2 ** License Applicability. Except to the extent portions of this file are
3 ** made subject to an alternative license as permitted in the SGI Free
4 ** Software License B, Version 1.1 (the "License"), the contents of this
5 ** file are subject only to the provisions of the License. You may not use
6 ** this file except in compliance with the License. You may obtain a copy
7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
10 ** http://oss.sgi.com/projects/FreeB
12 ** Note that, as provided in the License, the Software is distributed on an
13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
21 ** Copyright in any portions created by third parties is as indicated
22 ** elsewhere herein. All Rights Reserved.
24 ** Additional Notice Provisions: The application programming interfaces
25 ** established by SGI in conjunction with the Original Code are The
26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
31 ** published by SGI, but has not been independently verified as being
32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
41 #include "glimports.h"
44 #include "quicksort.h"
45 #include "directedLine.h"
49 #pragma warning 726 10
52 //we must return the newLine
53 directedLine* directedLine::deleteChain(directedLine* begin, directedLine* end)
55 if(begin->head()[0] == end->tail()[0] &&
56 begin->head()[1] == end->tail()[1]
59 directedLine *ret = begin->prev;
60 begin->prev->next = end->next;
61 end->next->prev = begin->prev;
70 directedLine* newLine;
71 sampledLine* sline = new sampledLine(begin->head(), end->tail());
72 newLine = new directedLine(INCREASING, sline);
73 directedLine *p = begin->prev;
74 directedLine *n = end->next;
88 void directedLine::deleteSingleLine(directedLine* dline)
90 //make sure that dline->prev->tail is the same as
91 //dline->next->head. This is for numerical erros.
92 //for example, if we delete a line which is almost degeneate
93 //within (epsilon), then we want to make that the polygon after deletion
94 //is still a valid polygon
96 dline->next->head()[0] = dline->prev->tail()[0];
97 dline->next->head()[1] = dline->prev->tail()[1];
99 dline->prev->next = dline->next;
100 dline->next->prev = dline->prev;
106 static Int myequal(Real a[2], Real b[2])
109 if(a[0]==b[0] && a[1] == b[1])
116 if(fabs(a[0]-b[0]) < 0.00001 &&
117 fabs(a[1]-b[1]) < 0.00001)
124 directedLine* directedLine::deleteDegenerateLines()
126 //if there is only one edge or two edges, don't do anything
127 if(this->next == this)
129 if(this->next == this->prev)
132 //find a nondegenerate line
134 directedLine* first = NULL;
135 if(! myequal(head(), tail()))
137 if(head()[0] != tail()[0] ||
138 head()[1] != tail()[1])
143 for(temp = this->next; temp != this; temp = temp->next)
146 if(temp->head()[0] != temp->tail()[0] ||
147 temp->head()[1] != temp->tail()[1])
149 if(! myequal(temp->head(), temp->tail()))
158 //if there are no non-degenerate lines, then we simply return NULL.
