| |
| /* |
| * Mesa 3-D graphics library |
| * Version: 3.3 |
| * Copyright (C) 1995-2000 Brian Paul |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library 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 |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public |
| * License along with this library; if not, write to the Free |
| * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| |
| /* |
| * This file is part of the polygon tesselation code contributed by |
| * Bogdan Sikorski |
| */ |
| |
| |
| #ifdef PC_HEADER |
| #include "all.h" |
| #else |
| #include <math.h> |
| #include <stdlib.h> |
| #include "gluP.h" |
| #include "tess.h" |
| #endif |
| |
| |
| |
| static GLenum store_polygon_as_contour(GLUtriangulatorObj *); |
| static void free_current_polygon(tess_polygon *); |
| static void prepare_projection_info(GLUtriangulatorObj *); |
| static GLdouble twice_the_polygon_area(tess_vertex *, tess_vertex *); |
| static GLenum verify_edge_vertex_intersections(GLUtriangulatorObj *); |
| void tess_find_contour_hierarchies(GLUtriangulatorObj *); |
| static GLenum test_for_overlapping_contours(GLUtriangulatorObj *); |
| static GLenum contours_overlap(tess_contour *, tess_polygon *); |
| static GLenum is_contour_contained_in(tess_contour *, tess_contour *); |
| static void add_new_exterior(GLUtriangulatorObj *, tess_contour *); |
| static void add_new_interior(GLUtriangulatorObj *, tess_contour *, |
| tess_contour *); |
| static void add_interior_with_hierarchy_check(GLUtriangulatorObj *, |
| tess_contour *, tess_contour *); |
| static void reverse_hierarchy_and_add_exterior(GLUtriangulatorObj *, |
| tess_contour *, |
| tess_contour *); |
| static GLboolean point_in_polygon(tess_contour *, GLdouble, GLdouble); |
| static void shift_interior_to_exterior(GLUtriangulatorObj *, tess_contour *); |
| static void add_exterior_with_check(GLUtriangulatorObj *, tess_contour *, |
| tess_contour *); |
| static GLenum cut_out_hole(GLUtriangulatorObj *, tess_contour *, |
| tess_contour *); |
| static GLenum merge_hole_with_contour(GLUtriangulatorObj *, |
| tess_contour *, tess_contour *, |
| tess_vertex *, tess_vertex *); |
| |
| static GLenum |
| find_normal(GLUtriangulatorObj * tobj) |
| { |
| tess_polygon *polygon = tobj->current_polygon; |
| tess_vertex *va, *vb, *vc; |
| GLdouble A, B, C; |
| GLdouble A0, A1, A2, B0, B1, B2; |
| |
| va = polygon->vertices; |
| vb = va->next; |
| A0 = vb->location[0] - va->location[0]; |
| A1 = vb->location[1] - va->location[1]; |
| A2 = vb->location[2] - va->location[2]; |
| for (vc = vb->next; vc != va; vc = vc->next) { |
| B0 = vc->location[0] - va->location[0]; |
| B1 = vc->location[1] - va->location[1]; |
| B2 = vc->location[2] - va->location[2]; |
| A = A1 * B2 - A2 * B1; |
| B = A2 * B0 - A0 * B2; |
| C = A0 * B1 - A1 * B0; |
| if (fabs(A) > EPSILON || fabs(B) > EPSILON || fabs(C) > EPSILON) { |
| polygon->A = A; |
| polygon->B = B; |
| polygon->C = C; |
| polygon->D = |
| -A * va->location[0] - B * va->location[1] - C * va->location[2]; |
| return GLU_NO_ERROR; |
| } |
| } |
| tess_call_user_error(tobj, GLU_TESS_ERROR7); |
| return GLU_ERROR; |
| } |
| |
| void |
| tess_test_polygon(GLUtriangulatorObj * tobj) |
| { |
| tess_polygon *polygon = tobj->current_polygon; |
| |
| /* any vertices defined? */ |
| if (polygon->vertex_cnt < 3) { |
| free_current_polygon(polygon); |
| return; |
| } |
| /* wrap pointers */ |
| polygon->last_vertex->next = polygon->vertices; |
| polygon->vertices->previous = polygon->last_vertex; |
| /* determine the normal */ |
| if (find_normal(tobj) == GLU_ERROR) |
