,0.f,0.f}, par_vec[3], q1[4]={1.f,0.f,0.f,0.f};
	float t, dt=1.f, result[3];

	if(par == NULL || type == PART_KINK_NO)
		return;

	CLAMP(time, 0.f, 1.f);

	if(shape!=0.0f && type!=PART_KINK_BRAID) {
		if(shape<0.0f)
			time= (float)pow(time, 1.f+shape);
		else
			time= (float)pow(time, 1.f/(1.f-shape));
	}

	t = time * freq *(float)M_PI;
	
	if(smooth_start) {
		dt = fabs(t);
		/* smooth the beginning of kink */
		CLAMP(dt, 0.f, (float)M_PI);
		dt = sin(dt/2.f);
	}

	if(type != PART_KINK_RADIAL) {
		float temp[3];

		kink[axis]=1.f;

		if(obmat)
			mul_mat3_m4_v3(obmat, kink);
		
		if(par_rot)
			mul_qt_v3(par_rot, kink);

		/* make sure kink is normal to strand */
		project_v3_v3v3(temp, kink, par->vel);
		sub_v3_v3(kink, temp);
		normalize_v3(kink);
	}

	copy_v3_v3(result, state->co);
	sub_v3_v3v3(par_vec, par->co, state->co);

	switch(type) {
	case PART_KINK_CURL:
	{
		mul_v3_fl(par_vec, -1.f);

		if(flat > 0.f) {
			float proj[3];
			project_v3_v3v3(proj, par_vec, par->vel);
			madd_v3_v3fl(par_vec, proj, -flat);

			project_v3_v3v3(proj, par_vec, kink);
			madd_v3_v3fl(par_vec, proj, -flat);
		}

		axis_angle_to_quat(q1, kink, (float)M_PI/2.f);

		mul_qt_v3(q1, par_vec);

		madd_v3_v3fl(par_vec, kink, amplitude);

		/* rotate kink vector around strand tangent */
		if(t!=0.f) {
			axis_angle_to_quat(q1, par->vel, t);
			mul_qt_v3(q1, par_vec);
		}

		add_v3_v3v3(result, par->co, par_vec);
		break;
	}
	case PART_KINK_RADIAL:
	{
		if(flat > 0.f) {
			float proj[3];
			/* flatten along strand */
			project_v3_v3v3(proj, par_vec, par->vel);
			madd_v3_v3fl(result, proj, flat);
		}

		madd_v3_v3fl(result, par_vec, -amplitude*(float)sin(t));
		break;
	}
	case PART_KINK_WAVE:
	{
		madd_v3_v3fl(result, kink, amplitude*(float)sin(t));

		if(flat > 0.f) {
			float proj[3];
			/* flatten along wave */
			project_v3_v3v3(proj, par_vec, kink);
			madd_v3_v3fl(result, proj, flat);

			/* flatten along strand */
			project_v3_v3v3(proj, par_vec, par->vel);
			madd_v3_v3fl(result, proj, flat);
		}
		break;
	}
	case PART_KINK_BRAID:
	{
		float y_vec[3]={0.f,1.f,0.f};
		float z_vec[3]={0.f,0.f,1.f};
		float vec_one[3], state_co[3];
		float inp_y, inp_z, length;

		if(par_rot) {
			mul_qt_v3(par_rot, y_vec);
			mul_qt_v3(par_rot, z_vec);
		}
		
		mul_v3_fl(par_vec, -1.f);
		normalize_v3_v3(vec_one, par_vec);

		inp_y=dot_v3v3(y_vec, vec_one);
		inp_z=dot_v3v3(z_vec, vec_one);

		if(inp_y > 0.5f){
			copy_v3_v3(state_co, y_vec);

			mul_v3_fl(y_vec, amplitude*(float)cos(t));
			mul_v3_fl(z_vec, amplitude/2.f*(float)sin(2.f*t));
		}
		else if(inp_z > 0.0f){
			mul_v3_v3fl(state_co, z_vec, (float)sin((float)M_PI/3.f));
			VECADDFAC(state_co,state_co,y_vec,-0.5f);

			mul_v3_fl(y_vec, -amplitude * (float)cos(t + (float)M_PI/3.f));
			mul_v3_fl(z_vec, amplitude/2.f * (float)cos(2.f*t + (float)M_PI/6.f));
		}
		else{
			mul_v3_v3fl(state_co, z_vec, -(float)sin((float)M_PI/3.f));
			madd_v3_v3fl(state_co, y_vec, -0.5f);

			mul_v3_fl(y_vec, amplitude * (float)-sin(t + (float)M_PI/6.f));
			mul_v3_fl(z_vec, amplitude/2.f * (float)-sin(2.f*t + (float)M_PI/3.f));
		}

		mul_v3_fl(state_co, amplitude);
		add_v3_v3(state_co, par->co);
		sub_v3_v3v3(par_vec, state->co, state_co);

		length = normalize_v3(par_vec);
		mul_v3_fl(par_vec, MIN2(length, amplitude/2.f));

		add_v3_v3v3(state_co, par->co, y_vec);
		add_v3_v3(state_co, z_vec);
		add_v3_v3(state_co, par_vec);

		shape = 2.f*(float)M_PI * (1.f+shape);

		if(t<shape){
			shape = t/shape;
			shape = (float)sqrt((double)shape);
			interp_v3_v3v3(result, result, state_co, shape);
		}
		else{
			copy_v3_v3(result, state_co);
		}
		break;
	}
	}

	/* blend the start of the kink */
	if(dt < 1.f)
		interp_v3_v3v3(state->co, state->co, result, dt);
	else
		copy_v3_v3(state->co, result);
}

static float do_clump(ParticleKey *state, ParticleKey *par, float time, float clumpfac, float clumppow, float pa_clump)
{
	float clump = 0.f;

	if(par && clumpfac!=0.0f){
		float cpow;

		if(clumppow < 0.0f)
			cpow=1.0f+clumppow;
		else
			cpow=1.0f+9.0f*clumppow;

		if(clumpfac < 0.0f) /* clump roots instead of tips */
			clump = -clumpfac*pa_clump*(float)pow(1.0-(double)time,(double)cpow);
		else
			clump = clumpfac*pa_clump*(float)pow((double)time,(double)cpow);

		interp_v3_v3v3(state->co,state->co,par->co,clump);
	}

	return clump;
}
void precalc_guides(ParticleSimulationData *sim, ListBase *effectors)
{
	EffectedPoint point;
	ParticleKey state;
	EffectorData efd;
	EffectorCache *eff;
	ParticleSystem *psys = sim->psys;
	EffectorWeights *weights = sim->psys->part->effector_weights;
	GuideEffectorData *data;
	PARTICLE_P;

	if(!effectors)
		return;

	LOOP_PARTICLES {
		psys_particle_on_emitter(sim->psmd,sim->psys->part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,state.co,0,0,0,0,0);
		
		mul_m4_v3(sim->ob->obmat, state.co);
		mul_mat3_m4_v3(sim->ob->obmat, state.vel);
		
		pd_point_from_particle(sim, pa, &state, &point);

		for(eff = effectors->first; eff; eff=eff->next) {
			if(eff->pd->forcefield != PFIELD_GUIDE)
				continue;

			if(!eff->guide_data)
				eff->guide_data = MEM_callocN(sizeof(GuideEffectorData)*psys->totpart, "GuideEffectorData");

			data = eff->guide_data + p;

			VECSUB(efd.vec_to_point, state.co, eff->guide_loc);
			VECCOPY(efd.nor, eff->guide_dir);
			efd.distance = len_v3(efd.vec_to_point);

			VECCOPY(data->vec_to_point, efd.vec_to_point);
			data->strength = effector_falloff(eff, &efd, &point, weights);
		}
	}
}
int do_guides(ListBase *effectors, ParticleKey *state, int index, float time)
{
	EffectorCache *eff;
	PartDeflect *pd;
	Curve *cu;
	ParticleKey key, par;
	GuideEffectorData *data;

	float effect[3] = {0.0f, 0.0f, 0.0f}, veffect[3] = {0.0f, 0.0f, 0.0f};
	float guidevec[4], guidedir[3], rot2[4], temp[3];
	float guidetime, radius, weight, angle, totstrength = 0.0f;
	float vec_to_point[3];

	if(effectors) for(eff = effectors->first; eff; eff=eff->next) {
		pd = eff->pd;

		if(pd->forcefield != PFIELD_GUIDE)
			continue;

		data = eff->guide_data + index;

		if(data->strength <= 0.0f)
			continue;

		guidetime = time / (1.0f - pd->free_end);

		if(guidetime>1.0f)
			continue;

		cu = (Curve*)eff->ob->data;

		if(pd->flag & PFIELD_GUIDE_PATH_ADD) {
			if(where_on_path(eff->ob, data->strength * guidetime, guidevec, guidedir, NULL, &radius, &weight)==0)
				return 0;
		}
		else {
			if(where_on_path(eff->ob, guidetime, guidevec, guidedir, NULL, &radius, &weight)==0)
				return 0;
		}

		mul_m4_v3(eff->ob->obmat, guidevec);
		mul_mat3_m4_v3(eff->ob->obmat, guidedir);

		normalize_v3(guidedir);

		VECCOPY(vec_to_point, data->vec_to_point);

		if(guidetime != 0.0f) {
			/* curve direction */
			cross_v3_v3v3(temp, eff->guide_dir, guidedir);
			angle = dot_v3v3(eff->guide_dir, guidedir)/(len_v3(eff->guide_dir));
			angle = saacos(angle);
			axis_angle_to_quat( rot2,temp, angle);
			mul_qt_v3(rot2, vec_to_point);

			/* curve tilt */
			axis_angle_to_quat( rot2,guidedir, guidevec[3] - eff->guide_loc[3]);
			mul_qt_v3(rot2, vec_to_point);
		}

		/* curve taper */
		if(cu->taperobj)
			mul_v3_fl(vec_to_point, calc_taper(eff->scene, cu->taperobj, (int)(data->strength*guidetime*100.0f), 100));

		else{ /* curve size*/
			if(cu->flag & CU_PATH_RADIUS) {
				mul_v3_fl(vec_to_point, radius);
			}
		}
		par.co[0] = par.co[1] = par.co[2] = 0.0f;
		VECCOPY(key.co, vec_to_point);
		do_kink(&key, &par, 0, guidetime, pd->kink_freq, pd->kink_shape, pd->kink_amp, 0.f, pd->kink, pd->kink_axis, 0, 0);
		do_clump(&key, &par, guidetime, pd->clump_fac, pd->clump_pow, 1.0f);
		VECCOPY(vec_to_point, key.co);

		VECADD(vec_to_point, vec_to_point, guidevec);

		//VECSUB(pa_loc,pa_loc,pa_zero);
		VECADDFAC(effect, effect, vec_to_point, data->strength);
		VECADDFAC(veffect, veffect, guidedir, data->strength);
		totstrength += data->strength;

		if(pd->flag & PFIELD_GUIDE_PATH_WEIGHT)
			totstrength *= weight;
	}

	if(totstrength != 0.0f){
		if(totstrength > 1.0f)
			mul_v3_fl(effect, 1.0f / totstrength);
		CLAMP(totstrength, 0.0f, 1.0f);
		//VECADD(effect,effect,pa_zero);
		interp_v3_v3v3(state->co, state->co, effect, totstrength);

		normalize_v3(veffect);
		mul_v3_fl(veffect, len_v3(state->vel));
		VECCOPY(state->vel, veffect);
		return 1;
	}
	return 0;
}
static void do_rough(float *loc, float mat[4][4], float t, float fac, float size, float thres, ParticleKey *state)
{
	float rough[3];
	float rco[3];

	if(thres != 0.0f)
		if((float)fabs((float)(-1.5f+loc[0]+loc[1]+loc[2]))<1.5f*thres) return;

	VECCOPY(rco,loc);
	mul_v3_fl(rco,t);
	rough[0]=-1.0f+2.0f*BLI_gTurbulence(size, rco[0], rco[1], rco[2], 2,0,2);
	rough[1]=-1.0f+2.0f*BLI_gTurbulence(size, rco[1], rco[2], rco[0], 2,0,2);
	rough[2]=-1.0f+2.0f*BLI_gTurbulence(size, rco[2], rco[0], rco[1], 2,0,2);

