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/*
* ***** 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 Blender Foundation.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): Geoffrey Bantle.
*
* ***** END GPL LICENSE BLOCK *****
*/
/** \file blender/bmesh/intern/bmesh_structure.c
* \ingroup bmesh
*
* Low level routines for manipulating the BM structure.
*/
#include "BLI_utildefines.h"
#include "bmesh.h"
#include "intern/bmesh_private.h"
/**
* MISC utility functions.
*/
void bmesh_disk_vert_swap(BMEdge *e, BMVert *v_dst, BMVert *v_src)
{
if (e->v1 == v_src) {
e->v1 = v_dst;
e->v1_disk_link.next = e->v1_disk_link.prev = NULL;
}
else if (e->v2 == v_src) {
e->v2 = v_dst;
e->v2_disk_link.next = e->v2_disk_link.prev = NULL;
}
else {
BLI_assert(0);
}
}
/**
* Handles all connected data, use with care.
*
* Assumes caller has setup correct state before the swap is done.
*/
void bmesh_edge_vert_swap(BMEdge *e, BMVert *v_dst, BMVert *v_src)
{
/* swap out loops */
if (e->l) {
BMLoop *l_iter, *l_first;
l_iter = l_first = e->l;
do {
if (l_iter->v == v_src) {
l_iter->v = v_dst;
}
} while ((l_iter = l_iter->radial_next) != l_first);
}
/* swap out edges */
bmesh_disk_vert_replace(e, v_dst, v_src);
}
void bmesh_disk_vert_replace(BMEdge *e, BMVert *v_dst, BMVert *v_src)
{
BLI_assert(e->v1 == v_src || e->v2 == v_src);
bmesh_disk_edge_remove(e, v_src); /* remove e from tv's disk cycle */
bmesh_disk_vert_swap(e, v_dst, v_src); /* swap out tv for v_new in e */
bmesh_disk_edge_append(e, v_dst); /* add e to v_dst's disk cycle */
BLI_assert(e->v1 != e->v2);
}
/**
* \section bm_cycles BMesh Cycles
* (this is somewhat outdate, though bits of its API are still used) - joeedh
*
* Cycles are circular doubly linked lists that form the basis of adjacency
* information in the BME modeler. Full adjacency relations can be derived
* from examining these cycles very quickly. Although each cycle is a double
* circular linked list, each one is considered to have a 'base' or 'head',
* and care must be taken by Euler code when modifying the contents of a cycle.
*
* The contents of this file are split into two parts. First there are the
* bmesh_cycle family of functions which are generic circular double linked list
* procedures. The second part contains higher level procedures for supporting
* modification of specific cycle types.
*
* The three cycles explicitly stored in the BM data structure are as follows:
*
*
* 1: The Disk Cycle - A circle of edges around a vertex
* Base: vertex->edge pointer.
*
* This cycle is the most complicated in terms of its structure. Each bmesh_Edge contains
* two bmesh_CycleNode structures to keep track of that edges membership in the disk cycle
* of each of its vertices. However for any given vertex it may be the first in some edges
* in its disk cycle and the second for others. The bmesh_disk_XXX family of functions contain
* some nice utilities for navigating disk cycles in a way that hides this detail from the
* tool writer.
*
* Note that the disk cycle is completely independent from face data. One advantage of this
* is that wire edges are fully integrated into the topology database. Another is that the
* the disk cycle has no problems dealing with non-manifold conditions involving faces.
*
* Functions relating to this cycle:
* - #bmesh_disk_vert_replace
* - #bmesh_disk_edge_append
* - #bmesh_disk_edge_remove
* - #bmesh_disk_edge_next
* - #bmesh_disk_edge_prev
* - #bmesh_disk_facevert_count
* - #bmesh_disk_faceedge_find_first
* - #bmesh_disk_faceedge_find_next
*
*
* 2: The Radial Cycle - A circle of face edges (bmesh_Loop) around an edge
* Base: edge->l->radial structure.
