/*
 * ***** 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) 2005 by the Blender Foundation.
 * All rights reserved.
 *
 * Contributor(s): Daniel Dunbar
 *                 Ton Roosendaal,
 *                 Ben Batt,
 *                 Brecht Van Lommel,
 *                 Campbell Barton
 *
 * ***** END GPL LICENSE BLOCK *****
 *
 */

/** \file blender/modifiers/intern/MOD_screw.c
 *  \ingroup modifiers
 */


/* Screw modifier: revolves the edges about an axis */

#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"

#include "BLI_math.h"
#include "BLI_utildefines.h"


#include "BKE_cdderivedmesh.h"

#include "depsgraph_private.h"
#include "MOD_modifiertypes.h"
#include "MEM_guardedalloc.h"

/* used for gathering edge connectivity */
typedef struct ScrewVertConnect {
	float dist;  /* distance from the center axis */
	float co[3]; /* loaction relative to the transformed axis */
	float no[3]; /* calc normal of the vertex */
	int v[2]; /* 2  verts on either side of this one */
	MEdge *e[2]; /* edges on either side, a bit of a waste since each edge ref's 2 edges */
	char flag;
} ScrewVertConnect;

typedef struct ScrewVertIter {
	ScrewVertConnect *v_array;
	ScrewVertConnect *v_poin;
	int v;
	int v_other;
	MEdge *e;
} ScrewVertIter;


static void screwvert_iter_init(ScrewVertIter *iter, ScrewVertConnect *array, int v_init, int dir)
{
	iter->v_array = array;
	iter->v = v_init;

	if (v_init >= 0) {
		iter->v_poin = &array[v_init];
		iter->v_other = iter->v_poin->v[dir];
		iter->e = iter->v_poin->e[!dir];
	}
	else {
		iter->v_poin = NULL;
		iter->e = NULL;
	}
}	


static void screwvert_iter_step(ScrewVertIter *iter)
{
	if (iter->v_poin->v[0] == iter->v_other) {
		iter->v_other = iter->v;
		iter->v = iter->v_poin->v[1];
	}
	else if (iter->v_poin->v[1] == iter->v_other) {
		iter->v_other = iter->v;
		iter->v = iter->v_poin->v[0];
	}
	if (iter->v >= 0) {
		iter->v_poin = &iter->v_array[iter->v];
		iter->e = iter->v_poin->e[(iter->v_poin->e[0] == iter->e)];
	}
	else {
		iter->e = NULL;
		iter->v_poin = NULL;
	}
}


static void initData(ModifierData *md)
{
	ScrewModifierData *ltmd = (ScrewModifierData *) md;
	ltmd->ob_axis = NULL;
	ltmd->angle = M_PI * 2.0;
	ltmd->axis = 2;
	ltmd->flag = MOD_SCREW_SMOOTH_SHADING;
	ltmd->steps = 16;
	ltmd->render_steps = 16;
	ltmd->iter = 1;
}

static void copyData(ModifierData *md, ModifierData *target)
{
	ScrewModifierData *sltmd = (ScrewModifierData *) md;
	ScrewModifierData *tltmd = (ScrewModifierData *) target;
	
	tltmd->ob_axis = sltmd->ob_axis;
	tltmd->angle = sltmd->angle;
	tltmd->axis = sltmd->axis;
	tltmd->flag = sltmd->flag;
	tltmd->steps = sltmd->steps;
	tltmd->render_steps = sltmd->render_steps;
	tltmd->screw_ofs = sltmd->screw_ofs;
	tltmd->iter = sltmd->iter;
}

static DerivedMesh *applyModifier(ModifierData *md, Object *ob,
                                  DerivedMesh *derivedData,
                                  ModifierApplyFlag flag)
{
	DerivedMesh *dm = derivedData;
	DerivedMesh *result;
	ScrewModifierData *ltmd = (ScrewModifierData *) md;
	const int useRenderParams = flag & MOD_APPLY_RENDER;
	
	int *origindex;
	int mpoly_index = 0;
	int step;
	int i, j;
	unsigned int i1, i2;
	int step_tot = useRenderParams ? ltmd->render_steps : ltmd->steps;
	const int do_flip = ltmd->flag & MOD_SCREW_NORMAL_FLIP ? 1 : 0;
	int maxVerts = 0, maxEdges = 0, maxPolys = 0;
	const unsigned int totvert = dm->getNumVerts(dm);
	const unsigned int totedge = dm->getNumEdges(dm);