| return; |
| /* compare the normals of previously defined contours and this one */ |
| /* first contour define ? */ |
| if (tobj->contours == NULL) { |
| tobj->A = polygon->A; |
| tobj->B = polygon->B; |
| tobj->C = polygon->C; |
| tobj->D = polygon->D; |
| /* determine the best projection to use */ |
| if (fabs(polygon->A) > fabs(polygon->B)) |
| if (fabs(polygon->A) > fabs(polygon->C)) |
| tobj->projection = OYZ; |
| else |
| tobj->projection = OXY; |
| else if (fabs(polygon->B) > fabs(polygon->C)) |
| tobj->projection = OXZ; |
| else |
| tobj->projection = OXY; |
| } |
| else { |
| GLdouble a[3], b[3]; |
| tess_vertex *vertex = polygon->vertices; |
| |
| a[0] = tobj->A; |
| a[1] = tobj->B; |
| a[2] = tobj->C; |
| b[0] = polygon->A; |
| b[1] = polygon->B; |
| b[2] = polygon->C; |
| |
| /* compare the normals */ |
| if (fabs(a[1] * b[2] - a[2] * b[1]) > EPSILON || |
| fabs(a[2] * b[0] - a[0] * b[2]) > EPSILON || |
| fabs(a[0] * b[1] - a[1] * b[0]) > EPSILON) { |
| /* not coplanar */ |
| tess_call_user_error(tobj, GLU_TESS_ERROR9); |
| return; |
| } |
| /* the normals are parallel - test for plane equation */ |
| if (fabs(a[0] * vertex->location[0] + a[1] * vertex->location[1] + |
| a[2] * vertex->location[2] + tobj->D) > EPSILON) { |
| /* not the same plane */ |
| tess_call_user_error(tobj, GLU_TESS_ERROR9); |
| return; |
| } |
| } |
| prepare_projection_info(tobj); |
| if (verify_edge_vertex_intersections(tobj) == GLU_ERROR) |
| return; |
| if (test_for_overlapping_contours(tobj) == GLU_ERROR) |
| return; |
| if (store_polygon_as_contour(tobj) == GLU_ERROR) |
| return; |
| } |
| |
| static GLenum |
| test_for_overlapping_contours(GLUtriangulatorObj * tobj) |
| { |
| tess_contour *contour; |
| tess_polygon *polygon; |
| |
| polygon = tobj->current_polygon; |
| for (contour = tobj->contours; contour != NULL; contour = contour->next) |
| if (contours_overlap(contour, polygon) != GLU_NO_ERROR) { |
| tess_call_user_error(tobj, GLU_TESS_ERROR5); |
| return GLU_ERROR; |
| } |
| return GLU_NO_ERROR; |
| } |
| |
| static GLenum |
| store_polygon_as_contour(GLUtriangulatorObj * tobj) |
| { |
| tess_polygon *polygon = tobj->current_polygon; |
| tess_contour *contour = tobj->contours; |
| |
| /* the first contour defined */ |
| if (contour == NULL) { |
| if ((contour = (tess_contour *) malloc(sizeof(tess_contour))) == NULL) { |
| tess_call_user_error(tobj, GLU_OUT_OF_MEMORY); |
| free_current_polygon(polygon); |
| return GLU_ERROR; |
| } |
| tobj->contours = tobj->last_contour = contour; |
| contour->next = contour->previous = NULL; |
| } |
| else { |
| if ((contour = (tess_contour *) malloc(sizeof(tess_contour))) == NULL) { |
| tess_call_user_error(tobj, GLU_OUT_OF_MEMORY); |
| free_current_polygon(polygon); |
| return GLU_ERROR; |
| } |
| contour->previous = tobj->last_contour; |
| tobj->last_contour->next = contour; |
| tobj->last_contour = contour; |
| contour->next = NULL; |
| } |
| /* mark all vertices in new contour as not special */ |
| /* and all are boundary edges */ |
| { |
| tess_vertex *vertex; |
| GLuint vertex_cnt, i; |
| |
| for (vertex = polygon->vertices, i = 0, vertex_cnt = |
| polygon->vertex_cnt; i < vertex_cnt; vertex = vertex->next, i++) { |
| vertex->shadow_vertex = NULL; |
| vertex->edge_flag = GL_TRUE; |
| } |
| } |
| contour->vertex_cnt = polygon->vertex_cnt; |
| contour->area = polygon->area; |
| contour->orientation = polygon->orientation; |
| contour->type = GLU_UNKNOWN; |
| contour->vertices = polygon->vertices; |
| contour->last_vertex = polygon->last_vertex; |
| polygon->vertices = polygon->last_vertex = NULL; |