161 deleteSinglePolygonWithSline();
165 directedLine* tempNext = NULL;
166 for(temp =first->next; temp != first; temp = tempNext)
168 tempNext = temp->getNext();
170 if(temp->head()[0] == temp->tail()[0] &&
171 temp->head()[1] == temp->tail()[1])
174 if(myequal(temp->head(), temp->tail()))
175 deleteSingleLine(temp);
180 directedLine* directedLine::deleteDegenerateLinesAllPolygons()
183 directedLine *tempNext = NULL;
184 directedLine* ret= NULL;
185 directedLine* retEnd = NULL;
186 for(temp=this; temp != NULL; temp = tempNext)
188 tempNext = temp->nextPolygon;
189 temp->nextPolygon = NULL;
192 ret = retEnd = temp->deleteDegenerateLines();
197 directedLine *newPolygon = temp->deleteDegenerateLines();
198 if(newPolygon != NULL)
200 retEnd->nextPolygon = temp->deleteDegenerateLines();
201 retEnd = retEnd->nextPolygon;
208 directedLine* directedLine::cutIntersectionAllPoly(int &cutOccur)
211 directedLine *tempNext = NULL;
212 directedLine* ret= NULL;
213 directedLine* retEnd = NULL;
215 for(temp=this; temp != NULL; temp = tempNext)
218 tempNext = temp->nextPolygon;
219 temp->nextPolygon = NULL;
223 ret = retEnd = DBG_cutIntersectionPoly(temp, eachCutOccur);
230 retEnd->nextPolygon = DBG_cutIntersectionPoly(temp, eachCutOccur);
231 retEnd = retEnd->nextPolygon;
240 void directedLine::deleteSinglePolygonWithSline()
242 directedLine *temp, *tempNext;
244 for(temp=this; temp != NULL; temp = tempNext)
246 tempNext = temp->next;
252 void directedLine::deletePolygonListWithSline()
254 directedLine *temp, *tempNext;
255 for(temp=this; temp != NULL; temp=tempNext)
257 tempNext = temp->nextPolygon;
258 temp->deleteSinglePolygonWithSline();
262 void directedLine::deleteSinglePolygon()
264 directedLine *temp, *tempNext;
266 for(temp=this; temp != NULL; temp = tempNext)
268 tempNext = temp->next;
273 void directedLine::deletePolygonList()
275 directedLine *temp, *tempNext;
276 for(temp=this; temp != NULL; temp=tempNext)
278 tempNext = temp->nextPolygon;
279 temp->deleteSinglePolygon();
285 directedLine::directedLine(short dir, sampledLine* sl)
292 // prevPolygon = NULL;
293 rootBit = 0;/*important to initilzae to 0 meaning not root yet*/
299 void directedLine::init(short dir, sampledLine* sl)
305 directedLine::directedLine()
310 rootBit = 0;/*important to initilzae to 0 meaning not root yet*/
312 direction = INCREASING;
316 directedLine::~directedLine()
320 Real* directedLine::head()
323 return (direction==INCREASING)? (sline->get_points())[0] : (sline->get_points())[sline->get_npoints()-1];
326 /*inline*/ Real* directedLine::getVertex(Int i)
328 return (direction==INCREASING)? (sline->get_points())[i] : (sline->get_points())[sline->get_npoints() - 1 -i];
331 Real* directedLine::tail()
333 return (direction==DECREASING)? (sline->get_points())[0] : (sline->get_points())[sline->get_npoints()-1];
336 /*insert a new line between prev and this*/
337 void directedLine::insert(directedLine* nl)
343 nl->rootLink = this; /*assuming that 'this' is the root!!!*/
346 Int directedLine::numEdges()
350 if(next == this) return 1;
353 for(temp = next; temp != this; temp = temp->next)
358 Int directedLine::numEdgesAllPolygons()
362 for(temp=this; temp!= NULL; temp=temp->nextPolygon)
364 ret += temp->numEdges();
369 /*return 1 if the double linked list forms a polygon.
371 short directedLine::isPolygon()
375 /*a polygon contains at least 3 edges*/
376 if(numEdges() <=2) return 0;
379 if(! isConnected()) return 0;
381 /*check all other edges*/
382 for(temp=next; temp != this; temp = temp->next){
383 if(!isConnected()) return 0;
388 /*check if the head of this edge is connected to
389 *the tail of the prev
391 short directedLine::isConnected()
393 if( (head()[0] == prev->tail()[0]) && (head()[1] == prev->tail()[1]))
399 Int compV2InY(Real A[2], Real B[2])
401 if(A[1] < B[1]) return -1;
402 if(A[1] == B[1] && A[0] < B[0]) return -1;
403 if(A[1] == B[1] && A[0] == B[0]) return 0;
407 Int compV2InX(Real A[2], Real B[2])
409 if(A[0] < B[0]) return -1;
410 if(A[0] == B[0] && A[1] < B[1]) return -1;
411 if(A[0] == B[0] && A[1] == B[1]) return 0;
415 /*compare two vertices NOT lines!