	char axis_char = 'X', close;
	float angle = ltmd->angle;
	float screw_ofs = ltmd->screw_ofs;
	float axis_vec[3] = {0.0f, 0.0f, 0.0f};
	float tmp_vec1[3], tmp_vec2[3]; 
	float mat3[3][3];
	float mtx_tx[4][4]; /* transform the coords by an object relative to this objects transformation */
	float mtx_tx_inv[4][4]; /* inverted */
	float mtx_tmp_a[4][4];
	
	int vc_tot_linked = 0;
	short other_axis_1, other_axis_2;
	float *tmpf1, *tmpf2;

	int edge_offset;
	
	MPoly *mpoly_new, *mp_new;
	MLoop *mloop_new, *ml_new;
	MEdge *medge_orig, *med_orig, *med_new, *med_new_firstloop, *medge_new;
	MVert *mvert_new, *mvert_orig, *mv_orig, *mv_new, *mv_new_base;

	ScrewVertConnect *vc, *vc_tmp, *vert_connect = NULL;

	const char mpoly_flag = (ltmd->flag & MOD_SCREW_SMOOTH_SHADING) ? ME_SMOOTH : 0;

	/* don't do anything? */
	if (!totvert)
		return CDDM_from_template(dm, 0, 0, 0, 0, 0);

	switch (ltmd->axis) {
		case 0:
			other_axis_1 = 1;
			other_axis_2 = 2;
			break;
		case 1:
			other_axis_1 = 0;
			other_axis_2 = 2;
			break;
		default: /* 2, use default to quiet warnings */
			other_axis_1 = 0;
			other_axis_2 = 1;
			break;
	}

	axis_vec[ltmd->axis] = 1.0f;

	if (ltmd->ob_axis) {
		/* calc the matrix relative to the axis object */
		invert_m4_m4(mtx_tmp_a, ob->obmat);
		copy_m4_m4(mtx_tx_inv, ltmd->ob_axis->obmat);
		mul_m4_m4m4(mtx_tx, mtx_tmp_a, mtx_tx_inv);

		/* calc the axis vec */
		mul_mat3_m4_v3(mtx_tx, axis_vec); /* only rotation component */
		normalize_v3(axis_vec);

		/* screw */
		if (ltmd->flag & MOD_SCREW_OBJECT_OFFSET) {
			/* find the offset along this axis relative to this objects matrix */
			float totlen = len_v3(mtx_tx[3]);

			if (totlen != 0.0f) {
				float zero[3] = {0.0f, 0.0f, 0.0f};
				float cp[3];
				screw_ofs = closest_to_line_v3(cp, mtx_tx[3], zero, axis_vec);
			}
			else {
				screw_ofs = 0.0f;
			}
		}

		/* angle */

#if 0   /* cant incluide this, not predictable enough, though quite fun. */
		if (ltmd->flag & MOD_SCREW_OBJECT_ANGLE) {
			float mtx3_tx[3][3];
			copy_m3_m4(mtx3_tx, mtx_tx);

			float vec[3] = {0, 1, 0};
			float cross1[3];
			float cross2[3];
			cross_v3_v3v3(cross1, vec, axis_vec);

			mul_v3_m3v3(cross2, mtx3_tx, cross1);
			{
				float c1[3];
				float c2[3];
				float axis_tmp[3];

				cross_v3_v3v3(c1, cross2, axis_vec);
				cross_v3_v3v3(c2, axis_vec, c1);


				angle = angle_v3v3(cross1, c2);

				cross_v3_v3v3(axis_tmp, cross1, c2);
				normalize_v3(axis_tmp);

				if (len_v3v3(axis_tmp, axis_vec) > 1.0f)
					angle = -angle;

			}
		}
#endif
	}
	else {
		/* exis char is used by i_rotate*/
		axis_char += ltmd->axis; /* 'X' + axis */

		/* useful to be able to use the axis vec in some cases still */
		zero_v3(axis_vec);
		axis_vec[ltmd->axis] = 1.0f;
	}

	/* apply the multiplier */
	angle *= ltmd->iter;
	screw_ofs *= ltmd->iter;