*
* The radial cycle is similar to the radial cycle in the radial edge data structure.*
* Unlike the radial edge however, the radial cycle does not require a large amount of memory
* to store non-manifold conditions since BM does not keep track of region/shell information.
*
* Functions relating to this cycle:
* - #bmesh_radial_append
* - #bmesh_radial_loop_remove
* - #bmesh_radial_facevert_count
* - #bmesh_radial_facevert_check
* - #bmesh_radial_faceloop_find_first
* - #bmesh_radial_faceloop_find_next
* - #bmesh_radial_validate
*
*
* 3: The Loop Cycle - A circle of face edges around a polygon.
* Base: polygon->lbase.
*
* The loop cycle keeps track of a faces vertices and edges. It should be noted that the
* direction of a loop cycle is either CW or CCW depending on the face normal, and is
* not oriented to the faces editedges.
*
* Functions relating to this cycle:
* - bmesh_cycle_XXX family of functions.
*
*
* \note the order of elements in all cycles except the loop cycle is undefined. This
* leads to slightly increased seek time for deriving some adjacency relations, however the
* advantage is that no intrinsic properties of the data structures are dependent upon the
* cycle order and all non-manifold conditions are represented trivially.
*/
void bmesh_disk_edge_append(BMEdge *e, BMVert *v)
{
if (!v->e) {
BMDiskLink *dl1 = bmesh_disk_edge_link_from_vert(e, v);
v->e = e;
dl1->next = dl1->prev = e;
}
else {
BMDiskLink *dl1, *dl2, *dl3;
dl1 = bmesh_disk_edge_link_from_vert(e, v);
dl2 = bmesh_disk_edge_link_from_vert(v->e, v);
dl3 = dl2->prev ? bmesh_disk_edge_link_from_vert(dl2->prev, v) : NULL;
dl1->next = v->e;
dl1->prev = dl2->prev;
dl2->prev = e;
if (dl3)
dl3->next = e;
}
}
void bmesh_disk_edge_remove(BMEdge *e, BMVert *v)
{
BMDiskLink *dl1, *dl2;
dl1 = bmesh_disk_edge_link_from_vert(e, v);
if (dl1->prev) {
dl2 = bmesh_disk_edge_link_from_vert(dl1->prev, v);
dl2->next = dl1->next;
}
if (dl1->next) {
dl2 = bmesh_disk_edge_link_from_vert(dl1->next, v);
dl2->prev = dl1->prev;
}
if (v->e == e)
v->e = (e != dl1->next) ? dl1->next : NULL;
dl1->next = dl1->prev = NULL;
}
BMEdge *bmesh_disk_edge_exists(const BMVert *v1, const BMVert *v2)
{
BMEdge *e_iter, *e_first;
if (v1->e) {
e_first = e_iter = v1->e;
do {
if (BM_verts_in_edge(v1, v2, e_iter)) {
return e_iter;
}
} while ((e_iter = bmesh_disk_edge_next(e_iter, v1)) != e_first);
}
return NULL;
}
int bmesh_disk_count(const BMVert *v)
{
int count = 0;
if (v->e) {
BMEdge *e_first, *e_iter;
e_iter = e_first = v->e;
do {
count++;
} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e_first);
}
return count;
}
int bmesh_disk_count_ex(const BMVert *v, const int count_max)
{
int count = 0;
if (v->e) {
BMEdge *e_first, *e_iter;
e_iter = e_first = v->e;
do {
count++;
if (count == count_max) {
break;
}
} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e_first);