	VECADDFAC(state->co,state->co,mat[0],fac*rough[0]);
	VECADDFAC(state->co,state->co,mat[1],fac*rough[1]);
	VECADDFAC(state->co,state->co,mat[2],fac*rough[2]);
}
static void do_rough_end(float *loc, float mat[4][4], float t, float fac, float shape, ParticleKey *state)
{
	float rough[2];
	float roughfac;

	roughfac=fac*(float)pow((double)t,shape);
	copy_v2_v2(rough,loc);
	rough[0]=-1.0f+2.0f*rough[0];
	rough[1]=-1.0f+2.0f*rough[1];
	mul_v2_fl(rough,roughfac);

	VECADDFAC(state->co,state->co,mat[0],rough[0]);
	VECADDFAC(state->co,state->co,mat[1],rough[1]);
}
static void do_path_effectors(ParticleSimulationData *sim, int i, ParticleCacheKey *ca, int k, int steps, float *UNUSED(rootco), float effector, float UNUSED(dfra), float UNUSED(cfra), float *length, float *vec)
{
	float force[3] = {0.0f,0.0f,0.0f};
	ParticleKey eff_key;
	EffectedPoint epoint;

	/* Don't apply effectors for dynamic hair, otherwise the effectors don't get applied twice. */
	if(sim->psys->flag & PSYS_HAIR_DYNAMICS)
		return;

	VECCOPY(eff_key.co,(ca-1)->co);
	VECCOPY(eff_key.vel,(ca-1)->vel);
	QUATCOPY(eff_key.rot,(ca-1)->rot);

	pd_point_from_particle(sim, sim->psys->particles+i, &eff_key, &epoint);
	pdDoEffectors(sim->psys->effectors, sim->colliders, sim->psys->part->effector_weights, &epoint, force, NULL);

	mul_v3_fl(force, effector*powf((float)k / (float)steps, 100.0f * sim->psys->part->eff_hair) / (float)steps);

	add_v3_v3(force, vec);

	normalize_v3(force);

	if(k < steps)
		sub_v3_v3v3(vec, (ca+1)->co, ca->co);

	madd_v3_v3v3fl(ca->co, (ca-1)->co, force, *length);

	if(k < steps)
		*length = len_v3(vec);
}
static int check_path_length(int k, ParticleCacheKey *keys, ParticleCacheKey *state, float max_length, float *cur_length, float length, float *dvec)
{
	if(*cur_length + length > max_length){
		mul_v3_fl(dvec, (max_length - *cur_length) / length);
		VECADD(state->co, (state - 1)->co, dvec);
		keys->steps = k;
		/* something over the maximum step value */
		return k=100000;
	}
	else {
		*cur_length+=length;
		return k;
	}
}
static void offset_child(ChildParticle *cpa, ParticleKey *par, float *par_rot, ParticleKey *child, float flat, float radius)
{
	copy_v3_v3(child->co, cpa->fuv);
	mul_v3_fl(child->co, radius);

	child->co[0]*=flat;

	copy_v3_v3(child->vel, par->vel);

	if(par_rot) {
		mul_qt_v3(par_rot, child->co);
		copy_qt_qt(child->rot, par_rot);
	}
	else
		unit_qt(child->rot);

	add_v3_v3(child->co, par->co);
}
float *psys_cache_vgroup(DerivedMesh *dm, ParticleSystem *psys, int vgroup)
{
	float *vg=0;

	if(vgroup < 0) {
		/* hair dynamics pinning vgroup */

	}
	else if(psys->vgroup[vgroup]){
		MDeformVert *dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
		if(dvert){
			int totvert=dm->getNumVerts(dm), i;
			vg=MEM_callocN(sizeof(float)*totvert, "vg_cache");
			if(psys->vg_neg&(1<<vgroup)){
				for(i=0; i<totvert; i++)
					vg[i]=1.0f-vert_weight(dvert+i,psys->vgroup[vgroup]-1);
			}
			else{
				for(i=0; i<totvert; i++)
					vg[i]=vert_weight(dvert+i,psys->vgroup[vgroup]-1);
			}
		}
	}
	return vg;
}
void psys_find_parents(ParticleSimulationData *sim)
{
	ParticleSettings *part=sim->psys->part;
	KDTree *tree;
	ChildParticle *cpa;
	int p, totparent,totchild=sim->psys->totchild;
	float co[3], orco[3];
	int from=PART_FROM_FACE;
	totparent=(int)(totchild*part->parents*0.3f);

	if(G.rendering && part->child_nbr && part->ren_child_nbr)
		totparent*=(float)part->child_nbr/(float)part->ren_child_nbr;

	tree=BLI_kdtree_new(totparent);

	for(p=0,cpa=sim->psys->child; p<totparent; p++,cpa++){
		psys_particle_on_emitter(sim->psmd,from,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,co,0,0,0,orco,0);
		BLI_kdtree_insert(tree, p, orco, NULL);
	}

	BLI_kdtree_balance(tree);

	for(; p<totchild; p++,cpa++){
		psys_particle_on_emitter(sim->psmd,from,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,co,0,0,0,orco,0);
		cpa->parent=BLI_kdtree_find_nearest(tree, orco, NULL, NULL);
	}

	BLI_kdtree_free(tree);
}

static void get_strand_normal(Material *ma, float *surfnor, float surfdist, float *nor)
{
	float cross[3], nstrand[3], vnor[3], blend;

	if(!((ma->mode & MA_STR_SURFDIFF) || (ma->strand_surfnor > 0.0f)))
		return;

	if(ma->mode & MA_STR_SURFDIFF) {
		cross_v3_v3v3(cross, surfnor, nor);
		cross_v3_v3v3(nstrand, nor, cross);

		blend= INPR(nstrand, surfnor);
		CLAMP(blend, 0.0f, 1.0f);

		interp_v3_v3v3(vnor, nstrand, surfnor, blend);
		normalize_v3(vnor);
	}
	else
		VECCOPY(vnor, nor)
	
	if(ma->strand_surfnor > 0.0f) {
		if(ma->strand_surfnor > surfdist) {
			blend= (ma->strand_surfnor - surfdist)/ma->strand_surfnor;
			interp_v3_v3v3(vnor, vnor, surfnor, blend);
			normalize_v3(vnor);
		}
	}

	VECCOPY(nor, vnor);
}

static int psys_threads_init_path(ParticleThread *threads, Scene *scene, float cfra, int editupdate)
{
	ParticleThreadContext *ctx= threads[0].ctx;
/*	Object *ob= ctx->sim.ob; */
	ParticleSystem *psys= ctx->sim.psys;
	ParticleSettings *part = psys->part;
/*	ParticleEditSettings *pset = &scene->toolsettings->particle; */
	int totparent=0, between=0;
	int steps = (int)pow(2.0, (double)part->draw_step);
	int totchild = psys->totchild;
	int i, seed, totthread= threads[0].tot;

	/*---start figuring out what is actually wanted---*/
	if(psys_in_edit_mode(scene, psys)) {
		ParticleEditSettings *pset = &scene->toolsettings->particle;

		if(psys->renderdata==0 && (psys->edit==NULL || pset->flag & PE_DRAW_PART)==0)
			totchild=0;

		steps = (int)pow(2.0, (double)pset->draw_step);
	}

	if(totchild && part->childtype==PART_CHILD_FACES){
		totparent=(int)(totchild*part->parents*0.3f);
		
		if(G.rendering && part->child_nbr && part->ren_child_nbr)
			totparent*=(float)part->child_nbr/(float)part->ren_child_nbr;

		/* part->parents could still be 0 so we can't test with totparent */
		between=1;
	}

	if(psys->renderdata)
		steps=(int)pow(2.0,(double)part->ren_step);
	else{
		totchild=(int)((float)totchild*(float)part->disp/100.0f);
		totparent=MIN2(totparent,totchild);
	}

	if(totchild==0) return 0;

	/* init random number generator */
	seed= 31415926 + ctx->sim.psys->seed;
	
	if(ctx->editupdate || totchild < 10000)
		totthread= 1;
	
	for(i=0; i<totthread; i++) {
		threads[i].rng_path= rng_new(seed);
		threads[i].tot= totthread;
	}

	/* fill context values */
	ctx->between= between;
	ctx->steps= steps;
	ctx->totchild= totchild;
	ctx->totparent= totparent;
	ctx->parent_pass= 0;
	ctx->cfra= cfra;
	ctx->editupdate= editupdate;

	psys->lattice = psys_get_lattice(&ctx->sim);

	/* cache all relevant vertex groups if they exist */
	ctx->vg_length = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_LENGTH);
	ctx->vg_clump = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_CLUMP);
	ctx->vg_kink = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_KINK);
	ctx->vg_rough1 = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_ROUGH1);
	ctx->vg_rough2 = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_ROUGH2);
	ctx->vg_roughe = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_ROUGHE);
	if(psys->part->flag & PART_CHILD_EFFECT)
		ctx->vg_effector = psys_cache_vgroup(ctx->dm,psys,PSYS_VG_EFFECTOR);

	/* set correct ipo timing */
#if 0 // XXX old animation system
	if(part->flag&PART_ABS_TIME && part->ipo){
		calc_ipo(part->ipo, cfra);
		execute_ipo((ID *)part, part->ipo);
	}
#endif // XXX old animation system

	return 1;
}

/* note: this function must be thread safe, except for branching! */
static void psys_thread_create_path(ParticleThread *thread, struct ChildParticle *cpa, ParticleCacheKey *child_keys, int i)
{
	ParticleThreadContext *ctx= thread->ctx;
	Object *ob= ctx->sim.ob;
	ParticleSystem *psys = ctx->sim.psys;
	ParticleSettings *part = psys->part;
	ParticleCacheKey **cache= psys->childcache;
	ParticleCacheKey **pcache= psys_in_edit_mode(ctx->sim.scene, psys) ? psys->edit->pathcache : psys->pathcache;
	ParticleCacheKey *child, *par = NULL, *key[4];
	ParticleTexture ptex;
	float *cpa_fuv=0, *par_rot=0, rot[4];
	float orco[3], ornor[3], hairmat[4][4], t, dvec[3], off1[4][3], off2[4][3];
	float length, max_length = 1.0f, cur_length = 0.0f;
	float eff_length, eff_vec[3], weight[4];
	int k, cpa_num;
	short cpa_from;

	if(!pcache)
		return;

	if(ctx->between){
		ParticleData *pa = psys->particles + cpa->pa[0];
		int w, needupdate;
		float foffset, wsum=0.f;
		float co[3];
		float p_min = part->parting_min;
		float p_max = part->parting_max;
		/* Virtual parents don't work nicely with parting. */
		float p_fac = part->parents > 0.f ? 0.f : part->parting_fac;

		if(ctx->editupdate) {
			needupdate= 0;
			w= 0;
			while(w<4 && cpa->pa[w]>=0) {
				if(psys->edit->points[cpa->pa[w]].flag & PEP_EDIT_RECALC) {
					needupdate= 1;
					break;
				}
				w++;
			}

			if(!needupdate)
				return;
			else
				memset(child_keys, 0, sizeof(*child_keys)*(ctx->steps+1));
		}

		/* get parent paths */
		for(w=0; w<4; w++) {
			if(cpa->pa[w] >= 0) {
				key[w] = pcache[cpa->pa[w]];
				weight[w] = cpa->w[w];
			}
			else {
				key[w] = pcache[0];
				weight[w] = 0.f;
			}
		}

		/* modify weights to create parting */
		if(p_fac > 0.f) {
			for(w=0; w<4; w++) {
				if(w && weight[w] > 0.f) {
					float d;
					if(part->flag & PART_CHILD_LONG_HAIR) {
						/* For long hair use tip distance/root distance as parting factor instead of root to tip angle. */
						float d1 = len_v3v3(key[0]->co, key[w]->co);
						float d2 = len_v3v3((key[0]+key[0]->steps-1)->co, (key[w]+key[w]->steps-1)->co);

						d = d1 > 0.f ? d2/d1 - 1.f : 10000.f;
					}
					else {
						float v1[3], v2[3];
						sub_v3_v3v3(v1, (key[0]+key[0]->steps-1)->co, key[0]->co);
						sub_v3_v3v3(v2, (key[w]+key[w]->steps-1)->co, key[w]->co);
						normalize_v3(v1);
						normalize_v3(v2);

						d = saacos(dot_v3v3(v1, v2)) * 180.0f/(float)M_PI;
					}

					if(p_max > p_min)
						d = (d - p_min)/(p_max - p_min);
					else
						d = (d - p_min) <= 0.f ? 0.f : 1.f;