	/* multiplying the steps is a bit tricky, this works best */
	step_tot = ((step_tot + 1) * ltmd->iter) - (ltmd->iter - 1);

	/* will the screw be closed?
	 * Note! smaller then FLT_EPSILON * 100 gives problems with float precision so its never closed. */
	if (fabsf(screw_ofs) <= (FLT_EPSILON * 100.0f) &&
	    fabsf(fabsf(angle) - ((float)M_PI * 2.0f)) <= (FLT_EPSILON * 100.0f))
	{
		close = 1;
		step_tot--;
		if (step_tot < 3) step_tot = 3;
	
		maxVerts = totvert  * step_tot;   /* -1 because we're joining back up */
		maxEdges = (totvert * step_tot) + /* these are the edges between new verts */
		           (totedge * step_tot);  /* -1 because vert edges join */
		maxPolys = totedge * step_tot;

		screw_ofs = 0.0f;
	}
	else {
		close = 0;
		if (step_tot < 3) step_tot = 3;

		maxVerts =  totvert  * step_tot; /* -1 because we're joining back up */
		maxEdges =  (totvert * (step_tot - 1)) + /* these are the edges between new verts */
		           (totedge * step_tot);  /* -1 because vert edges join */
		maxPolys =  totedge * (step_tot - 1);
	}
	
	result = CDDM_from_template(dm, maxVerts, maxEdges, 0, maxPolys * 4, maxPolys);
	
	/* copy verts from mesh */
	mvert_orig =    dm->getVertArray(dm);
	medge_orig =    dm->getEdgeArray(dm);
	
	mvert_new =     result->getVertArray(result);
	mpoly_new =     result->getPolyArray(result);
	mloop_new =     result->getLoopArray(result);
	medge_new =     result->getEdgeArray(result);

	if (!CustomData_has_layer(&result->polyData, CD_ORIGINDEX)) {
		CustomData_add_layer(&result->polyData, CD_ORIGINDEX, CD_CALLOC, NULL, maxPolys);
	}

	origindex = CustomData_get_layer(&result->polyData, CD_ORIGINDEX);

	DM_copy_vert_data(dm, result, 0, 0, totvert); /* copy first otherwise this overwrites our own vertex normals */
	
	/* Set the locations of the first set of verts */
	
	mv_new = mvert_new;
	mv_orig = mvert_orig;
	
	/* Copy the first set of edges */
	med_orig = medge_orig;
	med_new = medge_new;
	for (i = 0; i < totedge; i++, med_orig++, med_new++) {
		med_new->v1 = med_orig->v1;
		med_new->v2 = med_orig->v2;
		med_new->crease = med_orig->crease;
		med_new->flag = med_orig->flag &  ~ME_LOOSEEDGE;
	}
	
	if (ltmd->flag & MOD_SCREW_NORMAL_CALC) {
		/*
		 * Normal Calculation (for face flipping)
		 * Sort edge verts for correct face flipping
		 * NOT REALLY NEEDED but face flipping is nice.
		 *
		 * */


		/* Notice!
		 *
		 * Since we are only ordering the edges here it can avoid mallocing the
		 * extra space by abusing the vert array before its filled with new verts.
		 * The new array for vert_connect must be at least sizeof(ScrewVertConnect) * totvert
		 * and the size of our resulting meshes array is sizeof(MVert) * totvert * 3
		 * so its safe to use the second 2 thrids of MVert the array for vert_connect,
		 * just make sure ScrewVertConnect struct is no more than twice as big as MVert,
		 * at the moment there is no chance of that being a problem,
		 * unless MVert becomes half its current size.
		 *
		 * once the edges are ordered, vert_connect is not needed and it can be used for verts
		 *
		 * This makes the modifier faster with one less alloc.
		 */

		vert_connect = MEM_mallocN(sizeof(ScrewVertConnect) * totvert, "ScrewVertConnect");
		//vert_connect = (ScrewVertConnect *) &medge_new[totvert];  /* skip the first slice of verts */
		vc = vert_connect;