416 *A vertex is the head of a directed line.
417 *(x_1, y_1) <= (x_2, y_2) if
419 *or y_1 == y_2 && x_1 < x_2.
420 *return -1 if this->head() <= nl->head(),
423 Int directedLine::compInY(directedLine* nl)
425 if(head()[1] < nl->head()[1]) return -1;
426 if(head()[1] == nl->head()[1] && head()[0] < nl->head()[0]) return -1;
430 /*compare two vertices NOT lines!
431 *A vertex is the head of a directed line.
432 *(x_1, y_1) <= (x_2, y_2) if
434 *or x_1 == x_2 && y_1 < y_2.
435 *return -1 if this->head() <= nl->head(),
438 Int directedLine::compInX(directedLine* nl)
440 if(head()[0] < nl->head()[0]) return -1;
441 if(head()[0] == nl->head()[0] && head()[1] < nl->head()[1]) return -1;
445 /*used by sort precedures
447 static Int compInY2(directedLine* v1, directedLine* v2)
449 return v1->compInY(v2);
452 static Int compInX(directedLine* v1, directedLine* v2)
454 return v1->compInX(v2);
458 /*sort all the vertices NOT the lines!
459 *a vertex is the head of a directed line
461 directedLine** directedLine::sortAllPolygons()
463 Int total_num_edges = 0;
464 directedLine** array = toArrayAllPolygons(total_num_edges);
465 quicksort( (void**)array, 0, total_num_edges-1, (Int (*)(void *, void *)) compInY2);
470 void directedLine::printSingle()
472 if(direction == INCREASING)
473 printf("direction is INCREASING\n");
475 printf("direction is DECREASING\n");
476 printf("head=%f,%f)\n", head()[0], head()[1]);
480 /*print one polygon*/
481 void directedLine::printList()
485 for(temp = next; temp!=this; temp=temp->next)
489 /*print all the polygons*/
490 void directedLine::printAllPolygons()
493 for(temp = this; temp!=NULL; temp = temp->nextPolygon)
495 printf("polygon:\n");
500 /*insert this polygon into the head of the old polygon List*/
501 directedLine* directedLine::insertPolygon(directedLine* oldList)
503 /*this polygon is a root*/
505 if(oldList == NULL) return this;
506 nextPolygon = oldList;
507 /* oldList->prevPolygon = this;*/
511 /*cutoff means delete. but we don't deallocate any space,
512 *so we use cutoff instead of delete
514 directedLine* directedLine::cutoffPolygon(directedLine *p)
517 directedLine* prev_polygon = NULL;
518 if(p == NULL) return this;
520 for(temp=this; temp != p; temp = temp->nextPolygon)
524 fprintf(stderr, "in cutoffPolygon, not found\n");
530 /* prev_polygon = p->prevPolygon;*/
533 if(prev_polygon == NULL) /*this is the one to cutoff*/
536 prev_polygon->nextPolygon = p->nextPolygon;
541 Int directedLine::numPolygons()
543 if(nextPolygon == NULL) return 1;
544 else return 1+nextPolygon->numPolygons();
548 /*let array[index ...] denote
549 *all the edges in this polygon
550 *return the next available index of array.
552 Int directedLine::toArraySinglePolygon(directedLine** array, Int index)
555 array[index++] = this;
556 for(temp = next; temp != this; temp = temp->next)
558 array[index++] = temp;
563 /*the space is allocated. The caller is responsible for
564 *deallocate the space.
565 *total_num_edges is set to be the total number of edges of all polygons
567 directedLine** directedLine::toArrayAllPolygons(Int& total_num_edges)
569 total_num_edges=numEdgesAllPolygons();
570 directedLine** ret = (directedLine**) malloc(sizeof(directedLine*) * total_num_edges);
575 for(temp=this; temp != NULL; temp=temp->nextPolygon) {
576 index = temp->toArraySinglePolygon(ret, index);
581 /*assume the polygon is a simple polygon, return
582 *the area enclosed by it.
