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Paddle/paddle/fluid/operators/detection/gpc.cc

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// Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @file src/gpc.cpp
* @author huhan02(com@baidu.com)
* @date 2015/12/18 14:17:30
* @brief
*
* @modified by sunyipeng
* @email sunyipeng@baidu.com
* @date 2018/6/12
**/
#include "paddle/fluid/operators/detection/gpc.h"
namespace gpc {
typedef struct lmt_shape { /* Local minima table */
double y; /* Y coordinate at local minimum */
edge_node *first_bound; /* Pointer to bound list */
struct lmt_shape *next; /* Pointer to next local minimum */
} lmt_node;
typedef struct sbt_t_shape { /* Scanbeam tree */
double y; /* Scanbeam node y value */
struct sbt_t_shape *less; /* Pointer to nodes with lower y */
struct sbt_t_shape *more; /* Pointer to nodes with higher y */
} sb_tree;
typedef struct it_shape { /* Intersection table */
edge_node *ie[2]; /* Intersecting edge (bundle) pair */
gpc_vertex point; /* Point of intersection */
struct it_shape *next; /* The next intersection table node */
} it_node;
typedef struct st_shape { /* Sorted edge table */
edge_node *edge; /* Pointer to AET edge */
double xb; /* Scanbeam bottom x coordinate */
double xt; /* Scanbeam top x coordinate */
double dx; /* Change in x for a unit y increase */
struct st_shape *prev; /* Previous edge in sorted list */
} st_node;
typedef struct bbox_shape { /* Contour axis-aligned bounding box */
double xmin; /* Minimum x coordinate */
double ymin; /* Minimum y coordinate */
double xmax; /* Maximum x coordinate */
double ymax; /* Maximum y coordinate */
} bbox;
/*
===========================================================================
Global Data
===========================================================================
*/
/* Horizontal edge state transitions within scanbeam boundary */
const h_state next_h_state[3][6] = {
/* ABOVE BELOW CROSS */
/* L R L R L R */
/* NH */
{BH, TH, TH, BH, NH, NH},
/* BH */
{NH, NH, NH, NH, TH, TH},
/* TH */
{NH, NH, NH, NH, BH, BH}};
/*
===========================================================================
Private Functions
===========================================================================
*/
static void reset_it(it_node **it) {
it_node *itn;
while (*it) {
itn = (*it)->next;
gpc_free<it_node>(*it);
*it = itn;
}
}
static void reset_lmt(lmt_node **lmt) {
lmt_node *lmtn;
while (*lmt) {
lmtn = (*lmt)->next;
gpc_free<lmt_node>(*lmt);
*lmt = lmtn;
}
}
static void insert_bound(edge_node **b, edge_node *e) {
edge_node *existing_bound = NULL;
if (!*b) {
/* Link node e to the tail of the list */
*b = e;
} else {
/* Do primary sort on the x field */
if (e[0].bot.x < (*b)[0].bot.x) {
/* Insert a new node mid-list */
existing_bound = *b;
*b = e;
(*b)->next_bound = existing_bound;
} else {
if (e[0].bot.x == (*b)[0].bot.x) {
/* Do secondary sort on the dx field */
if (e[0].dx < (*b)[0].dx) {
/* Insert a new node mid-list */
existing_bound = *b;
*b = e;
(*b)->next_bound = existing_bound;
} else {
/* Head further down the list */
insert_bound(&((*b)->next_bound), e);
}
} else {
/* Head further down the list */
insert_bound(&((*b)->next_bound), e);
}
}
}
}
static edge_node **bound_list(lmt_node **lmt, double y) {
lmt_node *existing_node;
if (!*lmt) {
/* Add node onto the tail end of the LMT */
gpc_malloc<lmt_node>(*lmt, sizeof(lmt_node),
const_cast<char *>("LMT insertion"));
(*lmt)->y = y;
(*lmt)->first_bound = NULL;
(*lmt)->next = NULL;
return &((*lmt)->first_bound);
} else if (y < (*lmt)->y) {
/* Insert a new LMT node before the current node */
existing_node = *lmt;
gpc_malloc<lmt_node>(*lmt, sizeof(lmt_node),
const_cast<char *>("LMT insertion"));
(*lmt)->y = y;
(*lmt)->first_bound = NULL;
(*lmt)->next = existing_node;
return &((*lmt)->first_bound);
} else {
if (y > (*lmt)->y) {
/* Head further up the LMT */
return bound_list(&((*lmt)->next), y);
} else {
/* Use this existing LMT node */
return &((*lmt)->first_bound);
}
}
}
static void add_to_sbtree(int *entries, sb_tree **sbtree, double y) {
if (!*sbtree) {
/* Add a new tree node here */
gpc_malloc<sb_tree>(*sbtree, sizeof(sb_tree),
const_cast<char *>("scanbeam tree insertion"));
(*sbtree)->y = y;
(*sbtree)->less = NULL;
(*sbtree)->more = NULL;
(*entries)++;
} else {
if ((*sbtree)->y > y) {
/* Head into the 'less' sub-tree */
add_to_sbtree(entries, &((*sbtree)->less), y);
} else {
if ((*sbtree)->y < y) {
/* Head into the 'more' sub-tree */
add_to_sbtree(entries, &((*sbtree)->more), y);
}
}
}
}
static void build_sbt(int *entries, double *sbt, sb_tree *sbtree) {
if (sbtree->less) {
build_sbt(entries, sbt, sbtree->less);
}
sbt[*entries] = sbtree->y;
(*entries)++;
if (sbtree->more) {
build_sbt(entries, sbt, sbtree->more);
}
}
static void free_sbtree(sb_tree **sbtree) {
if (*sbtree) {
free_sbtree(&((*sbtree)->less));
free_sbtree(&((*sbtree)->more));
gpc_free<sb_tree>(*sbtree);
}
}
static int count_optimal_vertices(gpc_vertex_list c) {
int result = 0;
int i = 0;
/* Ignore non-contributing contours */
if (c.num_vertices > 0) {
for (i = 0; i < c.num_vertices; i++) {
/* Ignore superfluous vertices embedded in horizontal edges */
if (gpc_optimal(c.vertex, i, c.num_vertices)) {
result++;
}
}
}
return result;
}
static edge_node *build_lmt(lmt_node **lmt, sb_tree **sbtree, int *sbt_entries,
gpc_polygon *p, int type, gpc_op op) {
int c = 0;
int i = 0;
int min = 0;
int max = 0;
int num_edges = 0;
int v = 0;
int num_vertices = 0;
int total_vertices = 0;
int e_index = 0;
edge_node *e = NULL;
edge_node *edge_table = NULL;
for (c = 0; c < p->num_contours; c++) {
total_vertices += count_optimal_vertices(p->contour[c]);
}
/* Create the entire input polygon edge table in one go */
gpc_malloc<edge_node>(edge_table, total_vertices * sizeof(edge_node),
const_cast<char *>("edge table creation"));
for (c = 0; c < p->num_contours; c++) {
if (p->contour[c].num_vertices < 0) {
/* Ignore the non-contributing contour and repair the vertex count */
p->contour[c].num_vertices = -p->contour[c].num_vertices;
} else {
/* Perform contour optimisation */
num_vertices = 0;
for (i = 0; i < p->contour[c].num_vertices; i++) {
if (gpc_optimal(p->contour[c].vertex, i, p->contour[c].num_vertices)) {
edge_table[num_vertices].vertex.x = p->contour[c].vertex[i].x;
edge_table[num_vertices].vertex.y = p->contour[c].vertex[i].y;
/* Record vertex in the scanbeam table */
add_to_sbtree(sbt_entries, sbtree, edge_table[num_vertices].vertex.y);
num_vertices++;
}
}
/* Do the contour forward pass */
for (min = 0; min < num_vertices; min++) {
/* If a forward local minimum... */
if (gpc_fwd_min(edge_table, min, num_vertices)) {
/* Search for the next local maximum... */
num_edges = 1;
max = gpc_next_index(min, num_vertices);
while (gpc_not_fmax(edge_table, max, num_vertices)) {
num_edges++;
max = gpc_next_index(max, num_vertices);
}
/* Build the next edge list */
e = &edge_table[e_index];
e_index += num_edges;
v = min;
e[0].bstate[BELOW] = UNBUNDLED;