		/* Copy Vert Locations */
		/* - We can do this in a later loop - only do here if no normal calc */
		if (!totedge) {
			for (i = 0; i < totvert; i++, mv_orig++, mv_new++) {
				copy_v3_v3(mv_new->co, mv_orig->co);
				normalize_v3_v3(vc->no, mv_new->co); /* no edges- this is really a dummy normal */
			}
		}
		else {
			/*printf("\n\n\n\n\nStarting Modifier\n");*/
			/* set edge users */
			med_new = medge_new;
			mv_new = mvert_new;

			if (ltmd->ob_axis) {
				/*mtx_tx is initialized early on */
				for (i = 0; i < totvert; i++, mv_new++, mv_orig++, vc++) {
					vc->co[0] = mv_new->co[0] = mv_orig->co[0];
					vc->co[1] = mv_new->co[1] = mv_orig->co[1];
					vc->co[2] = mv_new->co[2] = mv_orig->co[2];

					vc->flag = 0;
					vc->e[0] = vc->e[1] = NULL;
					vc->v[0] = vc->v[1] = -1;

					mul_m4_v3(mtx_tx, vc->co);
					/* length in 2d, don't sqrt because this is only for comparison */
					vc->dist = vc->co[other_axis_1] * vc->co[other_axis_1] +
					           vc->co[other_axis_2] * vc->co[other_axis_2];

					/* printf("location %f %f %f -- %f\n", vc->co[0], vc->co[1], vc->co[2], vc->dist);*/
				}
			}
			else {
				for (i = 0; i < totvert; i++, mv_new++, mv_orig++, vc++) {
					vc->co[0] = mv_new->co[0] = mv_orig->co[0];
					vc->co[1] = mv_new->co[1] = mv_orig->co[1];
					vc->co[2] = mv_new->co[2] = mv_orig->co[2];

					vc->flag = 0;
					vc->e[0] = vc->e[1] = NULL;
					vc->v[0] = vc->v[1] = -1;

					/* length in 2d, don't sqrt because this is only for comparison */
					vc->dist = vc->co[other_axis_1] * vc->co[other_axis_1] +
					           vc->co[other_axis_2] * vc->co[other_axis_2];

					/* printf("location %f %f %f -- %f\n", vc->co[0], vc->co[1], vc->co[2], vc->dist);*/
				}
			}

			/* this loop builds connectivity info for verts */
			for (i = 0; i < totedge; i++, med_new++) {
				vc = &vert_connect[med_new->v1];

				if (vc->v[0] == -1) { /* unused */
					vc->v[0] = med_new->v2;
					vc->e[0] = med_new;
				}
				else if (vc->v[1] == -1) {
					vc->v[1] = med_new->v2;
					vc->e[1] = med_new;
				}
				else {
					vc->v[0] = vc->v[1] = -2; /* error value  - don't use, 3 edges on vert */
				}

				vc = &vert_connect[med_new->v2];

				/* same as above but swap v1/2 */
				if (vc->v[0] == -1) { /* unused */
					vc->v[0] = med_new->v1;
					vc->e[0] = med_new;
				}
				else if (vc->v[1] == -1) {
					vc->v[1] = med_new->v1;
					vc->e[1] = med_new;
				}
				else {
					vc->v[0] = vc->v[1] = -2; /* error value  - don't use, 3 edges on vert */
				}
			}

			/* find the first vert */
			vc = vert_connect;
			for (i = 0; i < totvert; i++, vc++) {
				/* Now do search for connected verts, order all edges and flip them
				 * so resulting faces are flipped the right way */
				vc_tot_linked = 0; /* count the number of linked verts for this loop */
				if (vc->flag == 0) {
					int v_best = -1, ed_loop_closed = 0; /* vert and vert new */
					ScrewVertIter lt_iter;
					float fl = -1.0f;

					/* compiler complains if not initialized, but it should be initialized below */
					int ed_loop_flip = 0;