					CLAMP(d, 0.f, 1.f);

					if(d > 0.f)
						weight[w] *= (1.f - d);
				}
				wsum += weight[w];
			}
			for(w=0; w<4; w++)
				weight[w] /= wsum;

			interp_v4_v4v4(weight, cpa->w, weight, p_fac);
		}

		/* get the original coordinates (orco) for texture usage */
		cpa_num = cpa->num;
		
		foffset = cpa->foffset;
		cpa_fuv = cpa->fuv;
		cpa_from = PART_FROM_FACE;

		psys_particle_on_emitter(ctx->sim.psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa->fuv,foffset,co,ornor,0,0,orco,0);

		mul_m4_v3(ob->obmat, co);

		for(w=0; w<4; w++)
			sub_v3_v3v3(off1[w], co, key[w]->co);

		psys_mat_hair_to_global(ob, ctx->sim.psmd->dm, psys->part->from, pa, hairmat);
	}
	else{
		ParticleData *pa = psys->particles + cpa->parent;
		float co[3];
		if(ctx->editupdate) {
			if(!(psys->edit->points[cpa->parent].flag & PEP_EDIT_RECALC))
				return;

			memset(child_keys, 0, sizeof(*child_keys)*(ctx->steps+1));
		}

		/* get the parent path */
		key[0] = pcache[cpa->parent];

		/* get the original coordinates (orco) for texture usage */
		cpa_from = part->from;
		cpa_num = pa->num;
		cpa_fuv = pa->fuv;

		psys_particle_on_emitter(ctx->sim.psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa_fuv,pa->foffset,co,ornor,0,0,orco,0);

		psys_mat_hair_to_global(ob, ctx->sim.psmd->dm, psys->part->from, pa, hairmat);
	}

	child_keys->steps = ctx->steps;

	/* get different child parameters from textures & vgroups */
	get_child_modifier_parameters(part, ctx, cpa, cpa_from, cpa_num, cpa_fuv, orco, &ptex);

	if(ptex.exist < PSYS_FRAND(i + 24)) {
		child_keys->steps = -1;
		return;
	}

	/* create the child path */
	for(k=0,child=child_keys; k<=ctx->steps; k++,child++){
		if(ctx->between){
			int w=0;

			zero_v3(child->co);
			zero_v3(child->vel);
			unit_qt(child->rot);

			for(w=0; w<4; w++) {
				copy_v3_v3(off2[w], off1[w]);

				if(part->flag & PART_CHILD_LONG_HAIR) {
					/* Use parent rotation (in addition to emission location) to determine child offset. */
					if(k)
						mul_qt_v3((key[w]+k)->rot, off2[w]);

					/* Fade the effect of rotation for even lengths in the end */
					project_v3_v3v3(dvec, off2[w], (key[w]+k)->vel);
					madd_v3_v3fl(off2[w], dvec, -(float)k/(float)ctx->steps);
				}

				add_v3_v3(off2[w], (key[w]+k)->co);
			}

			/* child position is the weighted sum of parent positions */
			interp_v3_v3v3v3v3(child->co, off2[0], off2[1], off2[2], off2[3], weight);
			interp_v3_v3v3v3v3(child->vel, (key[0]+k)->vel, (key[1]+k)->vel, (key[2]+k)->vel, (key[3]+k)->vel, weight);

			copy_qt_qt(child->rot, (key[0]+k)->rot);
		}
		else{
			if(k) {
				mul_qt_qtqt(rot, (key[0]+k)->rot, key[0]->rot);
				par_rot = rot;
			}
			else {
				par_rot = key[0]->rot;
			}
			/* offset the child from the parent position */
			offset_child(cpa, (ParticleKey*)(key[0]+k), par_rot, (ParticleKey*)child, part->childflat, part->childrad);
		}
	}

	/* apply effectors */
	if(part->flag & PART_CHILD_EFFECT) {
		for(k=0,child=child_keys; k<=ctx->steps; k++,child++) {
			if(k) {
				do_path_effectors(&ctx->sim, cpa->pa[0], child, k, ctx->steps, child_keys->co, ptex.effector, 0.0f, ctx->cfra, &eff_length, eff_vec);
			}
			else {
				sub_v3_v3v3(eff_vec, (child+1)->co, child->co);
				eff_length = len_v3(eff_vec);
			}
		}
	}

	for(k=0,child=child_keys; k<=ctx->steps; k++,child++){
		t = (float)k/(float)ctx->steps;

		if(ctx->totparent)
			/* this is now threadsafe, virtual parents are calculated before rest of children */
			par = (i >= ctx->totparent) ? cache[cpa->parent] : NULL;
		else if(cpa->parent >= 0)
			par = pcache[cpa->parent];

		if(par) {
			if(k) {
				mul_qt_qtqt(rot, (par+k)->rot, par->rot);
				par_rot = rot;
			}
			else {
				par_rot = par->rot;
			}
			par += k;
		}

		/* apply different deformations to the child path */
		do_child_modifiers(&ctx->sim, &ptex, (ParticleKey *)par, par_rot, cpa, orco, hairmat, (ParticleKey *)child, t);

		/* we have to correct velocity because of kink & clump */
		if(k>1){
			sub_v3_v3v3((child-1)->vel, child->co, (child-2)->co);
			mul_v3_fl((child-1)->vel, 0.5);

			if(ctx->ma && (part->draw_col == PART_DRAW_COL_MAT))
				get_strand_normal(ctx->ma, ornor, cur_length, (child-1)->vel);
		}

		if(k == ctx->steps)
			sub_v3_v3v3(child->vel, child->co, (child-1)->co);

		/* check if path needs to be cut before actual end of data points */
		if(k){
			sub_v3_v3v3(dvec, child->co, (child-1)->co);
			length = 1.0f/(float)ctx->steps;
			k = check_path_length(k, child_keys, child, max_length, &cur_length, length, dvec);
		}
		else{
			/* initialize length calculation */
			max_length = ptex.length;
			cur_length = 0.0f;
		}

		if(ctx->ma && (part->draw_col == PART_DRAW_COL_MAT)) {
			VECCOPY(child->col, &ctx->ma->r)
			get_strand_normal(ctx->ma, ornor, cur_length, child->vel);
		}
	}

	/* Hide virtual parents */
	if(i < ctx->totparent)
		child_keys->steps = -1;
}

static void *exec_child_path_cache(void *data)
{
	ParticleThread *thread= (ParticleThread*)data;
	ParticleThreadContext *ctx= thread->ctx;
	ParticleSystem *psys= ctx->sim.psys;
	ParticleCacheKey **cache= psys->childcache;
	ChildParticle *cpa;
	int i, totchild= ctx->totchild, first= 0;

	if(thread->tot > 1){
		first= ctx->parent_pass? 0 : ctx->totparent;
		totchild= ctx->parent_pass? ctx->totparent : ctx->totchild;
	}
	
	cpa= psys->child + first + thread->num;
	for(i=first+thread->num; i<totchild; i+=thread->tot, cpa+=thread->tot)
		psys_thread_create_path(thread, cpa, cache[i], i);

	return 0;
}

void psys_cache_child_paths(ParticleSimulationData *sim, float cfra, int editupdate)
{
	ParticleThread *pthreads;
	ParticleThreadContext *ctx;
	ListBase threads;
	int i, totchild, totparent, totthread;

	if(sim->psys->flag & PSYS_GLOBAL_HAIR)
		return;

	pthreads= psys_threads_create(sim);

	if(!psys_threads_init_path(pthreads, sim->scene, cfra, editupdate)) {
		psys_threads_free(pthreads);
		return;
	}

	ctx= pthreads[0].ctx;
	totchild= ctx->totchild;
	totparent= ctx->totparent;

	if(editupdate && sim->psys->childcache && totchild == sim->psys->totchildcache) {
		; /* just overwrite the existing cache */
	}
	else {
		/* clear out old and create new empty path cache */
		free_child_path_cache(sim->psys);
		sim->psys->childcache= psys_alloc_path_cache_buffers(&sim->psys->childcachebufs, totchild, ctx->steps+1);
		sim->psys->totchildcache = totchild;
	}

	totthread= pthreads[0].tot;

	if(totthread > 1) {

		/* make virtual child parents thread safe by calculating them first */
		if(totparent) {
			BLI_init_threads(&threads, exec_child_path_cache, totthread);
			
			for(i=0; i<totthread; i++) {
				pthreads[i].ctx->parent_pass = 1;
				BLI_insert_thread(&threads, &pthreads[i]);
			}

			BLI_end_threads(&threads);

			for(i=0; i<totthread; i++)
				pthreads[i].ctx->parent_pass = 0;
		}

		BLI_init_threads(&threads, exec_child_path_cache, totthread);

		for(i=0; i<totthread; i++)
			BLI_insert_thread(&threads, &pthreads[i]);

		BLI_end_threads(&threads);
	}
	else
		exec_child_path_cache(&pthreads[0]);

	psys_threads_free(pthreads);
}
/* figure out incremental rotations along path starting from unit quat */
static void cache_key_incremental_rotation(ParticleCacheKey *key0, ParticleCacheKey *key1, ParticleCacheKey *key2, float *prev_tangent, int i)
{
	float cosangle, angle, tangent[3], normal[3], q[4];

	switch(i) {
	case 0:
		/* start from second key */
		break;
	case 1:
		/* calculate initial tangent for incremental rotations */
		sub_v3_v3v3(prev_tangent, key0->co, key1->co);
		normalize_v3(prev_tangent);
		unit_qt(key1->rot);
		break;
	default:
		sub_v3_v3v3(tangent, key0->co, key1->co);
		normalize_v3(tangent);

		cosangle= dot_v3v3(tangent, prev_tangent);

		/* note we do the comparison on cosangle instead of
		* angle, since floating point accuracy makes it give
		* different results across platforms */
		if(cosangle > 0.999999f) {
			QUATCOPY(key1->rot, key2->rot);
		}
		else {
			angle= saacos(cosangle);
			cross_v3_v3v3(normal, prev_tangent, tangent);
			axis_angle_to_quat( q,normal, angle);
			mul_qt_qtqt(key1->rot, q, key2->rot);
		}

		copy_v3_v3(prev_tangent, tangent);
	}
}
/* Calculates paths ready for drawing/rendering.									*/
/* -Usefull for making use of opengl vertex arrays for super fast strand drawing.	*/
/* -Makes child strands possible and creates them too into the cache.				*/
/* -Cached path data is also used to determine cut position for the editmode tool.	*/
void psys_cache_paths(ParticleSimulationData *sim, float cfra)
{
	PARTICLE_PSMD;
	ParticleEditSettings *pset = &sim->scene->toolsettings->particle;
	ParticleSystem *psys = sim->psys;
	ParticleSettings *part = psys->part;
	ParticleCacheKey *ca, **cache;

	DerivedMesh *hair_dm = (psys->part->type==PART_HAIR && psys->flag & PSYS_HAIR_DYNAMICS) ? psys->hair_out_dm : NULL;
	
	ParticleKey result;
	
	Material *ma;
	ParticleInterpolationData pind;
	ParticleTexture ptex;

	PARTICLE_P;
	
	float birthtime = 0.0, dietime = 0.0;
	float t, time = 0.0, dfra = 1.0 /* , frs_sec = sim->scene->r.frs_sec*/ /*UNUSED*/;
	float col[4] = {0.5f, 0.5f, 0.5f, 1.0f};
	float prev_tangent[3] = {0.0f, 0.0f, 0.0f}, hairmat[4][4];
	float rotmat[3][3];
	int k;
	int steps = (int)pow(2.0, (double)(psys->renderdata ? part->ren_step : part->draw_step));
	int totpart = psys->totpart;
	float length, vec[3];
	float *vg_effector= NULL;
	float *vg_length= NULL, pa_length=1.0f;
	int keyed, baked;

	/* we don't have anything valid to create paths from so let's quit here */
	if((psys->flag & PSYS_HAIR_DONE || psys->flag & PSYS_KEYED || psys->pointcache)==0)
		return;

	if(psys_in_edit_mode(sim->scene, psys))
		if(psys->renderdata==0 && (psys->edit==NULL || pset->flag & PE_DRAW_PART)==0)
			return;
	