| polygon->vertex_cnt = 0; |
| ++(tobj->contour_cnt); |
| return GLU_NO_ERROR; |
| } |
| |
| static void |
| free_current_polygon(tess_polygon * polygon) |
| { |
| tess_vertex *vertex, *vertex_tmp; |
| GLuint i; |
| |
| /* free current_polygon structures */ |
| for (vertex = polygon->vertices, i = 0; i < polygon->vertex_cnt; i++) { |
| vertex_tmp = vertex->next; |
| free(vertex); |
| vertex = vertex_tmp; |
| } |
| polygon->vertices = polygon->last_vertex = NULL; |
| polygon->vertex_cnt = 0; |
| } |
| |
| static void |
| prepare_projection_info(GLUtriangulatorObj * tobj) |
| { |
| tess_polygon *polygon = tobj->current_polygon; |
| tess_vertex *vertex, *last_vertex_ptr; |
| GLdouble area; |
| |
| last_vertex_ptr = polygon->last_vertex; |
| switch (tobj->projection) { |
| case OXY: |
| for (vertex = polygon->vertices; vertex != last_vertex_ptr; |
| vertex = vertex->next) { |
| vertex->x = vertex->location[0]; |
| vertex->y = vertex->location[1]; |
| } |
| last_vertex_ptr->x = last_vertex_ptr->location[0]; |
| last_vertex_ptr->y = last_vertex_ptr->location[1]; |
| break; |
| case OXZ: |
| for (vertex = polygon->vertices; vertex != last_vertex_ptr; |
| vertex = vertex->next) { |
| vertex->x = vertex->location[0]; |
| vertex->y = vertex->location[2]; |
| } |
| last_vertex_ptr->x = last_vertex_ptr->location[0]; |
| last_vertex_ptr->y = last_vertex_ptr->location[2]; |
| break; |
| case OYZ: |
| for (vertex = polygon->vertices; vertex != last_vertex_ptr; |
| vertex = vertex->next) { |
| vertex->x = vertex->location[1]; |
| vertex->y = vertex->location[2]; |
| } |
| last_vertex_ptr->x = last_vertex_ptr->location[1]; |
| last_vertex_ptr->y = last_vertex_ptr->location[2]; |
| break; |
| } |
| area = twice_the_polygon_area(polygon->vertices, polygon->last_vertex); |
| if (area >= 0.0) { |
| polygon->orientation = GLU_CCW; |
| polygon->area = area; |
| } |
| else { |
| polygon->orientation = GLU_CW; |
| polygon->area = -area; |
| } |
| } |
| |
| static GLdouble |
| twice_the_polygon_area(tess_vertex * vertex, tess_vertex * last_vertex) |
| { |
| tess_vertex *next; |
| GLdouble area, x, y; |
| |
| area = 0.0; |
| x = vertex->x; |
| y = vertex->y; |
| vertex = vertex->next; |
| for (; vertex != last_vertex; vertex = vertex->next) { |
| next = vertex->next; |
| area += |
| (vertex->x - x) * (next->y - y) - (vertex->y - y) * (next->x - x); |
| } |
| return area; |
| } |
| |
| /* test if edges ab and cd intersect */ |
| /* if not return GLU_NO_ERROR, else if cross return GLU_TESS_ERROR8, */ |
| /* else if adjacent return GLU_TESS_ERROR4 */ |
| static GLenum |
| edge_edge_intersect(tess_vertex * a, |
| tess_vertex * b, tess_vertex * c, tess_vertex * d) |
| { |
| GLdouble denom, r, s; |
| GLdouble xba, ydc, yba, xdc, yac, xac; |
| |
| xba = b->x - a->x; |
| yba = b->y - a->y; |
| xdc = d->x - c->x; |
| ydc = d->y - c->y; |
| xac = a->x - c->x; |
| yac = a->y - c->y; |
| denom = xba * ydc - yba * xdc; |
| r = yac * xdc - xac * ydc; |
| /* parallel? */ |
| if (fabs(denom) < EPSILON) { |
| if (fabs(r) < EPSILON) { |
| /* colinear */ |
| if (fabs(xba) < EPSILON) { |
| /* compare the Y coordinate */ |
| if (yba > 0.0) { |
| if ( |
| (fabs(a->y - c->y) < EPSILON |
| && fabs(c->y - b->y) < EPSILON) |
| || (fabs(a->y - d->y) < EPSILON |
| && fabs(d->y - b->y) < |
| EPSILON)) return GLU_TESS_ERROR4; |
| |
| } |
| else { |
| if ( |
| (fabs(b->y - c->y) < EPSILON |
| && fabs(c->y - a->y) < EPSILON) |
| || (fabs(b->y - d->y) < EPSILON |
| && fabs(d->y - a->y) < |
| EPSILON)) return GLU_TESS_ERROR4; |
| } |
| } |
| else { |
| /* compare the X coordinate */ |