e[0].bundle[BELOW][CLIP] = 0;
e[0].bundle[BELOW][SUBJ] = 0;
for (i = 0; i < num_edges; i++) {
e[i].xb = edge_table[v].vertex.x;
e[i].bot.x = edge_table[v].vertex.x;
e[i].bot.y = edge_table[v].vertex.y;
v = gpc_next_index(v, num_vertices);
e[i].top.x = edge_table[v].vertex.x;
e[i].top.y = edge_table[v].vertex.y;
e[i].dx = (edge_table[v].vertex.x - e[i].bot.x) /
(e[i].top.y - e[i].bot.y);
e[i].type = type;
e[i].outp[ABOVE] = NULL;
e[i].outp[BELOW] = NULL;
e[i].next = NULL;
e[i].prev = NULL;
e[i].succ =
((num_edges > 1) && (i < (num_edges - 1))) ? &(e[i + 1]) : NULL;
e[i].pred = ((num_edges > 1) && (i > 0)) ? &(e[i - 1]) : NULL;
e[i].next_bound = NULL;
e[i].bside[CLIP] = (op == GPC_DIFF) ? RIGHT : LEFT;
e[i].bside[SUBJ] = LEFT;
}
insert_bound(bound_list(lmt, edge_table[min].vertex.y), e);
}
}
/* Do the contour reverse pass */
for (min = 0; min < num_vertices; min++) {
/* If a reverse local minimum... */
if (gpc_rev_min(edge_table, min, num_vertices)) {
/* Search for the previous local maximum... */
num_edges = 1;
max = gpc_prev_index(min, num_vertices);
while (gpc_not_rmax(edge_table, max, num_vertices)) {
num_edges++;
max = gpc_prev_index(max, num_vertices);
}
/* Build the previous edge list */
e = &edge_table[e_index];
e_index += num_edges;
v = min;
e[0].bstate[BELOW] = UNBUNDLED;
e[0].bundle[BELOW][CLIP] = 0;
e[0].bundle[BELOW][SUBJ] = 0;
for (i = 0; i < num_edges; i++) {
e[i].xb = edge_table[v].vertex.x;
e[i].bot.x = edge_table[v].vertex.x;
e[i].bot.y = edge_table[v].vertex.y;
v = gpc_prev_index(v, num_vertices);
e[i].top.x = edge_table[v].vertex.x;
e[i].top.y = edge_table[v].vertex.y;
e[i].dx = (edge_table[v].vertex.x - e[i].bot.x) /
(e[i].top.y - e[i].bot.y);
e[i].type = type;
e[i].outp[ABOVE] = NULL;
e[i].outp[BELOW] = NULL;
e[i].next = NULL;
e[i].prev = NULL;
e[i].succ =
((num_edges > 1) && (i < (num_edges - 1))) ? &(e[i + 1]) : NULL;
e[i].pred = ((num_edges > 1) && (i > 0)) ? &(e[i - 1]) : NULL;
e[i].next_bound = NULL;
e[i].bside[CLIP] = (op == GPC_DIFF) ? RIGHT : LEFT;
e[i].bside[SUBJ] = LEFT;
}
insert_bound(bound_list(lmt, edge_table[min].vertex.y), e);
}
}
}
}
return edge_table;
} // NOLINT
static void add_edge_to_aet(edge_node **aet, edge_node *edge, edge_node *prev) {
if (!*aet) {
/* Append edge onto the tail end of the AET */
*aet = edge;
edge->prev = prev;
edge->next = NULL;
} else {
/* Do primary sort on the xb field */
if (edge->xb < (*aet)->xb) {
/* Insert edge here (before the AET edge) */
edge->prev = prev;
edge->next = *aet;
(*aet)->prev = edge;
*aet = edge;
} else {
if (edge->xb == (*aet)->xb) {
/* Do secondary sort on the dx field */
if (edge->dx < (*aet)->dx) {
/* Insert edge here (before the AET edge) */
edge->prev = prev;
edge->next = *aet;
(*aet)->prev = edge;
*aet = edge;
} else {
/* Head further into the AET */
add_edge_to_aet(&((*aet)->next), edge, *aet);
}
} else {
/* Head further into the AET */
add_edge_to_aet(&((*aet)->next), edge, *aet);
}
}
}
}
static void add_intersection(it_node **it, edge_node *edge0, edge_node *edge1,
double x, double y) {
it_node *existing_node;
if (!*it) {
/* Append a new node to the tail of the list */
gpc_malloc<it_node>(*it, sizeof(it_node),
const_cast<char *>("IT insertion"));
(*it)->ie[0] = edge0;
(*it)->ie[1] = edge1;
(*it)->point.x = x;
(*it)->point.y = y;
(*it)->next = NULL;
} else {
if ((*it)->point.y > y) {
/* Insert a new node mid-list */
existing_node = *it;
gpc_malloc<it_node>(*it, sizeof(it_node),
const_cast<char *>("IT insertion"));
(*it)->ie[0] = edge0;
(*it)->ie[1] = edge1;
(*it)->point.x = x;
(*it)->point.y = y;
(*it)->next = existing_node;
} else {
/* Head further down the list */
add_intersection(&((*it)->next), edge0, edge1, x, y);
}
}
}
static void add_st_edge(st_node **st, it_node **it, edge_node *edge,
double dy) {
st_node *existing_node;
double den = 0.0;
double r = 0.0;
double x = 0.0;
double y = 0.0;
if (!*st) {
/* Append edge onto the tail end of the ST */
gpc_malloc<st_node>(*st, sizeof(st_node),
const_cast<char *>("ST insertion"));
(*st)->edge = edge;
(*st)->xb = edge->xb;
(*st)->xt = edge->xt;
(*st)->dx = edge->dx;
(*st)->prev = NULL;
} else {
den = ((*st)->xt - (*st)->xb) - (edge->xt - edge->xb);
/* If new edge and ST edge don't cross */
if ((edge->xt >= (*st)->xt) || (edge->dx == (*st)->dx) ||
(fabs(den) <= DBL_EPSILON)) {
/* No intersection - insert edge here (before the ST edge) */
existing_node = *st;
gpc_malloc<st_node>(*st, sizeof(st_node),
const_cast<char *>("ST insertion"));
(*st)->edge = edge;
(*st)->xb = edge->xb;
(*st)->xt = edge->xt;
(*st)->dx = edge->dx;
(*st)->prev = existing_node;
} else {
/* Compute intersection between new edge and ST edge */
r = (edge->xb - (*st)->xb) / den;
x = (*st)->xb + r * ((*st)->xt - (*st)->xb);
y = r * dy;
/* Insert the edge pointers and the intersection point in the IT */
add_intersection(it, (*st)->edge, edge, x, y);
/* Head further into the ST */
add_st_edge(&((*st)->prev), it, edge, dy);
}
}
}
static void build_intersection_table(it_node **it, edge_node *aet, double dy) {
st_node *st;
st_node *stp;
edge_node *edge = NULL;
/* Build intersection table for the current scanbeam */
reset_it(it);
st = NULL;
/* Process each AET edge */
for (edge = aet; edge; edge = edge->next) {
if ((edge->bstate[ABOVE] == BUNDLE_HEAD) || edge->bundle[ABOVE][CLIP] ||
edge->bundle[ABOVE][SUBJ]) {
add_st_edge(&st, it, edge, dy);
}
}
/* Free the sorted edge table */
while (st) {
stp = st->prev;
gpc_free<st_node>(st);
st = stp;
}
}
static int count_contours(polygon_node *polygon) {
int nc = 0;
int nv = 0;
vertex_node *v = NULL;
vertex_node *nextv = NULL;
for (nc = 0; polygon; polygon = polygon->next) {
if (polygon->active) {
/* Count the vertices in the current contour */
nv = 0;
for (v = polygon->proxy->v[LEFT]; v; v = v->next) {
nv++;
}
/* Record valid vertex counts in the active field */
if (nv > 2) {
polygon->active = nv;
nc++;
} else {
/* Invalid contour: just free the heap */
for (v = polygon->proxy->v[LEFT]; v; v = nextv) {
nextv = v->next;
gpc_free<vertex_node>(v);
}
polygon->active = 0;
}
}
}
return nc;
}
static void add_left(polygon_node *p, double x, double y) {
vertex_node *nv = NULL;
/* Create a new vertex node and set its fields */
gpc_malloc<vertex_node>(nv, sizeof(vertex_node),
const_cast<char *>("vertex node creation"));
nv->x = x;
nv->y = y;
/* Add vertex nv to the left end of the polygon's vertex list */
nv->next = p->proxy->v[LEFT];
/* Update proxy->[LEFT] to point to nv */
p->proxy->v[LEFT] = nv;
}
static void merge_left(polygon_node *p, polygon_node *q, polygon_node *list) {
polygon_node *target = NULL;
/* Label contour as a hole */
q->proxy->hole = 1;
if (p->proxy != q->proxy) {
/* Assign p's vertex list to the left end of q's list */
p->proxy->v[RIGHT]->next = q->proxy->v[LEFT];
q->proxy->v[LEFT] = p->proxy->v[LEFT];
/* Redirect any p->proxy references to q->proxy */
for (target = p->proxy; list; list = list->next) {
if (list->proxy == target) {
list->active = 0;
list->proxy = q->proxy;
}
}
}
}
static void add_right(polygon_node *p, double x, double y) {
