blender-archive/source/blender/blenkernel/intern/object_dupli.c

/*
 * 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) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 */

/** \file
 * \ingroup bke
 */

#include <limits.h>
#include <stdlib.h>
#include <stddef.h>

#include "MEM_guardedalloc.h"

#include "BLI_listbase.h"
#include "BLI_string_utf8.h"

#include "BLI_math.h"
#include "BLI_rand.h"

#include "DNA_anim_types.h"
#include "DNA_collection_types.h"
#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_scene_types.h"
#include "DNA_vfont_types.h"

#include "BKE_animsys.h"
#include "BKE_collection.h"
#include "BKE_font.h"
#include "BKE_global.h"
#include "BKE_idprop.h"
#include "BKE_lattice.h"
#include "BKE_main.h"
#include "BKE_mesh.h"
#include "BKE_mesh_iterators.h"
#include "BKE_mesh_runtime.h"
#include "BKE_object.h"
#include "BKE_particle.h"
#include "BKE_scene.h"
#include "BKE_editmesh.h"
#include "BKE_anim.h"

#include "DEG_depsgraph.h"
#include "DEG_depsgraph_query.h"

#include "BLI_strict_flags.h"
#include "BLI_hash.h"

/* Dupli-Geometry */

typedef struct DupliContext {
	Depsgraph *depsgraph;
	Collection *collection; /* XXX child objects are selected from this group if set, could be nicer */
	Object *obedit; /* Only to check if the object is in edit-mode. */

	Scene *scene;
	ViewLayer *view_layer;
	Object *object;
	float space_mat[4][4];

	int persistent_id[MAX_DUPLI_RECUR];
	int level;

	const struct DupliGenerator *gen;

	/* result containers */
	ListBase *duplilist; /* legacy doubly-linked list */
} DupliContext;

typedef struct DupliGenerator {
	short type;				/* dupli type */
	void (*make_duplis)(const DupliContext *ctx);
} DupliGenerator;

static const DupliGenerator *get_dupli_generator(const DupliContext *ctx);

/* create initial context for root object */
static void init_context(
        DupliContext *r_ctx, Depsgraph *depsgraph,
        Scene *scene, Object *ob, float space_mat[4][4])
{
	r_ctx->depsgraph = depsgraph;
	r_ctx->scene = scene;
	r_ctx->view_layer = DEG_get_evaluated_view_layer(depsgraph);
	r_ctx->collection = NULL;

	r_ctx->object = ob;
	r_ctx->obedit = OBEDIT_FROM_OBACT(ob);
	if (space_mat)
		copy_m4_m4(r_ctx->space_mat, space_mat);
	else
		unit_m4(r_ctx->space_mat);
	r_ctx->level = 0;

	r_ctx->gen = get_dupli_generator(r_ctx);

	r_ctx->duplilist = NULL;
}

/* create sub-context for recursive duplis */
static void copy_dupli_context(DupliContext *r_ctx, const DupliContext *ctx, Object *ob, float mat[4][4], int index)
{
	*r_ctx = *ctx;

	/* XXX annoying, previously was done by passing an ID* argument, this at least is more explicit */
	if (ctx->gen->type == OB_DUPLICOLLECTION)
		r_ctx->collection = ctx->object->instance_collection;

	r_ctx->object = ob;
	if (mat)
		mul_m4_m4m4(r_ctx->space_mat, (float (*)[4])ctx->space_mat, mat);
	r_ctx->persistent_id[r_ctx->level] = index;
	++r_ctx->level;

	r_ctx->gen = get_dupli_generator(r_ctx);
}

/* generate a dupli instance
 * mat is transform of the object relative to current context (including object obmat)
 */
static DupliObject *make_dupli(const DupliContext *ctx,
                               Object *ob, float mat[4][4], int index)
{
	DupliObject *dob;
	int i;

	/* add a DupliObject instance to the result container */
	if (ctx->duplilist) {
		dob = MEM_callocN(sizeof(DupliObject), "dupli object");
		BLI_addtail(ctx->duplilist, dob);
	}
	else {
		return NULL;
	}

	dob->ob = ob;
	mul_m4_m4m4(dob->mat, (float (*)[4])ctx->space_mat, mat);
	dob->type = ctx->gen->type;

