3
* Mesa 3-D graphics library
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* Copyright (C) 1995-2000 Brian Paul
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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* This file is part of the polygon tesselation code contributed by
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static GLenum store_polygon_as_contour(GLUtriangulatorObj *);
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static void free_current_polygon(tess_polygon *);
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static void prepare_projection_info(GLUtriangulatorObj *);
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static GLdouble twice_the_polygon_area(tess_vertex *, tess_vertex *);
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static GLenum verify_edge_vertex_intersections(GLUtriangulatorObj *);
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void tess_find_contour_hierarchies(GLUtriangulatorObj *);
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static GLenum test_for_overlapping_contours(GLUtriangulatorObj *);
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static GLenum contours_overlap(tess_contour *, tess_polygon *);
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static GLenum is_contour_contained_in(tess_contour *, tess_contour *);
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static void add_new_exterior(GLUtriangulatorObj *, tess_contour *);
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static void add_new_interior(GLUtriangulatorObj *, tess_contour *,
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static void add_interior_with_hierarchy_check(GLUtriangulatorObj *,
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tess_contour *, tess_contour *);
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static void reverse_hierarchy_and_add_exterior(GLUtriangulatorObj *,
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static GLboolean point_in_polygon(tess_contour *, GLdouble, GLdouble);
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static void shift_interior_to_exterior(GLUtriangulatorObj *, tess_contour *);
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static void add_exterior_with_check(GLUtriangulatorObj *, tess_contour *,
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static GLenum cut_out_hole(GLUtriangulatorObj *, tess_contour *,
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static GLenum merge_hole_with_contour(GLUtriangulatorObj *,
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tess_contour *, tess_contour *,
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tess_vertex *, tess_vertex *);
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find_normal(GLUtriangulatorObj * tobj)
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tess_polygon *polygon = tobj->current_polygon;
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tess_vertex *va, *vb, *vc;
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GLdouble A0, A1, A2, B0, B1, B2;
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va = polygon->vertices;
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A0 = vb->location[0] - va->location[0];
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A1 = vb->location[1] - va->location[1];
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A2 = vb->location[2] - va->location[2];
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for (vc = vb->next; vc != va; vc = vc->next) {
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B0 = vc->location[0] - va->location[0];
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B1 = vc->location[1] - va->location[1];
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B2 = vc->location[2] - va->location[2];
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A = A1 * B2 - A2 * B1;
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B = A2 * B0 - A0 * B2;
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C = A0 * B1 - A1 * B0;
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if (fabs(A) > EPSILON || fabs(B) > EPSILON || fabs(C) > EPSILON) {
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-A * va->location[0] - B * va->location[1] - C * va->location[2];
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tess_call_user_error(tobj, GLU_TESS_ERROR7);