	BLI_srandom(psys->seed);

	keyed = psys->flag & PSYS_KEYED;
	baked = psys->pointcache->mem_cache.first && psys->part->type != PART_HAIR;

	/* clear out old and create new empty path cache */
	psys_free_path_cache(psys, psys->edit);
	cache= psys->pathcache= psys_alloc_path_cache_buffers(&psys->pathcachebufs, totpart, steps+1);

	psys->lattice = psys_get_lattice(sim);
	ma= give_current_material(sim->ob, psys->part->omat);
	if(ma && (psys->part->draw_col == PART_DRAW_COL_MAT))
		VECCOPY(col, &ma->r)

	if((psys->flag & PSYS_GLOBAL_HAIR)==0) {
		if((psys->part->flag & PART_CHILD_EFFECT)==0)
			vg_effector = psys_cache_vgroup(psmd->dm, psys, PSYS_VG_EFFECTOR);
		
		if(!psys->totchild)
			vg_length = psys_cache_vgroup(psmd->dm, psys, PSYS_VG_LENGTH);
	}

	/*---first main loop: create all actual particles' paths---*/
	LOOP_SHOWN_PARTICLES {
		if(!psys->totchild) {
			psys_get_texture(sim, pa, &ptex, PAMAP_LENGTH, 0.f);
			pa_length = ptex.length * (1.0f - part->randlength * PSYS_FRAND(psys->seed + p));
			if(vg_length)
				pa_length *= psys_particle_value_from_verts(psmd->dm,part->from,pa,vg_length);
		}

		pind.keyed = keyed;
		pind.cache = baked ? psys->pointcache : NULL;
		pind.epoint = NULL;
		pind.bspline = (psys->part->flag & PART_HAIR_BSPLINE);
		pind.dm = hair_dm;

		memset(cache[p], 0, sizeof(*cache[p])*(steps+1));

		cache[p]->steps = steps;

		/*--get the first data points--*/
		init_particle_interpolation(sim->ob, sim->psys, pa, &pind);

		/* hairmat is needed for for non-hair particle too so we get proper rotations */
		psys_mat_hair_to_global(sim->ob, psmd->dm, psys->part->from, pa, hairmat);
		VECCOPY(rotmat[0], hairmat[2]);
		VECCOPY(rotmat[1], hairmat[1]);
		VECCOPY(rotmat[2], hairmat[0]);

		if(part->draw & PART_ABS_PATH_TIME) {
			birthtime = MAX2(pind.birthtime, part->path_start);
			dietime = MIN2(pind.dietime, part->path_end);
		}
		else {
			float tb = pind.birthtime;
			birthtime = tb + part->path_start * (pind.dietime - tb);
			dietime = tb + part->path_end * (pind.dietime - tb);
		}

		if(birthtime >= dietime) {
			cache[p]->steps = -1;
			continue;
		}

		dietime = birthtime + pa_length * (dietime - birthtime);

		/*--interpolate actual path from data points--*/
		for(k=0, ca=cache[p]; k<=steps; k++, ca++){
			time = (float)k / (float)steps;
			t = birthtime + time * (dietime - birthtime);
			result.time = -t;
			do_particle_interpolation(psys, p, pa, t, &pind, &result);
			copy_v3_v3(ca->co, result.co);

			/* dynamic hair is in object space */
			/* keyed and baked are already in global space */
			if(hair_dm)
				mul_m4_v3(sim->ob->obmat, ca->co);
			else if(!keyed && !baked && !(psys->flag & PSYS_GLOBAL_HAIR))
				mul_m4_v3(hairmat, ca->co);

			copy_v3_v3(ca->col, col);
		}
		
		/*--modify paths and calculate rotation & velocity--*/

		if(!(psys->flag & PSYS_GLOBAL_HAIR)) {
			/* apply effectors */
			if((psys->part->flag & PART_CHILD_EFFECT) == 0) {
				float effector= 1.0f;
				if(vg_effector)
					effector*= psys_particle_value_from_verts(psmd->dm,psys->part->from,pa,vg_effector);

				sub_v3_v3v3(vec,(cache[p]+1)->co,cache[p]->co);
				length = len_v3(vec);

				for(k=1, ca=cache[p]+1; k<=steps; k++, ca++)
					do_path_effectors(sim, p, ca, k, steps, cache[p]->co, effector, dfra, cfra, &length, vec);
			}

			/* apply guide curves to path data */
			if(sim->psys->effectors && (psys->part->flag & PART_CHILD_EFFECT)==0) {
				for(k=0, ca=cache[p]; k<=steps; k++, ca++)
					/* ca is safe to cast, since only co and vel are used */
					do_guides(sim->psys->effectors, (ParticleKey*)ca, p, (float)k/(float)steps);
			}

			/* lattices have to be calculated separately to avoid mixups between effector calculations */
			if(psys->lattice) {
				for(k=0, ca=cache[p]; k<=steps; k++, ca++)
					calc_latt_deform(psys->lattice, ca->co, 1.0f);
			}
		}

		/* finally do rotation & velocity */
		for(k=1, ca=cache[p]+1; k<=steps; k++, ca++) {
			cache_key_incremental_rotation(ca, ca - 1, ca - 2, prev_tangent, k);

			if(k == steps)
				copy_qt_qt(ca->rot, (ca - 1)->rot);

			/* set velocity */
			sub_v3_v3v3(ca->vel, ca->co, (ca-1)->co);

			if(k==1)
				copy_v3_v3((ca-1)->vel, ca->vel);
		}
		/* First rotation is based on emitting face orientation.
		 * This is way better than having flipping rotations resulting
		 * from using a global axis as a rotation pole (vec_to_quat()).
		 * It's not an ideal solution though since it disregards the
		 * initial tangent, but taking that in to account will allow
		 * the possibility of flipping again. -jahka
		 */
		mat3_to_quat_is_ok(cache[p]->rot, rotmat);
	}

	psys->totcached = totpart;

	if(psys && psys->lattice){
		end_latt_deform(psys->lattice);
		psys->lattice= NULL;
	}

	if(vg_effector)
		MEM_freeN(vg_effector);

	if(vg_length)
		MEM_freeN(vg_length);
}
void psys_cache_edit_paths(Scene *scene, Object *ob, PTCacheEdit *edit, float cfra)
{
	ParticleCacheKey *ca, **cache= edit->pathcache;
	ParticleEditSettings *pset = &scene->toolsettings->particle;
	
	PTCacheEditPoint *point = NULL;
	PTCacheEditKey *ekey = NULL;

	ParticleSystem *psys = edit->psys;
	ParticleSystemModifierData *psmd = psys_get_modifier(ob, psys);
	ParticleData *pa = psys ? psys->particles : NULL;

	ParticleInterpolationData pind;
	ParticleKey result;
	
	float birthtime = 0.0f, dietime = 0.0f;
	float t, time = 0.0f, keytime = 0.0f, frs_sec;
	float hairmat[4][4], rotmat[3][3], prev_tangent[3] = {0.0f, 0.0f, 0.0f};
	int k, i;
	int steps = (int)pow(2.0, (double)pset->draw_step);
	int totpart = edit->totpoint, recalc_set=0;
	float sel_col[3];
	float nosel_col[3];

	steps = MAX2(steps, 4);

	if(!cache || edit->totpoint != edit->totcached) {
		/* clear out old and create new empty path cache */
		psys_free_path_cache(edit->psys, edit);
		cache= edit->pathcache= psys_alloc_path_cache_buffers(&edit->pathcachebufs, totpart, steps+1);

		/* set flag for update (child particles check this too) */
		for(i=0, point=edit->points; i<totpart; i++, point++)
			point->flag |= PEP_EDIT_RECALC;
		recalc_set = 1;
	}

	frs_sec = (psys || edit->pid.flag & PTCACHE_VEL_PER_SEC) ? 25.0f : 1.0f;

	if(pset->brushtype == PE_BRUSH_WEIGHT) {
		;/* use weight painting colors now... */
	}
	else{
		sel_col[0] = (float)edit->sel_col[0] / 255.0f;
		sel_col[1] = (float)edit->sel_col[1] / 255.0f;
		sel_col[2] = (float)edit->sel_col[2] / 255.0f;
		nosel_col[0] = (float)edit->nosel_col[0] / 255.0f;
		nosel_col[1] = (float)edit->nosel_col[1] / 255.0f;
		nosel_col[2] = (float)edit->nosel_col[2] / 255.0f;
	}

	/*---first main loop: create all actual particles' paths---*/
	for(i=0, point=edit->points; i<totpart; i++, pa+=pa?1:0, point++){
		if(edit->totcached && !(point->flag & PEP_EDIT_RECALC))
			continue;

		ekey = point->keys;

		pind.keyed = 0;
		pind.cache = NULL;
		pind.epoint = point;
		pind.bspline = psys ? (psys->part->flag & PART_HAIR_BSPLINE) : 0;
		pind.dm = NULL;


		/* should init_particle_interpolation set this ? */
		if(pset->brushtype==PE_BRUSH_WEIGHT){
			pind.hkey[0] = NULL;
			/* pa != NULL since the weight brush is only available for hair */
			pind.hkey[1] = pa->hair;
		}


		memset(cache[i], 0, sizeof(*cache[i])*(steps+1));

		cache[i]->steps = steps;

		/*--get the first data points--*/
		init_particle_interpolation(ob, psys, pa, &pind);

		if(psys) {
			psys_mat_hair_to_global(ob, psmd->dm, psys->part->from, pa, hairmat);
			copy_v3_v3(rotmat[0], hairmat[2]);
			copy_v3_v3(rotmat[1], hairmat[1]);
			copy_v3_v3(rotmat[2], hairmat[0]);
		}

		birthtime = pind.birthtime;
		dietime = pind.dietime;

		if(birthtime >= dietime) {
			cache[i]->steps = -1;
			continue;
		}

		/*--interpolate actual path from data points--*/
		for(k=0, ca=cache[i]; k<=steps; k++, ca++){
			time = (float)k / (float)steps;
			t = birthtime + time * (dietime - birthtime);
			result.time = -t;
			do_particle_interpolation(psys, i, pa, t, &pind, &result);
			copy_v3_v3(ca->co, result.co);

			 /* non-hair points are already in global space */
			if(psys && !(psys->flag & PSYS_GLOBAL_HAIR)) {
				mul_m4_v3(hairmat, ca->co);

				if(k) {
					cache_key_incremental_rotation(ca, ca - 1, ca - 2, prev_tangent, k);

					if(k == steps)
						copy_qt_qt(ca->rot, (ca - 1)->rot);

					/* set velocity */
					sub_v3_v3v3(ca->vel, ca->co, (ca - 1)->co);

					if(k==1)
						copy_v3_v3((ca - 1)->vel, ca->vel);
				}
			}
			else {
				ca->vel[0] = ca->vel[1] = 0.0f;
				ca->vel[1] = 1.0f;
			}