					/*printf("Loop on connected vert: %i\n", i);*/

					for (j = 0; j < 2; j++) {
						/*printf("\tSide: %i\n", j);*/
						screwvert_iter_init(&lt_iter, vert_connect, i, j);
						if (j == 1) {
							screwvert_iter_step(&lt_iter);
						}
						while (lt_iter.v_poin) {
							/*printf("\t\tVERT: %i\n", lt_iter.v);*/
							if (lt_iter.v_poin->flag) {
								/*printf("\t\t\tBreaking Found end\n");*/
								//endpoints[0] = endpoints[1] = -1;
								ed_loop_closed = 1; /* circle */
								break;
							}
							lt_iter.v_poin->flag = 1;
							vc_tot_linked++;
							/*printf("Testing 2 floats %f : %f\n", fl, lt_iter.v_poin->dist);*/
							if (fl <= lt_iter.v_poin->dist) {
								fl = lt_iter.v_poin->dist;
								v_best = lt_iter.v;
								/*printf("\t\t\tVERT BEST: %i\n", v_best);*/
							}
							screwvert_iter_step(&lt_iter);
							if (!lt_iter.v_poin) {
								/*printf("\t\t\tFound End Also Num %i\n", j);*/
								/*endpoints[j] = lt_iter.v_other;*/ /* other is still valid */
								break;
							}
						}
					}

					/* now we have a collection of used edges. flip their edges the right way*/
					/*if (v_best != -1) - */

					/*printf("Done Looking - vc_tot_linked: %i\n", vc_tot_linked);*/

					if (vc_tot_linked > 1) {
						float vf_1, vf_2, vf_best;

						vc_tmp = &vert_connect[v_best];

						tmpf1 = vert_connect[vc_tmp->v[0]].co;
						tmpf2 = vert_connect[vc_tmp->v[1]].co;


						/* edge connects on each side! */
						if ((vc_tmp->v[0] > -1) && (vc_tmp->v[1] > -1)) {
							/*printf("Verts on each side (%i %i)\n", vc_tmp->v[0], vc_tmp->v[1]);*/
							/* find out which is higher */

							vf_1 = tmpf1[ltmd->axis];
							vf_2 = tmpf2[ltmd->axis];
							vf_best = vc_tmp->co[ltmd->axis];

							if (vf_1 < vf_best && vf_best < vf_2) {
								ed_loop_flip = 0;
							}
							else if (vf_1 > vf_best && vf_best > vf_2) {
								ed_loop_flip = 1;
							}
							else {
								/* not so simple to work out which edge is higher */
								sub_v3_v3v3(tmp_vec1, tmpf1, vc_tmp->co);
								sub_v3_v3v3(tmp_vec2, tmpf2, vc_tmp->co);
								normalize_v3(tmp_vec1);
								normalize_v3(tmp_vec2);

								if (tmp_vec1[ltmd->axis] < tmp_vec2[ltmd->axis]) {
									ed_loop_flip = 1;
								}
								else {
									ed_loop_flip = 0;
								}
							}
						}
						else if (vc_tmp->v[0] >= 0) { /*vertex only connected on 1 side */
							/*printf("Verts on ONE side (%i %i)\n", vc_tmp->v[0], vc_tmp->v[1]);*/
							if (tmpf1[ltmd->axis] < vc_tmp->co[ltmd->axis]) { /* best is above */
								ed_loop_flip = 1;
							}
							else { /* best is below or even... in even case we cant know whet  to do. */
								ed_loop_flip = 0;
							}

						}
#if 0
						else {
							printf("No Connected ___\n");
						}
#endif

						/*printf("flip direction %i\n", ed_loop_flip);*/


						/* switch the flip option if set
						 * note: flip is now done at face level so copying vgroup slizes is easier */
#if 0
						if (do_flip)
							ed_loop_flip = !ed_loop_flip;
#endif

						if (angle < 0.0f)
							ed_loop_flip = !ed_loop_flip;

						/* if its closed, we only need 1 loop */
						for (j = ed_loop_closed; j < 2; j++) {
							/*printf("Ordering Side J %i\n", j);*/

							screwvert_iter_init(&lt_iter, vert_connect, v_best, j);
							/*printf("\n\nStarting - Loop\n");*/
							lt_iter.v_poin->flag = 1; /* so a non loop will traverse the other side */