vertex_node *nv = NULL;
/* Create a new vertex node and set its fields */
gpc_malloc<vertex_node>(nv, sizeof(vertex_node),
const_cast<char *>("vertex node creation"));
nv->x = x;
nv->y = y;
nv->next = NULL;
/* Add vertex nv to the right end of the polygon's vertex list */
p->proxy->v[RIGHT]->next = nv;
/* Update proxy->v[RIGHT] to point to nv */
p->proxy->v[RIGHT] = nv;
}
static void merge_right(polygon_node *p, polygon_node *q, polygon_node *list) {
polygon_node *target = NULL;
/* Label contour as external */
q->proxy->hole = 0;
if (p->proxy != q->proxy) {
/* Assign p's vertex list to the right end of q's list */
q->proxy->v[RIGHT]->next = p->proxy->v[LEFT];
q->proxy->v[RIGHT] = p->proxy->v[RIGHT];
/* Redirect any p->proxy references to q->proxy */
for (target = p->proxy; list; list = list->next) {
if (list->proxy == target) {
list->active = 0;
list->proxy = q->proxy;
}
}
}
}
static void add_local_min(polygon_node **p, edge_node *edge, double x,
double y) {
polygon_node *existing_min = NULL;
vertex_node *nv = NULL;
existing_min = *p;
gpc_malloc<polygon_node>(*p, sizeof(polygon_node),
const_cast<char *>("polygon node creation"));
/* Create a new vertex node and set its fields */
gpc_malloc<vertex_node>(nv, sizeof(vertex_node),
const_cast<char *>("vertex node creation"));
nv->x = x;
nv->y = y;
nv->next = NULL;
/* Initialise proxy to point to p itself */
(*p)->proxy = (*p);
(*p)->active = 1;
(*p)->next = existing_min;
/* Make v[LEFT] and v[RIGHT] point to new vertex nv */
(*p)->v[LEFT] = nv;
(*p)->v[RIGHT] = nv;
/* Assign polygon p to the edge */
edge->outp[ABOVE] = *p;
}
static int count_tristrips(polygon_node *tn) {
int total = 0;
for (total = 0; tn; tn = tn->next) {
if (tn->active > 2) {
total++;
}
}
return total;
}
void add_vertex(vertex_node **t, double x, double y) {
if (!(*t)) {
gpc_malloc<vertex_node>(*t, sizeof(vertex_node),
const_cast<char *>("tristrip vertex creation"));
(*t)->x = x;
(*t)->y = y;
(*t)->next = NULL;
} else {
/* Head further down the list */
add_vertex(&((*t)->next), x, y);
}
}
void gpc_vertex_create(edge_node *e, int p, int s, double x, double y) {
add_vertex(&(e->outp[p]->v[s]), x, y);
e->outp[p]->active++;
}
static void new_tristrip(polygon_node **tn, edge_node *edge, double x,
double y) {
if (!(*tn)) {
gpc_malloc<polygon_node>(*tn, sizeof(polygon_node),
const_cast<char *>("tristrip node creation"));
(*tn)->next = NULL;
(*tn)->v[LEFT] = NULL;
(*tn)->v[RIGHT] = NULL;
(*tn)->active = 1;
add_vertex(&((*tn)->v[LEFT]), x, y);
edge->outp[ABOVE] = *tn;
} else {
/* Head further down the list */
new_tristrip(&((*tn)->next), edge, x, y);
}
}
static bbox *create_contour_bboxes(gpc_polygon *p) {
bbox *box;
int c = 0;
int v = 0;
gpc_malloc<bbox>(box, p->num_contours * sizeof(bbox),
const_cast<char *>("Bounding box creation"));
/* Construct contour bounding boxes */
for (c = 0; c < p->num_contours; c++) {
/* Initialise bounding box extent */
box[c].xmin = DBL_MAX;
box[c].ymin = DBL_MAX;
box[c].xmax = -DBL_MAX;
box[c].ymax = -DBL_MAX;
for (v = 0; v < p->contour[c].num_vertices; v++) {
/* Adjust bounding box */
if (p->contour[c].vertex[v].x < box[c].xmin) {
box[c].xmin = p->contour[c].vertex[v].x;
}
if (p->contour[c].vertex[v].y < box[c].ymin) {
box[c].ymin = p->contour[c].vertex[v].y;
}
if (p->contour[c].vertex[v].x > box[c].xmax) {
box[c].xmax = p->contour[c].vertex[v].x;
}
if (p->contour[c].vertex[v].y > box[c].ymax) {
box[c].ymax = p->contour[c].vertex[v].y;
}
}
}
return box;
}
static void minimax_test(gpc_polygon *subj, gpc_polygon *clip, gpc_op op) {
bbox *s_bbox;
bbox *c_bbox;
int s = 0;
int c = 0;
int *o_table = NULL;
int overlap = 0;
s_bbox = create_contour_bboxes(subj);
c_bbox = create_contour_bboxes(clip);
gpc_malloc<int>(o_table,
subj->num_contours * clip->num_contours * sizeof(int),
const_cast<char *>("overlap table creation"));
/* Check all subject contour bounding boxes against clip boxes */
for (s = 0; s < subj->num_contours; s++) {
for (c = 0; c < clip->num_contours; c++) {
o_table[c * subj->num_contours + s] =
(!((s_bbox[s].xmax < c_bbox[c].xmin) ||
(s_bbox[s].xmin > c_bbox[c].xmax))) &&
(!((s_bbox[s].ymax < c_bbox[c].ymin) ||
(s_bbox[s].ymin > c_bbox[c].ymax)));
}
}
/* For each clip contour, search for any subject contour overlaps */
for (c = 0; c < clip->num_contours; c++) {
overlap = 0;
for (s = 0; (!overlap) && (s < subj->num_contours); s++) {
overlap = o_table[c * subj->num_contours + s];
}
if (!overlap) {
/* Flag non contributing status by negating vertex count */
clip->contour[c].num_vertices = -clip->contour[c].num_vertices;
}
}
if (op == GPC_INT) {
/* For each subject contour, search for any clip contour overlaps */
for (s = 0; s < subj->num_contours; s++) {
overlap = 0;
for (c = 0; (!overlap) && (c < clip->num_contours); c++) {
overlap = o_table[c * subj->num_contours + s];
}
if (!overlap) {
/* Flag non contributing status by negating vertex count */
subj->contour[s].num_vertices = -subj->contour[s].num_vertices;
}
}
}
gpc_free<bbox>(s_bbox);
gpc_free<bbox>(c_bbox);
gpc_free<int>(o_table);
}
/*
===========================================================================
Public Functions
===========================================================================
*/
void gpc_free_polygon(gpc_polygon *p) {
int c = 0;
for (c = 0; c < p->num_contours; c++) {
gpc_free<gpc_vertex>(p->contour[c].vertex);
}
gpc_free<int>(p->hole);
gpc_free<gpc_vertex_list>(p->contour);
p->num_contours = 0;
}
/*
void gpc_read_polygon(FILE *fp, int read_hole_flags, gpc_polygon *p) {
int c = 0;
int v = 0;
fscanf(fp, "%d", &(p->num_contours));
gpc_malloc<int>(p->hole, p->num_contours * sizeof(int),
(char *)"hole flag array creation");
gpc_malloc<gpc_vertex_list>(p->contour,
p->num_contours * sizeof(gpc_vertex_list),
(char *)"contour creation");
for (c = 0; c < p->num_contours; c++) {
fscanf(fp, "%d", &(p->contour[c].num_vertices));
if (read_hole_flags) {
fscanf(fp, "%d", &(p->hole[c]));
} else {
p->hole[c] = 0; // Assume all contours to be external
}
gpc_malloc<gpc_vertex>(p->contour[c].vertex,
p->contour[c].num_vertices * sizeof(gpc_vertex),
(char *)"vertex creation");
for (v = 0; v < p->contour[c].num_vertices; v++) {
fscanf(fp, "%lf %lf", &(p->contour[c].vertex[v].x),
&(p->contour[c].vertex[v].y));
}
}
}
void gpc_write_polygon(FILE *fp, int write_hole_flags, gpc_polygon *p) {
int c = 0;
int v = 0;
fprintf(fp, "%d\n", p->num_contours);
for (c = 0; c < p->num_contours; c++) {
fprintf(fp, "%d\n", p->contour[c].num_vertices);
if (write_hole_flags) {
fprintf(fp, "%d\n", p->hole[c]);
}
for (v = 0; v < p->contour[c].num_vertices; v++) {
fprintf(fp, "% .*lf % .*lf\n", DBL_DIG, p->contour[c].vertex[v].x,
DBL_DIG, p->contour[c].vertex[v].y);
}
}
}
*/
void gpc_add_contour(gpc_polygon *p, gpc_vertex_list *new_contour, int hole) {
int *extended_hole = NULL;
int c = 0;
int v = 0;
gpc_vertex_list *extended_contour = NULL;
/* Create an extended hole array */
gpc_malloc<int>(extended_hole, (p->num_contours + 1) * sizeof(int),