| if (xba > 0.0) { |
| if ( |
| (fabs(a->x - c->x) < EPSILON |
| && fabs(c->x - b->x) < EPSILON) |
| || (fabs(a->x - d->x) < EPSILON |
| && fabs(d->x - b->x) < |
| EPSILON)) return GLU_TESS_ERROR4; |
| } |
| else { |
| if ( |
| (fabs(b->x - c->x) < EPSILON |
| && fabs(c->x - a->x) < EPSILON) |
| || (fabs(b->x - d->x) < EPSILON |
| && fabs(d->x - a->x) < |
| EPSILON)) return GLU_TESS_ERROR4; |
| } |
| } |
| } |
| return GLU_NO_ERROR; |
| } |
| r /= denom; |
| s = (yac * xba - xac * yba) / denom; |
| /* test if one vertex lies on other edge */ |
| if (((fabs(r) < EPSILON || (r < 1.0 + EPSILON && r > 1.0 - EPSILON)) && |
| s > -EPSILON && s < 1.0 + EPSILON) || |
| ((fabs(s) < EPSILON || (s < 1.0 + EPSILON && s > 1.0 - EPSILON)) && |
| r > -EPSILON && r < 1.0 + EPSILON)) { |
| return GLU_TESS_ERROR4; |
| } |
| /* test for crossing */ |
| if (r > -EPSILON && r < 1.0 + EPSILON && s > -EPSILON && s < 1.0 + EPSILON) { |
| return GLU_TESS_ERROR8; |
| } |
| return GLU_NO_ERROR; |
| } |
| |
| static GLenum |
| verify_edge_vertex_intersections(GLUtriangulatorObj * tobj) |
| { |
| tess_polygon *polygon = tobj->current_polygon; |
| tess_vertex *vertex1, *last_vertex, *vertex2; |
| GLenum test; |
| |
| last_vertex = polygon->last_vertex; |
| vertex1 = last_vertex; |
| for (vertex2 = vertex1->next->next; |
| vertex2->next != last_vertex; vertex2 = vertex2->next) { |
| test = edge_edge_intersect(vertex1, vertex1->next, vertex2, |
| vertex2->next); |
| if (test != GLU_NO_ERROR) { |
| tess_call_user_error(tobj, test); |
| return GLU_ERROR; |
| } |
| } |
| for (vertex1 = polygon->vertices; |
| vertex1->next->next != last_vertex; vertex1 = vertex1->next) { |
| for (vertex2 = vertex1->next->next; |
| vertex2 != last_vertex; vertex2 = vertex2->next) { |
| test = edge_edge_intersect(vertex1, vertex1->next, vertex2, |
| vertex2->next); |
| if (test != GLU_NO_ERROR) { |
| tess_call_user_error(tobj, test); |
| return GLU_ERROR; |
| } |
| } |
| } |
| return GLU_NO_ERROR; |
| } |
| |
| static int |
| #ifdef WIN32 |
| __cdecl |
| #endif |
| area_compare(const void *a, const void *b) |
| { |
| GLdouble area1, area2; |
| |
| area1 = (*((tess_contour **) a))->area; |
| area2 = (*((tess_contour **) b))->area; |
| if (area1 < area2) |
| return 1; |
| if (area1 > area2) |
| return -1; |
| return 0; |
| } |
| |
| void |
| tess_find_contour_hierarchies(GLUtriangulatorObj * tobj) |
| { |
| tess_contour **contours; /* dinamic array of pointers */ |
| tess_contour *tmp_contour_ptr = tobj->contours; |
| GLuint cnt, i; |
| GLenum result; |
| GLboolean hierarchy_changed; |
| |
| /* any contours? */ |
| if (tobj->contour_cnt < 2) { |
| tobj->contours->type = GLU_EXTERIOR; |
| return; |
| } |
| if ((contours = (tess_contour **) |
| malloc(sizeof(tess_contour *) * (tobj->contour_cnt))) == NULL) { |
| tess_call_user_error(tobj, GLU_OUT_OF_MEMORY); |
| return; |
| } |
| for (tmp_contour_ptr = tobj->contours, cnt = 0; |
| tmp_contour_ptr != NULL; tmp_contour_ptr = tmp_contour_ptr->next) |
| contours[cnt++] = tmp_contour_ptr; |
| /* now sort the contours in decreasing area size order */ |
| qsort((void *) contours, (size_t) cnt, (size_t) sizeof(tess_contour *), |
| area_compare); |
| /* we leave just the first contour - remove others from list */ |
| tobj->contours = contours[0]; |
| tobj->contours->next = tobj->contours->previous = NULL; |
| tobj->last_contour = tobj->contours; |
| tobj->contour_cnt = 1; |
| /* first contour is the one with greatest area */ |
| /* must be EXTERIOR */ |
| tobj->contours->type = GLU_EXTERIOR; |
| tmp_contour_ptr = tobj->contours; |
| /* now we play! */ |
