Point Cache Refactoring

=======================

Caching and Baking:
- The point cache is now cleared on DAG_object_flush_update(), and not cleared for time dependency graph updates.
- There is now a Bake button instead of Protect. Also cache start and end frames were added to softbody and particles.
- The cloth autoprotect feature was removed.
- The Ctrl+B menu now also bakes cloth and particles next to softbody and fluids. Additionally there are now frree bake and free cache menu entries.
- The point cache api has been changed. There is now a PTCacheID struct for each point cache type that can be filled and then used to call the point cache functions.
- PointCache struct was added to DNA and is automatically allocated for each physics type.
- Soft body now supports Bake Editing just like cloth.
- Tried to make the systems deal consistently with time ipo's and offsets. Still not sure it all works correct, but too complicated to solve completely now.

Library Linking:
- Added some more warnings to prevent editing settings on library linked objects.
- Linked objects now read from the cache located next to the original library file, and never write to it. This restores old behavior for softbodies. For local simulation the mesh and not the object should be linked.
- Dupligroups and proxies can't create local point caches at the moment, how to implement that I'm not sure. We probably need a proxy point cache for that to work (ugh).

Physics UI:
- Renamed deflection panel to collision for consistency and reorganized the buttons. Also removed some softbody collision buttons from the softbody panel that were duplicated in this panel for cloth.
- Tweaked field panel buttons to not jump around when changing options.
- Tabbing e.g. Soft Body Collision into the Soft Body panel, it now only shows Collision to make the panel names readable.
- I tried to make enabled/disabling physics more consistent, since all three system did things different. Now the two modifier buttons to enable the modifier for the viewport and rendering are also duplicated in the physics panels. Toggling the Soft Body and Cloth buttons now both remove their modifiers.
- Fixed modifier error drawing glitch.

Particles:
- Particles are now recalculated more often than before. Previously it did partial updates based on the changes, but that doesn't work well with DAG_object_flush_update() ..
- Fixed memory leak loading keyed particle system. Now keys are not written to file anymore but always created after loading.
- Make particle threads work with autothreads.

Continue Physics:
- The timeline play now has a Continue Physics option in the playback menu, which keeps the simulations going without writing them to the cache.
- This doesn't always work that well, some changes are not immediately updated, but this can be improved later. Still it's fun to get a feel for the physics.

Todo:
- Point cache can get out of sync with and undo and changing a file without saving it.
- Change the point cache file format to store a version (so old point cache files can be either converted or at least ignored), and to do correct endian conversion.
- Menu item and/or buttons for Ctrl+B.
- A system("rm ..") was changed to remove() since the former is very slow for clearing point caches. These system() calls were already giving trouble in a bug in the tracker, but really most use of this system("") should be changed and tested.
- The Soft Body Collision and Clot Collision panel titles don't mention there's point cache settings there too, doing that makes them unreadable with the default panel setup.. but may need to make the names longer anyway.

1 files changed, 298 insertions, 177 deletions

diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c
index 8bde0afb752..cd0d6b5d113 100644
--- a/source/blender/blenkernel/intern/particle_system.c
+++ b/source/blender/blenkernel/intern/particle_system.c
@@ -121,7 +121,48 @@ static int get_current_display_percentage(ParticleSystem *psys)
 		return psys->part->disp;
 }
 
-static void alloc_particles(Object *ob, ParticleSystem *psys, int new_totpart)
+void psys_reset(ParticleSystem *psys, int mode)
+{
+	ParticleSettings *part= psys->part;
+	ParticleData *pa;
+	int i;
+
+	if(ELEM(mode, PSYS_RESET_ALL, PSYS_RESET_DEPSGRAPH)) {
+		if(mode == PSYS_RESET_ALL || !(part->type == PART_HAIR && (psys->flag & PSYS_EDITED))) {
+			if(psys->particles) {
+				if(psys->particles->keys)
+					MEM_freeN(psys->particles->keys);
+
+				for(i=0, pa=psys->particles; i<psys->totpart; i++, pa++)
+					if(pa->hair) MEM_freeN(pa->hair);
+
+				MEM_freeN(psys->particles);
+				psys->particles= NULL;
+			}
+
+			psys->totpart= 0;
+			psys->totkeyed= 0;
+			psys->flag &= ~(PSYS_HAIR_DONE|PSYS_KEYED);
+		}
+	}
+
+	/* reset children */
+	if(psys->child) {
+		MEM_freeN(psys->child);
+		psys->child= 0;
+	}
+
+	psys->totchild= 0;
+
+	/* reset path cache */
+	psys_free_path_cache(psys);
+
+	/* reset point cache */
+	psys->pointcache->flag &= ~PTCACHE_SIMULATION_VALID;
+	psys->pointcache->simframe= 0;
+}
+
+static void realloc_particles(Object *ob, ParticleSystem *psys, int new_totpart)
 {
 	ParticleData *newpars = 0, *pa;
 	int i, totpart, totsaved = 0;
@@ -145,6 +186,12 @@ static void alloc_particles(Object *ob, ParticleSystem *psys, int new_totpart)
 		if(totsaved)
 			memcpy(newpars,psys->particles,totsaved*sizeof(ParticleData));
 