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tess_test_polygon(GLUtriangulatorObj * tobj)
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tess_polygon *polygon = tobj->current_polygon;
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/* any vertices defined? */
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if (polygon->vertex_cnt < 3) {
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free_current_polygon(polygon);
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polygon->last_vertex->next = polygon->vertices;
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polygon->vertices->previous = polygon->last_vertex;
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/* determine the normal */
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if (find_normal(tobj) == GLU_ERROR)
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/* compare the normals of previously defined contours and this one */
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/* first contour define ? */
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if (tobj->contours == NULL) {
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tobj->A = polygon->A;
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tobj->B = polygon->B;
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tobj->C = polygon->C;
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tobj->D = polygon->D;
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/* determine the best projection to use */
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if (fabs(polygon->A) > fabs(polygon->B))
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if (fabs(polygon->A) > fabs(polygon->C))
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tobj->projection = OYZ;
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tobj->projection = OXY;
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else if (fabs(polygon->B) > fabs(polygon->C))
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tobj->projection = OXZ;
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tobj->projection = OXY;
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tess_vertex *vertex = polygon->vertices;
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/* compare the normals */
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if (fabs(a[1] * b[2] - a[2] * b[1]) > EPSILON ||
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fabs(a[2] * b[0] - a[0] * b[2]) > EPSILON ||
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fabs(a[0] * b[1] - a[1] * b[0]) > EPSILON) {
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tess_call_user_error(tobj, GLU_TESS_ERROR9);
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/* the normals are parallel - test for plane equation */
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if (fabs(a[0] * vertex->location[0] + a[1] * vertex->location[1] +
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a[2] * vertex->location[2] + tobj->D) > EPSILON) {
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/* not the same plane */
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tess_call_user_error(tobj, GLU_TESS_ERROR9);
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prepare_projection_info(tobj);
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if (verify_edge_vertex_intersections(tobj) == GLU_ERROR)
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if (test_for_overlapping_contours(tobj) == GLU_ERROR)
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if (store_polygon_as_contour(tobj) == GLU_ERROR)
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test_for_overlapping_contours(GLUtriangulatorObj * tobj)
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tess_contour *contour;
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tess_polygon *polygon;
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polygon = tobj->current_polygon;
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for (contour = tobj->contours; contour != NULL; contour = contour->next)
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if (contours_overlap(contour, polygon) != GLU_NO_ERROR) {
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tess_call_user_error(tobj, GLU_TESS_ERROR5);
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store_polygon_as_contour(GLUtriangulatorObj * tobj)
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tess_polygon *polygon = tobj->current_polygon;