const_cast<char *>("contour hole addition"));
/* Create an extended contour array */
gpc_malloc<gpc_vertex_list>(extended_contour,
(p->num_contours + 1) * sizeof(gpc_vertex_list),
const_cast<char *>("contour addition"));
/* Copy the old contour and hole data into the extended arrays */
for (c = 0; c < p->num_contours; c++) {
extended_hole[c] = p->hole[c];
extended_contour[c] = p->contour[c];
}
/* Copy the new contour and hole onto the end of the extended arrays */
c = p->num_contours;
extended_hole[c] = hole;
extended_contour[c].num_vertices = new_contour->num_vertices;
gpc_malloc<gpc_vertex>(extended_contour[c].vertex,
new_contour->num_vertices * sizeof(gpc_vertex),
const_cast<char *>("contour addition"));
for (v = 0; v < new_contour->num_vertices; v++) {
extended_contour[c].vertex[v] = new_contour->vertex[v];
}
/* Dispose of the old contour */
gpc_free<gpc_vertex_list>(p->contour);
gpc_free<int>(p->hole);
/* Update the polygon information */
p->num_contours++;
p->hole = extended_hole;
p->contour = extended_contour;
}
// gpc_polygon_clip
void gpc_polygon_clip(gpc_op op, gpc_polygon *subj, gpc_polygon *clip,
gpc_polygon *result) {
sb_tree *sbtree = NULL;
it_node *it = NULL;
it_node *intersect = NULL;
edge_node *edge = NULL;
edge_node *prev_edge = NULL;
edge_node *next_edge = NULL;
edge_node *succ_edge = NULL;
edge_node *e0 = NULL;
edge_node *e1 = NULL;
edge_node *aet = NULL;
edge_node *c_heap = NULL;
edge_node *s_heap = NULL;
lmt_node *lmt = NULL;
lmt_node *local_min = NULL;
polygon_node *out_poly = NULL;
polygon_node *p = NULL;
polygon_node *q = NULL;
polygon_node *poly = NULL;
polygon_node *npoly = NULL;
polygon_node *cf = NULL;
vertex_node *vtx = NULL;
vertex_node *nv = NULL;
h_state horiz[2];
int in[2];
int exists[2];
int parity[2] = {LEFT, LEFT};
int c = 0;
int v = 0;
int contributing = 0;
int search = 0;
int scanbeam = 0;
int sbt_entries = 0;
int vclass = 0;
int bl = 0;
int br = 0;
int tl = 0;
int tr = 0;
double *sbt = NULL;
double xb = 0.0;
double px = 0.0;
double yb = 0.0;
double yt = 0.0;
double dy = 0.0;
double ix = 0.0;
double iy = 0.0;
/* Test for trivial NULL result cases */
if (((subj->num_contours == 0) && (clip->num_contours == 0)) ||
((subj->num_contours == 0) && ((op == GPC_INT) || (op == GPC_DIFF))) ||
((clip->num_contours == 0) && (op == GPC_INT))) {
result->num_contours = 0;
result->hole = NULL;
result->contour = NULL;
return;
}
/* Identify potentialy contributing contours */
if (((op == GPC_INT) || (op == GPC_DIFF)) && (subj->num_contours > 0) &&
(clip->num_contours > 0)) {
minimax_test(subj, clip, op);
}
/* Build LMT */
if (subj->num_contours > 0) {
s_heap = build_lmt(&lmt, &sbtree, &sbt_entries, subj, SUBJ, op);
}
if (clip->num_contours > 0) {
c_heap = build_lmt(&lmt, &sbtree, &sbt_entries, clip, CLIP, op);
}
/* Return a NULL result if no contours contribute */
if (lmt == NULL) {
result->num_contours = 0;
result->hole = NULL;
result->contour = NULL;
reset_lmt(&lmt);
gpc_free<edge_node>(s_heap);
gpc_free<edge_node>(c_heap);
return;
}
/* Build scanbeam table from scanbeam tree */
gpc_malloc<double>(sbt, sbt_entries * sizeof(double),
const_cast<char *>("sbt creation"));
build_sbt(&scanbeam, sbt, sbtree);
scanbeam = 0;
free_sbtree(&sbtree);
/* Allow pointer re-use without causing memory leak */
if (subj == result) {
gpc_free_polygon(subj);
}
if (clip == result) {
gpc_free_polygon(clip);
}
/* Invert clip polygon for difference operation */
if (op == GPC_DIFF) {
parity[CLIP] = RIGHT;
}
local_min = lmt;
// Process each scanbeam
while (scanbeam < sbt_entries) {
/* Set yb and yt to the bottom and top of the scanbeam */
yb = sbt[scanbeam++];
if (scanbeam < sbt_entries) {
yt = sbt[scanbeam];
dy = yt - yb;
}
/* === SCANBEAM BOUNDARY PROCESSING ================================ */
/* If LMT node corresponding to yb exists */
if (local_min) {
if (local_min->y == yb) {
/* Add edges starting at this local minimum to the AET */
for (edge = local_min->first_bound; edge; edge = edge->next_bound) {
add_edge_to_aet(&aet, edge, NULL);
}
local_min = local_min->next;
}
}
/* Set dummy previous x value */
px = -DBL_MAX;
/* Create bundles within AET */
e0 = aet;
e1 = aet;
/* Set up bundle fields of first edge */
aet->bundle[ABOVE][aet->type] = (aet->top.y != yb);
aet->bundle[ABOVE][!aet->type] = 0;
aet->bstate[ABOVE] = UNBUNDLED;
for (next_edge = aet->next; next_edge; next_edge = next_edge->next) {
/* Set up bundle fields of next edge */
next_edge->bundle[ABOVE][next_edge->type] = (next_edge->top.y != yb);
next_edge->bundle[ABOVE][!next_edge->type] = 0;
next_edge->bstate[ABOVE] = UNBUNDLED;
/* Bundle edges above the scanbeam boundary if they coincide */
if (next_edge->bundle[ABOVE][next_edge->type]) {
if (gpc_eq(e0->xb, next_edge->xb) && gpc_eq(e0->dx, next_edge->dx) &&
(e0->top.y != yb)) {
next_edge->bundle[ABOVE][next_edge->type] ^=
e0->bundle[ABOVE][next_edge->type];
next_edge->bundle[ABOVE][!next_edge->type] =
e0->bundle[ABOVE][!next_edge->type];
next_edge->bstate[ABOVE] = BUNDLE_HEAD;
e0->bundle[ABOVE][CLIP] = 0;
e0->bundle[ABOVE][SUBJ] = 0;
e0->bstate[ABOVE] = BUNDLE_TAIL;
}
e0 = next_edge;
}
}
horiz[CLIP] = NH;
horiz[SUBJ] = NH;
// Process each edge at this scanbeam boundary
for (edge = aet; edge; edge = edge->next) {
exists[CLIP] =
edge->bundle[ABOVE][CLIP] + (edge->bundle[BELOW][CLIP] << 1);
exists[SUBJ] =
edge->bundle[ABOVE][SUBJ] + (edge->bundle[BELOW][SUBJ] << 1);
if (exists[CLIP] || exists[SUBJ]) {
/* Set bundle side */
edge->bside[CLIP] = parity[CLIP];
edge->bside[SUBJ] = parity[SUBJ];
/* Determine contributing status and quadrant occupancies */
switch (op) {
case GPC_DIFF:
case GPC_INT:
contributing = (exists[CLIP] && (parity[SUBJ] || horiz[SUBJ])) ||
(exists[SUBJ] && (parity[CLIP] || horiz[CLIP])) ||
(exists[CLIP] && exists[SUBJ] &&
(parity[CLIP] == parity[SUBJ]));
br = (parity[CLIP]) && (parity[SUBJ]);
bl = (parity[CLIP] ^ edge->bundle[ABOVE][CLIP]) &&
(parity[SUBJ] ^ edge->bundle[ABOVE][SUBJ]);
tr = (parity[CLIP] ^ (horiz[CLIP] != NH)) &&
(parity[SUBJ] ^ (horiz[SUBJ] != NH));
tl = (parity[CLIP] ^ (horiz[CLIP] != NH) ^
edge->bundle[BELOW][CLIP]) &&
(parity[SUBJ] ^ (horiz[SUBJ] != NH) ^
edge->bundle[BELOW][SUBJ]);
break;
case GPC_XOR:
contributing = exists[CLIP] || exists[SUBJ];
br = (parity[CLIP]) ^ (parity[SUBJ]);
bl = (parity[CLIP] ^ edge->bundle[ABOVE][CLIP]) ^
(parity[SUBJ] ^ edge->bundle[ABOVE][SUBJ]);
tr = (parity[CLIP] ^ (horiz[CLIP] != NH)) ^
(parity[SUBJ] ^ (horiz[SUBJ] != NH));
tl = (parity[CLIP] ^ (horiz[CLIP] != NH) ^
edge->bundle[BELOW][CLIP]) ^
(parity[SUBJ] ^ (horiz[SUBJ] != NH) ^
edge->bundle[BELOW][SUBJ]);
break;
case GPC_UNION:
contributing = (exists[CLIP] && (!parity[SUBJ] || horiz[SUBJ])) ||
(exists[SUBJ] && (!parity[CLIP] || horiz[CLIP])) ||
(exists[CLIP] && exists[SUBJ] &&
(parity[CLIP] == parity[SUBJ]));
br = (parity[CLIP]) || (parity[SUBJ]);
bl = (parity[CLIP] ^ edge->bundle[ABOVE][CLIP]) ||
(parity[SUBJ] ^ edge->bundle[ABOVE][SUBJ]);
tr = (parity[CLIP] ^ (horiz[CLIP] != NH)) ||
(parity[SUBJ] ^ (horiz[SUBJ] != NH));