+		if(psys->particles->keys)
+			MEM_freeN(psys->particles->keys);
+
+		for(i=0, pa=psys->particles; i<totsaved; i++, pa++)
+			if(pa->keys) pa->keys= NULL;
+
 		for(i=totsaved, pa=psys->particles+totsaved; i<psys->totpart; i++, pa++)
 			if(pa->hair) MEM_freeN(pa->hair);
 
@@ -1313,7 +1360,7 @@ static void distribute_particles_on_dm(DerivedMesh *finaldm, Object *ob, Particl
 	ParticleThreadContext *ctx;
 	int i, totthread;
 
-	pthreads= psys_threads_create(ob, psys, G.scene->r.threads);
+	pthreads= psys_threads_create(ob, psys);
 
 	if(!psys_threads_init_distribution(pthreads, finaldm, from)) {
 		psys_threads_free(pthreads);
@@ -1385,11 +1432,16 @@ static void distribute_particles(Object *ob, ParticleSystem *psys, int from)
 }
 
 /* threaded child particle distribution and path caching */
-ParticleThread *psys_threads_create(struct Object *ob, struct ParticleSystem *psys, int totthread)
+ParticleThread *psys_threads_create(struct Object *ob, struct ParticleSystem *psys)
 {
 	ParticleThread *threads;
 	ParticleThreadContext *ctx;
-	int i;
+	int i, totthread;
+
+	if(G.scene->r.mode & R_FIXED_THREADS)
+		totthread= G.scene->r.threads;
+	else
+		totthread= BLI_system_thread_count();
 	
 	threads= MEM_callocN(sizeof(ParticleThread)*totthread, "ParticleThread");
 	ctx= MEM_callocN(sizeof(ParticleThreadContext), "ParticleThreadContext");
@@ -1922,7 +1974,8 @@ int psys_count_keyed_targets(Object *ob, ParticleSystem *psys)
 	BLI_freelistN(&lb);
 	return select;
 }
-void set_keyed_keys(Object *ob, ParticleSystem *psys)
+
+static void set_keyed_keys(Object *ob, ParticleSystem *psys)
 {
 	Object *kob = ob;
 	ParticleSystem *kpsys = psys;
@@ -1932,17 +1985,16 @@ void set_keyed_keys(Object *ob, ParticleSystem *psys)
 	float prevtime, nexttime, keyedtime;
 
 	/* no proper targets so let's clear and bail out */
-	if(psys->totkeyed==0){
+	if(psys->totkeyed==0) {
 		free_keyed_keys(psys);
 		psys->flag &= ~PSYS_KEYED;
 		return;
 	}
 
-	if(totpart && psys->particles->totkey != totkeys){
+	if(totpart && psys->particles->totkey != totkeys) {
 		free_keyed_keys(psys);
 		
-		psys->particles->keys = MEM_callocN(psys->totpart * totkeys * sizeof(ParticleKey),"Keyed keys");
-
+		psys->particles->keys = MEM_callocN(psys->totpart*totkeys*sizeof(ParticleKey), "Keyed keys");
 		psys->particles->totkey = totkeys;
 		
 		for(i=1, pa=psys->particles+1; i<totpart; i++,pa++){
@@ -1954,9 +2006,10 @@ void set_keyed_keys(Object *ob, ParticleSystem *psys)
 	psys->flag &= ~PSYS_KEYED;
 	state.time=-1.0;
 