| for (i = 1; i < cnt; i++) { |
| hierarchy_changed = GL_FALSE; |
| for (tmp_contour_ptr = tobj->contours; |
| tmp_contour_ptr != NULL; tmp_contour_ptr = tmp_contour_ptr->next) { |
| if (tmp_contour_ptr->type == GLU_EXTERIOR) { |
| /* check if contour completely contained in EXTERIOR */ |
| result = is_contour_contained_in(tmp_contour_ptr, contours[i]); |
| switch (result) { |
| case GLU_INTERIOR: |
| /* now we have to check if contour is inside interiors */ |
| /* or not */ |
| /* any interiors? */ |
| if (tmp_contour_ptr->next != NULL && |
| tmp_contour_ptr->next->type == GLU_INTERIOR) { |
| /* for all interior, check if inside any of them */ |
| /* if not inside any of interiors, its another */ |
| /* interior */ |
| /* or it may contain some interiors, then change */ |
| /* the contained interiors to exterior ones */ |
| add_interior_with_hierarchy_check(tobj, |
| tmp_contour_ptr, |
| contours[i]); |
| } |
| else { |
| /* not in interior, add as new interior contour */ |
| add_new_interior(tobj, tmp_contour_ptr, contours[i]); |
| } |
| hierarchy_changed = GL_TRUE; |
| break; |
| case GLU_EXTERIOR: |
| /* ooops, the marked as EXTERIOR (contours[i]) is */ |
| /* actually an interior of tmp_contour_ptr */ |
| /* reverse the local hierarchy */ |
| reverse_hierarchy_and_add_exterior(tobj, tmp_contour_ptr, |
| contours[i]); |
| hierarchy_changed = GL_TRUE; |
| break; |
| case GLU_NO_ERROR: |
| break; |
| default: |
| abort(); |
| } |
| } |
| if (hierarchy_changed) |
| break; /* break from for loop */ |
| } |
| if (hierarchy_changed == GL_FALSE) { |
| /* disjoint with all contours, add to contour list */ |
| add_new_exterior(tobj, contours[i]); |
| } |
| } |
| free(contours); |
| } |
| |
| /* returns GLU_INTERIOR if inner is completey enclosed within outer */ |
| /* returns GLU_EXTERIOR if outer is completely enclosed within inner */ |
| /* returns GLU_NO_ERROR if contours are disjoint */ |
| static GLenum |
| is_contour_contained_in(tess_contour * outer, tess_contour * inner) |
| { |
| GLenum relation_flag; |
| |
| /* set relation_flag to relation of containment of first inner vertex */ |
| /* regarding outer contour */ |
| if (point_in_polygon(outer, inner->vertices->x, inner->vertices->y)) |
| relation_flag = GLU_INTERIOR; |
| else |
| relation_flag = GLU_EXTERIOR; |
| if (relation_flag == GLU_INTERIOR) |
| return GLU_INTERIOR; |
| if (point_in_polygon(inner, outer->vertices->x, outer->vertices->y)) |
| return GLU_EXTERIOR; |
| return GLU_NO_ERROR; |
| } |
| |
| static GLboolean |
| point_in_polygon(tess_contour * contour, GLdouble x, GLdouble y) |
| { |
| tess_vertex *v1, *v2; |
| GLuint i, vertex_cnt; |
| GLdouble xp1, yp1, xp2, yp2; |
| GLboolean tst; |
| |
| tst = GL_FALSE; |
| v1 = contour->vertices; |
| v2 = contour->vertices->previous; |
| for (i = 0, vertex_cnt = contour->vertex_cnt; i < vertex_cnt; i++) { |
| xp1 = v1->x; |
| yp1 = v1->y; |
| xp2 = v2->x; |
| yp2 = v2->y; |
| if ((((yp1 <= y) && (y < yp2)) || ((yp2 <= y) && (y < yp1))) && |
| (x < (xp2 - xp1) * (y - yp1) / (yp2 - yp1) + xp1)) |
| tst = (tst == GL_FALSE ? GL_TRUE : GL_FALSE); |
| v2 = v1; |
| v1 = v1->next; |
| } |
| return tst; |
| } |
| |
| static GLenum |
| contours_overlap(tess_contour * contour, tess_polygon * polygon) |
| { |
| tess_vertex *vertex1, *vertex2; |
| GLuint vertex1_cnt, vertex2_cnt, i, j; |
| GLenum test; |
| |
| vertex1 = contour->vertices; |
| vertex2 = polygon->vertices; |
| vertex1_cnt = contour->vertex_cnt; |
| vertex2_cnt = polygon->vertex_cnt; |
| for (i = 0; i < vertex1_cnt; vertex1 = vertex1->next, i++) { |