}
return count;
}
bool bmesh_disk_validate(int len, BMEdge *e, BMVert *v)
{
BMEdge *e_iter;
if (!BM_vert_in_edge(e, v))
return false;
if (bmesh_disk_count_ex(v, len + 1) != len || len == 0)
return false;
e_iter = e;
do {
if (len != 1 && bmesh_disk_edge_prev(e_iter, v) == e_iter) {
return false;
}
} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e);
return true;
}
/**
* \brief DISK COUNT FACE VERT
*
* Counts the number of loop users
* for this vertex. Note that this is
* equivalent to counting the number of
* faces incident upon this vertex
*/
int bmesh_disk_facevert_count(const BMVert *v)
{
/* is there an edge on this vert at all */
int count = 0;
if (v->e) {
BMEdge *e_first, *e_iter;
/* first, loop around edge */
e_first = e_iter = v->e;
do {
if (e_iter->l) {
count += bmesh_radial_facevert_count(e_iter->l, v);
}
} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e_first);
}
return count;
}
int bmesh_disk_facevert_count_ex(const BMVert *v, const int count_max)
{
/* is there an edge on this vert at all */
int count = 0;
if (v->e) {
BMEdge *e_first, *e_iter;
/* first, loop around edge */
e_first = e_iter = v->e;
do {
if (e_iter->l) {
count += bmesh_radial_facevert_count_ex(e_iter->l, v, count_max - count);
if (count == count_max) {
break;
}
}
} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e_first);
}
return count;
}
/**
* \brief FIND FIRST FACE EDGE
*
* Finds the first edge in a vertices
* Disk cycle that has one of this
* vert's loops attached
* to it.
*/
BMEdge *bmesh_disk_faceedge_find_first(const BMEdge *e, const BMVert *v)
{
const BMEdge *e_find = e;
do {
if (e_find->l && bmesh_radial_facevert_check(e_find->l, v)) {
return (BMEdge *)e_find;
}
} while ((e_find = bmesh_disk_edge_next(e_find, v)) != e);
return NULL;
}
BMEdge *bmesh_disk_faceedge_find_next(const BMEdge *e, const BMVert *v)
{
BMEdge *e_find;
e_find = bmesh_disk_edge_next(e, v);
do {
if (e_find->l && bmesh_radial_facevert_check(e_find->l, v)) {
return e_find;
}
} while ((e_find = bmesh_disk_edge_next(e_find, v)) != e);
return (BMEdge *)e;
}
/*****radial cycle functions, e.g. loops surrounding edges**** */
bool bmesh_radial_validate(int radlen, BMLoop *l)
{
BMLoop *l_iter = l;
int i = 0;
if (bmesh_radial_length(l) != radlen)
return false;
do {
if (UNLIKELY(!l_iter)) {
BMESH_ASSERT(0);
return false;
}
if (l_iter->e != l->e)
return false;
if (l_iter->v != l->e->v1 && l_iter->v != l->e->v2)
return false;
if (UNLIKELY(i > BM_LOOP_RADIAL_MAX)) {
BMESH_ASSERT(0);
return false;
}
i++;
} while ((l_iter = l_iter->radial_next) != l);
return true;
}
/**
* \brief BMESH RADIAL REMOVE LOOP
*
* Removes a loop from an radial cycle. If edge e is non-NULL
* it should contain the radial cycle, and it will also get
* updated (in the case that the edge's link into the radial
* cycle was the loop which is being removed from the cycle).