-	for(k=0; k<totkeys; k++){
-		for(i=0,pa=psys->particles; i<totpart; i++, pa++){
-			psys_get_particle_state(kob, kpsys, i%kpsys->totpart, pa->keys + k, 1);
+	for(k=0; k<totkeys; k++) {
+		for(i=0,pa=psys->particles; i<totpart; i++, pa++) {
+			if(kpsys->totpart > 0)
+				psys_get_particle_state(kob, kpsys, i%kpsys->totpart, pa->keys + k, 1);
 
 			if(k==0)
 				pa->keys->time = pa->time;
@@ -2097,60 +2150,57 @@ void psys_get_reactor_target(Object *ob, ParticleSystem *psys, Object **target_o
 /************************************************/
 /*			Point Cache							*/
 /************************************************/
-void clear_particles_from_cache(Object *ob, ParticleSystem *psys, int cfra)
-{
-	ParticleSystemModifierData *psmd = psys_get_modifier(ob,psys);
-	int stack_index = modifiers_indexInObject(ob,(ModifierData*)psmd);
-
-	BKE_ptcache_id_clear((ID *)ob, PTCACHE_CLEAR_ALL, cfra, stack_index);
 
-	/* reactors need to initialize particles always since their birth times might have changed */
-	if(psys && psys->part && psys->part->type == PART_REACTOR)
-		psys->recalc |= PSYS_INIT;
-}
 static void write_particles_to_cache(Object *ob, ParticleSystem *psys, int cfra)
 {
-	FILE *fp = NULL;
-	ParticleSystemModifierData *psmd = psys_get_modifier(ob,psys);
+	PTCacheID pid;
+	PTCacheFile *pf;
 	ParticleData *pa;
-	int stack_index = modifiers_indexInObject(ob,(ModifierData*)psmd);
-	int i, totpart = psys->totpart;
+	int i, totpart= psys->totpart;
 
-	if(totpart == 0) return;
+	if(totpart == 0)
+		return;
 
-	fp = BKE_ptcache_id_fopen((ID *)ob, 'w', cfra, stack_index);
-	if(!fp) return;
+	BKE_ptcache_id_from_particles(&pid, ob, psys);
+	pf= BKE_ptcache_file_open(&pid, PTCACHE_FILE_WRITE, cfra);
+	if(!pf)
+		return;
 
+	/* assuming struct consists of tightly packed floats */
 	for(i=0, pa=psys->particles; i<totpart; i++, pa++)
-		fwrite(&pa->state, sizeof(ParticleKey), 1, fp);
+		BKE_ptcache_file_write_floats(pf, (float*)&pa->state, sizeof(ParticleKey)/sizeof(float));
 	
-	fclose(fp);
+	BKE_ptcache_file_close(pf);
 }
+
 static int get_particles_from_cache(Object *ob, ParticleSystem *psys, int cfra)
 {
-	FILE *fp = NULL;
-	ParticleSystemModifierData *psmd = psys_get_modifier(ob,psys);
+	PTCacheID pid;
+	PTCacheFile *pf;
 	ParticleData *pa;
-	int stack_index = modifiers_indexInObject(ob,(ModifierData*)psmd);
-	int i, totpart = psys->totpart, ret = 1;
+	int i, totpart= psys->totpart;
 
-	if(totpart == 0) return 0;
+	if(totpart == 0)
+		return 0;
 
-	fp = BKE_ptcache_id_fopen((ID *)ob, 'r', cfra, stack_index);
-	if(!fp)
-		ret = 0;
-	else {
-		for(i=0, pa=psys->particles; i<totpart; i++, pa++)
-			if((fread(&pa->state, sizeof(ParticleKey), 1, fp)) != 1) {
-				ret = 0;
-				break;
-			}
-		
-		fclose(fp);
+	BKE_ptcache_id_from_particles(&pid, ob, psys);
+	pf= BKE_ptcache_file_open(&pid, PTCACHE_FILE_READ, cfra);
+	if(!pf)
+		return 0;
+
+	/* assuming struct consists of tightly packed floats */
+	for(i=0, pa=psys->particles; i<totpart; i++, pa++) {
+		if(!BKE_ptcache_file_read_floats(pf, (float*)&pa->state, sizeof(ParticleKey)/sizeof(float))) {
+			BKE_ptcache_file_close(pf);
+			return 0;
+		}
 	}
 
-	return ret;
+	BKE_ptcache_file_close(pf);
+
+	return 1;
 }
+
 /************************************************/
 /*			Effectors							*/
 /************************************************/
@@ -4203,7 +4253,7 @@ static void dynamics_step(Object *ob, ParticleSystem *psys, ParticleSystemModifi
 				copy_particle_key(key,&pa->state,1);
 			}
 