tl = (parity[CLIP] ^ (horiz[CLIP] != NH) ^
edge->bundle[BELOW][CLIP]) ||
(parity[SUBJ] ^ (horiz[SUBJ] != NH) ^
edge->bundle[BELOW][SUBJ]);
break;
}
// Update parity
parity[CLIP] ^= edge->bundle[ABOVE][CLIP];
parity[SUBJ] ^= edge->bundle[ABOVE][SUBJ];
/* Update horizontal state */
if (exists[CLIP]) {
horiz[CLIP] = next_h_state[horiz[CLIP]]
[((exists[CLIP] - 1) << 1) + parity[CLIP]];
}
if (exists[SUBJ]) {
horiz[SUBJ] = next_h_state[horiz[SUBJ]]
[((exists[SUBJ] - 1) << 1) + parity[SUBJ]];
}
vclass = tr + (tl << 1) + (br << 2) + (bl << 3);
if (contributing) {
xb = edge->xb;
switch (vclass) {
case EMN:
case IMN:
add_local_min(&out_poly, edge, xb, yb);
px = xb;
cf = edge->outp[ABOVE];
break;
case ERI:
if (xb != px) {
add_right(cf, xb, yb);
px = xb;
}
edge->outp[ABOVE] = cf;
cf = NULL;
break;
case ELI:
add_left(edge->outp[BELOW], xb, yb);
px = xb;
cf = edge->outp[BELOW];
break;
case EMX:
if (xb != px) {
add_left(cf, xb, yb);
px = xb;
}
merge_right(cf, edge->outp[BELOW], out_poly);
cf = NULL;
break;
case ILI:
if (xb != px) {
add_left(cf, xb, yb);
px = xb;
}
edge->outp[ABOVE] = cf;
cf = NULL;
break;
case IRI:
add_right(edge->outp[BELOW], xb, yb);
px = xb;
cf = edge->outp[BELOW];
edge->outp[BELOW] = NULL;
break;
case IMX:
if (xb != px) {
add_right(cf, xb, yb);
px = xb;
}
merge_left(cf, edge->outp[BELOW], out_poly);
cf = NULL;
edge->outp[BELOW] = NULL;
break;
case IMM:
if (xb != px) {
add_right(cf, xb, yb);
px = xb;
}
merge_left(cf, edge->outp[BELOW], out_poly);
edge->outp[BELOW] = NULL;
add_local_min(&out_poly, edge, xb, yb);
cf = edge->outp[ABOVE];
break;
case EMM:
if (xb != px) {
add_left(cf, xb, yb);
px = xb;
}
merge_right(cf, edge->outp[BELOW], out_poly);
edge->outp[BELOW] = NULL;
add_local_min(&out_poly, edge, xb, yb);
cf = edge->outp[ABOVE];
break;
case LED:
if (edge->bot.y == yb) {
add_left(edge->outp[BELOW], xb, yb);
}
edge->outp[ABOVE] = edge->outp[BELOW];
px = xb;
break;
case RED:
if (edge->bot.y == yb) {
add_right(edge->outp[BELOW], xb, yb);
}
edge->outp[ABOVE] = edge->outp[BELOW];
px = xb;
break;
default:
break;
} /* End of switch */
} /* End of contributing conditional */
} /* End of edge exists conditional */
} // End of AET loop
/* Delete terminating edges from the AET, otherwise compute xt */
for (edge = aet; edge; edge = edge->next) {
if (edge->top.y == yb) {
prev_edge = edge->prev;
next_edge = edge->next;
if (prev_edge) {
prev_edge->next = next_edge;
} else {
aet = next_edge;
}
if (next_edge) {
next_edge->prev = prev_edge;
}
/* Copy bundle head state to the adjacent tail edge if required */
if ((edge->bstate[BELOW] == BUNDLE_HEAD) && prev_edge) {
if (prev_edge->bstate[BELOW] == BUNDLE_TAIL) {
prev_edge->outp[BELOW] = edge->outp[BELOW];
prev_edge->bstate[BELOW] = UNBUNDLED;
if (prev_edge->prev) {
if (prev_edge->prev->bstate[BELOW] == BUNDLE_TAIL) {
prev_edge->bstate[BELOW] = BUNDLE_HEAD;
}
}
}
}
} else {
if (edge->top.y == yt) {
edge->xt = edge->top.x;
} else {
edge->xt = edge->bot.x + edge->dx * (yt - edge->bot.y);
}
}
}
if (scanbeam < sbt_entries) {
/* === SCANBEAM INTERIOR PROCESSING ============================== */
build_intersection_table(&it, aet, dy);
/* Process each node in the intersection table */
for (intersect = it; intersect; intersect = intersect->next) {
e0 = intersect->ie[0];
e1 = intersect->ie[1];
/* Only generate output for contributing intersections */
if ((e0->bundle[ABOVE][CLIP] || e0->bundle[ABOVE][SUBJ]) &&
(e1->bundle[ABOVE][CLIP] || e1->bundle[ABOVE][SUBJ])) {
p = e0->outp[ABOVE];
q = e1->outp[ABOVE];
ix = intersect->point.x;
iy = intersect->point.y + yb;
in[CLIP] = (e0->bundle[ABOVE][CLIP] && !e0->bside[CLIP]) ||
(e1->bundle[ABOVE][CLIP] && e1->bside[CLIP]) ||
(!e0->bundle[ABOVE][CLIP] && !e1->bundle[ABOVE][CLIP] &&
e0->bside[CLIP] && e1->bside[CLIP]);
in[SUBJ] = (e0->bundle[ABOVE][SUBJ] && !e0->bside[SUBJ]) ||
(e1->bundle[ABOVE][SUBJ] && e1->bside[SUBJ]) ||
(!e0->bundle[ABOVE][SUBJ] && !e1->bundle[ABOVE][SUBJ] &&
e0->bside[SUBJ] && e1->bside[SUBJ]);
// Determine quadrant occupancies
switch (op) {
case GPC_DIFF:
case GPC_INT:
tr = (in[CLIP]) && (in[SUBJ]);
tl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP]) &&
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ]);
br = (in[CLIP] ^ e0->bundle[ABOVE][CLIP]) &&
(in[SUBJ] ^ e0->bundle[ABOVE][SUBJ]);
bl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP] ^
e0->bundle[ABOVE][CLIP]) &&
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ] ^
e0->bundle[ABOVE][SUBJ]);
break;
case GPC_XOR:
tr = (in[CLIP]) ^ (in[SUBJ]);
tl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP]) ^
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ]);
br = (in[CLIP] ^ e0->bundle[ABOVE][CLIP]) ^
(in[SUBJ] ^ e0->bundle[ABOVE][SUBJ]);
bl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP] ^
e0->bundle[ABOVE][CLIP]) ^
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ] ^
e0->bundle[ABOVE][SUBJ]);
break;
case GPC_UNION:
tr = (in[CLIP]) || (in[SUBJ]);
tl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP]) ||
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ]);
br = (in[CLIP] ^ e0->bundle[ABOVE][CLIP]) ||
(in[SUBJ] ^ e0->bundle[ABOVE][SUBJ]);
bl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP] ^
e0->bundle[ABOVE][CLIP]) ||
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ] ^
e0->bundle[ABOVE][SUBJ]);
break;
}
vclass = tr + (tl << 1) + (br << 2) + (bl << 3);
switch (vclass) {
case EMN:
add_local_min(&out_poly, e0, ix, iy);
e1->outp[ABOVE] = e0->outp[ABOVE];
break;
case ERI:
if (p) {
add_right(p, ix, iy);
e1->outp[ABOVE] = p;
e0->outp[ABOVE] = NULL;
}
break;
case ELI:
if (q) {
add_left(q, ix, iy);
e0->outp[ABOVE] = q;
e1->outp[ABOVE] = NULL;
}
break;
case EMX:
if (p && q) {
add_left(p, ix, iy);
merge_right(p, q, out_poly);
e0->outp[ABOVE] = NULL;
e1->outp[ABOVE] = NULL;
}
break;
case IMN:
add_local_min(&out_poly, e0, ix, iy);
e1->outp[ABOVE] = e0->outp[ABOVE];
break;
case ILI:
if (p) {
add_left(p, ix, iy);
e1->outp[ABOVE] = p;
e0->outp[ABOVE] = NULL;
}
break;
case IRI:
if (q) {
add_right(q, ix, iy);
e0->outp[ABOVE] = q;
e1->outp[ABOVE] = NULL;
}
break;
case IMX:
if (p && q) {
add_right(p, ix, iy);
merge_left(p, q, out_poly);
e0->outp[ABOVE] = NULL;
e1->outp[ABOVE] = NULL;
}
break;
case IMM:
if (p && q) {
add_right(p, ix, iy);
merge_left(p, q, out_poly);
add_local_min(&out_poly, e0, ix, iy);
e1->outp[ABOVE] = e0->outp[ABOVE];
}
break;
case EMM:
if (p && q) {
add_left(p, ix, iy);
merge_right(p, q, out_poly);
add_local_min(&out_poly, e0, ix, iy);
e1->outp[ABOVE] = e0->outp[ABOVE];
}
break;
default:
break;
} // End of switch
} /* End of contributing intersection conditional */
/* Swap bundle sides in response to edge crossing */
if (e0->bundle[ABOVE][CLIP]) {
e1->bside[CLIP] = !e1->bside[CLIP];
}
if (e1->bundle[ABOVE][CLIP]) {
e0->bside[CLIP] = !e0->bside[CLIP];
}
if (e0->bundle[ABOVE][SUBJ]) {
e1->bside[SUBJ] = !e1->bside[SUBJ];
}
if (e1->bundle[ABOVE][SUBJ]) {
e0->bside[SUBJ] = !e0->bside[SUBJ];
}
/* Swap e0 and e1 bundles in the AET */
prev_edge = e0->prev;