	/* set persistent id, which is an array with a persistent index for each level
	 * (particle number, vertex number, ..). by comparing this we can find the same
	 * dupli object between frames, which is needed for motion blur. last level
	 * goes first in the array. */
	dob->persistent_id[0] = index;
	for (i = 1; i < ctx->level + 1; i++)
		dob->persistent_id[i] = ctx->persistent_id[ctx->level - i];
	/* fill rest of values with INT_MAX which index will never have as value */
	for (; i < MAX_DUPLI_RECUR; i++)
		dob->persistent_id[i] = INT_MAX;

	/* metaballs never draw in duplis, they are instead merged into one by the basis
	 * mball outside of the group. this does mean that if that mball is not in the
	 * scene, they will not show up at all, limitation that should be solved once. */
	if (ob->type == OB_MBALL)
		dob->no_draw = true;

	/* random number */
	/* the logic here is designed to match Cycles */
	dob->random_id = BLI_hash_string(dob->ob->id.name + 2);

	if (dob->persistent_id[0] != INT_MAX) {
		for (i = 0; i < MAX_DUPLI_RECUR * 2; i++) {
			dob->random_id = BLI_hash_int_2d(dob->random_id, (unsigned int)dob->persistent_id[i]);
		}
	}
	else {
		dob->random_id = BLI_hash_int_2d(dob->random_id, 0);
	}

	if (ctx->object != ob) {
		dob->random_id ^= BLI_hash_int(BLI_hash_string(ctx->object->id.name + 2));
	}

	return dob;
}

/* recursive dupli objects
 * space_mat is the local dupli space (excluding dupli object obmat!)
 */
static void make_recursive_duplis(const DupliContext *ctx, Object *ob, float space_mat[4][4], int index)
{
	/* simple preventing of too deep nested collections with MAX_DUPLI_RECUR */
	if (ctx->level < MAX_DUPLI_RECUR) {
		DupliContext rctx;
		copy_dupli_context(&rctx, ctx, ob, space_mat, index);
		if (rctx.gen) {
			rctx.gen->make_duplis(&rctx);
		}
	}
}

/* ---- Child Duplis ---- */

typedef void (*MakeChildDuplisFunc)(const DupliContext *ctx, void *userdata, Object *child);

static bool is_child(const Object *ob, const Object *parent)
{
	const Object *ob_parent = ob->parent;
	while (ob_parent) {
		if (ob_parent == parent)
			return true;
		ob_parent = ob_parent->parent;
	}
	return false;
}

/* create duplis from every child in scene or collection */
static void make_child_duplis(const DupliContext *ctx, void *userdata, MakeChildDuplisFunc make_child_duplis_cb)
{
	Object *parent = ctx->object;

	if (ctx->collection) {
		eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
		FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(ctx->collection, ob, mode)
		{
			if ((ob != ctx->obedit) && is_child(ob, parent)) {
				DupliContext pctx;
				copy_dupli_context(&pctx, ctx, ctx->object, NULL, _base_id);

				/* metaballs have a different dupli handling */
				if (ob->type != OB_MBALL) {
					ob->flag |= OB_DONE;  /* doesn't render */
				}
				make_child_duplis_cb(&pctx, userdata, ob);
			}
		}
		FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
	}
	else {
		int baseid = 0;
		ViewLayer *view_layer = ctx->view_layer;
		for (Base *base = view_layer->object_bases.first; base; base = base->next, baseid++) {
			Object *ob = base->object;
			if ((ob != ctx->obedit) && is_child(ob, parent)) {
				DupliContext pctx;
				copy_dupli_context(&pctx, ctx, ctx->object, NULL, baseid);

				/* metaballs have a different dupli handling */
				if (ob->type != OB_MBALL)
					ob->flag |= OB_DONE;  /* doesn't render */

				make_child_duplis_cb(&pctx, userdata, ob);
			}
		}
	}
}


/*---- Implementations ----*/

/* OB_DUPLICOLLECTION */
static void make_duplis_collection(const DupliContext *ctx)
{
	Object *ob = ctx->object;
	Collection *collection;
	float collection_mat[4][4];

	if (ob->instance_collection == NULL) return;
	collection = ob->instance_collection;

	/* combine collection offset and obmat */
	unit_m4(collection_mat);
	sub_v3_v3(collection_mat[3], collection->instance_offset);
	mul_m4_m4m4(collection_mat, ob->obmat, collection_mat);
	/* don't access 'ob->obmat' from now on. */

	eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
	FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(collection, cob, mode)
	{
		if (cob != ob) {
			float mat[4][4];