-			if(dfra>0.0 || psys->recalc){
+			if(1) {
 				
 				if(psys->reactevents.first && ELEM(pa->alive,PARS_DEAD,PARS_KILLED)==0)
 					react_to_events(psys,p);
@@ -4306,7 +4356,7 @@ static void psys_update_path_cache(Object *ob, ParticleSystemModifierData *psmd,
 
 	if(distr){
 		if(alloc)
-			alloc_particles(ob,psys,psys->totpart);
+			realloc_particles(ob,psys,psys->totpart);
 
 		if(get_psys_tot_child(psys)) {
 			/* don't generate children while computing the hair keys */
@@ -4366,7 +4416,7 @@ static void hair_step(Object *ob, ParticleSystemModifierData *psmd, ParticleSyst
 }
 
 /* updates cached particles' alive & other flags etc..*/
-static void cached_step(Object *ob, ParticleSystemModifierData *psmd, ParticleSystem *psys, float cfra, float *vg_size)
+static void cached_step(Object *ob, ParticleSystemModifierData *psmd, ParticleSystem *psys, float cfra)
 {
 	ParticleSettings *part=psys->part;
 	ParticleData *pa;
@@ -4374,7 +4424,10 @@ static void cached_step(Object *ob, ParticleSystemModifierData *psmd, ParticleSy
 	IpoCurve *icu_esize=find_ipocurve(part->ipo,PART_EMIT_SIZE);
 	Material *ma=give_current_material(ob,part->omat);
 	int p;
-	float ipotime=cfra, disp, birthtime, dietime;
+	float ipotime=cfra, disp, birthtime, dietime, *vg_size= NULL;
+
+	if(part->from!=PART_FROM_PARTICLE)
+		vg_size= psys_cache_vgroup(psmd->dm,psys,PSYS_VG_SIZE);
 
 	if(psys->effectors.first)
 		psys_end_effectors(psys);
@@ -4437,10 +4490,48 @@ static void cached_step(Object *ob, ParticleSystemModifierData *psmd, ParticleSy
 
 	/* make sure that children are up to date */
 	if(psys->part->childtype && psys->totchild != get_psys_tot_child(psys)) {
-		alloc_particles(ob, psys, psys->totpart);
+		realloc_particles(ob, psys, psys->totpart);
 		distribute_particles(ob, psys, PART_FROM_CHILD);
 	}
+
+	if(vg_size)
+		MEM_freeN(vg_size);
 }
+
+void psys_changed_type(ParticleSystem *psys)
+{
+	ParticleSettings *part;
+
+	part= psys->part;
+
+	/* system type has changed so set sensible defaults and clear non applicable flags */
+	if(part->from == PART_FROM_PARTICLE) {
+		if(part->type != PART_REACTOR)
+			part->from = PART_FROM_FACE;
+		if(part->distr == PART_DISTR_GRID)
+			part->distr = PART_DISTR_JIT;
+	}
+
+	if(psys->part->phystype != PART_PHYS_KEYED)
+		psys->flag &= ~PSYS_KEYED;
+
+	if(part->type == PART_HAIR) {
+		part->draw_as = PART_DRAW_PATH;
+		part->rotfrom = PART_ROT_IINCR;
+	}
+	else {
+		free_hair(psys, 1);
+
+		if(part->draw_as == PART_DRAW_PATH)
+			if(psys->part->phystype != PART_PHYS_KEYED)
+				part->draw_as = PART_DRAW_DOT;
+	}
+
+	psys->softflag= 0;
+
+	psys_reset(psys, PSYS_RESET_ALL);
+}
+
 static void particles_fluid_step(Object *ob, ParticleSystem *psys, int cfra)
 {
 	if(psys->particles){
@@ -4448,6 +4539,7 @@ static void particles_fluid_step(Object *ob, ParticleSystem *psys, int cfra)
 		psys->particles = 0;
 		psys->totpart = 0;
 	}
+
 	/* fluid sim particle import handling, actual loading of particles from file */
 	#ifndef DISABLE_ELBEEM
 	if( (1) && (ob->fluidsimFlag & OB_FLUIDSIM_ENABLE) &&  // broken, disabled for now!
@@ -4488,7 +4580,7 @@ static void particles_fluid_step(Object *ob, ParticleSystem *psys, int cfra)
 		part->lifetime = G.scene->r.efra + 1;
 
 		/* initialize particles */
-		alloc_particles(ob, psys, part->totpart);
+		realloc_particles(ob, psys, part->totpart);
 		initialize_all_particles(ob, psys, 0);
 