next_edge = e1->next;
if (next_edge) {
next_edge->prev = e0;
}
if (e0->bstate[ABOVE] == BUNDLE_HEAD) {
search = 1;
while (search) {
prev_edge = prev_edge->prev;
if (prev_edge) {
if (prev_edge->bstate[ABOVE] != BUNDLE_TAIL) {
search = 0;
}
} else {
search = 0;
}
}
}
if (!prev_edge) {
aet->prev = e1;
e1->next = aet;
aet = e0->next;
} else {
prev_edge->next->prev = e1;
e1->next = prev_edge->next;
prev_edge->next = e0->next;
}
e0->next->prev = prev_edge;
e1->next->prev = e1;
e0->next = next_edge;
} /* End of IT loop*/
// Prepare for next scanbeam
for (edge = aet; edge; edge = next_edge) {
next_edge = edge->next;
succ_edge = edge->succ;
if ((edge->top.y == yt) && succ_edge) {
/* Replace AET edge by its successor */
succ_edge->outp[BELOW] = edge->outp[ABOVE];
succ_edge->bstate[BELOW] = edge->bstate[ABOVE];
succ_edge->bundle[BELOW][CLIP] = edge->bundle[ABOVE][CLIP];
succ_edge->bundle[BELOW][SUBJ] = edge->bundle[ABOVE][SUBJ];
prev_edge = edge->prev;
if (prev_edge) {
prev_edge->next = succ_edge;
} else {
aet = succ_edge;
}
if (next_edge) {
next_edge->prev = succ_edge;
}
succ_edge->prev = prev_edge;
succ_edge->next = next_edge;
} else {
/* Update this edge */
edge->outp[BELOW] = edge->outp[ABOVE];
edge->bstate[BELOW] = edge->bstate[ABOVE];
edge->bundle[BELOW][CLIP] = edge->bundle[ABOVE][CLIP];
edge->bundle[BELOW][SUBJ] = edge->bundle[ABOVE][SUBJ];
edge->xb = edge->xt;
}
edge->outp[ABOVE] = NULL;
}
}
} /* === END OF SCANBEAM PROCESSING ================================== */
// Generate result polygon from out_poly
result->contour = NULL;
result->hole = NULL;
result->num_contours = count_contours(out_poly);
if (result->num_contours > 0) {
gpc_malloc<int>(result->hole, result->num_contours * sizeof(int),
const_cast<char *>("hole flag table creation"));
gpc_malloc<gpc_vertex_list>(result->contour,
result->num_contours * sizeof(gpc_vertex_list),
const_cast<char *>("contour creation"));
c = 0;
for (poly = out_poly; poly; poly = npoly) {
npoly = poly->next;
if (poly->active) {
result->hole[c] = poly->proxy->hole;
result->contour[c].num_vertices = poly->active;
gpc_malloc<gpc_vertex>(
result->contour[c].vertex,
result->contour[c].num_vertices * sizeof(gpc_vertex),
const_cast<char *>("vertex creation"));
v = result->contour[c].num_vertices - 1;
for (vtx = poly->proxy->v[LEFT]; vtx; vtx = nv) {
nv = vtx->next;
result->contour[c].vertex[v].x = vtx->x;
result->contour[c].vertex[v].y = vtx->y;
gpc_free<vertex_node>(vtx);
v--;
}
c++;
}
gpc_free<polygon_node>(poly);
}
} else {
for (poly = out_poly; poly; poly = npoly) {
npoly = poly->next;
gpc_free<polygon_node>(poly);
}
}
// Tidy up
reset_it(&it);
reset_lmt(&lmt);
gpc_free<edge_node>(c_heap);
gpc_free<edge_node>(s_heap);
gpc_free<double>(sbt);
} // NOLINT
void gpc_free_tristrip(gpc_tristrip *t) {
int s = 0;
for (s = 0; s < t->num_strips; s++) {
gpc_free<gpc_vertex>(t->strip[s].vertex);
}
gpc_free<gpc_vertex_list>(t->strip);
t->num_strips = 0;
}
void gpc_polygon_to_tristrip(gpc_polygon *s, gpc_tristrip *t) {
gpc_polygon c;
c.num_contours = 0;
c.hole = NULL;
c.contour = NULL;
gpc_tristrip_clip(GPC_DIFF, s, &c, t);
}
// gpc_tristrip_clip
void gpc_tristrip_clip(gpc_op op, gpc_polygon *subj, gpc_polygon *clip,
gpc_tristrip *result) {
sb_tree *sbtree = NULL;
it_node *it = NULL;
it_node *intersect = NULL;
edge_node *edge = NULL;
edge_node *prev_edge = NULL;
edge_node *next_edge = NULL;
edge_node *succ_edge = NULL;
edge_node *e0 = NULL;
edge_node *e1 = NULL;
edge_node *aet = NULL;
edge_node *c_heap = NULL;
edge_node *s_heap = NULL;
edge_node *cf = NULL;
lmt_node *lmt = NULL;
lmt_node *local_min = NULL;
polygon_node *tlist = NULL;
polygon_node *tn = NULL;
polygon_node *tnn = NULL;
polygon_node *p = NULL;
polygon_node *q = NULL;
vertex_node *lt = NULL;
vertex_node *ltn = NULL;
vertex_node *rt = NULL;
vertex_node *rtn = NULL;
h_state horiz[2];
vertex_type cft = NUL;
int in[2];
int exists[2];
int parity[2] = {LEFT, LEFT};
int s = 0;
int v = 0;
int contributing = 0;
int search = 0;
int scanbeam = 0;
int sbt_entries = 0;
int vclass = 0;
int bl = 0;
int br = 0;
int tl = 0;
int tr = 0;
double *sbt = NULL;
double xb = 0.0;
double px = 0.0;
double nx = 0.0;
double yb = 0.0;
double yt = 0.0;
double dy = 0.0;
double ix = 0.0;
double iy = 0.0;
/* Test for trivial NULL result cases */
if (((subj->num_contours == 0) && (clip->num_contours == 0)) ||
((subj->num_contours == 0) && ((op == GPC_INT) || (op == GPC_DIFF))) ||
((clip->num_contours == 0) && (op == GPC_INT))) {
result->num_strips = 0;
result->strip = NULL;
return;
}
/* Identify potentialy contributing contours */
if (((op == GPC_INT) || (op == GPC_DIFF)) && (subj->num_contours > 0) &&
(clip->num_contours > 0)) {
minimax_test(subj, clip, op);
}
/* Build LMT */
if (subj->num_contours > 0) {
s_heap = build_lmt(&lmt, &sbtree, &sbt_entries, subj, SUBJ, op);
}
if (clip->num_contours > 0) {
c_heap = build_lmt(&lmt, &sbtree, &sbt_entries, clip, CLIP, op);
}
/* Return a NULL result if no contours contribute */
if (lmt == NULL) {
result->num_strips = 0;
result->strip = NULL;
reset_lmt(&lmt);
gpc_free<edge_node>(s_heap);
gpc_free<edge_node>(c_heap);
return;
}
/* Build scanbeam table from scanbeam tree */
gpc_malloc<double>(sbt, sbt_entries * sizeof(double),
const_cast<char *>("sbt creation"));
build_sbt(&scanbeam, sbt, sbtree);
scanbeam = 0;
free_sbtree(&sbtree);
/* Invert clip polygon for difference operation */
if (op == GPC_DIFF) {
parity[CLIP] = RIGHT;
}
local_min = lmt;
// Process each scanbeam
while (scanbeam < sbt_entries) {
/* Set yb and yt to the bottom and top of the scanbeam */
yb = sbt[scanbeam++];
if (scanbeam < sbt_entries) {
yt = sbt[scanbeam];
dy = yt - yb;
}
/* === SCANBEAM BOUNDARY PROCESSING ================================ */
/* If LMT node corresponding to yb exists */
if (local_min) {
if (local_min->y == yb) {
/* Add edges starting at this local minimum to the AET */
for (edge = local_min->first_bound; edge; edge = edge->next_bound) {
add_edge_to_aet(&aet, edge, NULL);
}
local_min = local_min->next;
}
}
/* Set dummy previous x value */
/* Create bundles within AET */
px = -DBL_MAX;
e0 = aet;
e1 = aet;
/* Set up bundle fields of first edge */
aet->bundle[ABOVE][aet->type] = (aet->top.y != yb);
aet->bundle[ABOVE][!aet->type] = 0;
aet->bstate[ABOVE] = UNBUNDLED;
for (next_edge = aet->next; next_edge; next_edge = next_edge->next) {
/* Set up bundle fields of next edge */
next_edge->bundle[ABOVE][next_edge->type] = (next_edge->top.y != yb);
next_edge->bundle[ABOVE][!next_edge->type] = 0;
next_edge->bstate[ABOVE] = UNBUNDLED;
/* Bundle edges above the scanbeam boundary if they coincide */
if (next_edge->bundle[ABOVE][next_edge->type]) {
if (gpc_eq(e0->xb, next_edge->xb) && gpc_eq(e0->dx, next_edge->dx) &&
(e0->top.y != yb)) {
next_edge->bundle[ABOVE][next_edge->type] ^=
e0->bundle[ABOVE][next_edge->type];
next_edge->bundle[ABOVE][!next_edge->type] =
e0->bundle[ABOVE][!next_edge->type];
next_edge->bstate[ABOVE] = BUNDLE_HEAD;
e0->bundle[ABOVE][CLIP] = 0;
e0->bundle[ABOVE][SUBJ] = 0;