							/* If this is the vert off the best vert and
							 * the best vert has 2 edges connected too it
							 * then swap the flip direction */
							if (j == 1 && (vc_tmp->v[0] > -1) && (vc_tmp->v[1] > -1))
								ed_loop_flip = !ed_loop_flip;

							while (lt_iter.v_poin && lt_iter.v_poin->flag != 2) {
								/*printf("\tOrdering Vert V %i\n", lt_iter.v);*/

								lt_iter.v_poin->flag = 2;
								if (lt_iter.e) {
									if (lt_iter.v == lt_iter.e->v1) {
										if (ed_loop_flip == 0) {
											/*printf("\t\t\tFlipping 0\n");*/
											SWAP(unsigned int, lt_iter.e->v1, lt_iter.e->v2);
										}
										/* else {
										    printf("\t\t\tFlipping Not 0\n");
										   }*/
									}
									else if (lt_iter.v == lt_iter.e->v2) {
										if (ed_loop_flip == 1) {
											/*printf("\t\t\tFlipping 1\n");*/
											SWAP(unsigned int, lt_iter.e->v1, lt_iter.e->v2);
										}
										/* else {
										    printf("\t\t\tFlipping Not 1\n");
										   }*/
									}
									/* else {
									    printf("\t\tIncorrect edge topology");
									   }*/
								}
								/* else {
								    printf("\t\tNo Edge at this point\n");
								   }*/
								screwvert_iter_step(&lt_iter);
							}
						}
					}
				}

				/* *VERTEX NORMALS*
				 * we know the surrounding edges are ordered correctly now
				 * so its safe to create vertex normals.
				 *
				 * calculate vertex normals that can be propagated on lathing
				 * use edge connectivity work this out */
				if (vc->v[0] >= 0) {
					if (vc->v[1] >= 0) {
						/* 2 edges connedted */
						/* make 2 connecting vert locations relative to the middle vert */
						sub_v3_v3v3(tmp_vec1, mvert_new[vc->v[0]].co, mvert_new[i].co);
						sub_v3_v3v3(tmp_vec2, mvert_new[vc->v[1]].co, mvert_new[i].co);
						/* normalize so both edges have the same influence, no matter their length */
						normalize_v3(tmp_vec1);
						normalize_v3(tmp_vec2);

						/* vc_no_tmp1 - this line is the average direction of both connecting edges
						 *
						 * Use the edge order to make the subtraction, flip the normal the right way
						 * edge should be there but check just in case... */
						if (vc->e[0]->v1 == i) {
							sub_v3_v3(tmp_vec1, tmp_vec2);
						}
						else {
							sub_v3_v3v3(tmp_vec1, tmp_vec2, tmp_vec1);
						}
					}
					else {
						/* only 1 edge connected - same as above except
						 * don't need to average edge direction */
						if (vc->e[0]->v2 == i) {
							sub_v3_v3v3(tmp_vec1, mvert_new[i].co, mvert_new[vc->v[0]].co);
						}
						else {
							sub_v3_v3v3(tmp_vec1, mvert_new[vc->v[0]].co, mvert_new[i].co);
						}
					}

					/* vc_no_tmp2 - is a line 90d from the pivot to the vec
					 * This is used so the resulting normal points directly away from the middle */
					cross_v3_v3v3(tmp_vec2, axis_vec, vc->co);

					/* edge average vector and right angle to the pivot make the normal */
					cross_v3_v3v3(vc->no, tmp_vec1, tmp_vec2);

				}
				else {
					copy_v3_v3(vc->no, vc->co);
				}

				/* we wont be looping on this data again so copy normals here */
				if (angle < 0.0f)
					negate_v3(vc->no);

				normalize_v3(vc->no);
				normal_float_to_short_v3(mvert_new[i].no, vc->no);

				/* Done with normals */
			}
		}
	}
	else {
		mv_orig = mvert_orig;
		mv_new = mvert_new;

		for (i = 0; i < totvert; i++, mv_new++, mv_orig++) {
			copy_v3_v3(mv_new->co, mv_orig->co);
		}
	}
	/* done with edge connectivity based normal flipping */
	
	/* Add Faces */
	for (step = 1; step < step_tot; step++) {
		const int varray_stride = totvert * step;
		float step_angle;
		float nor_tx[3];
		float mat[4][4];
		/* Rotation Matrix */
		step_angle = (angle / (step_tot - (!close))) * step;

		if (ltmd->ob_axis) {
			axis_angle_normalized_to_mat3(mat3, axis_vec, step_angle);
			copy_m4_m3(mat, mat3);
		}
		else {
			unit_m4(mat);
			rotate_m4(mat, axis_char, step_angle);
			copy_m3_m4(mat3, mat);
		}

		if (screw_ofs)
			madd_v3_v3fl(mat[3], axis_vec, screw_ofs * ((float)step / (float)(step_tot - 1)));