 		// set up reading mask
@@ -4496,8 +4588,7 @@ static void particles_fluid_step(Object *ob, ParticleSystem *psys, int cfra)
 		
 		for(p=0, pa=psys->particles; p<totpart; p++, pa++) {
 			int ptype=0;
-			short shsize=0;
-			float convertSize=0.0;
+
 			gzread(gzf, &ptype, sizeof( ptype )); 
 			if(ptype&readMask) {
 				activeParts++;
@@ -4540,113 +4631,107 @@ static void particles_fluid_step(Object *ob, ParticleSystem *psys, int cfra)
 	} // fluid sim particles done
 	#endif // DISABLE_ELBEEM
 }
+
 /* Calculates the next state for all particles of the system */
 /* In particles code most fra-ending are frames, time-ending are fra*timestep (seconds)*/
 static void system_step(Object *ob, ParticleSystem *psys, ParticleSystemModifierData *psmd, float cfra)
 {
 	ParticleSettings *part;
 	ParticleData *pa;
-	int totpart,oldtotpart=0,p;
-	float disp, *vg_vel=0, *vg_tan=0, *vg_rot=0, *vg_size=0;
-	int init=0,distr=0,alloc=0;
+	PointCache *cache;
+	PTCacheID pid;
+	int totpart, oldtotpart, totchild, oldtotchild, p;
+	float disp, *vg_vel= 0, *vg_tan= 0, *vg_rot= 0, *vg_size= 0;
+	int init= 0, distr= 0, alloc= 0, usecache= 0;
+	int framenr, framedelta, startframe, endframe;
 
-	/*----start validity checks----*/
+	part= psys->part;
+	cache= psys->pointcache;
 
-	part=psys->part;
+	framenr= (int)CFRA;
+	framedelta= framenr - cache->simframe;
 
-	if(part->flag&PART_ABS_TIME && part->ipo){
+	BKE_ptcache_id_from_particles(&pid, ob, psys);
+	BKE_ptcache_id_time(&pid, 0.0f, &startframe, &endframe, NULL);
+
+	/* update ipo's */
+	if((part->flag & PART_ABS_TIME) && part->ipo) {
 		calc_ipo(part->ipo, cfra);
 		execute_ipo((ID *)part, part->ipo);
 	}
 
-	if(part->from!=PART_FROM_PARTICLE && part->type!=PART_FLUID)
-		vg_size=psys_cache_vgroup(psmd->dm,psys,PSYS_VG_SIZE);
-
-	if(part->type == PART_HAIR) {
-		if(psys->flag & PSYS_HAIR_DONE) {
-			hair_step(ob, psmd, psys, cfra);
-			psys->cfra = cfra;
-			psys->recalc = 0;
-			return;
-		}
+	/* hair if it's already done is handled separate */
+	if(part->type == PART_HAIR && (psys->flag & PSYS_HAIR_DONE)) {
+		hair_step(ob, psmd, psys, cfra);
+		psys->cfra = cfra;
+		psys->recalc = 0;
+		return;
 	}
+	/* fluid is also handled separate */
 	else if(part->type == PART_FLUID) {
-		particles_fluid_step(ob, psys, (int)cfra);
+		particles_fluid_step(ob, psys, framenr);
 		psys->cfra = cfra;
 		psys->recalc = 0;
 		return;
 	}
-	else if(ELEM(part->phystype, PART_PHYS_NO, PART_PHYS_KEYED))
-		; /* cache shouldn't be used for "none" or "keyed" physics */
-	else {
-		if(psys->recalc && (psys->flag & PSYS_PROTECT_CACHE) == 0)
-			clear_particles_from_cache(ob,psys,(int)cfra);
-		else if(get_particles_from_cache(ob, psys, (int)cfra)) {
-			cached_step(ob,psmd,psys,cfra,vg_size);
-			psys->cfra=cfra;
-			psys->recalc = 0;
-			return;
-		}
-	}
 
-	/* if still here react to events */
+	/* cache shouldn't be used for hair or "none" or "first keyed" physics */
+	if(part->type == PART_HAIR || part->phystype == PART_PHYS_NO)
+		usecache= 0;
+	else if(part->type == PART_PHYS_KEYED && (psys->flag & PSYS_FIRST_KEYED))
+		usecache= 0;
+	else if(BKE_ptcache_get_continue_physics())
+		usecache= 0;
+	else
+		usecache= 1;
 