			/* collection dupli offset, should apply after everything else */
			mul_m4_m4m4(mat, collection_mat, cob->obmat);

			make_dupli(ctx, cob, mat, _base_id);

			/* recursion */
			make_recursive_duplis(ctx, cob, collection_mat, _base_id);
		}
	}
	FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
}

static const DupliGenerator gen_dupli_collection = {
    OB_DUPLICOLLECTION,             /* type */
    make_duplis_collection          /* make_duplis */
};

/* OB_DUPLIVERTS */
typedef struct VertexDupliData {
	Mesh *me_eval;
	BMEditMesh *edit_mesh;
	int totvert;
	float (*orco)[3];
	bool use_rotation;

	const DupliContext *ctx;
	Object *inst_ob; /* object to instantiate (argument for vertex map callback) */
	float child_imat[4][4];
} VertexDupliData;

static void get_duplivert_transform(const float co[3], const short no[3],
                                    bool use_rotation, short axis, short upflag, float mat[4][4])
{
	float quat[4];
	const float size[3] = {1.0f, 1.0f, 1.0f};

	if (use_rotation) {
		/* construct rotation matrix from normals */
		float nor_f[3];
		nor_f[0] = (float)-no[0];
		nor_f[1] = (float)-no[1];
		nor_f[2] = (float)-no[2];
		vec_to_quat(quat, nor_f, axis, upflag);
	}
	else
		unit_qt(quat);

	loc_quat_size_to_mat4(mat, co, quat, size);
}

static void vertex_dupli(const VertexDupliData *vdd, int index, const float co[3], const short no[3])
{
	Object *inst_ob = vdd->inst_ob;
	DupliObject *dob;
	float obmat[4][4], space_mat[4][4];

	/* obmat is transform to vertex */
	get_duplivert_transform(co, no, vdd->use_rotation, inst_ob->trackflag, inst_ob->upflag, obmat);
	/* make offset relative to inst_ob using relative child transform */
	mul_mat3_m4_v3((float (*)[4])vdd->child_imat, obmat[3]);
	/* apply obmat _after_ the local vertex transform */
	mul_m4_m4m4(obmat, inst_ob->obmat, obmat);

	/* space matrix is constructed by removing obmat transform,
	 * this yields the worldspace transform for recursive duplis
	 */
	mul_m4_m4m4(space_mat, obmat, inst_ob->imat);

	dob = make_dupli(vdd->ctx, vdd->inst_ob, obmat, index);

	if (vdd->orco)
		copy_v3_v3(dob->orco, vdd->orco[index]);

	/* recursion */
	make_recursive_duplis(vdd->ctx, vdd->inst_ob, space_mat, index);
}

static void make_child_duplis_verts(const DupliContext *ctx, void *userdata, Object *child)
{
	VertexDupliData *vdd = userdata;
	Mesh *me_eval = vdd->me_eval;

	vdd->inst_ob = child;
	invert_m4_m4(child->imat, child->obmat);
	/* relative transform from parent to child space */
	mul_m4_m4m4(vdd->child_imat, child->imat, ctx->object->obmat);

	const MVert *mvert = me_eval->mvert;
	const int *origindex = CustomData_get_layer(&me_eval->vdata, CD_ORIGINDEX);

	for (int i = 0, j = 0; i < me_eval->totvert; i++) {
		if (origindex == NULL || origindex[i] != ORIGINDEX_NONE) {
			vertex_dupli(vdd, j++, mvert[i].co, mvert[i].no);
		}
	}
}

static void make_duplis_verts(const DupliContext *ctx)
{
	Object *parent = ctx->object;
	VertexDupliData vdd;

	vdd.ctx = ctx;
	vdd.use_rotation = parent->transflag & OB_DUPLIROT;

	/* gather mesh info */
	{
		vdd.edit_mesh = BKE_editmesh_from_object(parent);