e0->bstate[ABOVE] = BUNDLE_TAIL;
}
e0 = next_edge;
}
}
horiz[CLIP] = NH;
horiz[SUBJ] = NH;
/* Process each edge at this scanbeam boundary */
for (edge = aet; edge; edge = edge->next) {
exists[CLIP] =
edge->bundle[ABOVE][CLIP] + (edge->bundle[BELOW][CLIP] << 1);
exists[SUBJ] =
edge->bundle[ABOVE][SUBJ] + (edge->bundle[BELOW][SUBJ] << 1);
if (exists[CLIP] || exists[SUBJ]) {
/* Set bundle side */
edge->bside[CLIP] = parity[CLIP];
edge->bside[SUBJ] = parity[SUBJ];
/* Determine contributing status and quadrant occupancies */
switch (op) {
case GPC_DIFF:
case GPC_INT:
contributing = (exists[CLIP] && (parity[SUBJ] || horiz[SUBJ])) ||
(exists[SUBJ] && (parity[CLIP] || horiz[CLIP])) ||
(exists[CLIP] && exists[SUBJ] &&
(parity[CLIP] == parity[SUBJ]));
br = (parity[CLIP]) && (parity[SUBJ]);
bl = (parity[CLIP] ^ edge->bundle[ABOVE][CLIP]) &&
(parity[SUBJ] ^ edge->bundle[ABOVE][SUBJ]);
tr = (parity[CLIP] ^ (horiz[CLIP] != NH)) &&
(parity[SUBJ] ^ (horiz[SUBJ] != NH));
tl = (parity[CLIP] ^ (horiz[CLIP] != NH) ^
edge->bundle[BELOW][CLIP]) &&
(parity[SUBJ] ^ (horiz[SUBJ] != NH) ^
edge->bundle[BELOW][SUBJ]);
break;
case GPC_XOR:
contributing = exists[CLIP] || exists[SUBJ];
br = (parity[CLIP]) ^ (parity[SUBJ]);
bl = (parity[CLIP] ^ edge->bundle[ABOVE][CLIP]) ^
(parity[SUBJ] ^ edge->bundle[ABOVE][SUBJ]);
tr = (parity[CLIP] ^ (horiz[CLIP] != NH)) ^
(parity[SUBJ] ^ (horiz[SUBJ] != NH));
tl = (parity[CLIP] ^ (horiz[CLIP] != NH) ^
edge->bundle[BELOW][CLIP]) ^
(parity[SUBJ] ^ (horiz[SUBJ] != NH) ^
edge->bundle[BELOW][SUBJ]);
break;
case GPC_UNION:
contributing = (exists[CLIP] && (!parity[SUBJ] || horiz[SUBJ])) ||
(exists[SUBJ] && (!parity[CLIP] || horiz[CLIP])) ||
(exists[CLIP] && exists[SUBJ] &&
(parity[CLIP] == parity[SUBJ]));
br = (parity[CLIP]) || (parity[SUBJ]);
bl = (parity[CLIP] ^ edge->bundle[ABOVE][CLIP]) ||
(parity[SUBJ] ^ edge->bundle[ABOVE][SUBJ]);
tr = (parity[CLIP] ^ (horiz[CLIP] != NH)) ||
(parity[SUBJ] ^ (horiz[SUBJ] != NH));
tl = (parity[CLIP] ^ (horiz[CLIP] != NH) ^
edge->bundle[BELOW][CLIP]) ||
(parity[SUBJ] ^ (horiz[SUBJ] != NH) ^
edge->bundle[BELOW][SUBJ]);
break;
}
// Update parity
parity[CLIP] ^= edge->bundle[ABOVE][CLIP];
parity[SUBJ] ^= edge->bundle[ABOVE][SUBJ];
/* Update horizontal state */
if (exists[CLIP]) {
horiz[CLIP] = next_h_state[horiz[CLIP]]
[((exists[CLIP] - 1) << 1) + parity[CLIP]];
}
if (exists[SUBJ]) {
horiz[SUBJ] = next_h_state[horiz[SUBJ]]
[((exists[SUBJ] - 1) << 1) + parity[SUBJ]];
}
vclass = tr + (tl << 1) + (br << 2) + (bl << 3);
if (contributing) {
xb = edge->xb;
switch (vclass) {
case EMN:
new_tristrip(&tlist, edge, xb, yb);
cf = edge;
break;
case ERI:
edge->outp[ABOVE] = cf->outp[ABOVE];
if (xb != cf->xb) {
gpc_vertex_create(edge, ABOVE, RIGHT, xb, yb);
}
cf = NULL;
break;
case ELI:
gpc_vertex_create(edge, BELOW, LEFT, xb, yb);
edge->outp[ABOVE] = NULL;
cf = edge;
break;
case EMX:
if (xb != cf->xb) {
gpc_vertex_create(edge, BELOW, RIGHT, xb, yb);
}
edge->outp[ABOVE] = NULL;
cf = NULL;
break;
case IMN:
if (cft == LED) {
if (cf->bot.y != yb) {
gpc_vertex_create(cf, BELOW, LEFT, cf->xb, yb);
}
new_tristrip(&tlist, cf, cf->xb, yb);
}
edge->outp[ABOVE] = cf->outp[ABOVE];
gpc_vertex_create(edge, ABOVE, RIGHT, xb, yb);
break;
case ILI:
new_tristrip(&tlist, edge, xb, yb);
cf = edge;
cft = ILI;
break;
case IRI:
if (cft == LED) {
if (cf->bot.y != yb) {
gpc_vertex_create(cf, BELOW, LEFT, cf->xb, yb);
}
new_tristrip(&tlist, cf, cf->xb, yb);
}
gpc_vertex_create(edge, BELOW, RIGHT, xb, yb);
edge->outp[ABOVE] = NULL;
break;
case IMX:
gpc_vertex_create(edge, BELOW, LEFT, xb, yb);
edge->outp[ABOVE] = NULL;
cft = IMX;
break;
case IMM:
gpc_vertex_create(edge, BELOW, LEFT, xb, yb);
edge->outp[ABOVE] = cf->outp[ABOVE];
if (xb != cf->xb) {
gpc_vertex_create(cf, ABOVE, RIGHT, xb, yb);
}
cf = edge;
break;
case EMM:
gpc_vertex_create(edge, BELOW, RIGHT, xb, yb);
edge->outp[ABOVE] = NULL;
new_tristrip(&tlist, edge, xb, yb);
cf = edge;
break;
case LED:
if (edge->bot.y == yb) {
gpc_vertex_create(edge, BELOW, LEFT, xb, yb);
}
edge->outp[ABOVE] = edge->outp[BELOW];
cf = edge;
cft = LED;
break;
case RED:
edge->outp[ABOVE] = cf->outp[ABOVE];
if (cft == LED) {
if (cf->bot.y == yb) {
gpc_vertex_create(edge, BELOW, RIGHT, xb, yb);
} else {
if (edge->bot.y == yb) {
gpc_vertex_create(cf, BELOW, LEFT, cf->xb, yb);
gpc_vertex_create(edge, BELOW, RIGHT, xb, yb);
}
}
} else {
gpc_vertex_create(edge, BELOW, RIGHT, xb, yb);
gpc_vertex_create(edge, ABOVE, RIGHT, xb, yb);
}
cf = NULL;
break;
default:
break;
} /* End of switch */
} /* End of contributing conditional */
} /* End of edge exists conditional */
} // End of AET loop
/* Delete terminating edges from the AET, otherwise compute xt */
for (edge = aet; edge; edge = edge->next) {
if (edge->top.y == yb) {
prev_edge = edge->prev;
next_edge = edge->next;
if (prev_edge) {
prev_edge->next = next_edge;
} else {
aet = next_edge;
}
if (next_edge) {
next_edge->prev = prev_edge;
}
/* Copy bundle head state to the adjacent tail edge if required */
if ((edge->bstate[BELOW] == BUNDLE_HEAD) && prev_edge) {
if (prev_edge->bstate[BELOW] == BUNDLE_TAIL) {
prev_edge->outp[BELOW] = edge->outp[BELOW];
prev_edge->bstate[BELOW] = UNBUNDLED;
if (prev_edge->prev) {
if (prev_edge->prev->bstate[BELOW] == BUNDLE_TAIL) {
prev_edge->bstate[BELOW] = BUNDLE_HEAD;
}
}
}
}
} else {
if (edge->top.y == yt) {
edge->xt = edge->top.x;
} else {
edge->xt = edge->bot.x + edge->dx * (yt - edge->bot.y);
}
}
}
if (scanbeam < sbt_entries) {
/* === SCANBEAM INTERIOR PROCESSING ============================== */
build_intersection_table(&it, aet, dy);
/* Process each node in the intersection table */
for (intersect = it; intersect; intersect = intersect->next) {
e0 = intersect->ie[0];
e1 = intersect->ie[1];
/* Only generate output for contributing intersections */
if ((e0->bundle[ABOVE][CLIP] || e0->bundle[ABOVE][SUBJ]) &&
(e1->bundle[ABOVE][CLIP] || e1->bundle[ABOVE][SUBJ])) {
p = e0->outp[ABOVE];
q = e1->outp[ABOVE];
ix = intersect->point.x;
iy = intersect->point.y + yb;
in[CLIP] = (e0->bundle[ABOVE][CLIP] && !e0->bside[CLIP]) ||
(e1->bundle[ABOVE][CLIP] && e1->bside[CLIP]) ||
(!e0->bundle[ABOVE][CLIP] && !e1->bundle[ABOVE][CLIP] &&
e0->bside[CLIP] && e1->bside[CLIP]);
in[SUBJ] = (e0->bundle[ABOVE][SUBJ] && !e0->bside[SUBJ]) ||
(e1->bundle[ABOVE][SUBJ] && e1->bside[SUBJ]) ||
(!e0->bundle[ABOVE][SUBJ] && !e1->bundle[ABOVE][SUBJ] &&
e0->bside[SUBJ] && e1->bside[SUBJ]);
switch (op) { // Determine quadrant occupancies
case GPC_DIFF:
case GPC_INT:
tr = (in[CLIP]) && (in[SUBJ]);
tl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP]) &&
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ]);
br = (in[CLIP] ^ e0->bundle[ABOVE][CLIP]) &&
(in[SUBJ] ^ e0->bundle[ABOVE][SUBJ]);
bl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP] ^
e0->bundle[ABOVE][CLIP]) &&
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ] ^
e0->bundle[ABOVE][SUBJ]);
break;
case GPC_XOR:
tr = (in[CLIP]) ^ (in[SUBJ]);
tl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP]) ^