-	if(psys->recalc&PSYS_TYPE) {
-		/* system type has changed so set sensible defaults and clear non applicable flags */
-		if(part->from == PART_FROM_PARTICLE) {
-			if(part->type != PART_REACTOR)
-				part->from = PART_FROM_FACE;
-			if(part->distr == PART_DISTR_GRID)
-				part->distr = PART_DISTR_JIT;
+	if(usecache) {
+		/* frame clamping */
+		if(framenr < startframe) {
+			psys_reset(psys, PSYS_RESET_DEPSGRAPH);
+			psys->cfra = cfra;
+			psys->recalc = 0;
+			return;
 		}
-
-		if(psys->part->phystype != PART_PHYS_KEYED)
-			psys->flag &= ~PSYS_KEYED;
-
-		if(part->type == PART_HAIR) {
-			part->draw_as = PART_DRAW_PATH;
-			part->rotfrom = PART_ROT_IINCR;
+		else if(framenr > endframe) {
+			framenr= endframe;
 		}
-		else
-			free_hair(psys, 1);
-
-		psys->softflag= 0;
-		psys->recalc &= ~PSYS_TYPE;
-		alloc = 1;
-
-		/* this is a bad level call, but currently type change
-		 * can happen after redraw, so force redraw from here */
-		allqueue(REDRAWBUTSOBJECT, 0);
 	}
-	else
-		oldtotpart = psys->totpart;
+
+	/* verify if we need to reallocate */
+	oldtotpart = psys->totpart;
+	oldtotchild = psys->totchild;
 
 	if(part->distr == PART_DISTR_GRID)
-		totpart = part->grid_res * part->grid_res * part->grid_res;
+		totpart = part->grid_res*part->grid_res*part->grid_res;
 	else
 		totpart = psys->part->totpart;
+	totchild = get_psys_tot_child(psys);
 
-	if(oldtotpart != totpart || psys->recalc&PSYS_ALLOC || (psys->part->childtype && psys->totchild != get_psys_tot_child(psys)))
+	if(oldtotpart != totpart || (psys->part->childtype && oldtotchild != totchild)) {
+		realloc_particles(ob, psys, totpart);
 		alloc = 1;
+		distr= 1;
+		init= 1;
+	}
 
-	if(alloc || psys->recalc&PSYS_DISTR || (psys->vgroup[PSYS_VG_DENSITY] && (G.f & G_WEIGHTPAINT) && ob==OBACT))
-		distr = 1;
-
-	if(distr || psys->recalc&PSYS_INIT)
-		init = 1;
+	if(psys->recalc & PSYS_DISTR) {
+		distr= 1;
+		init= 1;
+	}
 
 	if(init) {
 		if(distr) {
 			if(alloc)
-				alloc_particles(ob, psys, totpart);
+				realloc_particles(ob, psys, totpart);
 
 			distribute_particles(ob, psys, part->from);
 
 			if((psys->part->type == PART_HAIR) && !(psys->flag & PSYS_HAIR_DONE))
-				/* don't generate children while growing hair - waste of time */
-				psys_free_children(psys);
-			else if(get_psys_tot_child(psys))
-				distribute_particles(ob, psys, PART_FROM_CHILD);
+			/* don't generate children while growing hair - waste of time */
+			psys_free_children(psys);
+		else if(get_psys_tot_child(psys))
+			distribute_particles(ob, psys, PART_FROM_CHILD);
 		}
 		initialize_all_particles(ob, psys, psmd);
 
@@ -4657,17 +4742,59 @@ static void system_step(Object *ob, ParticleSystem *psys, ParticleSystemModifier
 		psmd->flag |= eParticleSystemFlag_Pars;
 	}
 
+	/* try to read from the cache */
+	if(usecache) {
+		if(get_particles_from_cache(ob, psys, framenr)) {
+			if(part->phystype==PART_PHYS_KEYED && psys->flag&PSYS_FIRST_KEYED) {
+				psys_count_keyed_targets(ob,psys);
+				set_keyed_keys(ob, psys);
+			}
+
+			cached_step(ob,psmd,psys,cfra);
+			psys->cfra=cfra;
+			psys->recalc = 0;
+
+			if(part->phystype==PART_PHYS_KEYED && psys->flag&PSYS_FIRST_KEYED) {
+				psys_update_path_cache(ob,psmd,psys,framenr);
+			}
+
+			return;
+		}
+		else if(ob->id.lib || (cache->flag & PTCACHE_BAKED)) {
+			psys_reset(psys, PSYS_RESET_DEPSGRAPH);
+			psys->cfra=cfra;
+			psys->recalc = 0;
+			return;
+		}
+
+		if(framenr != startframe && framedelta != 1) {
+			psys_reset(psys, PSYS_RESET_DEPSGRAPH);
+			psys->cfra = cfra;
+			psys->recalc = 0;
+			return;
+		}
+	}
+	else {
+		cache->flag &= ~PTCACHE_SIMULATION_VALID;
+		cache->simframe= 0;
+	}
+
+	/* if on second frame, write cache for first frame */
+	if(usecache && framenr == startframe+1)
+		write_particles_to_cache(ob, psys, startframe);
 
 	if(part->phystype==PART_PHYS_KEYED && psys->flag&PSYS_FIRST_KEYED)
 		psys_count_keyed_targets(ob,psys);
 