		/* We do not need any render-specific handling anymore, depsgraph takes care of that. */
		/* NOTE: Do direct access to the evaluated mesh: this function is used
		 * during meta balls evaluation. But even without those all the objects
		 * which are needed for correct instancing are already evaluated. */
		if (vdd.edit_mesh != NULL) {
			vdd.me_eval = vdd.edit_mesh->mesh_eval_cage;
		}
		else {
			vdd.me_eval = parent->runtime.mesh_eval;
		}

		if (vdd.me_eval == NULL) {
			return;
		}

		vdd.orco = CustomData_get_layer(&vdd.me_eval->vdata, CD_ORCO);
		vdd.totvert = vdd.me_eval->totvert;
	}

	make_child_duplis(ctx, &vdd, make_child_duplis_verts);

	vdd.me_eval = NULL;
}

static const DupliGenerator gen_dupli_verts = {
    OB_DUPLIVERTS,                  /* type */
    make_duplis_verts               /* make_duplis */
};

/* OB_DUPLIVERTS - FONT */
static Object *find_family_object(Main *bmain, const char *family, size_t family_len, unsigned int ch, GHash *family_gh)
{
	Object **ob_pt;
	Object *ob;
	void *ch_key = POINTER_FROM_UINT(ch);

	if ((ob_pt = (Object **)BLI_ghash_lookup_p(family_gh, ch_key))) {
		ob = *ob_pt;
	}
	else {
		char ch_utf8[7];
		size_t ch_utf8_len;

		ch_utf8_len = BLI_str_utf8_from_unicode(ch, ch_utf8);
		ch_utf8[ch_utf8_len] = '\0';
		ch_utf8_len += 1;  /* compare with null terminator */

		for (ob = bmain->objects.first; ob; ob = ob->id.next) {
			if (STREQLEN(ob->id.name + 2 + family_len, ch_utf8, ch_utf8_len)) {
				if (STREQLEN(ob->id.name + 2, family, family_len)) {
					break;
				}
			}
		}

		/* inserted value can be NULL, just to save searches in future */
		BLI_ghash_insert(family_gh, ch_key, ob);
	}

	return ob;
}

static void make_duplis_font(const DupliContext *ctx)
{
	Object *par = ctx->object;
	GHash *family_gh;
	Object *ob;
	Curve *cu;
	struct CharTrans *ct, *chartransdata = NULL;
	float vec[3], obmat[4][4], pmat[4][4], fsize, xof, yof;
	int text_len, a;
	size_t family_len;
	const wchar_t *text = NULL;
	bool text_free = false;

	/* font dupliverts not supported inside collections */
	if (ctx->collection)
		return;

	copy_m4_m4(pmat, par->obmat);

	/* in par the family name is stored, use this to find the other objects */

	BKE_vfont_to_curve_ex(par, par->data, FO_DUPLI, NULL,
	                      &text, &text_len, &text_free, &chartransdata);

	if (text == NULL || chartransdata == NULL) {
		return;
	}

	cu = par->data;
	fsize = cu->fsize;
	xof = cu->xof;
	yof = cu->yof;

	ct = chartransdata;

	/* cache result */
	family_len = strlen(cu->family);
	family_gh = BLI_ghash_int_new_ex(__func__, 256);

	/* advance matching BLI_strncpy_wchar_from_utf8 */
	for (a = 0; a < text_len; a++, ct++) {

		/* XXX That G.main is *really* ugly, but not sure what to do here...
		 * Definitively don't think it would be safe to put back Main *bmain pointer in DupliContext as done in 2.7x? */
		ob = find_family_object(G.main, cu->family, family_len, (unsigned int)text[a], family_gh);
		if (ob) {
			vec[0] = fsize * (ct->xof - xof);
			vec[1] = fsize * (ct->yof - yof);
			vec[2] = 0.0;

			mul_m4_v3(pmat, vec);

			copy_m4_m4(obmat, par->obmat);

			if (UNLIKELY(ct->rot != 0.0f)) {
				float rmat[4][4];

				zero_v3(obmat[3]);
				axis_angle_to_mat4_single(rmat, 'Z', -ct->rot);
				mul_m4_m4m4(obmat, obmat, rmat);
			}

			copy_v3_v3(obmat[3], vec);

			make_dupli(ctx, ob, obmat, a);
		}
	}

	if (text_free) {
		MEM_freeN((void *)text);
	}

	BLI_ghash_free(family_gh, NULL, NULL);

	MEM_freeN(chartransdata);
}

static const DupliGenerator gen_dupli_verts_font = {
    OB_DUPLIVERTS,                  /* type */
    make_duplis_font                /* make_duplis */
};