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tess_contour *contour = tobj->contours;
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/* the first contour defined */
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if (contour == NULL) {
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if ((contour = (tess_contour *) malloc(sizeof(tess_contour))) == NULL) {
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tess_call_user_error(tobj, GLU_OUT_OF_MEMORY);
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free_current_polygon(polygon);
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tobj->contours = tobj->last_contour = contour;
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contour->next = contour->previous = NULL;
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if ((contour = (tess_contour *) malloc(sizeof(tess_contour))) == NULL) {
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tess_call_user_error(tobj, GLU_OUT_OF_MEMORY);
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free_current_polygon(polygon);
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contour->previous = tobj->last_contour;
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tobj->last_contour->next = contour;
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tobj->last_contour = contour;
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contour->next = NULL;
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/* mark all vertices in new contour as not special */
213
/* and all are boundary edges */
216
GLuint vertex_cnt, i;
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for (vertex = polygon->vertices, i = 0, vertex_cnt =
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polygon->vertex_cnt; i < vertex_cnt; vertex = vertex->next, i++) {
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vertex->shadow_vertex = NULL;
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vertex->edge_flag = GL_TRUE;
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contour->vertex_cnt = polygon->vertex_cnt;
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contour->area = polygon->area;
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contour->orientation = polygon->orientation;
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contour->type = GLU_UNKNOWN;
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contour->vertices = polygon->vertices;
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contour->last_vertex = polygon->last_vertex;
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polygon->vertices = polygon->last_vertex = NULL;
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polygon->vertex_cnt = 0;
232
++(tobj->contour_cnt);
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free_current_polygon(tess_polygon * polygon)
239
tess_vertex *vertex, *vertex_tmp;
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/* free current_polygon structures */
243
for (vertex = polygon->vertices, i = 0; i < polygon->vertex_cnt; i++) {
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vertex_tmp = vertex->next;
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polygon->vertices = polygon->last_vertex = NULL;
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polygon->vertex_cnt = 0;
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prepare_projection_info(GLUtriangulatorObj * tobj)
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tess_polygon *polygon = tobj->current_polygon;
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tess_vertex *vertex, *last_vertex_ptr;
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last_vertex_ptr = polygon->last_vertex;
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switch (tobj->projection) {
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for (vertex = polygon->vertices; vertex != last_vertex_ptr;
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vertex = vertex->next) {
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vertex->x = vertex->location[0];
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vertex->y = vertex->location[1];
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last_vertex_ptr->x = last_vertex_ptr->location[0];
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last_vertex_ptr->y = last_vertex_ptr->location[1];