-	if(part->from!=PART_FROM_PARTICLE){
-		vg_vel=psys_cache_vgroup(psmd->dm,psys,PSYS_VG_VEL);
-		vg_tan=psys_cache_vgroup(psmd->dm,psys,PSYS_VG_TAN);
-		vg_rot=psys_cache_vgroup(psmd->dm,psys,PSYS_VG_ROT);
+	/* initialize vertex groups */
+	if(part->from!=PART_FROM_PARTICLE) {
+		vg_vel= psys_cache_vgroup(psmd->dm,psys,PSYS_VG_VEL);
+		vg_tan= psys_cache_vgroup(psmd->dm,psys,PSYS_VG_TAN);
+		vg_rot= psys_cache_vgroup(psmd->dm,psys,PSYS_VG_ROT);
+		vg_size= psys_cache_vgroup(psmd->dm,psys,PSYS_VG_SIZE);
 	}
 
-	/* set particles to be not calculated */
+	/* set particles to be not calculated TODO: can't work with pointcache */
 	disp= (float)get_current_display_percentage(psys)/50.0f-1.0f;
 
 	for(p=0, pa=psys->particles; p<totpart; p++,pa++){
@@ -4680,15 +4807,16 @@ static void system_step(Object *ob, ParticleSystem *psys, ParticleSystemModifier
 	/* ok now we're all set so let's go */
 	if(psys->totpart)
 		dynamics_step(ob,psys,psmd,cfra,vg_vel,vg_tan,vg_rot,vg_size);
+	
+	cache->simframe= framenr;
+	cache->flag |= PTCACHE_SIMULATION_VALID;
 
 	psys->recalc = 0;
 	psys->cfra = cfra;
 
-	if(part->type == PART_HAIR || part->phystype == PART_PHYS_NO
-		|| (part->phystype == PART_PHYS_KEYED && psys->flag & PSYS_FIRST_KEYED))
-		; /* cache shouldn't be used for hair or "none" or "first keyed" physics */
-	else
-		write_particles_to_cache(ob, psys, cfra);
+	/* only write cache starting from second frame */
+	if(usecache && framenr != startframe)
+		write_particles_to_cache(ob, psys, framenr);
 
 	/* for keyed particles the path is allways known so it can be drawn */
 	if(part->phystype==PART_PHYS_KEYED && psys->flag&PSYS_FIRST_KEYED){
@@ -4698,9 +4826,11 @@ static void system_step(Object *ob, ParticleSystem *psys, ParticleSystemModifier
 	else if(psys->pathcache)
 		psys_free_path_cache(psys);
 
+	/* cleanup */
 	if(vg_vel) MEM_freeN(vg_vel);
 	if(vg_tan) MEM_freeN(vg_tan);
 	if(vg_rot) MEM_freeN(vg_rot);
+	if(vg_size) MEM_freeN(vg_size);
 
 	if(psys->lattice){
 		end_latt_deform();
@@ -4708,106 +4838,97 @@ static void system_step(Object *ob, ParticleSystem *psys, ParticleSystemModifier
 	}
 }
 
-void psys_to_softbody(Object *ob, ParticleSystem *psys, int force_recalc)
+void psys_to_softbody(Object *ob, ParticleSystem *psys)
 {
 	SoftBody *sb;
 	short softflag; 
 
-	if((psys->softflag&OB_SB_ENABLE)==0) return;
-
-	if(psys->recalc || force_recalc)
-		psys->softflag|=OB_SB_REDO;
+	if(!(psys->softflag & OB_SB_ENABLE))
+		return;
 
 	/* let's replace the object's own softbody with the particle softbody */
 	/* a temporary solution before cloth simulation is implemented, jahka */
 
 	/* save these */
-	sb=ob->soft;
-	softflag=ob->softflag;
+	sb= ob->soft;
+	softflag= ob->softflag;
 