/* OB_DUPLIFACES */
typedef struct FaceDupliData {
	Mesh *me_eval;
	int totface;
	MPoly *mpoly;
	MLoop *mloop;
	MVert *mvert;
	float (*orco)[3];
	MLoopUV *mloopuv;
	bool use_scale;
} FaceDupliData;

static void get_dupliface_transform(MPoly *mpoly, MLoop *mloop, MVert *mvert,
                                    bool use_scale, float scale_fac, float mat[4][4])
{
	float loc[3], quat[4], scale, size[3];
	float f_no[3];

	/* location */
	BKE_mesh_calc_poly_center(mpoly, mloop, mvert, loc);
	/* rotation */
	{
		const float *v1, *v2, *v3;
		BKE_mesh_calc_poly_normal(mpoly, mloop, mvert, f_no);
		v1 = mvert[mloop[0].v].co;
		v2 = mvert[mloop[1].v].co;
		v3 = mvert[mloop[2].v].co;
		tri_to_quat_ex(quat, v1, v2, v3, f_no);
	}
	/* scale */
	if (use_scale) {
		float area = BKE_mesh_calc_poly_area(mpoly, mloop, mvert);
		scale = sqrtf(area) * scale_fac;
	}
	else
		scale = 1.0f;
	size[0] = size[1] = size[2] = scale;

	loc_quat_size_to_mat4(mat, loc, quat, size);
}

static void make_child_duplis_faces(const DupliContext *ctx, void *userdata, Object *inst_ob)
{
	FaceDupliData *fdd = userdata;
	MPoly *mpoly = fdd->mpoly, *mp;
	MLoop *mloop = fdd->mloop;
	MVert *mvert = fdd->mvert;
	float (*orco)[3] = fdd->orco;
	MLoopUV *mloopuv = fdd->mloopuv;
	int a, totface = fdd->totface;
	float child_imat[4][4];
	DupliObject *dob;

	invert_m4_m4(inst_ob->imat, inst_ob->obmat);
	/* relative transform from parent to child space */
	mul_m4_m4m4(child_imat, inst_ob->imat, ctx->object->obmat);

	for (a = 0, mp = mpoly; a < totface; a++, mp++) {
		MLoop *loopstart = mloop + mp->loopstart;
		float space_mat[4][4], obmat[4][4];

		if (UNLIKELY(mp->totloop < 3))
			continue;

		/* obmat is transform to face */
		get_dupliface_transform(mp, loopstart, mvert, fdd->use_scale, ctx->object->instance_faces_scale, obmat);
		/* make offset relative to inst_ob using relative child transform */
		mul_mat3_m4_v3(child_imat, obmat[3]);

		/* XXX ugly hack to ensure same behavior as in master
		 * this should not be needed, parentinv is not consistent
		 * outside of parenting.
		 */
		{
			float imat[3][3];
			copy_m3_m4(imat, inst_ob->parentinv);
			mul_m4_m3m4(obmat, imat, obmat);
		}

		/* apply obmat _after_ the local face transform */
		mul_m4_m4m4(obmat, inst_ob->obmat, obmat);

		/* space matrix is constructed by removing obmat transform,
		 * this yields the worldspace transform for recursive duplis
		 */
		mul_m4_m4m4(space_mat, obmat, inst_ob->imat);

		dob = make_dupli(ctx, inst_ob, obmat, a);

		const float w = 1.0f / (float)mp->totloop;
		if (orco) {
			for (int j = 0; j < mp->totloop; j++) {
				madd_v3_v3fl(dob->orco, orco[loopstart[j].v], w);
			}
		}
		if (mloopuv) {
			for (int j = 0; j < mp->totloop; j++) {
				madd_v2_v2fl(dob->uv, mloopuv[mp->loopstart + j].uv, w);
			}
		}

		/* recursion */
		make_recursive_duplis(ctx, inst_ob, space_mat, a);
	}
}

static void make_duplis_faces(const DupliContext *ctx)
{
	Object *parent = ctx->object;
	FaceDupliData fdd;

	fdd.use_scale = ((parent->transflag & OB_DUPLIFACES_SCALE) != 0);

	/* gather mesh info */
	{
		BMEditMesh *em = BKE_editmesh_from_object(parent);