		/* copy a slice */
		DM_copy_vert_data(dm, result, 0, varray_stride, totvert);
		
		mv_new_base = mvert_new;
		mv_new = &mvert_new[varray_stride]; /* advance to the next slice */
		
		for (j = 0; j < totvert; j++, mv_new_base++, mv_new++) {
			/* set normal */
			if (vert_connect) {
				mul_v3_m3v3(nor_tx, mat3, vert_connect[j].no);

				/* set the normal now its transformed */
				normal_float_to_short_v3(mv_new->no, nor_tx);
			}
			
			/* set location */
			copy_v3_v3(mv_new->co, mv_new_base->co);
			
			/* only need to set these if using non cleared memory */
			/*mv_new->mat_nr = mv_new->flag = 0;*/
				
			if (ltmd->ob_axis) {
				sub_v3_v3(mv_new->co, mtx_tx[3]);

				mul_m4_v3(mat, mv_new->co);

				add_v3_v3(mv_new->co, mtx_tx[3]);
			}
			else {
				mul_m4_v3(mat, mv_new->co);
			}
			
			/* add the new edge */
			med_new->v1 = varray_stride + j;
			med_new->v2 = med_new->v1 - totvert;
			med_new->flag = ME_EDGEDRAW | ME_EDGERENDER;
			med_new++;
		}
	}

	/* we can avoid if using vert alloc trick */
	if (vert_connect) {
		MEM_freeN(vert_connect);
		vert_connect = NULL;
	}

	if (close) {
		/* last loop of edges, previous loop dosnt account for the last set of edges */
		const int varray_stride = (step_tot - 1) * totvert;

		for (i = 0; i < totvert; i++) {
			med_new->v1 = i;
			med_new->v2 = varray_stride + i;
			med_new->flag = ME_EDGEDRAW | ME_EDGERENDER;
			med_new++;
		}
	}
	
	mp_new = mpoly_new;
	ml_new = mloop_new;
	med_new_firstloop = medge_new;
	
	/* more of an offset in this case */
	edge_offset = totedge + (totvert * (step_tot - (close ? 0 : 1)));

	for (i = 0; i < totedge; i++, med_new_firstloop++) {
		/* for each edge, make a cylinder of quads */
		i1 = med_new_firstloop->v1;
		i2 = med_new_firstloop->v2;

		for (step = 0; step < step_tot - 1; step++) {
			
			/* new face */
			if (do_flip) {
				ml_new[3].v = i1;
				ml_new[2].v = i2;
				ml_new[1].v = i2 + totvert;
				ml_new[0].v = i1 + totvert;

				ml_new[2].e = step == 0 ? i : (edge_offset + step + (i * (step_tot - 1))) - 1;
				ml_new[1].e = totedge + i2;
				ml_new[0].e = edge_offset + step + (i * (step_tot - 1));
				ml_new[3].e = totedge + i1;
			}
			else {
				ml_new[0].v = i1;
				ml_new[1].v = i2;
				ml_new[2].v = i2 + totvert;
				ml_new[3].v = i1 + totvert;

				ml_new[0].e = step == 0 ? i : (edge_offset + step + (i * (step_tot - 1))) - 1;
				ml_new[1].e = totedge + i2;
				ml_new[2].e = edge_offset + step + (i * (step_tot - 1));
				ml_new[3].e = totedge + i1;
			}


			mp_new->loopstart = mpoly_index * 4;
			mp_new->totloop = 4;
			mp_new->flag = mpoly_flag;
			origindex[mpoly_index] = ORIGINDEX_NONE;
			mp_new++;
			ml_new += 4;
			mpoly_index++;
			
			/* new vertical edge */
			if (step) { /* The first set is already dome */
				med_new->v1 = i1;
				med_new->v2 = i2;
				med_new->flag = med_new_firstloop->flag;
				med_new->crease = med_new_firstloop->crease;
				med_new++;
			}
			i1 += totvert;
			i2 += totvert;
		}
		