 	/* swich to new ones */
-	ob->soft=psys->soft;
-	ob->softflag=psys->softflag;
+	ob->soft= psys->soft;
+	ob->softflag= psys->softflag;
 
 	/* do softbody */
 	sbObjectStep(ob, (float)G.scene->r.cfra, NULL, psys_count_keys(psys));
 
 	/* return things back to normal */
-	psys->soft=ob->soft;
-	psys->softflag=ob->softflag;
+	psys->soft= ob->soft;
+	psys->softflag= ob->softflag;
 	
-	ob->soft=sb;
-	ob->softflag=softflag;
+	ob->soft= sb;
+	ob->softflag= softflag;
 }
+
 static int hair_needs_recalc(ParticleSystem *psys)
 {
-	if((psys->flag & PSYS_EDITED)==0 && (
-		(psys->flag & PSYS_HAIR_DONE)==0
-		|| psys->recalc & PSYS_RECALC_HAIR)
-		) {
+	if((psys->flag & PSYS_EDITED)==0 &&
+		((psys->flag & PSYS_HAIR_DONE)==0 || psys->recalc & PSYS_RECALC_HAIR)) {
 		psys->recalc &= ~PSYS_RECALC_HAIR;
 		return 1;
 	}
 
 	return 0;
 }
-/* main particle update call, checks that things are ok on the large scale before actual particle calculations */
-void particle_system_update(Object *ob, ParticleSystem *psys){
 
-	ParticleSystemModifierData *psmd=0;
+/* main particle update call, checks that things are ok on the large scale before actual particle calculations */
+void particle_system_update(Object *ob, ParticleSystem *psys)
+{
+	ParticleSystemModifierData *psmd;
 	float cfra;
 
 	if(!psys_check_enabled(ob, psys))
 		return;
 
-	cfra=bsystem_time(ob,(float)CFRA,0.0);
+	cfra= bsystem_time(ob, CFRA, 0.0f);
 	psmd= psys_get_modifier(ob, psys);
 
 	/* system was already updated from modifier stack */
-	if(psmd->flag&eParticleSystemFlag_psys_updated) {
+	if(psmd->flag & eParticleSystemFlag_psys_updated) {
 		psmd->flag &= ~eParticleSystemFlag_psys_updated;
 		/* make sure it really was updated to cfra */
-		if(psys->cfra==cfra)
+		if(psys->cfra == cfra)
 			return;
 	}
 
 	if(!psmd->dm)
 		return;
 
-	/* baked path softbody */
-	if(psys->part->type==PART_HAIR && psys->soft)
-		psys_to_softbody(ob, psys, 0);
-
-	/* not needed, this is all handled in hair_step */
-	///* is the mesh changing under the edited particles? */
-	//if((psys->flag & PSYS_EDITED) &&  psys->part->type==PART_HAIR && psys->recalc & PSYS_RECALC_HAIR) {
-	//	/* Just update the particles on the mesh */
-	//	psys_update_edithair_dmfaces(ob, psmd->dm, psys);
-	//}
-	
-	if(psys->part->type==PART_HAIR && hair_needs_recalc(psys)){
+	/* (re-)create hair */
+	if(psys->part->type==PART_HAIR && hair_needs_recalc(psys)) {
 		float hcfra=0.0f;
 		int i;
 
 		free_hair(psys, 0);
 
 		/* first step is negative so particles get killed and reset */
-		psys->cfra=1.0f;
+		psys->cfra= 1.0f;
 
 		for(i=0; i<=psys->part->hair_step; i++){
 			hcfra=100.0f*(float)i/(float)psys->part->hair_step;
-			system_step(ob,psys,psmd,hcfra);
-			save_hair(ob,psys,psmd,hcfra);
+			system_step(ob, psys, psmd, hcfra);
+			save_hair(ob, psys, psmd, hcfra);
 		}
 
 		psys->flag |= PSYS_HAIR_DONE;
-
-		if(psys->softflag&OB_SB_ENABLE)
-			psys_to_softbody(ob,psys,1);
 	}
 
-	system_step(ob,psys,psmd,cfra);
+	/* handle softbody hair */
+	if(psys->part->type==PART_HAIR && psys->soft)
+		psys_to_softbody(ob, psys);
+
+	/* the main particle system step */
+	system_step(ob, psys, psmd, cfra);
 
-	Mat4Invert(psys->imat, ob->obmat);	/* used for duplicators */
+	/* save matrix for duplicators */
+	Mat4Invert(psys->imat, ob->obmat);
 }