		/* We do not need any render-smecific handling anymore, depsgraph takes care of that. */
		/* NOTE: Do direct access to the evaluated mesh: this function is used
		 * during meta balls evaluation. But even without those all the objects
		 * which are needed for correct instancing are already evaluated. */
		if (em != NULL) {
			fdd.me_eval = em->mesh_eval_cage;
		}
		else {
			fdd.me_eval = parent->runtime.mesh_eval;
		}

		if (fdd.me_eval == NULL) {
			return;
		}

		fdd.orco = CustomData_get_layer(&fdd.me_eval->vdata, CD_ORCO);
		const int uv_idx = CustomData_get_render_layer(&fdd.me_eval->ldata, CD_MLOOPUV);
		fdd.mloopuv = CustomData_get_layer_n(&fdd.me_eval->ldata, CD_MLOOPUV, uv_idx);

		fdd.totface = fdd.me_eval->totpoly;
		fdd.mpoly = fdd.me_eval->mpoly;
		fdd.mloop = fdd.me_eval->mloop;
		fdd.mvert = fdd.me_eval->mvert;
	}

	make_child_duplis(ctx, &fdd, make_child_duplis_faces);

	fdd.me_eval = NULL;
}

static const DupliGenerator gen_dupli_faces = {
    OB_DUPLIFACES,                  /* type */
    make_duplis_faces               /* make_duplis */
};

/* OB_DUPLIPARTS */
static void make_duplis_particle_system(const DupliContext *ctx, ParticleSystem *psys)
{
	Scene *scene = ctx->scene;
	Object *par = ctx->object;
	eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
	bool for_render = mode == DAG_EVAL_RENDER;

	Object *ob = NULL, **oblist = NULL;
	DupliObject *dob;
	ParticleDupliWeight *dw;
	ParticleSettings *part;
	ParticleData *pa;
	ChildParticle *cpa = NULL;
	ParticleKey state;
	ParticleCacheKey *cache;
	float ctime, scale = 1.0f;
	float tmat[4][4], mat[4][4], pamat[4][4], size = 0.0;
	int a, b, hair = 0;
	int totpart, totchild;

	int no_draw_flag = PARS_UNEXIST;

	if (psys == NULL) return;

	part = psys->part;

	if (part == NULL)
		return;

	if (!psys_check_enabled(par, psys, for_render))
		return;

	if (!for_render)
		no_draw_flag |= PARS_NO_DISP;

	ctime = DEG_get_ctime(ctx->depsgraph); /* NOTE: in old animsys, used parent object's timeoffset... */

	totpart = psys->totpart;
	totchild = psys->totchild;

	if ((for_render || part->draw_as == PART_DRAW_REND) && ELEM(part->ren_as, PART_DRAW_OB, PART_DRAW_GR)) {
		ParticleSimulationData sim = {NULL};
		sim.depsgraph = ctx->depsgraph;
		sim.scene = scene;
		sim.ob = par;
		sim.psys = psys;
		sim.psmd = psys_get_modifier(par, psys);
		/* make sure emitter imat is in global coordinates instead of render view coordinates */
		invert_m4_m4(par->imat, par->obmat);

		/* first check for loops (particle system object used as dupli object) */
		if (part->ren_as == PART_DRAW_OB) {
			if (ELEM(part->instance_object, NULL, par))
				return;
		}
		else { /*PART_DRAW_GR */
			if (part->instance_collection == NULL)
				return;

			const ListBase dup_collection_objects = BKE_collection_object_cache_get(part->instance_collection);
			if (BLI_listbase_is_empty(&dup_collection_objects))
				return;

			if (BLI_findptr(&dup_collection_objects, par, offsetof(Base, object))) {
				return;
			}
		}

		/* if we have a hair particle system, use the path cache */
		if (part->type == PART_HAIR) {
			if (psys->flag & PSYS_HAIR_DONE)
				hair = (totchild == 0 || psys->childcache) && psys->pathcache;
			if (!hair)
				return;

			/* we use cache, update totchild according to cached data */
			totchild = psys->totchildcache;
			totpart = psys->totcached;
		}

		RNG *rng = BLI_rng_new_srandom(31415926u + (unsigned int)psys->seed);

		psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);