*/
void bmesh_radial_loop_remove(BMLoop *l, BMEdge *e)
{
/* if e is non-NULL, l must be in the radial cycle of e */
if (UNLIKELY(e && e != l->e)) {
BMESH_ASSERT(0);
}
if (l->radial_next != l) {
if (e && l == e->l)
e->l = l->radial_next;
l->radial_next->radial_prev = l->radial_prev;
l->radial_prev->radial_next = l->radial_next;
}
else {
if (e) {
if (l == e->l) {
e->l = NULL;
}
else {
BMESH_ASSERT(0);
}
}
}
/* l is no longer in a radial cycle; empty the links
* to the cycle and the link back to an edge */
l->radial_next = l->radial_prev = NULL;
l->e = NULL;
}
/**
* \brief BME RADIAL FIND FIRST FACE VERT
*
* Finds the first loop of v around radial
* cycle
*/
BMLoop *bmesh_radial_faceloop_find_first(const BMLoop *l, const BMVert *v)
{
const BMLoop *l_iter;
l_iter = l;
do {
if (l_iter->v == v) {
return (BMLoop *)l_iter;
}
} while ((l_iter = l_iter->radial_next) != l);
return NULL;
}
BMLoop *bmesh_radial_faceloop_find_next(const BMLoop *l, const BMVert *v)
{
BMLoop *l_iter;
l_iter = l->radial_next;
do {
if (l_iter->v == v) {
return l_iter;
}
} while ((l_iter = l_iter->radial_next) != l);
return (BMLoop *)l;
}
int bmesh_radial_length(const BMLoop *l)
{
const BMLoop *l_iter = l;
int i = 0;
if (!l)
return 0;
do {
if (UNLIKELY(!l_iter)) {
/* radial cycle is broken (not a circulat loop) */
BMESH_ASSERT(0);
return 0;
}
i++;
if (UNLIKELY(i >= BM_LOOP_RADIAL_MAX)) {
BMESH_ASSERT(0);
return -1;
}
} while ((l_iter = l_iter->radial_next) != l);
return i;
}
void bmesh_radial_append(BMEdge *e, BMLoop *l)
{
if (e->l == NULL) {
e->l = l;
l->radial_next = l->radial_prev = l;
}
else {
l->radial_prev = e->l;
l->radial_next = e->l->radial_next;
e->l->radial_next->radial_prev = l;
e->l->radial_next = l;
e->l = l;
}
if (UNLIKELY(l->e && l->e != e)) {
/* l is already in a radial cycle for a different edge */
BMESH_ASSERT(0);
}
l->e = e;
}
/**
* \brief RADIAL COUNT FACE VERT
*
* Returns the number of times a vertex appears
* in a radial cycle
*/
int bmesh_radial_facevert_count(const BMLoop *l, const BMVert *v)
{
const BMLoop *l_iter;
int count = 0;
l_iter = l;
do {
if (l_iter->v == v) {
count++;
}
} while ((l_iter = l_iter->radial_next) != l);
return count;
}
int bmesh_radial_facevert_count_ex(const BMLoop *l, const BMVert *v, const int count_max)
{
const BMLoop *l_iter;
int count = 0;
l_iter = l;
do {
if (l_iter->v == v) {
count++;
if (count == count_max) {
break;
}
}
} while ((l_iter = l_iter->radial_next) != l);
return count;
}
/**
* \brief RADIAL CHECK FACE VERT
*
* Quicker check for ``bmesh_radial_facevert_count(...) != 0``
*/
bool bmesh_radial_facevert_check(const BMLoop *l, const BMVert *v)
{
const BMLoop *l_iter;
l_iter = l;
do {
if (l_iter->v == v) {
return true;
}
} while ((l_iter = l_iter->radial_next) != l);
return false;
}
/*****loop cycle functions, e.g. loops surrounding a face**** */
bool bmesh_loop_validate(BMFace *f)
{
int i;
int len = f->len;
BMLoop *l_iter, *l_first;
l_first = BM_FACE_FIRST_LOOP(f);
if (l_first == NULL) {
return false;
}
/* Validate that the face loop cycle is the length specified by f->len */
for (i = 1, l_iter = l_first->next; i < len; i++, l_iter = l_iter->next) {
if ((l_iter->f != f) ||
(l_iter == l_first))
{
return false;
}
}
if (l_iter != l_first) {
return false;
}
/* Validate the loop->prev links also form a cycle of length f->len */
for (i = 1, l_iter = l_first->prev; i < len; i++, l_iter = l_iter->prev) {
if (l_iter == l_first) {
return false;
}
}
if (l_iter != l_first) {
return false;
}
return true;
}
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