			/* selection coloring in edit mode */
			if(pset->brushtype==PE_BRUSH_WEIGHT){
				float t2;

				if(k==0) {
					weight_to_rgb(pind.hkey[1]->weight, ca->col, ca->col+1, ca->col+2);
				} else {
					float w1[3], w2[3];
					keytime = (t - (*pind.ekey[0]->time))/((*pind.ekey[1]->time) - (*pind.ekey[0]->time));

					weight_to_rgb(pind.hkey[0]->weight, w1, w1+1, w1+2);
					weight_to_rgb(pind.hkey[1]->weight, w2, w2+1, w2+2);

					interp_v3_v3v3(ca->col, w1, w2, keytime);
				}

				/* at the moment this is only used for weight painting.
				 * will need to move out of this check if its used elsewhere. */
				t2 = birthtime + ((float)k/(float)steps) * (dietime - birthtime);

				while (pind.hkey[1]->time < t2) pind.hkey[1]++;
				pind.hkey[0] = pind.hkey[1] - 1;
			}
			else {
				if((ekey + (pind.ekey[0] - point->keys))->flag & PEK_SELECT){
					if((ekey + (pind.ekey[1] - point->keys))->flag & PEK_SELECT){
						VECCOPY(ca->col, sel_col);
					}
					else{
						keytime = (t - (*pind.ekey[0]->time))/((*pind.ekey[1]->time) - (*pind.ekey[0]->time));
						interp_v3_v3v3(ca->col, sel_col, nosel_col, keytime);
					}
				}
				else{
					if((ekey + (pind.ekey[1] - point->keys))->flag & PEK_SELECT){
						keytime = (t - (*pind.ekey[0]->time))/((*pind.ekey[1]->time) - (*pind.ekey[0]->time));
						interp_v3_v3v3(ca->col, nosel_col, sel_col, keytime);
					}
					else{
						VECCOPY(ca->col, nosel_col);
					}
				}
			}

			ca->time = t;
		}
		if(psys && !(psys->flag & PSYS_GLOBAL_HAIR)) {
			/* First rotation is based on emitting face orientation.
			 * This is way better than having flipping rotations resulting
			 * from using a global axis as a rotation pole (vec_to_quat()).
			 * It's not an ideal solution though since it disregards the
			 * initial tangent, but taking that in to account will allow
			 * the possibility of flipping again. -jahka
			 */
			mat3_to_quat_is_ok(cache[i]->rot, rotmat);
		}
	}

	edit->totcached = totpart;

	if(psys) {
		ParticleSimulationData sim= {0};
		sim.scene= scene;
		sim.ob= ob;
		sim.psys= psys;
		sim.psmd= psys_get_modifier(ob, psys);

		psys_cache_child_paths(&sim, cfra, 1);
	}

	/* clear recalc flag if set here */
	if(recalc_set) {
		for(i=0, point=edit->points; i<totpart; i++, point++)
			point->flag &= ~PEP_EDIT_RECALC;
	}
}
/************************************************/
/*			Particle Key handling				*/
/************************************************/
void copy_particle_key(ParticleKey *to, ParticleKey *from, int time){
	if(time){
		memcpy(to,from,sizeof(ParticleKey));
	}
	else{
		float to_time=to->time;
		memcpy(to,from,sizeof(ParticleKey));
		to->time=to_time;
	}
}
void psys_get_from_key(ParticleKey *key, float *loc, float *vel, float *rot, float *time){
	if(loc) VECCOPY(loc,key->co);
	if(vel) VECCOPY(vel,key->vel);
	if(rot) QUATCOPY(rot,key->rot);
	if(time) *time=key->time;
}
/*-------changing particle keys from space to another-------*/
#if 0
static void key_from_object(Object *ob, ParticleKey *key){
	float q[4];

	VECADD(key->vel,key->vel,key->co);

	mul_m4_v3(ob->obmat,key->co);
	mul_m4_v3(ob->obmat,key->vel);
	mat4_to_quat(q,ob->obmat);

	VECSUB(key->vel,key->vel,key->co);
	mul_qt_qtqt(key->rot,q,key->rot);
}
#endif

static void triatomat(float *v1, float *v2, float *v3, float (*uv)[2], float mat[][4])
{
	float det, w1, w2, d1[2], d2[2];

	memset(mat, 0, sizeof(float)*4*4);
	mat[3][3]= 1.0f;

	/* first axis is the normal */
	normal_tri_v3( mat[2],v1, v2, v3);

	/* second axis along (1, 0) in uv space */
	if(uv) {
		d1[0]= uv[1][0] - uv[0][0];
		d1[1]= uv[1][1] - uv[0][1];
		d2[0]= uv[2][0] - uv[0][0];
		d2[1]= uv[2][1] - uv[0][1];

		det = d2[0]*d1[1] - d2[1]*d1[0];

		if(det != 0.0f) {
			det= 1.0f/det;
			w1= -d2[1]*det;
			w2= d1[1]*det;

			mat[1][0]= w1*(v2[0] - v1[0]) + w2*(v3[0] - v1[0]);
			mat[1][1]= w1*(v2[1] - v1[1]) + w2*(v3[1] - v1[1]);
			mat[1][2]= w1*(v2[2] - v1[2]) + w2*(v3[2] - v1[2]);
			normalize_v3(mat[1]);
		}
		else
			mat[1][0]= mat[1][1]= mat[1][2]= 0.0f;
	}
	else {
		sub_v3_v3v3(mat[1], v2, v1);
		normalize_v3(mat[1]);
	}
	
	/* third as a cross product */
	cross_v3_v3v3(mat[0], mat[1], mat[2]);
}

static void psys_face_mat(Object *ob, DerivedMesh *dm, ParticleData *pa, float mat[][4], int orco)
{
	float v[3][3];
	MFace *mface;
	OrigSpaceFace *osface;
	float (*orcodata)[3];

	int i = pa->num_dmcache==DMCACHE_NOTFOUND ? pa->num : pa->num_dmcache;
	
	if (i==-1 || i >= dm->getNumFaces(dm)) { unit_m4(mat); return; }

	mface=dm->getFaceData(dm,i,CD_MFACE);
	osface=dm->getFaceData(dm,i,CD_ORIGSPACE);
	
	if(orco && (orcodata=dm->getVertDataArray(dm, CD_ORCO))) {
		VECCOPY(v[0], orcodata[mface->v1]);
		VECCOPY(v[1], orcodata[mface->v2]);
		VECCOPY(v[2], orcodata[mface->v3]);

		/* ugly hack to use non-transformed orcos, since only those
		 * give symmetric results for mirroring in particle mode */
		if(DM_get_vert_data_layer(dm, CD_ORIGINDEX))
			transform_mesh_orco_verts(ob->data, v, 3, 1);
	}
	else {
		dm->getVertCo(dm,mface->v1,v[0]);
		dm->getVertCo(dm,mface->v2,v[1]);
		dm->getVertCo(dm,mface->v3,v[2]);
	}

	triatomat(v[0], v[1], v[2], (osface)? osface->uv: NULL, mat);
}

void psys_mat_hair_to_object(Object *UNUSED(ob), DerivedMesh *dm, short from, ParticleData *pa, float hairmat[][4])
{
	float vec[3];

	psys_face_mat(0, dm, pa, hairmat, 0);
	psys_particle_on_dm(dm, from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, vec, 0, 0, 0, 0, 0);
	VECCOPY(hairmat[3],vec);
}

void psys_mat_hair_to_orco(Object *ob, DerivedMesh *dm, short from, ParticleData *pa, float hairmat[][4])
{
	float vec[3], orco[3];

	psys_face_mat(ob, dm, pa, hairmat, 1);
	psys_particle_on_dm(dm, from, pa->num, pa->num_dmcache, pa->fuv, pa->foffset, vec, 0, 0, 0, orco, 0);

	/* see psys_face_mat for why this function is called */
	if(DM_get_vert_data_layer(dm, CD_ORIGINDEX))
		transform_mesh_orco_verts(ob->data, &orco, 1, 1);
	VECCOPY(hairmat[3],orco);
}

void psys_vec_rot_to_face(DerivedMesh *dm, ParticleData *pa, float *vec)
{
	float mat[4][4];

	psys_face_mat(0, dm, pa, mat, 0);
	transpose_m4(mat); /* cheap inverse for rotation matrix */
	mul_mat3_m4_v3(mat, vec);
}

void psys_mat_hair_to_global(Object *ob, DerivedMesh *dm, short from, ParticleData *pa, float hairmat[][4])
{
	float facemat[4][4];

	psys_mat_hair_to_object(ob, dm, from, pa, facemat);

	mul_m4_m4m4(hairmat, facemat, ob->obmat);
}

/************************************************/
/*			ParticleSettings handling			*/
/************************************************/
ModifierData *object_add_particle_system(Scene *scene, Object *ob, const char *name)
{
	ParticleSystem *psys;
	ModifierData *md;
	ParticleSystemModifierData *psmd;

	if(!ob || ob->type != OB_MESH)
		return NULL;

	psys = ob->particlesystem.first;
	for(; psys; psys=psys->next)
		psys->flag &= ~PSYS_CURRENT;

	psys = MEM_callocN(sizeof(ParticleSystem), "particle_system");
	psys->pointcache = BKE_ptcache_add(&psys->ptcaches);
	BLI_addtail(&ob->particlesystem, psys);

	psys->part = psys_new_settings("ParticleSettings", NULL);

	if(BLI_countlist(&ob->particlesystem)>1)
		sprintf(psys->name, "ParticleSystem %i", BLI_countlist(&ob->particlesystem));
	else
		strcpy(psys->name, "ParticleSystem");

	md= modifier_new(eModifierType_ParticleSystem);

	if(name)	BLI_strncpy(md->name, name, sizeof(md->name));
	else		sprintf(md->name, "ParticleSystem %i", BLI_countlist(&ob->particlesystem));
	modifier_unique_name(&ob->modifiers, md);

	psmd= (ParticleSystemModifierData*) md;
	psmd->psys=psys;
	BLI_addtail(&ob->modifiers, md);

	psys->totpart=0;
	psys->flag = PSYS_ENABLED|PSYS_CURRENT;
	psys->cfra=bsystem_time(scene,ob,scene->r.cfra+1,0.0);

	DAG_scene_sort(G.main, scene);
	DAG_id_tag_update(&ob->id, OB_RECALC_DATA);

	return md;
}
void object_remove_particle_system(Scene *scene, Object *ob)
{
	ParticleSystem *psys = psys_get_current(ob);
	ParticleSystemModifierData *psmd;
	ModifierData *md;

	if(!psys)
		return;

	/* clear all other appearances of this pointer (like on smoke flow modifier) */
	if((md = modifiers_findByType(ob, eModifierType_Smoke)))
	{
		SmokeModifierData *smd = (SmokeModifierData *)md;
		if((smd->type == MOD_SMOKE_TYPE_FLOW) && smd->flow && smd->flow->psys)
			if(smd->flow->psys == psys)
				smd->flow->psys = NULL;
	}

	/* clear modifier */
	psmd= psys_get_modifier(ob, psys);
	BLI_remlink(&ob->modifiers, psmd);
	modifier_free((ModifierData *)psmd);

	/* clear particle system */
	BLI_remlink(&ob->particlesystem, psys);
	psys_free(ob,psys);

	if(ob->particlesystem.first)
		((ParticleSystem *) ob->particlesystem.first)->flag |= PSYS_CURRENT;
	else
		ob->mode &= ~OB_MODE_PARTICLE_EDIT;

	DAG_scene_sort(G.main, scene);
	DAG_id_tag_update(&ob->id, OB_RECALC_DATA);
}
static void default_particle_settings(ParticleSettings *part)
{
	part->type= PART_EMITTER;
	part->distr= PART_DISTR_JIT;
	part->draw_as = PART_DRAW_REND;
	part->ren_as = PART_DRAW_HALO;
	part->bb_uv_split=1;
	part->bb_align=PART_BB_VIEW;
	part->bb_split_offset=PART_BB_OFF_LINEAR;
	part->flag=PART_EDISTR|PART_TRAND|PART_HIDE_ADVANCED_HAIR;

	part->sta= 1.0;
	part->end= 200.0;
	part->lifetime= 50.0;
	part->jitfac= 1.0;
	part->totpart= 1000;
	part->grid_res= 10;
	part->timetweak= 1.0;
	
	part->integrator= PART_INT_MIDPOINT;
	part->phystype= PART_PHYS_NEWTON;
	part->hair_step= 5;
	part->keys_step= 5;
	part->draw_step= 2;
	part->ren_step= 3;
	part->adapt_angle= 5;
	part->adapt_pix= 3;
	part->kink_axis= 2;
	part->kink_amp_clump= 1.f;
	part->reactevent= PART_EVENT_DEATH;
	part->disp=100;
	part->from= PART_FROM_FACE;

	part->normfac= 1.0f;

	part->mass=1.0;
	part->size=0.05;
	part->childsize=1.0;

	part->rotmode = PART_ROT_VEL;
	part->avemode = PART_AVE_SPIN;

	part->child_nbr=10;
	part->ren_child_nbr=100;
	part->childrad=0.2f;
	part->childflat=0.0f;
	part->clumppow=0.0f;
	part->kink_amp=0.2f;
	part->kink_freq=2.0;

	part->rough1_size=1.0;
	part->rough2_size=1.0;
	part->rough_end_shape=1.0;

	part->clength=1.0f;
	part->clength_thres=0.0f;

	part->draw= PART_DRAW_EMITTER;
	part->draw_line[0]=0.5;
	part->path_start = 0.0f;
	part->path_end = 1.0f;

	part->keyed_loops = 1;

	part->color_vec_max = 1.f;
	part->draw_col = PART_DRAW_COL_MAT;

	part->simplify_refsize= 1920;
	part->simplify_rate= 1.0f;
	part->simplify_transition= 0.1f;
	part->simplify_viewport= 0.8;

	if(!part->effector_weights)
		part->effector_weights = BKE_add_effector_weights(NULL);
}