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for (vertex = polygon->vertices; vertex != last_vertex_ptr;
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vertex = vertex->next) {
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vertex->x = vertex->location[0];
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vertex->y = vertex->location[2];
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last_vertex_ptr->x = last_vertex_ptr->location[0];
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last_vertex_ptr->y = last_vertex_ptr->location[2];
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for (vertex = polygon->vertices; vertex != last_vertex_ptr;
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vertex = vertex->next) {
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vertex->x = vertex->location[1];
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vertex->y = vertex->location[2];
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last_vertex_ptr->x = last_vertex_ptr->location[1];
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last_vertex_ptr->y = last_vertex_ptr->location[2];
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area = twice_the_polygon_area(polygon->vertices, polygon->last_vertex);
291
polygon->orientation = GLU_CCW;
292
polygon->area = area;
295
polygon->orientation = GLU_CW;
296
polygon->area = -area;
301
twice_the_polygon_area(tess_vertex * vertex, tess_vertex * last_vertex)
309
vertex = vertex->next;
310
for (; vertex != last_vertex; vertex = vertex->next) {
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(vertex->x - x) * (next->y - y) - (vertex->y - y) * (next->x - x);
318
/* test if edges ab and cd intersect */
319
/* if not return GLU_NO_ERROR, else if cross return GLU_TESS_ERROR8, */
320
/* else if adjacent return GLU_TESS_ERROR4 */
322
edge_edge_intersect(tess_vertex * a,
323
tess_vertex * b, tess_vertex * c, tess_vertex * d)
325
GLdouble denom, r, s;
326
GLdouble xba, ydc, yba, xdc, yac, xac;
334
denom = xba * ydc - yba * xdc;
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r = yac * xdc - xac * ydc;
337
if (fabs(denom) < EPSILON) {
338
if (fabs(r) < EPSILON) {
340
if (fabs(xba) < EPSILON) {
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/* compare the Y coordinate */
344
(fabs(a->y - c->y) < EPSILON
345
&& fabs(c->y - b->y) < EPSILON)
346
|| (fabs(a->y - d->y) < EPSILON
347
&& fabs(d->y - b->y) <
348
EPSILON)) return GLU_TESS_ERROR4;
353
(fabs(b->y - c->y) < EPSILON
354
&& fabs(c->y - a->y) < EPSILON)
355
|| (fabs(b->y - d->y) < EPSILON
356
&& fabs(d->y - a->y) <
357
EPSILON)) return GLU_TESS_ERROR4;
361
/* compare the X coordinate */
364
(fabs(a->x - c->x) < EPSILON
365
&& fabs(c->x - b->x) < EPSILON)
366
|| (fabs(a->x - d->x) < EPSILON
367
&& fabs(d->x - b->x) <
368
EPSILON)) return GLU_TESS_ERROR4;
372
(fabs(b->x - c->x) < EPSILON
373
&& fabs(c->x - a->x) < EPSILON)
374
|| (fabs(b->x - d->x) < EPSILON
375
&& fabs(d->x - a->x) <
376
EPSILON)) return GLU_TESS_ERROR4;
383
s = (yac * xba - xac * yba) / denom;
384
/* test if one vertex lies on other edge */
385
if (((fabs(r) < EPSILON || (r < 1.0 + EPSILON && r > 1.0 - EPSILON)) &&
386
s > -EPSILON && s < 1.0 + EPSILON) ||
387
((fabs(s) < EPSILON || (s < 1.0 + EPSILON && s > 1.0 - EPSILON)) &&
388
r > -EPSILON && r < 1.0 + EPSILON)) {
389
return GLU_TESS_ERROR4;
391
/* test for crossing */
392
if (r > -EPSILON && r < 1.0 + EPSILON && s > -EPSILON && s < 1.0 + EPSILON) {
393
return GLU_TESS_ERROR8;
399
verify_edge_vertex_intersections(GLUtriangulatorObj * tobj)
401
tess_polygon *polygon = tobj->current_polygon;
402
tess_vertex *vertex1, *last_vertex, *vertex2;
405
last_vertex = polygon->last_vertex;
406
vertex1 = last_vertex;
407
for (vertex2 = vertex1->next->next;
408
vertex2->next != last_vertex; vertex2 = vertex2->next) {
409
test = edge_edge_intersect(vertex1, vertex1->next, vertex2,
411
if (test != GLU_NO_ERROR) {
412
tess_call_user_error(tobj, test);
416
for (vertex1 = polygon->vertices;
417
vertex1->next->next != last_vertex; vertex1 = vertex1->next) {
418
for (vertex2 = vertex1->next->next;
419
vertex2 != last_vertex; vertex2 = vertex2->next) {
420
test = edge_edge_intersect(vertex1, vertex1->next, vertex2,
422
if (test != GLU_NO_ERROR) {
423
tess_call_user_error(tobj, test);
435
area_compare(const void *a, const void *b)
437
GLdouble area1, area2;
439
area1 = (*((tess_contour **) a))->area;