		/* close the loop*/
		if (close) {
			if (do_flip) {
				ml_new[3].v = i1;
				ml_new[2].v = i2;
				ml_new[1].v = med_new_firstloop->v2;
				ml_new[0].v = med_new_firstloop->v1;

				ml_new[2].e = (edge_offset + step + (i * (step_tot - 1))) - 1;
				ml_new[1].e = totedge + i2;
				ml_new[0].e = i;
				ml_new[3].e = totedge + i1;
			}
			else {
				ml_new[0].v = i1;
				ml_new[1].v = i2;
				ml_new[2].v = med_new_firstloop->v2;
				ml_new[3].v = med_new_firstloop->v1;

				ml_new[0].e = (edge_offset + step + (i * (step_tot - 1))) - 1;
				ml_new[1].e = totedge + i2;
				ml_new[2].e = i;
				ml_new[3].e = totedge + i1;
			}

			mp_new->loopstart = mpoly_index * 4;
			mp_new->totloop = 4;
			mp_new->flag = mpoly_flag;
			origindex[mpoly_index] = ORIGINDEX_NONE;
			mp_new++;
			ml_new += 4;
			mpoly_index++;
		}
		
		/* new vertical edge */
		med_new->v1 = i1;
		med_new->v2 = i2;
		med_new->flag = med_new_firstloop->flag & ~ME_LOOSEEDGE;
		med_new->crease = med_new_firstloop->crease;
		med_new++;
	}

	/* validate loop edges */
#if 0
	{
		i = 0;
		printf("\n");
		for (; i < maxPolys * 4; i += 4) {
			int ii;
			ml_new = mloop_new + i;
			ii = findEd(medge_new, maxEdges, ml_new[0].v, ml_new[1].v);
			printf("%d %d -- ", ii, ml_new[0].e);
			ml_new[0].e = ii;

			ii = findEd(medge_new, maxEdges, ml_new[1].v, ml_new[2].v);
			printf("%d %d -- ", ii, ml_new[1].e);
			ml_new[1].e = ii;

			ii = findEd(medge_new, maxEdges, ml_new[2].v, ml_new[3].v);
			printf("%d %d -- ", ii, ml_new[2].e);
			ml_new[2].e = ii;

			ii = findEd(medge_new, maxEdges, ml_new[3].v, ml_new[0].v);
			printf("%d %d\n", ii, ml_new[3].e);
			ml_new[3].e = ii;

		}
	}
#endif

	if ((ltmd->flag & MOD_SCREW_NORMAL_CALC) == 0) {
		result->dirty |= DM_DIRTY_NORMALS;
	}

	return result;
}


static void updateDepgraph(ModifierData *md, DagForest *forest,
                           struct Scene *UNUSED(scene),
                           Object *UNUSED(ob),
                           DagNode *obNode)
{
	ScrewModifierData *ltmd = (ScrewModifierData *) md;

	if (ltmd->ob_axis) {
		DagNode *curNode = dag_get_node(forest, ltmd->ob_axis);

		dag_add_relation(forest, curNode, obNode,
		                 DAG_RL_DATA_DATA | DAG_RL_OB_DATA,
		                 "Screw Modifier");
	}
}

static void foreachObjectLink(
        ModifierData *md, Object *ob,
        void (*walk)(void *userData, Object *ob, Object **obpoin),
        void *userData)
{
	ScrewModifierData *ltmd = (ScrewModifierData *) md;

	walk(userData, ob, &ltmd->ob_axis);
}

ModifierTypeInfo modifierType_Screw = {
	/* name */              "Screw",
	/* structName */        "ScrewModifierData",
	/* structSize */        sizeof(ScrewModifierData),
	/* type */              eModifierTypeType_Constructive,

	/* flags */             eModifierTypeFlag_AcceptsMesh |
	                        eModifierTypeFlag_AcceptsCVs |
	                        eModifierTypeFlag_SupportsEditmode |
	                        eModifierTypeFlag_EnableInEditmode,

	/* copyData */          copyData,
	/* deformVerts */       NULL,
	/* deformMatrices */    NULL,
	/* deformVertsEM */     NULL,
	/* deformMatricesEM */  NULL,
	/* applyModifier */     applyModifier,
	/* applyModifierEM */   NULL,
	/* initData */          initData,
	/* requiredDataMask */  NULL,
	/* freeData */          NULL,
	/* isDisabled */        NULL,
	/* updateDepgraph */    updateDepgraph,
	/* dependsOnTime */     NULL,
	/* dependsOnNormals */	NULL,
	/* foreachObjectLink */ foreachObjectLink,
	/* foreachIDLink */     NULL,
	/* foreachTexLink */    NULL,
};