		/* gather list of objects or single object */
		int totcollection = 0;

		if (part->ren_as == PART_DRAW_GR) {
			if (part->draw & PART_DRAW_COUNT_GR) {
				psys_find_group_weights(part);

				for (dw = part->instance_weights.first; dw; dw = dw->next) {
					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->instance_collection, object, mode)
					{
						if (dw->ob == object) {
							totcollection += dw->count;
							break;
						}
					}
					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
				}
			}
			else {
				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->instance_collection, object, mode)
				{
					(void) object;
					totcollection++;
				}
				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
			}

			oblist = MEM_callocN((size_t)totcollection * sizeof(Object *), "dupcollection object list");

			if (part->draw & PART_DRAW_COUNT_GR) {
				a = 0;
				for (dw = part->instance_weights.first; dw; dw = dw->next) {
					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->instance_collection, object, mode)
					{
						if (dw->ob == object) {
							for (b = 0; b < dw->count; b++, a++) {
								oblist[a] = dw->ob;
							}
							break;
						}
					}
					FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
				}
			}
			else {
				a = 0;
				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->instance_collection, object, mode)
				{
					oblist[a] = object;
					a++;
				}
				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
			}
		}
		else {
			ob = part->instance_object;
		}

		if (totchild == 0 || part->draw & PART_DRAW_PARENT)
			a = 0;
		else
			a = totpart;

		for (pa = psys->particles; a < totpart + totchild; a++, pa++) {
			if (a < totpart) {
				/* handle parent particle */
				if (pa->flag & no_draw_flag)
					continue;

				/* pa_num = pa->num; */ /* UNUSED */
				size = pa->size;
			}
			else {
				/* handle child particle */
				cpa = &psys->child[a - totpart];

				/* pa_num = a; */ /* UNUSED */
				size = psys_get_child_size(psys, cpa, ctime, NULL);
			}

			/* some hair paths might be non-existent so they can't be used for duplication */
			if (hair && psys->pathcache &&
			    ((a < totpart && psys->pathcache[a]->segments < 0) ||
			     (a >= totpart && psys->childcache[a - totpart]->segments < 0)))
			{
				continue;
			}

			if (part->ren_as == PART_DRAW_GR) {
				/* prevent divide by zero below [#28336] */
				if (totcollection == 0)
					continue;

				/* for collections, pick the object based on settings */
				if (part->draw & PART_DRAW_RAND_GR)
					b = BLI_rng_get_int(rng) % totcollection;
				else
					b = a % totcollection;

				ob = oblist[b];
			}

			if (hair) {
				/* hair we handle separate and compute transform based on hair keys */
				if (a < totpart) {
					cache = psys->pathcache[a];
					psys_get_dupli_path_transform(&sim, pa, NULL, cache, pamat, &scale);
				}
				else {
					cache = psys->childcache[a - totpart];
					psys_get_dupli_path_transform(&sim, NULL, cpa, cache, pamat, &scale);
				}

				copy_v3_v3(pamat[3], cache->co);
				pamat[3][3] = 1.0f;

			}
			else {
				/* first key */
				state.time = ctime;
				if (psys_get_particle_state(&sim, a, &state, 0) == 0) {
					continue;
				}
				else {
					float tquat[4];
					normalize_qt_qt(tquat, state.rot);
					quat_to_mat4(pamat, tquat);
					copy_v3_v3(pamat[3], state.co);
					pamat[3][3] = 1.0f;
				}
			}

			if (part->ren_as == PART_DRAW_GR && psys->part->draw & PART_DRAW_WHOLE_GR) {
				b = 0;
				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN(part->instance_collection, object, mode)
				{
					copy_m4_m4(tmat, oblist[b]->obmat);

					/* apply particle scale */
					mul_mat3_m4_fl(tmat, size * scale);
					mul_v3_fl(tmat[3], size * scale);

					/* collection dupli offset, should apply after everything else */
					if (!is_zero_v3(part->instance_collection->instance_offset)) {
						sub_v3_v3(tmat[3], part->instance_collection->instance_offset);
					}

					/* individual particle transform */
					mul_m4_m4m4(mat, pamat, tmat);

					dob = make_dupli(ctx, object, mat, a);
					dob->particle_system = psys;

					psys_get_dupli_texture(psys, part, sim.psmd, pa, cpa, dob->uv, dob->orco);

					b++;
				}
				FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
			}
			else {
				float obmat[4][4];
				copy_m4_m4(obmat, ob->obmat);

				float vec[3];
				copy_v3_v3(vec, obmat[3]);
				zero_v3(obmat[3]);