| for (j = 0; j < vertex2_cnt; vertex2 = vertex2->next, j++) |
| if ((test = edge_edge_intersect(vertex1, vertex1->next, vertex2, |
| vertex2->next)) != GLU_NO_ERROR) |
| return test; |
| } |
| return GLU_NO_ERROR; |
| } |
| |
| static void |
| add_new_exterior(GLUtriangulatorObj * tobj, tess_contour * contour) |
| { |
| contour->type = GLU_EXTERIOR; |
| contour->next = NULL; |
| contour->previous = tobj->last_contour; |
| tobj->last_contour->next = contour; |
| tobj->last_contour = contour; |
| } |
| |
| static void |
| add_new_interior(GLUtriangulatorObj * tobj, |
| tess_contour * outer, tess_contour * contour) |
| { |
| contour->type = GLU_INTERIOR; |
| contour->next = outer->next; |
| contour->previous = outer; |
| if (outer->next != NULL) |
| outer->next->previous = contour; |
| outer->next = contour; |
| if (tobj->last_contour == outer) |
| tobj->last_contour = contour; |
| } |
| |
| static void |
| add_interior_with_hierarchy_check(GLUtriangulatorObj * tobj, |
| tess_contour * outer, |
| tess_contour * contour) |
| { |
| tess_contour *ptr; |
| |
| /* for all interiors of outer check if they are interior of contour */ |
| /* if so, change that interior to exterior and move it of of the */ |
| /* interior sequence */ |
| if (outer->next != NULL && outer->next->type == GLU_INTERIOR) { |
| GLenum test; |
| |
| for (ptr = outer->next; ptr != NULL && ptr->type == GLU_INTERIOR; |
| ptr = ptr->next) { |
| test = is_contour_contained_in(ptr, contour); |
| switch (test) { |
| case GLU_INTERIOR: |
| /* contour is contained in one of the interiors */ |
| /* check if possibly contained in other exteriors */ |
| /* move ptr to first EXTERIOR */ |
| for (; ptr != NULL && ptr->type == GLU_INTERIOR; ptr = ptr->next); |
| if (ptr == NULL) |
| /* another exterior */ |
| add_new_exterior(tobj, contour); |
| else |
| add_exterior_with_check(tobj, ptr, contour); |
| return; |
| case GLU_EXTERIOR: |
| /* one of the interiors is contained in the contour */ |
| /* change it to EXTERIOR, and shift it away from the */ |
| /* interior sequence */ |
| shift_interior_to_exterior(tobj, ptr); |
| break; |
| case GLU_NO_ERROR: |
| /* disjoint */ |
| break; |
| default: |
| abort(); |
| } |
| } |
| } |
| /* add contour to the interior sequence */ |
| add_new_interior(tobj, outer, contour); |
| } |
| |
| static void |
| reverse_hierarchy_and_add_exterior(GLUtriangulatorObj * tobj, |
| tess_contour * outer, |
| tess_contour * contour) |
| { |
| tess_contour *ptr; |
| |
| /* reverse INTERIORS to EXTERIORS */ |
| /* any INTERIORS? */ |
| if (outer->next != NULL && outer->next->type == GLU_INTERIOR) |
| for (ptr = outer->next; ptr != NULL && ptr->type == GLU_INTERIOR; |
| ptr = ptr->next) ptr->type = GLU_EXTERIOR; |
| /* the outer now becomes inner */ |
| outer->type = GLU_INTERIOR; |
| /* contour is the EXTERIOR */ |
| contour->next = outer; |
| if (tobj->contours == outer) { |
| /* first contour beeing reversed */ |
| contour->previous = NULL; |
| tobj->contours = contour; |
| } |
| else { |
| outer->previous->next = contour; |
| contour->previous = outer->previous; |
| } |
| outer->previous = contour; |
| } |
| |
| static void |
| shift_interior_to_exterior(GLUtriangulatorObj * tobj, tess_contour * contour) |
| { |
| contour->previous->next = contour->next; |
| if (contour->next != NULL) |
| contour->next->previous = contour->previous; |
| else |
| tobj->last_contour = contour->previous; |
| } |
| |
| static void |
| add_exterior_with_check(GLUtriangulatorObj * tobj, |
| tess_contour * outer, tess_contour * contour) |
| { |
| GLenum test; |
| |
| /* this contour might be interior to further exteriors - check */ |