ParticleSettings *psys_new_settings(const char *name, Main *main)
{
	ParticleSettings *part;

	if(main==NULL)
		main = G.main;

	part= alloc_libblock(&main->particle, ID_PA, name);
	
	default_particle_settings(part);

	return part;
}

ParticleSettings *psys_copy_settings(ParticleSettings *part)
{
	ParticleSettings *partn;
	int a;

	partn= copy_libblock(part);
	partn->pd= MEM_dupallocN(part->pd);
	partn->pd2= MEM_dupallocN(part->pd2);
	partn->effector_weights= MEM_dupallocN(part->effector_weights);
	partn->fluid= MEM_dupallocN(part->fluid);

	partn->boids = boid_copy_settings(part->boids);

	for(a=0; a<MAX_MTEX; a++) {
		if(part->mtex[a]) {
			partn->mtex[a]= MEM_mallocN(sizeof(MTex), "psys_copy_tex");
			memcpy(partn->mtex[a], part->mtex[a], sizeof(MTex));
			id_us_plus((ID *)partn->mtex[a]->tex);
		}
	}

	BLI_duplicatelist(&partn->dupliweights, &part->dupliweights);
	
	return partn;
}

void make_local_particlesettings(ParticleSettings *part)
{
	Object *ob;
	ParticleSettings *par;
	int local=0, lib=0;

	/* - only lib users: do nothing
		* - only local users: set flag
		* - mixed: make copy
		*/
	
	if(part->id.lib==0) return;
	if(part->id.us==1) {
		part->id.lib= 0;
		part->id.flag= LIB_LOCAL;
		new_id(0, (ID *)part, 0);
		return;
	}
	
	/* test objects */
	ob= G.main->object.first;
	while(ob) {
		ParticleSystem *psys=ob->particlesystem.first;
		for(; psys; psys=psys->next){
			if(psys->part==part) {
				if(ob->id.lib) lib= 1;
				else local= 1;
			}
		}
		ob= ob->id.next;
	}
	
	if(local && lib==0) {
		part->id.lib= 0;
		part->id.flag= LIB_LOCAL;
		new_id(0, (ID *)part, 0);
	}
	else if(local && lib) {
		
		par= psys_copy_settings(part);
		par->id.us= 0;
		
		/* do objects */
		ob= G.main->object.first;
		while(ob) {
			ParticleSystem *psys=ob->particlesystem.first;
			for(; psys; psys=psys->next){
				if(psys->part==part && ob->id.lib==0) {
					psys->part= par;
					par->id.us++;
					part->id.us--;
				}
			}
			ob= ob->id.next;
		}
	}
}

/************************************************/
/*			Textures							*/
/************************************************/

static int get_particle_uv(DerivedMesh *dm, ParticleData *pa, int face_index, float *fuv, char *name, float *texco)
{
	MFace *mf;
	MTFace *tf;
	int i;
	
	tf= CustomData_get_layer_named(&dm->faceData, CD_MTFACE, name);

	if(tf == NULL)
		tf= CustomData_get_layer(&dm->faceData, CD_MTFACE);

	if(tf == NULL)
		return 0;

	if(pa) {
		i= (pa->num_dmcache==DMCACHE_NOTFOUND)? pa->num: pa->num_dmcache;
		if(i >= dm->getNumFaces(dm))
			i = -1;
	}
	else
		i= face_index;

	if (i==-1) {
		texco[0]= 0.0f;
		texco[1]= 0.0f;
		texco[2]= 0.0f;
	}
	else {
		mf= dm->getFaceData(dm, i, CD_MFACE);

		psys_interpolate_uvs(&tf[i], mf->v4, fuv, texco);

		texco[0]= texco[0]*2.0f - 1.0f;
		texco[1]= texco[1]*2.0f - 1.0f;
		texco[2]= 0.0f;
	}

	return 1;
}

#define SET_PARTICLE_TEXTURE(type, pvalue, texfac) if((event & mtex->mapto) & type) {pvalue = texture_value_blend(def, pvalue, value, texfac, blend);}
#define CLAMP_PARTICLE_TEXTURE_POS(type, pvalue) if(event & type) { if(pvalue < 0.f) pvalue = 1.f+pvalue; CLAMP(pvalue, 0.0f, 1.0f); }
#define CLAMP_PARTICLE_TEXTURE_POSNEG(type, pvalue) if(event & type) { CLAMP(pvalue, -1.0f, 1.0f); }

static void get_cpa_texture(DerivedMesh *dm, ParticleSystem *psys, ParticleSettings *part, ParticleData *par, int child_index, int face_index, float *fw, float *orco, ParticleTexture *ptex, int event, float cfra)
{
	MTex *mtex, **mtexp = part->mtex;
	int m;
	float value, rgba[4], texvec[3];

	ptex->ivel = ptex->life = ptex->exist = ptex->size = ptex->damp =
		ptex->gravity = ptex->field = ptex->time = ptex->clump = ptex->kink =
		ptex->effector = ptex->rough1 = ptex->rough2 = ptex->roughe = 1.f;

	ptex->length= 1.0f - part->randlength * PSYS_FRAND(child_index + 26);
	ptex->length*= part->clength_thres < PSYS_FRAND(child_index + 27) ? part->clength : 1.0f;

	for(m=0; m<MAX_MTEX; m++, mtexp++){
		mtex = *mtexp;
		if(mtex && mtex->mapto){
			float def=mtex->def_var;
			short blend=mtex->blendtype;
			short texco = mtex->texco;

			if(ELEM(texco, TEXCO_UV, TEXCO_ORCO) && (ELEM(part->from, PART_FROM_FACE, PART_FROM_VOLUME) == 0 || part->distr == PART_DISTR_GRID))
				texco = TEXCO_GLOB;

			switch(texco) {
			case TEXCO_GLOB:
				copy_v3_v3(texvec, par->state.co);
				break;
			case TEXCO_OBJECT:
				copy_v3_v3(texvec, par->state.co);
				if(mtex->object)
					mul_m4_v3(mtex->object->imat, texvec);
				break;
			case TEXCO_UV:
				if(fw && get_particle_uv(dm, NULL, face_index, fw, mtex->uvname, texvec))
					break;
				/* no break, failed to get uv's, so let's try orco's */
			case TEXCO_ORCO:
				copy_v3_v3(texvec, orco);
				break;
			case TEXCO_PARTICLE:
				/* texture coordinates in range [-1,1] */
				texvec[0] = 2.f * (cfra - par->time)/(par->dietime-par->time) - 1.f;
				texvec[1] = 0.f;
				texvec[2] = 0.f;
				break;
			}

			externtex(mtex, texvec, &value, rgba, rgba+1, rgba+2, rgba+3, 0);

			if((event & mtex->mapto) & PAMAP_ROUGH)
				ptex->rough1= ptex->rough2= ptex->roughe= texture_value_blend(def,ptex->rough1,value,mtex->roughfac,blend);

			SET_PARTICLE_TEXTURE(PAMAP_LENGTH, ptex->length, mtex->lengthfac);
			SET_PARTICLE_TEXTURE(PAMAP_CLUMP, ptex->clump, mtex->clumpfac);
			SET_PARTICLE_TEXTURE(PAMAP_KINK, ptex->kink, mtex->kinkfac);
			SET_PARTICLE_TEXTURE(PAMAP_DENS, ptex->exist, mtex->padensfac);
		}
	}

	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LENGTH, ptex->length);
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_CLUMP, ptex->clump);
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_KINK, ptex->kink);
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_ROUGH, ptex->rough1);
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist);
}
void psys_get_texture(ParticleSimulationData *sim, ParticleData *pa, ParticleTexture *ptex, int event, float cfra)
{
	ParticleSettings *part = sim->psys->part;
	MTex **mtexp = part->mtex;
	MTex *mtex;
	int m;
	float value, rgba[4], co[3], texvec[3];
	int setvars=0;

	/* initialize ptex */
	ptex->ivel = ptex->life = ptex->exist = ptex->size = ptex->damp =
		ptex->gravity = ptex->field = ptex->length = ptex->clump = ptex->kink =
		ptex->effector = ptex->rough1 = ptex->rough2 = ptex->roughe = 1.f;

	ptex->time = (float)(pa - sim->psys->particles)/(float)sim->psys->totpart;

	for(m=0; m<MAX_MTEX; m++, mtexp++){
		mtex = *mtexp;
		if(mtex && mtex->mapto){
			float def=mtex->def_var;
			short blend=mtex->blendtype;
			short texco = mtex->texco;

			if(texco == TEXCO_UV && (ELEM(part->from, PART_FROM_FACE, PART_FROM_VOLUME) == 0 || part->distr == PART_DISTR_GRID))
				texco = TEXCO_GLOB;

			switch(texco) {
			case TEXCO_GLOB:
				copy_v3_v3(texvec, pa->state.co);
				break;
			case TEXCO_OBJECT:
				copy_v3_v3(texvec, pa->state.co);
				if(mtex->object)
					mul_m4_v3(mtex->object->imat, texvec);
				break;
			case TEXCO_UV:
				if(get_particle_uv(sim->psmd->dm, pa, 0, pa->fuv, mtex->uvname, texvec))
					break;
				/* no break, failed to get uv's, so let's try orco's */
			case TEXCO_ORCO:
				psys_particle_on_emitter(sim->psmd,sim->psys->part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,co,0,0,0,texvec, 0);
				break;
			case TEXCO_PARTICLE:
				/* texture coordinates in range [-1,1] */
				texvec[0] = 2.f * (cfra - pa->time)/(pa->dietime-pa->time) - 1.f;
				texvec[1] = 0.f;
				texvec[2] = 0.f;
				break;
			}

			externtex(mtex, texvec, &value, rgba, rgba+1, rgba+2, rgba+3, 0);

			if((event & mtex->mapto) & PAMAP_TIME) {
				/* the first time has to set the base value for time regardless of blend mode */
				if((setvars&MAP_PA_TIME)==0){
					int flip= (mtex->timefac < 0.0f);
					float timefac= fabsf(mtex->timefac);
					ptex->time *= 1.0f - timefac;
					ptex->time += timefac * ((flip)? 1.0f - value : value);
					setvars |= MAP_PA_TIME;
				}
				else
					ptex->time= texture_value_blend(def,ptex->time,value,mtex->timefac,blend);
			}
			SET_PARTICLE_TEXTURE(PAMAP_LIFE, ptex->life, mtex->lifefac)
			SET_PARTICLE_TEXTURE(PAMAP_DENS, ptex->exist, mtex->padensfac)
			SET_PARTICLE_TEXTURE(PAMAP_SIZE, ptex->size, mtex->sizefac)
			SET_PARTICLE_TEXTURE(PAMAP_IVEL, ptex->ivel, mtex->ivelfac)
			SET_PARTICLE_TEXTURE(PAMAP_FIELD, ptex->field, mtex->fieldfac)
			SET_PARTICLE_TEXTURE(PAMAP_GRAVITY, ptex->gravity, mtex->gravityfac)
			SET_PARTICLE_TEXTURE(PAMAP_DAMP, ptex->damp, mtex->dampfac)
			SET_PARTICLE_TEXTURE(PAMAP_LENGTH, ptex->length, mtex->lengthfac)
		}
	}