583 *if thee order is counterclock wise, the area is positive.
585 Real directedLine::polyArea()
590 x1 = this->head()[0];
591 y1 = this->head()[1];
592 x2 = this->next->head()[0];
593 y2 = this->next->head()[1];
594 ret = -(x2*y1-x1*y2);
595 for(temp=this->next; temp!=this; temp = temp->next)
597 x1 = temp->head()[0];
598 y1 = temp->head()[1];
599 x2 = temp->next->head()[0];
600 y2 = temp->next->head()[1];
601 ret += -( x2*y1-x1*y2);
603 return Real(0.5)*ret;
606 /*******************split or combine polygons begin********************/
607 /*conect a diagonal of a single simple polygon or two simple polygons.
608 *If the two vertices v1 (head) and v2 (head) are in the same simple polygon,
609 *then we actually split the simple polygon into two polygons.
610 *If instead two vertices velong to two difference polygons,
611 *then we combine the two polygons into one polygon.
612 *It is upto the caller to decide whether this is a split or a
616 *split a single simple polygon into two simple polygons by
617 *connecting a diagonal (two vertices).
618 *v1, v2: the two vertices are the head() of the two directedLines.
619 * this routine generates one new sampledLine which is returned in
621 *and it generates two directedLines returned in ret_p1 and ret_p2.
622 *ret_p1 and ret_p2 are used as the entry to the two new polygons.
623 *Notice the caller should not deallocate the space of v2 and v2 after
624 *calling this function, since all of the edges are connected to
628 *combine two simpolygons into one by connecting one diagonal.
629 *the returned polygon is returned in ret_p1.
632 void directedLine::connectDiagonal(directedLine* v1, directedLine* v2,
633 directedLine** ret_p1,
634 directedLine** ret_p2,
635 sampledLine** generatedLine,
636 directedLine* polygonList )
638 sampledLine *nsline = new sampledLine(2);
642 nsline->setPoint(0, v1->head());
643 nsline->setPoint(1, v2->head());
647 /*the increasing line is from v1 head to v2 head*/
648 directedLine* newLineInc = new directedLine(INCREASING, nsline);
652 directedLine* newLineDec = new directedLine(DECREASING, nsline);
655 directedLine* v1Prev = v1->prev;
656 directedLine* v2Prev = v2->prev;
658 v1 ->prev = newLineDec;
659 v2Prev ->next = newLineDec;
660 newLineDec->next = v1;
661 newLineDec->prev = v2Prev;
663 v2 ->prev = newLineInc;
664 v1Prev ->next = newLineInc;
665 newLineInc->next = v2;
666 newLineInc->prev = v1Prev;
668 *ret_p1 = newLineDec;
669 *ret_p2 = newLineInc;
670 *generatedLine = nsline;
673 //see the function connectDiangle
675 void directedLine::connectDiagonal_2slines(directedLine* v1, directedLine* v2,
676 directedLine** ret_p1,
677 directedLine** ret_p2,
678 directedLine* polygonList )
680 sampledLine *nsline = new sampledLine(2);
681 sampledLine *nsline2 = new sampledLine(2);
683 nsline->setPoint(0, v1->head());
684 nsline->setPoint(1, v2->head());
685 nsline2->setPoint(0, v1->head());
686 nsline2->setPoint(1, v2->head());
688 /*the increasing line is from v1 head to v2 head*/
689 directedLine* newLineInc = new directedLine(INCREASING, nsline);
691 directedLine* newLineDec = new directedLine(DECREASING, nsline2);
693 directedLine* v1Prev = v1->prev;