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ]);
br = (in[CLIP] ^ e0->bundle[ABOVE][CLIP]) ^
(in[SUBJ] ^ e0->bundle[ABOVE][SUBJ]);
bl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP] ^
e0->bundle[ABOVE][CLIP]) ^
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ] ^
e0->bundle[ABOVE][SUBJ]);
break;
case GPC_UNION:
tr = (in[CLIP]) || (in[SUBJ]);
tl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP]) ||
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ]);
br = (in[CLIP] ^ e0->bundle[ABOVE][CLIP]) ||
(in[SUBJ] ^ e0->bundle[ABOVE][SUBJ]);
bl = (in[CLIP] ^ e1->bundle[ABOVE][CLIP] ^
e0->bundle[ABOVE][CLIP]) ||
(in[SUBJ] ^ e1->bundle[ABOVE][SUBJ] ^
e0->bundle[ABOVE][SUBJ]);
break;
}
vclass = tr + (tl << 1) + (br << 2) + (bl << 3);
switch (vclass) {
case EMN:
new_tristrip(&tlist, e1, ix, iy);
e0->outp[ABOVE] = e1->outp[ABOVE];
break;
case ERI:
if (p) {
gpc_p_edge(prev_edge, e0, ABOVE);
gpc_vertex_create(prev_edge, ABOVE, LEFT, px, iy);
gpc_vertex_create(e0, ABOVE, RIGHT, ix, iy);
e1->outp[ABOVE] = e0->outp[ABOVE];
e0->outp[ABOVE] = NULL;
}
break;
case ELI:
if (q) {
gpc_n_edge(next_edge, e1, ABOVE);
gpc_vertex_create(e1, ABOVE, LEFT, ix, iy);
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
e0->outp[ABOVE] = e1->outp[ABOVE];
e1->outp[ABOVE] = NULL;
}
break;
case EMX:
if (p && q) {
gpc_vertex_create(e0, ABOVE, LEFT, ix, iy);
e0->outp[ABOVE] = NULL;
e1->outp[ABOVE] = NULL;
}
break;
case IMN:
gpc_p_edge(prev_edge, e0, ABOVE);
gpc_vertex_create(prev_edge, ABOVE, LEFT, px, iy);
gpc_n_edge(next_edge, e1, ABOVE);
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
new_tristrip(&tlist, prev_edge, px, iy);
e1->outp[ABOVE] = prev_edge->outp[ABOVE];
gpc_vertex_create(e1, ABOVE, RIGHT, ix, iy);
new_tristrip(&tlist, e0, ix, iy);
next_edge->outp[ABOVE] = e0->outp[ABOVE];
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
break;
case ILI:
if (p) {
gpc_vertex_create(e0, ABOVE, LEFT, ix, iy);
gpc_n_edge(next_edge, e1, ABOVE);
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
e1->outp[ABOVE] = e0->outp[ABOVE];
e0->outp[ABOVE] = NULL;
}
break;
case IRI:
if (q) {
gpc_vertex_create(e1, ABOVE, RIGHT, ix, iy);
gpc_p_edge(prev_edge, e0, ABOVE);
gpc_vertex_create(prev_edge, ABOVE, LEFT, px, iy);
e0->outp[ABOVE] = e1->outp[ABOVE];
e1->outp[ABOVE] = NULL;
}
break;
case IMX:
if (p && q) {
gpc_vertex_create(e0, ABOVE, RIGHT, ix, iy);
gpc_vertex_create(e1, ABOVE, LEFT, ix, iy);
e0->outp[ABOVE] = NULL;
e1->outp[ABOVE] = NULL;
gpc_p_edge(prev_edge, e0, ABOVE);
gpc_vertex_create(prev_edge, ABOVE, LEFT, px, iy);
new_tristrip(&tlist, prev_edge, px, iy);
gpc_n_edge(next_edge, e1, ABOVE);
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
next_edge->outp[ABOVE] = prev_edge->outp[ABOVE];
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
}
break;
case IMM:
if (p && q) {
gpc_vertex_create(e0, ABOVE, RIGHT, ix, iy);
gpc_vertex_create(e1, ABOVE, LEFT, ix, iy);
gpc_p_edge(prev_edge, e0, ABOVE);
gpc_vertex_create(prev_edge, ABOVE, LEFT, px, iy);
new_tristrip(&tlist, prev_edge, px, iy);
gpc_n_edge(next_edge, e1, ABOVE);
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
e1->outp[ABOVE] = prev_edge->outp[ABOVE];
gpc_vertex_create(e1, ABOVE, RIGHT, ix, iy);
new_tristrip(&tlist, e0, ix, iy);
next_edge->outp[ABOVE] = e0->outp[ABOVE];
gpc_vertex_create(next_edge, ABOVE, RIGHT, nx, iy);
}
break;
case EMM:
if (p && q) {
gpc_vertex_create(e0, ABOVE, LEFT, ix, iy);
new_tristrip(&tlist, e1, ix, iy);
e0->outp[ABOVE] = e1->outp[ABOVE];
}
break;
default:
break;
} /* End of switch */
} /* End of contributing intersection conditional */
// Swap bundle sides in response to edge crossing
if (e0->bundle[ABOVE][CLIP]) {
e1->bside[CLIP] = !e1->bside[CLIP];
}
if (e1->bundle[ABOVE][CLIP]) {
e0->bside[CLIP] = !e0->bside[CLIP];
}
if (e0->bundle[ABOVE][SUBJ]) {
e1->bside[SUBJ] = !e1->bside[SUBJ];
}
if (e1->bundle[ABOVE][SUBJ]) {
e0->bside[SUBJ] = !e0->bside[SUBJ];
}
/* Swap e0 and e1 bundles in the AET */
prev_edge = e0->prev;
next_edge = e1->next;
if (e1->next) {
e1->next->prev = e0;
}
if (e0->bstate[ABOVE] == BUNDLE_HEAD) {
search = 1;
while (search) {
prev_edge = prev_edge->prev;
if (prev_edge) {
if (prev_edge->bundle[ABOVE][CLIP] ||
prev_edge->bundle[ABOVE][SUBJ] ||
(prev_edge->bstate[ABOVE] == BUNDLE_HEAD)) {
search = 0;
}
} else {
search = 0;
}
}
}
if (!prev_edge) {
e1->next = aet;
aet = e0->next;
} else {
e1->next = prev_edge->next;
prev_edge->next = e0->next;
}
e0->next->prev = prev_edge;
e1->next->prev = e1;
e0->next = next_edge;
} /* End of IT loop*/
/* Prepare for next scanbeam */
for (edge = aet; edge; edge = next_edge) {
next_edge = edge->next;
succ_edge = edge->succ;
if ((edge->top.y == yt) && succ_edge) {
/* Replace AET edge by its successor */
succ_edge->outp[BELOW] = edge->outp[ABOVE];
succ_edge->bstate[BELOW] = edge->bstate[ABOVE];
succ_edge->bundle[BELOW][CLIP] = edge->bundle[ABOVE][CLIP];
succ_edge->bundle[BELOW][SUBJ] = edge->bundle[ABOVE][SUBJ];
prev_edge = edge->prev;
if (prev_edge) {
prev_edge->next = succ_edge;
} else {
aet = succ_edge;
}
if (next_edge) {
next_edge->prev = succ_edge;
}
succ_edge->prev = prev_edge;
succ_edge->next = next_edge;
} else {
/* Update this edge */
edge->outp[BELOW] = edge->outp[ABOVE];
edge->bstate[BELOW] = edge->bstate[ABOVE];
edge->bundle[BELOW][CLIP] = edge->bundle[ABOVE][CLIP];
edge->bundle[BELOW][SUBJ] = edge->bundle[ABOVE][SUBJ];
edge->xb = edge->xt;
}
edge->outp[ABOVE] = NULL;
}
}
} /* === END OF SCANBEAM PROCESSING ================================== */
// Generate result tristrip from tlist
result->strip = NULL;
result->num_strips = count_tristrips(tlist);
if (result->num_strips > 0) {
gpc_malloc<gpc_vertex_list>(result->strip,
result->num_strips * sizeof(gpc_vertex_list),
const_cast<char *>("tristrip list creation"));
s = 0;
for (tn = tlist; tn; tn = tnn) {
tnn = tn->next;
if (tn->active > 2) {
/* Valid tristrip: copy the vertices and free the heap */
result->strip[s].num_vertices = tn->active;
gpc_malloc<gpc_vertex>(result->strip[s].vertex,
tn->active * sizeof(gpc_vertex),
const_cast<char *>("tristrip creation"));
v = 0;
if (0) {
lt = tn->v[RIGHT];
rt = tn->v[LEFT];
} else {
lt = tn->v[LEFT];
rt = tn->v[RIGHT];
}
while (lt || rt) {
if (lt) {
ltn = lt->next;
result->strip[s].vertex[v].x = lt->x;
result->strip[s].vertex[v].y = lt->y;
v++;
gpc_free<vertex_node>(lt);
lt = ltn;
}
if (rt) {
rtn = rt->next;
result->strip[s].vertex[v].x = rt->x;
result->strip[s].vertex[v].y = rt->y;
v++;
gpc_free<vertex_node>(rt);
rt = rtn;
}
}
s++;
} else {
/* Invalid tristrip: just free the heap */
for (lt = tn->v[LEFT]; lt; lt = ltn) {
ltn = lt->next;
gpc_free<vertex_node>(lt);
}
for (rt = tn->v[RIGHT]; rt; rt = rtn) {
rtn = rt->next;
gpc_free<vertex_node>(rt);
}
}
gpc_free<polygon_node>(tn);
}
}
// Tidy up
reset_it(&it);
reset_lmt(&lmt);
gpc_free<edge_node>(c_heap);
gpc_free<edge_node>(s_heap);
gpc_free<double>(sbt);
} // NOLINT
} // namespace gpc
/* vim: set expandtab ts=4 sw=4 sts=4 tw=100: */
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