	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_TIME, ptex->time)
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LIFE, ptex->life)
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DENS, ptex->exist)
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_SIZE, ptex->size)
	CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_IVEL, ptex->ivel)
	CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_FIELD, ptex->field)
	CLAMP_PARTICLE_TEXTURE_POSNEG(PAMAP_GRAVITY, ptex->gravity)
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_DAMP, ptex->damp)
	CLAMP_PARTICLE_TEXTURE_POS(PAMAP_LENGTH, ptex->length)
}
/************************************************/
/*			Particle State						*/
/************************************************/
float psys_get_timestep(ParticleSimulationData *sim)
{
	return 0.04f * sim->psys->part->timetweak;
}
float psys_get_child_time(ParticleSystem *psys, ChildParticle *cpa, float cfra, float *birthtime, float *dietime)
{
	ParticleSettings *part = psys->part;
	float time, life;

	if(part->childtype==PART_CHILD_FACES){
		int w=0;
		time=0.0;
		while(w<4 && cpa->pa[w]>=0){
			time+=cpa->w[w]*(psys->particles+cpa->pa[w])->time;
			w++;
		}

		life = part->lifetime * (1.0f - part->randlife * PSYS_FRAND(cpa - psys->child + 25));
	}
	else{
		ParticleData *pa = psys->particles + cpa->parent;

		time = pa->time;
		life = pa->lifetime;
	}

	if(birthtime)
		*birthtime = time;
	if(dietime)
		*dietime = time+life;

	return (cfra-time)/life;
}
float psys_get_child_size(ParticleSystem *psys, ChildParticle *cpa, float UNUSED(cfra), float *UNUSED(pa_time))
{
	ParticleSettings *part = psys->part;
	float size; // time XXX
	
	if(part->childtype==PART_CHILD_FACES)
		size=part->size;
	else
		size=psys->particles[cpa->parent].size;

	size*=part->childsize;

	if(part->childrandsize != 0.0f)
		size *= 1.0f - part->childrandsize * PSYS_FRAND(cpa - psys->child + 26);

	return size;
}
static void get_child_modifier_parameters(ParticleSettings *part, ParticleThreadContext *ctx, ChildParticle *cpa, short cpa_from, int cpa_num, float *cpa_fuv, float *orco, ParticleTexture *ptex)
{
	ParticleSystem *psys = ctx->sim.psys;
	int i = cpa - psys->child;

	get_cpa_texture(ctx->dm, psys, part, psys->particles + cpa->pa[0], i, cpa_num, cpa_fuv, orco, ptex, PAMAP_DENS|PAMAP_CHILD, psys->cfra);


	if(ptex->exist < PSYS_FRAND(i + 24))
		return;

	if(ctx->vg_length)
		ptex->length*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_length);
	if(ctx->vg_clump)
		ptex->clump*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_clump);
	if(ctx->vg_kink)
		ptex->kink*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_kink);
	if(ctx->vg_rough1)
		ptex->rough1*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_rough1);
	if(ctx->vg_rough2)
		ptex->rough2*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_rough2);
	if(ctx->vg_roughe)
		ptex->roughe*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_roughe);
	if(ctx->vg_effector)
		ptex->effector*=psys_interpolate_value_from_verts(ctx->dm,cpa_from,cpa_num,cpa_fuv,ctx->vg_effector);
}
static void do_child_modifiers(ParticleSimulationData *sim, ParticleTexture *ptex, ParticleKey *par, float *par_rot, ChildParticle *cpa, float *orco, float mat[4][4], ParticleKey *state, float t)
{
	ParticleSettings *part = sim->psys->part;
	int i = cpa - sim->psys->child;
	int guided = 0;

	float kink_freq = part->kink_freq;
	float rough1 = part->rough1;
	float rough2 = part->rough2;
	float rough_end = part->rough_end;

	if(ptex) {
		kink_freq *= ptex->kink;
		rough1 *= ptex->rough1;
		rough2 *= ptex->rough2;
		rough_end *= ptex->roughe;
	}

	if(part->flag & PART_CHILD_EFFECT)
		/* state is safe to cast, since only co and vel are used */
		guided = do_guides(sim->psys->effectors, (ParticleKey*)state, cpa->parent, t);

	if(guided==0){
		float clump = do_clump(state, par, t, part->clumpfac, part->clumppow, ptex ? ptex->clump : 1.f);

		if(kink_freq != 0.f) {
			float kink_amp = part->kink_amp * (1.f - part->kink_amp_clump * clump);

			do_kink(state, par, par_rot, t, kink_freq, part->kink_shape,
					kink_amp, part->kink_flat, part->kink, part->kink_axis,
					sim->ob->obmat, sim->psys->part->childtype == PART_CHILD_FACES);
		}
	}

	if(rough1 > 0.f)
		do_rough(orco, mat, t, rough1, part->rough1_size, 0.0, state);

	if(rough2 > 0.f)
		do_rough(sim->psys->frand + ((i + 27) % (PSYS_FRAND_COUNT - 3)), mat, t, rough2, part->rough2_size, part->rough2_thres, state);

	if(rough_end > 0.f)
		do_rough_end(sim->psys->frand + ((i + 27) % (PSYS_FRAND_COUNT - 3)), mat, t, rough_end, part->rough_end_shape, state);
}
/* get's hair (or keyed) particles state at the "path time" specified in state->time */
void psys_get_particle_on_path(ParticleSimulationData *sim, int p, ParticleKey *state, int vel)
{
	PARTICLE_PSMD;
	ParticleSystem *psys = sim->psys;
	ParticleSettings *part = sim->psys->part;
	Material *ma = give_current_material(sim->ob, part->omat);
	ParticleData *pa;
	ChildParticle *cpa;
	ParticleTexture ptex;
	ParticleKey *par=0, keys[4], tstate;
	ParticleThreadContext ctx; /* fake thread context for child modifiers */
	ParticleInterpolationData pind;

	float t;
	float co[3], orco[3];
	float hairmat[4][4];
	int totpart = psys->totpart;
	int totchild = psys->totchild;
	short between = 0, edit = 0;

	int keyed = part->phystype & PART_PHYS_KEYED && psys->flag & PSYS_KEYED;
	int cached = !keyed && part->type != PART_HAIR;

	float *cpa_fuv; int cpa_num; short cpa_from;

	/* initialize keys to zero */
	memset(keys, 0, 4*sizeof(ParticleKey));

	t=state->time;
	CLAMP(t, 0.0f, 1.0f);

	if(p<totpart){
		pa = psys->particles + p;
		pind.keyed = keyed;
		pind.cache = cached ? psys->pointcache : NULL;
		pind.epoint = NULL;
		pind.bspline = (psys->part->flag & PART_HAIR_BSPLINE);
		/* pind.dm disabled in editmode means we dont get effectors taken into
		 * account when subdividing for instance */
		pind.dm = psys_in_edit_mode(sim->scene, psys) ? NULL : psys->hair_out_dm;
		init_particle_interpolation(sim->ob, psys, pa, &pind);
		do_particle_interpolation(psys, p, pa, t, &pind, state);

		if(!keyed && !cached) {
			if((pa->flag & PARS_REKEY)==0) {
				psys_mat_hair_to_global(sim->ob, sim->psmd->dm, part->from, pa, hairmat);
				mul_m4_v3(hairmat, state->co);
				mul_mat3_m4_v3(hairmat, state->vel);

				if(sim->psys->effectors && (part->flag & PART_CHILD_GUIDE)==0) {
					do_guides(sim->psys->effectors, state, p, state->time);
					/* TODO: proper velocity handling */
				}

				if(psys->lattice && edit==0)
					calc_latt_deform(psys->lattice, state->co,1.0f);
			}
		}
	}
	else if(totchild){
		//invert_m4_m4(imat,ob->obmat);

		cpa=psys->child+p-totpart;

		if(state->time < 0.0f)
			t = psys_get_child_time(psys, cpa, -state->time, NULL, NULL);
		
		if(totchild && part->childtype==PART_CHILD_FACES){
			/* part->parents could still be 0 so we can't test with totparent */
			between=1;
		}
		if(between){
			int w = 0;
			float foffset;

			/* get parent states */
			while(w<4 && cpa->pa[w]>=0){
				keys[w].time = state->time;
				psys_get_particle_on_path(sim, cpa->pa[w], keys+w, 1);
				w++;
			}

			/* get the original coordinates (orco) for texture usage */
			cpa_num=cpa->num;
			
			foffset= cpa->foffset;
			cpa_fuv = cpa->fuv;
			cpa_from = PART_FROM_FACE;

			psys_particle_on_emitter(psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa->fuv,foffset,co,0,0,0,orco,0);

			/* we need to save the actual root position of the child for positioning it accurately to the surface of the emitter */
			//VECCOPY(cpa_1st,co);

			//mul_m4_v3(ob->obmat,cpa_1st);

			pa = psys->particles + cpa->parent;

			if(part->type == PART_HAIR)
				psys_mat_hair_to_global(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
			else
				unit_m4(hairmat);

			pa=0;
		}
		else{
			/* get the parent state */
			keys->time = state->time;
			psys_get_particle_on_path(sim, cpa->parent, keys,1);

			/* get the original coordinates (orco) for texture usage */
			pa=psys->particles+cpa->parent;

			cpa_from=part->from;
			cpa_num=pa->num;
			cpa_fuv=pa->fuv;

			

			if(part->type == PART_HAIR) {
				psys_particle_on_emitter(psmd,cpa_from,cpa_num,DMCACHE_ISCHILD,cpa_fuv,pa->foffset,co,0,0,0,orco,0);
				psys_mat_hair_to_global(sim->ob, sim->psmd->dm, psys->part->from, pa, hairmat);
			}
			else {
				copy_v3_v3(orco, cpa->fuv);
				unit_m4(hairmat);
			}
		}

		/* correct child ipo timing */
#if 0 // XXX old animation system
		if((part->flag&PART_ABS_TIME)==0 && part->ipo){
			calc_ipo(part->ipo, 100.0f*t);
			execute_ipo((ID *)part, part->ipo);
		}
#endif // XXX old animation system
		
		/* get different child parameters from textures & vgroups */
		memset(&ctx, 0, sizeof(ParticleThreadContext));
		ctx.sim = *sim;
		ctx.dm = psmd->dm;
		ctx.ma = ma;
		/* TODO: assign vertex groups */
		get_child_modifier_parameters(part, &ctx, cpa, cpa_from, cpa_num, cpa_fuv, orco, &ptex);

		if(between){
			int w=0;

			state->co[0] = state->co[1] = state->co[2] = 0.0f;
			state->vel[0] = state->vel[1] = state->vel[2] = 0.0f;

			/* child position is the weighted sum of parent positions */
			while(w<4 && cpa->pa[w]>=0){
				state->co[0] += cpa->w[w] * keys[w].co[0];
				state->co[1] += cpa->w[w] * keys[w].co[1];
				state->co[2] += cpa->w[w] * keys[w].co[2];

				state->vel[0] += cpa->w[w] * keys[w].vel[0];
				state->vel[1] += cpa->w[w] * keys[w].vel[1];
				state->vel[2] += cpa->w[w] * keys[w].vel[2];
				w++;
			}
			/* apply offset for correct positioning */
			//VECADD(state->co,state->co,cpa_1st);
		}
		else{
			/* offset the child from the parent position */
			offset_child(cpa, keys, keys->rot, state, part->childflat, part->childrad);
		}

		par = keys;

		if(vel)
			copy_particle_key(&tstate, state, 1);

		/* apply different deformations to the child path */
		do_child_modifiers(sim, &ptex, par, par->rot, cpa, orco, hairmat, state, t);

		/* try to estimate correct velocity */
		if(vel){
			ParticleKey tstate;
			float length = len_v3(state->vel);

			if(t>=0.001f){
				tstate.time=t-0.001f;
				psys_get_particle_on_path(sim,p,&tstate,0);
				VECSUB(state->vel,state->co,tstate.co);
				normalize_v3(state->vel);
			}
			else{
				tstate.time=t+0.001f;
				psys_get_particle_on_path(sim,p,&tstate,0);
				VECSUB(state->vel,tstate.co,state->co);
				normalize_v3(state->vel);
			}

			mul_v3_fl(state->vel, length);
		}
	}
}
/* gets particle's state at a time, returns 1 if particle exists and can be seen and 0 if not */
int psys_get_particle_state(ParticleSimulationData *sim, int p, ParticleKey *state, int always){
	ParticleSystem *psys = sim->psys;
	ParticleSettings *part = psys->part;
	ParticleData *pa = NULL;
	ChildParticle *cpa = NULL;
	float cfra;
	int totpart = psys->totpart;
	float timestep = psys_get_timestep(sim);