440
area2 = (*((tess_contour **) b))->area;
449
tess_find_contour_hierarchies(GLUtriangulatorObj * tobj)
451
tess_contour **contours; /* dinamic array of pointers */
452
tess_contour *tmp_contour_ptr = tobj->contours;
455
GLboolean hierarchy_changed;
458
if (tobj->contour_cnt < 2) {
459
tobj->contours->type = GLU_EXTERIOR;
462
if ((contours = (tess_contour **)
463
malloc(sizeof(tess_contour *) * (tobj->contour_cnt))) == NULL) {
464
tess_call_user_error(tobj, GLU_OUT_OF_MEMORY);
467
for (tmp_contour_ptr = tobj->contours, cnt = 0;
468
tmp_contour_ptr != NULL; tmp_contour_ptr = tmp_contour_ptr->next)
469
contours[cnt++] = tmp_contour_ptr;
470
/* now sort the contours in decreasing area size order */
471
qsort((void *) contours, (size_t) cnt, (size_t) sizeof(tess_contour *),
473
/* we leave just the first contour - remove others from list */
474
tobj->contours = contours[0];
475
tobj->contours->next = tobj->contours->previous = NULL;
476
tobj->last_contour = tobj->contours;
477
tobj->contour_cnt = 1;
478
/* first contour is the one with greatest area */
479
/* must be EXTERIOR */
480
tobj->contours->type = GLU_EXTERIOR;
481
tmp_contour_ptr = tobj->contours;
483
for (i = 1; i < cnt; i++) {
484
hierarchy_changed = GL_FALSE;
485
for (tmp_contour_ptr = tobj->contours;
486
tmp_contour_ptr != NULL; tmp_contour_ptr = tmp_contour_ptr->next) {
487
if (tmp_contour_ptr->type == GLU_EXTERIOR) {
488
/* check if contour completely contained in EXTERIOR */
489
result = is_contour_contained_in(tmp_contour_ptr, contours[i]);
492
/* now we have to check if contour is inside interiors */
495
if (tmp_contour_ptr->next != NULL &&
496
tmp_contour_ptr->next->type == GLU_INTERIOR) {
497
/* for all interior, check if inside any of them */
498
/* if not inside any of interiors, its another */
500
/* or it may contain some interiors, then change */
501
/* the contained interiors to exterior ones */
502
add_interior_with_hierarchy_check(tobj,
507
/* not in interior, add as new interior contour */
508
add_new_interior(tobj, tmp_contour_ptr, contours[i]);
510
hierarchy_changed = GL_TRUE;
513
/* ooops, the marked as EXTERIOR (contours[i]) is */
514
/* actually an interior of tmp_contour_ptr */
515
/* reverse the local hierarchy */
516
reverse_hierarchy_and_add_exterior(tobj, tmp_contour_ptr,
518
hierarchy_changed = GL_TRUE;
526
if (hierarchy_changed)
527
break; /* break from for loop */
529
if (hierarchy_changed == GL_FALSE) {
530
/* disjoint with all contours, add to contour list */
531
add_new_exterior(tobj, contours[i]);
537
/* returns GLU_INTERIOR if inner is completey enclosed within outer */
538
/* returns GLU_EXTERIOR if outer is completely enclosed within inner */
539
/* returns GLU_NO_ERROR if contours are disjoint */
541
is_contour_contained_in(tess_contour * outer, tess_contour * inner)
543
GLenum relation_flag;
545
/* set relation_flag to relation of containment of first inner vertex */
546
/* regarding outer contour */
547
if (point_in_polygon(outer, inner->vertices->x, inner->vertices->y))
548
relation_flag = GLU_INTERIOR;
550
relation_flag = GLU_EXTERIOR;
551
if (relation_flag == GLU_INTERIOR)
553
if (point_in_polygon(inner, outer->vertices->x, outer->vertices->y))
559
point_in_polygon(tess_contour * contour, GLdouble x, GLdouble y)
561
tess_vertex *v1, *v2;
562
GLuint i, vertex_cnt;
563
GLdouble xp1, yp1, xp2, yp2;
567
v1 = contour->vertices;
568
v2 = contour->vertices->previous;
569
for (i = 0, vertex_cnt = contour->vertex_cnt; i < vertex_cnt; i++) {
574
if ((((yp1 <= y) && (y < yp2)) || ((yp2 <= y) && (y < yp1))) &&
575
(x < (xp2 - xp1) * (y - yp1) / (yp2 - yp1) + xp1))
576
tst = (tst == GL_FALSE ? GL_TRUE : GL_FALSE);
584
contours_overlap(tess_contour * contour, tess_polygon * polygon)
586
tess_vertex *vertex1, *vertex2;
587
GLuint vertex1_cnt, vertex2_cnt, i, j;
590
vertex1 = contour->vertices;
591
vertex2 = polygon->vertices;
592
vertex1_cnt = contour->vertex_cnt;
593
vertex2_cnt = polygon->vertex_cnt;
594
for (i = 0; i < vertex1_cnt; vertex1 = vertex1->next, i++) {
595
for (j = 0; j < vertex2_cnt; vertex2 = vertex2->next, j++)
596
if ((test = edge_edge_intersect(vertex1, vertex1->next, vertex2,
597
vertex2->next)) != GLU_NO_ERROR)
604
add_new_exterior(GLUtriangulatorObj * tobj, tess_contour * contour)
606
contour->type = GLU_EXTERIOR;
607
contour->next = NULL;
608
contour->previous = tobj->last_contour;
609
tobj->last_contour->next = contour;