694 directedLine* v2Prev = v2->prev;
696 v1 ->prev = newLineDec;
697 v2Prev ->next = newLineDec;
698 newLineDec->next = v1;
699 newLineDec->prev = v2Prev;
701 v2 ->prev = newLineInc;
702 v1Prev ->next = newLineInc;
703 newLineInc->next = v2;
704 newLineInc->prev = v1Prev;
706 *ret_p1 = newLineDec;
707 *ret_p2 = newLineInc;
711 Int directedLine::samePolygon(directedLine* v1, directedLine* v2)
713 if(v1 == v2) return 1;
715 for(temp = v1->next; temp != v1; temp = temp->next)
717 if(temp == v2) return 1;
722 directedLine* directedLine::findRoot()
724 if(rootBit) return this;
726 for(temp = next; temp != this; temp = temp->next)
727 if(temp -> rootBit ) return temp;
728 return NULL; /*should not happen*/
731 directedLine* directedLine::rootLinkFindRoot()
733 directedLine* tempRoot;
734 directedLine* tempLink;
737 while(tempLink != NULL){
739 tempLink = tempRoot->rootLink;
744 /*******************split or combine polygons end********************/
746 /*****************IO stuff begin*******************/
756 void directedLine::writeAllPolygons(char* filename)
758 FILE* fp = fopen(filename, "w");
760 Int nPolygons = numPolygons();
762 fprintf(fp, "%i\n", nPolygons);
763 for(root = this; root != NULL; root = root->nextPolygon)
767 npoints = root->get_npoints()-1;
768 for(temp = root->next; temp != root; temp=temp->next)
769 npoints += temp->get_npoints()-1;
770 fprintf(fp, "%i\n", npoints/*root->numEdges()*/);
773 for(Int i=0; i<root->get_npoints()-1; i++){
774 fprintf(fp, "%f ", root->getVertex(i)[0]);
775 fprintf(fp, "%f ", root->getVertex(i)[1]);
778 for(temp=root->next; temp != root; temp = temp->next)
780 for(Int i=0; i<temp->get_npoints()-1; i++){
782 fprintf(fp, "%f ", temp->getVertex(i)[0]);
783 fprintf(fp, "%f ", temp->getVertex(i)[1]);
792 directedLine* readAllPolygons(char* filename)
795 FILE* fp = fopen(filename, "r");
800 result = fscanf(fp, "%i", &nPolygons);
801 assert(result != EOF);
802 directedLine *ret = NULL;
804 for(i=0; i<nPolygons; i++)
807 result = fscanf(fp, "%i", &nEdges);
808 assert(result != EOF);
809 Real vert[2][2] = { { 0 } };
811 /*the first two vertices*/
812 result = fscanf(fp, "%f", &(vert[0][0]));
813 assert(result != EOF);
814 result = fscanf(fp, "%f", &(vert[0][1]));
815 assert(result != EOF);
816 result = fscanf(fp, "%f", &(vert[1][0]));
817 assert(result != EOF);
818 result = fscanf(fp, "%f", &(vert[1][1]));
819 assert(result != EOF);
820 VV[1][0] = vert[0][0];
821 VV[1][1] = vert[0][1];
822 sampledLine *sLine = new sampledLine(2, vert);
823 directedLine *thisPoly = new directedLine(INCREASING, sLine);
824 thisPoly->rootLinkSet(NULL);
827 for(j=2; j<nEdges; j++)
829 vert[0][0]=vert[1][0];
830 vert[0][1]=vert[1][1];
831 result = fscanf(fp, "%f", &(vert[1][0]));
832 assert(result != EOF);
833 result = fscanf(fp, "%f", &(vert[1][1]));
834 assert(result != EOF);
835 sLine = new sampledLine(2,vert);
836 dLine = new directedLine(INCREASING, sLine);
837 dLine->rootLinkSet(thisPoly);
838 thisPoly->insert(dLine);
843 sLine = new sampledLine(2,VV);
844 dLine = new directedLine(INCREASING, sLine);
845 dLine->rootLinkSet(thisPoly);
846 thisPoly->insert(dLine);
848 ret = thisPoly->insertPolygon(ret);