	/* negative time means "use current time" */
	cfra = state->time > 0 ? state->time : bsystem_time(sim->scene, 0, (float)sim->scene->r.cfra, 0.0);

	if(p>=totpart){
		if(!psys->totchild)
			return 0;

		if(part->childtype == PART_CHILD_FACES){
			if(!(psys->flag & PSYS_KEYED))
				return 0;

			cpa = psys->child + p - totpart;

			state->time = psys_get_child_time(psys, cpa, cfra, NULL, NULL);

			if(!always)
				if((state->time < 0.0f && !(part->flag & PART_UNBORN))
					|| (state->time > 1.0f && !(part->flag & PART_DIED)))
					return 0;

			state->time= (cfra - (part->sta + (part->end - part->sta) * PSYS_FRAND(p + 23))) / (part->lifetime * PSYS_FRAND(p + 24));

			psys_get_particle_on_path(sim, p, state,1);
			return 1;
		}
		else {
			cpa = sim->psys->child + p - totpart;
			pa = sim->psys->particles + cpa->parent;
		}
	}
	else {
		pa = sim->psys->particles + p;
	}

	if(pa) {
		if(!always)
			if((cfra < pa->time && (part->flag & PART_UNBORN)==0)
				|| (cfra > pa->dietime && (part->flag & PART_DIED)==0))
				return 0;

		cfra = MIN2(cfra, pa->dietime);
	}

	if(sim->psys->flag & PSYS_KEYED){
		state->time= -cfra;
		psys_get_particle_on_path(sim, p, state,1);
		return 1;
	}
	else{
		if(cpa){
			float mat[4][4];
			ParticleKey *key1;
			float t = (cfra - pa->time) / pa->lifetime;

			key1=&pa->state;
			offset_child(cpa, key1, key1->rot, state, part->childflat, part->childrad);

			CLAMP(t, 0.0f, 1.0f);

			unit_m4(mat);
			do_child_modifiers(sim, NULL, key1, key1->rot, cpa, cpa->fuv, mat, state, t);

			if(psys->lattice)
				calc_latt_deform(sim->psys->lattice, state->co,1.0f);
		}
		else{
			if(pa->state.time==cfra || ELEM(part->phystype,PART_PHYS_NO,PART_PHYS_KEYED))
				copy_particle_key(state, &pa->state, 1);
			else if(pa->prev_state.time==cfra)
				copy_particle_key(state, &pa->prev_state, 1);
			else {
				float dfra, frs_sec = sim->scene->r.frs_sec;
				/* let's interpolate to try to be as accurate as possible */
				if(pa->state.time + 2.f >= state->time && pa->prev_state.time - 2.f <= state->time) {
					if(pa->prev_state.time >= pa->state.time || pa->prev_state.time < 0.f) {
						/* prev_state is wrong so let's not use it, this can happen at frames 1, 0 or particle birth */
						dfra = state->time - pa->state.time;

						copy_particle_key(state, &pa->state, 1);

						madd_v3_v3v3fl(state->co, state->co, state->vel, dfra/frs_sec);
					}
					else {
						ParticleKey keys[4];
						float keytime;

						copy_particle_key(keys+1, &pa->prev_state, 1);
						copy_particle_key(keys+2, &pa->state, 1);

						dfra = keys[2].time - keys[1].time;

						keytime = (state->time - keys[1].time) / dfra;

						/* convert velocity to timestep size */
						mul_v3_fl(keys[1].vel, dfra * timestep);
						mul_v3_fl(keys[2].vel, dfra * timestep);
						
						psys_interpolate_particle(-1, keys, keytime, state, 1);
						
						/* convert back to real velocity */
						mul_v3_fl(state->vel, 1.f / (dfra * timestep));

						interp_v3_v3v3(state->ave, keys[1].ave, keys[2].ave, keytime);
						interp_qt_qtqt(state->rot, keys[1].rot, keys[2].rot, keytime);
					}
				}
				else if(pa->state.time + 1.f >= state->time && pa->state.time - 1.f <= state->time) {
					/* linear interpolation using only pa->state */

					dfra = state->time - pa->state.time;

					copy_particle_key(state, &pa->state, 1);

					madd_v3_v3v3fl(state->co, state->co, state->vel, dfra/frs_sec);
				}
				else {
					/* extrapolating over big ranges is not accurate so let's just give something close to reasonable back */
					copy_particle_key(state, &pa->state, 0);
				}
			}

			if(sim->psys->lattice)
				calc_latt_deform(sim->psys->lattice, state->co,1.0f);
		}
		
		return 1;
	}
}

void psys_get_dupli_texture(ParticleSystem *psys, ParticleSettings *part, ParticleSystemModifierData *psmd, ParticleData *pa, ChildParticle *cpa, float *uv, float *orco)
{
	MFace *mface;
	MTFace *mtface;
	float loc[3];
	int num;

	uv[0] = uv[1] = 0.f;

	if(cpa) {
		if(part->childtype == PART_CHILD_FACES) {
			mtface= CustomData_get_layer(&psmd->dm->faceData, CD_MTFACE);
			if(mtface) {
				mface= psmd->dm->getFaceData(psmd->dm, cpa->num, CD_MFACE);
				mtface += cpa->num;
				psys_interpolate_uvs(mtface, mface->v4, cpa->fuv, uv);
			}
		
			psys_particle_on_emitter(psmd,PART_FROM_FACE,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,loc,0,0,0,orco,0);
			return;
		}
		else {
			pa = psys->particles + cpa->pa[0];
		}
	}

	if(part->from == PART_FROM_FACE) {
		mtface= CustomData_get_layer(&psmd->dm->faceData, CD_MTFACE);
		num= pa->num_dmcache;

		if(num == DMCACHE_NOTFOUND)
			num= pa->num;

		if (num >= psmd->dm->getNumFaces(psmd->dm)) {
			/* happens when simplify is enabled
				* gives invalid coords but would crash otherwise */
			num= DMCACHE_NOTFOUND;
		}

		if(mtface && num != DMCACHE_NOTFOUND) {
			mface= psmd->dm->getFaceData(psmd->dm, num, CD_MFACE);
			mtface += num;
			psys_interpolate_uvs(mtface, mface->v4, pa->fuv, uv);
		}
	}

	psys_particle_on_emitter(psmd,part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,loc,0,0,0,orco,0);
}

void psys_get_dupli_path_transform(ParticleSimulationData *sim, ParticleData *pa, ChildParticle *cpa, ParticleCacheKey *cache, float mat[][4], float *scale)
{
	Object *ob = sim->ob;
	ParticleSystem *psys = sim->psys;
	ParticleSystemModifierData *psmd = sim->psmd;
	float loc[3], nor[3], vec[3], side[3], len, obrotmat[4][4], qmat[4][4];
	float xvec[3] = {-1.0, 0.0, 0.0}, q[4], nmat[3][3];

	sub_v3_v3v3(vec, (cache+cache->steps)->co, cache->co);
	len= normalize_v3(vec);

	if(psys->part->rotmode) {
		if(pa == NULL)
			pa= psys->particles+cpa->pa[0];

		vec_to_quat( q,xvec, ob->trackflag, ob->upflag);
		quat_to_mat4( obrotmat,q);
		obrotmat[3][3]= 1.0f;

		quat_to_mat4( qmat,pa->state.rot);
		mul_m4_m4m4(mat, obrotmat, qmat);
	}
	else {
		if(pa == NULL && psys->part->childflat != PART_CHILD_FACES)
			pa = psys->particles + cpa->pa[0];

		if(pa)
			psys_particle_on_emitter(psmd,sim->psys->part->from,pa->num,pa->num_dmcache,pa->fuv,pa->foffset,loc,nor,0,0,0,0);
		else
			psys_particle_on_emitter(psmd,PART_FROM_FACE,cpa->num,DMCACHE_ISCHILD,cpa->fuv,cpa->foffset,loc,nor,0,0,0,0);
		
		copy_m3_m4(nmat, ob->imat);
		transpose_m3(nmat);
		mul_m3_v3(nmat, nor);

		/* make sure that we get a proper side vector */
		if(fabs(dot_v3v3(nor,vec))>0.999999) {
			if(fabs(dot_v3v3(nor,xvec))>0.999999) {
				nor[0] = 0.0f;
				nor[1] = 1.0f;
				nor[2] = 0.0f;
			}
			else {
				nor[0] = 1.0f;
				nor[1] = 0.0f;
				nor[2] = 0.0f;
			}
		}
		cross_v3_v3v3(side, nor, vec);
		normalize_v3(side);
		cross_v3_v3v3(nor, vec, side);

		unit_m4(mat);
		VECCOPY(mat[0], vec);
		VECCOPY(mat[1], side);
		VECCOPY(mat[2], nor);
	}

	*scale= len;
}

void psys_make_billboard(ParticleBillboardData *bb, float xvec[3], float yvec[3], float zvec[3], float center[3])
{
	float onevec[3] = {0.0f,0.0f,0.0f}, tvec[3], tvec2[3];

	xvec[0] = 1.0f; xvec[1] = 0.0f; xvec[2] = 0.0f;
	yvec[0] = 0.0f; yvec[1] = 1.0f; yvec[2] = 0.0f;

    /* can happen with bad pointcache or physics calculation
     * since this becomes geometry, nan's and inf's crash raytrace code.
     * better not allow this. */
    if( !finite(bb->vec[0]) || !finite(bb->vec[1]) || !finite(bb->vec[2]) ||
        !finite(bb->vel[0]) || !finite(bb->vel[1]) || !finite(bb->vel[2]) )
    {
        zero_v3(bb->vec);
        zero_v3(bb->vel);
        
        zero_v3(xvec);
        zero_v3(yvec);
        zero_v3(zvec);
        zero_v3(center);

        return;
    }

	if(bb->align < PART_BB_VIEW)
		onevec[bb->align]=1.0f;

	if(bb->lock && (bb->align == PART_BB_VIEW)) {
		normalize_v3_v3(xvec, bb->ob->obmat[0]);
		normalize_v3_v3(yvec, bb->ob->obmat[1]);
		normalize_v3_v3(zvec, bb->ob->obmat[2]);
	}
	else if(bb->align == PART_BB_VEL) {
		float temp[3];

		normalize_v3_v3(temp, bb->vel);

		VECSUB(zvec, bb->ob->obmat[3], bb->vec);

		if(bb->lock) {
			float fac = -dot_v3v3(zvec, temp);

			VECADDFAC(zvec, zvec, temp, fac);
		}
		normalize_v3(zvec);

		cross_v3_v3v3(xvec,temp,zvec);
		normalize_v3(xvec);

		cross_v3_v3v3(yvec,zvec,xvec);
	}
	else {
		VECSUB(zvec, bb->ob->obmat[3], bb->vec);
		if(bb->lock)
			zvec[bb->align] = 0.0f;
		normalize_v3(zvec);

		if(bb->align < PART_BB_VIEW)
			cross_v3_v3v3(xvec, onevec, zvec);
		else
			cross_v3_v3v3(xvec, bb->ob->obmat[1], zvec);
		normalize_v3(xvec);

		cross_v3_v3v3(yvec,zvec,xvec);
	}

	VECCOPY(tvec, xvec);
	VECCOPY(tvec2, yvec);

	mul_v3_fl(xvec, cos(bb->tilt * (float)M_PI));
	mul_v3_fl(tvec2, sin(bb->tilt * (float)M_PI));
	VECADD(xvec, xvec, tvec2);

	mul_v3_fl(yvec, cos(bb->tilt * (float)M_PI));
	mul_v3_fl(tvec, -sin(bb->tilt * (float)M_PI));
	VECADD(yvec, yvec, tvec);

	mul_v3_fl(xvec, bb->size);
	mul_v3_fl(yvec, bb->size);

	VECADDFAC(center, bb->vec, xvec, bb->offset[0]);
	VECADDFAC(center, center, yvec, bb->offset[1]);
}


void psys_apply_hair_lattice(Scene *scene, Object *ob, ParticleSystem *psys) {
	ParticleSimulationData sim= {0};
	sim.scene= scene;
	sim.ob= ob;
	sim.psys= psys;
	sim.psmd= psys_get_modifier(ob, psys);

	psys->lattice = psys_get_lattice(&sim);

	if(psys->lattice) {
		ParticleData *pa = psys->particles;
		HairKey *hkey;
		int p, h;
		float hairmat[4][4], imat[4][4];

		for(p=0; p<psys->totpart; p++, pa++) {
			psys_mat_hair_to_global(sim.ob, sim.psmd->dm, psys->part->from, pa, hairmat);
			invert_m4_m4(imat, hairmat);

			hkey = pa->hair;
			for(h=0; h<pa->totkey; h++, hkey++) {
				mul_m4_v3(hairmat, hkey->co);
				calc_latt_deform(psys->lattice, hkey->co, 1.0f);
				mul_m4_v3(imat, hkey->co);
			}
		}
		
		end_latt_deform(psys->lattice);
		psys->lattice= NULL;

		/* protect the applied shape */
		psys->flag |= PSYS_EDITED;
	}
}