610
tobj->last_contour = contour;
614
add_new_interior(GLUtriangulatorObj * tobj,
615
tess_contour * outer, tess_contour * contour)
617
contour->type = GLU_INTERIOR;
618
contour->next = outer->next;
619
contour->previous = outer;
620
if (outer->next != NULL)
621
outer->next->previous = contour;
622
outer->next = contour;
623
if (tobj->last_contour == outer)
624
tobj->last_contour = contour;
628
add_interior_with_hierarchy_check(GLUtriangulatorObj * tobj,
629
tess_contour * outer,
630
tess_contour * contour)
634
/* for all interiors of outer check if they are interior of contour */
635
/* if so, change that interior to exterior and move it of of the */
636
/* interior sequence */
637
if (outer->next != NULL && outer->next->type == GLU_INTERIOR) {
640
for (ptr = outer->next; ptr != NULL && ptr->type == GLU_INTERIOR;
642
test = is_contour_contained_in(ptr, contour);
645
/* contour is contained in one of the interiors */
646
/* check if possibly contained in other exteriors */
647
/* move ptr to first EXTERIOR */
648
for (; ptr != NULL && ptr->type == GLU_INTERIOR; ptr = ptr->next);
650
/* another exterior */
651
add_new_exterior(tobj, contour);
653
add_exterior_with_check(tobj, ptr, contour);
656
/* one of the interiors is contained in the contour */
657
/* change it to EXTERIOR, and shift it away from the */
658
/* interior sequence */
659
shift_interior_to_exterior(tobj, ptr);
669
/* add contour to the interior sequence */
670
add_new_interior(tobj, outer, contour);
674
reverse_hierarchy_and_add_exterior(GLUtriangulatorObj * tobj,
675
tess_contour * outer,
676
tess_contour * contour)
680
/* reverse INTERIORS to EXTERIORS */
682
if (outer->next != NULL && outer->next->type == GLU_INTERIOR)
683
for (ptr = outer->next; ptr != NULL && ptr->type == GLU_INTERIOR;
684
ptr = ptr->next) ptr->type = GLU_EXTERIOR;
685
/* the outer now becomes inner */
686
outer->type = GLU_INTERIOR;
687
/* contour is the EXTERIOR */
688
contour->next = outer;
689
if (tobj->contours == outer) {
690
/* first contour beeing reversed */
691
contour->previous = NULL;
692
tobj->contours = contour;
695
outer->previous->next = contour;
696
contour->previous = outer->previous;
698
outer->previous = contour;
702
shift_interior_to_exterior(GLUtriangulatorObj * tobj, tess_contour * contour)
704
contour->previous->next = contour->next;
705
if (contour->next != NULL)
706
contour->next->previous = contour->previous;
708
tobj->last_contour = contour->previous;
712
add_exterior_with_check(GLUtriangulatorObj * tobj,
713
tess_contour * outer, tess_contour * contour)
717
/* this contour might be interior to further exteriors - check */
718
/* if not, just add as a new exterior */
719
for (; outer != NULL && outer->type == GLU_EXTERIOR; outer = outer->next) {
720
test = is_contour_contained_in(outer, contour);
723
/* now we have to check if contour is inside interiors */
726
if (outer->next != NULL && outer->next->type == GLU_INTERIOR) {
727
/* for all interior, check if inside any of them */
728
/* if not inside any of interiors, its another */
730
/* or it may contain some interiors, then change */
731
/* the contained interiors to exterior ones */
732
add_interior_with_hierarchy_check(tobj, outer, contour);
735
/* not in interior, add as new interior contour */
736
add_new_interior(tobj, outer, contour);
746
/* add contour to the exterior sequence */
747
add_new_exterior(tobj, contour);
751
tess_handle_holes(GLUtriangulatorObj * tobj)
753
tess_contour *contour, *hole;
754
GLenum exterior_orientation;
756
/* verify hole orientation */
757
for (contour = tobj->contours; contour != NULL;) {
758
exterior_orientation = contour->orientation;
759
for (contour = contour->next;
760
contour != NULL && contour->type == GLU_INTERIOR;
761
contour = contour->next) {
762
if (contour->orientation == exterior_orientation) {
763
tess_call_user_error(tobj, GLU_TESS_ERROR5);
768
/* now cut-out holes */
769
for (contour = tobj->contours; contour != NULL;) {
770
hole = contour->next;
771
while (hole != NULL && hole->type == GLU_INTERIOR) {
772
if (cut_out_hole(tobj, contour, hole) == GLU_ERROR)
774
hole = contour->next;
776
contour = contour->next;
781
cut_out_hole(GLUtriangulatorObj * tobj,
782
tess_contour * contour, tess_contour * hole)
784
tess_contour *tmp_hole;
785
tess_vertex *v1, *v2, *tmp_vertex;
786
GLuint vertex1_cnt, vertex2_cnt, tmp_vertex_cnt;
790