				/* particle rotation uses x-axis as the aligned axis, so pre-rotate the object accordingly */
				if ((part->draw & PART_DRAW_ROTATE_OB) == 0) {
					float xvec[3], q[4], size_mat[4][4], original_size[3];

					mat4_to_size(original_size, obmat);
					size_to_mat4(size_mat, original_size);

					xvec[0] = -1.f;
					xvec[1] = xvec[2] = 0;
					vec_to_quat(q, xvec, ob->trackflag, ob->upflag);
					quat_to_mat4(obmat, q);
					obmat[3][3] = 1.0f;

					/* add scaling if requested */
					if ((part->draw & PART_DRAW_NO_SCALE_OB) == 0)
						mul_m4_m4m4(obmat, obmat, size_mat);
				}
				else if (part->draw & PART_DRAW_NO_SCALE_OB) {
					/* remove scaling */
					float size_mat[4][4], original_size[3];

					mat4_to_size(original_size, obmat);
					size_to_mat4(size_mat, original_size);
					invert_m4(size_mat);

					mul_m4_m4m4(obmat, obmat, size_mat);
				}

				mul_m4_m4m4(tmat, pamat, obmat);
				mul_mat3_m4_fl(tmat, size * scale);

				copy_m4_m4(mat, tmat);

				if (part->draw & PART_DRAW_GLOBAL_OB)
					add_v3_v3v3(mat[3], mat[3], vec);

				dob = make_dupli(ctx, ob, mat, a);
				dob->particle_system = psys;
				psys_get_dupli_texture(psys, part, sim.psmd, pa, cpa, dob->uv, dob->orco);
			}
		}

		BLI_rng_free(rng);
	}

	/* clean up */
	if (oblist)
		MEM_freeN(oblist);

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

static void make_duplis_particles(const DupliContext *ctx)
{
	ParticleSystem *psys;
	int psysid;

	/* particle system take up one level in id, the particles another */
	for (psys = ctx->object->particlesystem.first, psysid = 0; psys; psys = psys->next, psysid++) {
		/* particles create one more level for persistent psys index */
		DupliContext pctx;
		copy_dupli_context(&pctx, ctx, ctx->object, NULL, psysid);
		make_duplis_particle_system(&pctx, psys);
	}
}

static const DupliGenerator gen_dupli_particles = {
    OB_DUPLIPARTS,                  /* type */
    make_duplis_particles           /* make_duplis */
};

/* ------------- */

/* select dupli generator from given context */
static const DupliGenerator *get_dupli_generator(const DupliContext *ctx)
{
	int transflag = ctx->object->transflag;
	int restrictflag = ctx->object->restrictflag;

	if ((transflag & OB_DUPLI) == 0)
		return NULL;

	/* Should the dupli's be generated for this object? - Respect restrict flags */
	if (DEG_get_mode(ctx->depsgraph) == DAG_EVAL_RENDER ? (restrictflag & OB_RESTRICT_RENDER) : (restrictflag & OB_RESTRICT_VIEW))
		return NULL;

	if (transflag & OB_DUPLIPARTS) {
		return &gen_dupli_particles;
	}
	else if (transflag & OB_DUPLIVERTS) {
		if (ctx->object->type == OB_MESH) {
			return &gen_dupli_verts;
		}
		else if (ctx->object->type == OB_FONT) {
			return &gen_dupli_verts_font;
		}
	}
	else if (transflag & OB_DUPLIFACES) {
		if (ctx->object->type == OB_MESH)
			return &gen_dupli_faces;
	}
	else if (transflag & OB_DUPLICOLLECTION) {
		return &gen_dupli_collection;
	}

	return NULL;
}


/* ---- ListBase dupli container implementation ---- */

/* Returns a list of DupliObject */
ListBase *object_duplilist(Depsgraph *depsgraph, Scene *sce, Object *ob)
{
	ListBase *duplilist = MEM_callocN(sizeof(ListBase), "duplilist");
	DupliContext ctx;
	init_context(&ctx, depsgraph, sce, ob, NULL);
	if (ctx.gen) {
		ctx.duplilist = duplilist;
		ctx.gen->make_duplis(&ctx);
	}

	return duplilist;
}

void free_object_duplilist(ListBase *lb)
{
	BLI_freelistN(lb);
	MEM_freeN(lb);
}