| /* if not, just add as a new exterior */ |
| for (; outer != NULL && outer->type == GLU_EXTERIOR; outer = outer->next) { |
| test = is_contour_contained_in(outer, contour); |
| switch (test) { |
| case GLU_INTERIOR: |
| /* now we have to check if contour is inside interiors */ |
| /* or not */ |
| /* any interiors? */ |
| if (outer->next != NULL && outer->next->type == GLU_INTERIOR) { |
| /* for all interior, check if inside any of them */ |
| /* if not inside any of interiors, its another */ |
| /* interior */ |
| /* or it may contain some interiors, then change */ |
| /* the contained interiors to exterior ones */ |
| add_interior_with_hierarchy_check(tobj, outer, contour); |
| } |
| else { |
| /* not in interior, add as new interior contour */ |
| add_new_interior(tobj, outer, contour); |
| } |
| return; |
| case GLU_NO_ERROR: |
| /* disjoint */ |
| break; |
| default: |
| abort(); |
| } |
| } |
| /* add contour to the exterior sequence */ |
| add_new_exterior(tobj, contour); |
| } |
| |
| void |
| tess_handle_holes(GLUtriangulatorObj * tobj) |
| { |
| tess_contour *contour, *hole; |
| GLenum exterior_orientation; |
| |
| /* verify hole orientation */ |
| for (contour = tobj->contours; contour != NULL;) { |
| exterior_orientation = contour->orientation; |
| for (contour = contour->next; |
| contour != NULL && contour->type == GLU_INTERIOR; |
| contour = contour->next) { |
| if (contour->orientation == exterior_orientation) { |
| tess_call_user_error(tobj, GLU_TESS_ERROR5); |
| return; |
| } |
| } |
| } |
| /* now cut-out holes */ |
| for (contour = tobj->contours; contour != NULL;) { |
| hole = contour->next; |
| while (hole != NULL && hole->type == GLU_INTERIOR) { |
| if (cut_out_hole(tobj, contour, hole) == GLU_ERROR) |
| return; |
| hole = contour->next; |
| } |
| contour = contour->next; |
| } |
| } |
| |
| static GLenum |
| cut_out_hole(GLUtriangulatorObj * tobj, |
| tess_contour * contour, tess_contour * hole) |
| { |
| tess_contour *tmp_hole; |
| tess_vertex *v1, *v2, *tmp_vertex; |
| GLuint vertex1_cnt, vertex2_cnt, tmp_vertex_cnt; |
| GLuint i, j, k; |
| GLenum test = 0; |
| |
| /* find an edge connecting contour and hole not intersecting any other */ |
| /* edge belonging to either the contour or any of the other holes */ |
| for (v1 = contour->vertices, vertex1_cnt = contour->vertex_cnt, i = 0; |
| i < vertex1_cnt; i++, v1 = v1->next) { |
| for (v2 = hole->vertices, vertex2_cnt = hole->vertex_cnt, j = 0; |
| j < vertex2_cnt; j++, v2 = v2->next) { |
| /* does edge (v1,v2) intersect any edge of contour */ |
| for (tmp_vertex = contour->vertices, tmp_vertex_cnt = |
| contour->vertex_cnt, k = 0; k < tmp_vertex_cnt; |
| tmp_vertex = tmp_vertex->next, k++) { |
| /* skip edge tests for edges directly connected */ |
| if (v1 == tmp_vertex || v1 == tmp_vertex->next) |
| continue; |
| test = edge_edge_intersect(v1, v2, tmp_vertex, tmp_vertex->next); |
| if (test != GLU_NO_ERROR) |
| break; |
| } |
| if (test == GLU_NO_ERROR) { |
| /* does edge (v1,v2) intersect any edge of hole */ |
| for (tmp_vertex = hole->vertices, |
| tmp_vertex_cnt = hole->vertex_cnt, k = 0; |
| k < tmp_vertex_cnt; tmp_vertex = tmp_vertex->next, k++) { |
| /* skip edge tests for edges directly connected */ |
| if (v2 == tmp_vertex || v2 == tmp_vertex->next) |
| continue; |
| test = |
| edge_edge_intersect(v1, v2, tmp_vertex, tmp_vertex->next); |
| if (test != GLU_NO_ERROR) |
| break; |
| } |
| if (test == GLU_NO_ERROR) { |
| /* does edge (v1,v2) intersect any other hole? */ |
| for (tmp_hole = hole->next; |