/* find an edge connecting contour and hole not intersecting any other */
791
/* edge belonging to either the contour or any of the other holes */
792
for (v1 = contour->vertices, vertex1_cnt = contour->vertex_cnt, i = 0;
793
i < vertex1_cnt; i++, v1 = v1->next) {
794
for (v2 = hole->vertices, vertex2_cnt = hole->vertex_cnt, j = 0;
795
j < vertex2_cnt; j++, v2 = v2->next) {
796
/* does edge (v1,v2) intersect any edge of contour */
797
for (tmp_vertex = contour->vertices, tmp_vertex_cnt =
798
contour->vertex_cnt, k = 0; k < tmp_vertex_cnt;
799
tmp_vertex = tmp_vertex->next, k++) {
800
/* skip edge tests for edges directly connected */
801
if (v1 == tmp_vertex || v1 == tmp_vertex->next)
803
test = edge_edge_intersect(v1, v2, tmp_vertex, tmp_vertex->next);
804
if (test != GLU_NO_ERROR)
807
if (test == GLU_NO_ERROR) {
808
/* does edge (v1,v2) intersect any edge of hole */
809
for (tmp_vertex = hole->vertices,
810
tmp_vertex_cnt = hole->vertex_cnt, k = 0;
811
k < tmp_vertex_cnt; tmp_vertex = tmp_vertex->next, k++) {
812
/* skip edge tests for edges directly connected */
813
if (v2 == tmp_vertex || v2 == tmp_vertex->next)
816
edge_edge_intersect(v1, v2, tmp_vertex, tmp_vertex->next);
817
if (test != GLU_NO_ERROR)
820
if (test == GLU_NO_ERROR) {
821
/* does edge (v1,v2) intersect any other hole? */
822
for (tmp_hole = hole->next;
823
tmp_hole != NULL && tmp_hole->type == GLU_INTERIOR;
824
tmp_hole = tmp_hole->next) {
825
/* does edge (v1,v2) intersect any edge of hole */
826
for (tmp_vertex = tmp_hole->vertices,
827
tmp_vertex_cnt = tmp_hole->vertex_cnt, k = 0;
828
k < tmp_vertex_cnt; tmp_vertex = tmp_vertex->next, k++) {
829
test = edge_edge_intersect(v1, v2, tmp_vertex,
831
if (test != GLU_NO_ERROR)
834
if (test != GLU_NO_ERROR)
839
if (test == GLU_NO_ERROR) {
840
/* edge (v1,v2) is good for eliminating the hole */
841
if (merge_hole_with_contour(tobj, contour, hole, v1, v2)
849
/* other holes are blocking all possible connections of hole */
850
/* with contour, we shift this hole as the last hole and retry */
851
for (tmp_hole = hole;
852
tmp_hole != NULL && tmp_hole->type == GLU_INTERIOR;
853
tmp_hole = tmp_hole->next);
854
contour->next = hole->next;
855
hole->next->previous = contour;
856
if (tmp_hole == NULL) {
857
/* last EXTERIOR contour, shift hole as last contour */
859
hole->previous = tobj->last_contour;
860
tobj->last_contour->next = hole;
861
tobj->last_contour = hole;
864
tmp_hole->previous->next = hole;
865
hole->previous = tmp_hole->previous;
866
tmp_hole->previous = hole;
867
hole->next = tmp_hole;
869
hole = contour->next;
870
/* try once again - recurse */
871
return cut_out_hole(tobj, contour, hole);
875
merge_hole_with_contour(GLUtriangulatorObj * tobj,
876
tess_contour * contour,
878
tess_vertex * v1, tess_vertex * v2)
880
tess_vertex *v1_new, *v2_new;
882
/* make copies of v1 and v2, place them respectively after their originals */
883
if ((v1_new = (tess_vertex *) malloc(sizeof(tess_vertex))) == NULL) {
884
tess_call_user_error(tobj, GLU_OUT_OF_MEMORY);
887
if ((v2_new = (tess_vertex *) malloc(sizeof(tess_vertex))) == NULL) {
888
tess_call_user_error(tobj, GLU_OUT_OF_MEMORY);
891
v1_new->edge_flag = GL_TRUE;
892
v1_new->data = v1->data;
893
v1_new->location[0] = v1->location[0];
894
v1_new->location[1] = v1->location[1];
895
v1_new->location[2] = v1->location[2];
898
v1_new->shadow_vertex = v1;
899
v1->shadow_vertex = v1_new;
900
v1_new->next = v1->next;
901
v1_new->previous = v1;
902
v1->next->previous = v1_new;
904
v2_new->edge_flag = GL_TRUE;
905
v2_new->data = v2->data;
906
v2_new->location[0] = v2->location[0];
907
v2_new->location[1] = v2->location[1];
908
v2_new->location[2] = v2->location[2];
911
v2_new->shadow_vertex = v2;
912
v2->shadow_vertex = v2_new;
913
v2_new->next = v2->next;
914
v2_new->previous = v2;
915
v2->next->previous = v2_new;
917
/* link together the two lists */
919
v2_new->previous = v1;
921
v1_new->previous = v2;
922
/* update the vertex count of the contour */
923
contour->vertex_cnt += hole->vertex_cnt + 2;
924
/* remove the INTERIOR contour */
925
contour->next = hole->next;
926
if (hole->next != NULL)
927
hole->next->previous = contour;
929
/* update tobj structure */
930
--(tobj->contour_cnt);
931
if (contour->last_vertex == v1)
932
contour->last_vertex = v1_new;
933
/* mark two vertices with edge_flag */
934
v2->edge_flag = GL_FALSE;
935
v1->edge_flag = GL_FALSE;