| tmp_hole != NULL && tmp_hole->type == GLU_INTERIOR; |
| tmp_hole = tmp_hole->next) { |
| /* does edge (v1,v2) intersect any edge of hole */ |
| for (tmp_vertex = tmp_hole->vertices, |
| tmp_vertex_cnt = tmp_hole->vertex_cnt, k = 0; |
| k < tmp_vertex_cnt; tmp_vertex = tmp_vertex->next, k++) { |
| test = edge_edge_intersect(v1, v2, tmp_vertex, |
| tmp_vertex->next); |
| if (test != GLU_NO_ERROR) |
| break; |
| } |
| if (test != GLU_NO_ERROR) |
| break; |
| } |
| } |
| } |
| if (test == GLU_NO_ERROR) { |
| /* edge (v1,v2) is good for eliminating the hole */ |
| if (merge_hole_with_contour(tobj, contour, hole, v1, v2) |
| == GLU_NO_ERROR) |
| return GLU_NO_ERROR; |
| else |
| return GLU_ERROR; |
| } |
| } |
| } |
| /* other holes are blocking all possible connections of hole */ |
| /* with contour, we shift this hole as the last hole and retry */ |
| for (tmp_hole = hole; |
| tmp_hole != NULL && tmp_hole->type == GLU_INTERIOR; |
| tmp_hole = tmp_hole->next); |
| contour->next = hole->next; |
| hole->next->previous = contour; |
| if (tmp_hole == NULL) { |
| /* last EXTERIOR contour, shift hole as last contour */ |
| hole->next = NULL; |
| hole->previous = tobj->last_contour; |
| tobj->last_contour->next = hole; |
| tobj->last_contour = hole; |
| } |
| else { |
| tmp_hole->previous->next = hole; |
| hole->previous = tmp_hole->previous; |
| tmp_hole->previous = hole; |
| hole->next = tmp_hole; |
| } |
| hole = contour->next; |
| /* try once again - recurse */ |
| return cut_out_hole(tobj, contour, hole); |
| } |
| |
| static GLenum |
| merge_hole_with_contour(GLUtriangulatorObj * tobj, |
| tess_contour * contour, |
| tess_contour * hole, |
| tess_vertex * v1, tess_vertex * v2) |
| { |
| tess_vertex *v1_new, *v2_new; |
| |
| /* make copies of v1 and v2, place them respectively after their originals */ |
| if ((v1_new = (tess_vertex *) malloc(sizeof(tess_vertex))) == NULL) { |
| tess_call_user_error(tobj, GLU_OUT_OF_MEMORY); |
| return GLU_ERROR; |
| } |
| if ((v2_new = (tess_vertex *) malloc(sizeof(tess_vertex))) == NULL) { |
| tess_call_user_error(tobj, GLU_OUT_OF_MEMORY); |
| return GLU_ERROR; |
| } |
| v1_new->edge_flag = GL_TRUE; |
| v1_new->data = v1->data; |
| v1_new->location[0] = v1->location[0]; |
| v1_new->location[1] = v1->location[1]; |
| v1_new->location[2] = v1->location[2]; |
| v1_new->x = v1->x; |
| v1_new->y = v1->y; |
| v1_new->shadow_vertex = v1; |
| v1->shadow_vertex = v1_new; |
| v1_new->next = v1->next; |
| v1_new->previous = v1; |
| v1->next->previous = v1_new; |
| v1->next = v1_new; |
| v2_new->edge_flag = GL_TRUE; |
| v2_new->data = v2->data; |
| v2_new->location[0] = v2->location[0]; |
| v2_new->location[1] = v2->location[1]; |
| v2_new->location[2] = v2->location[2]; |
| v2_new->x = v2->x; |
| v2_new->y = v2->y; |
| v2_new->shadow_vertex = v2; |
| v2->shadow_vertex = v2_new; |
| v2_new->next = v2->next; |
| v2_new->previous = v2; |
| v2->next->previous = v2_new; |
| v2->next = v2_new; |
| /* link together the two lists */ |
| v1->next = v2_new; |
| v2_new->previous = v1; |
| v2->next = v1_new; |
| v1_new->previous = v2; |
| /* update the vertex count of the contour */ |
| contour->vertex_cnt += hole->vertex_cnt + 2; |
| /* remove the INTERIOR contour */ |
| contour->next = hole->next; |
| if (hole->next != NULL) |
| hole->next->previous = contour; |
| free(hole); |
| /* update tobj structure */ |
| --(tobj->contour_cnt); |
| if (contour->last_vertex == v1) |
| contour->last_vertex = v1_new; |
| /* mark two vertices with edge_flag */ |
| v2->edge_flag = GL_FALSE; |
| v1->edge_flag = GL_FALSE; |
| return GLU_NO_ERROR; |
| } |