| /* |
| ** License Applicability. Except to the extent portions of this file are |
| ** made subject to an alternative license as permitted in the SGI Free |
| ** Software License B, Version 1.1 (the "License"), the contents of this |
| ** file are subject only to the provisions of the License. You may not use |
| ** this file except in compliance with the License. You may obtain a copy |
| ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600 |
| ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at: |
| ** |
| ** http://oss.sgi.com/projects/FreeB |
| ** |
| ** Note that, as provided in the License, the Software is distributed on an |
| ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS |
| ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND |
| ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A |
| ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT. |
| ** |
| ** Original Code. The Original Code is: OpenGL Sample Implementation, |
| ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics, |
| ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc. |
| ** Copyright in any portions created by third parties is as indicated |
| ** elsewhere herein. All Rights Reserved. |
| ** |
| ** Additional Notice Provisions: The application programming interfaces |
| ** established by SGI in conjunction with the Original Code are The |
| ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released |
| ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version |
| ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X |
| ** Window System(R) (Version 1.3), released October 19, 1998. This software |
| ** was created using the OpenGL(R) version 1.2.1 Sample Implementation |
| ** published by SGI, but has not been independently verified as being |
| ** compliant with the OpenGL(R) version 1.2.1 Specification. |
| ** |
| ** $Date: 2012/03/29 17:22:17 $ $Revision: 1.1.1.1 $ |
| */ |
| /* |
| ** $Header: /cvs/bao-parsec/pkgs/libs/mesa/src/src/glu/sgi/libnurbs/nurbtess/partitionY.cc,v 1.1.1.1 2012/03/29 17:22:17 uid42307 Exp $ |
| */ |
| |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <time.h> |
| |
| #include "zlassert.h" |
| #include "partitionY.h" |
| #include "searchTree.h" |
| #include "quicksort.h" |
| #include "polyUtil.h" |
| |
| |
| #define max(a,b) ((a>b)? a:b) |
| #define min(a,b) ((a>b)? b:a) |
| |
| |
| /*retrurn |
| *-1: if A < B (Ya<Yb) || (Ya==Yb) |
| * 0: if A == B |
| * 1: if A>B |
| */ |
| static Int compVertInY(Real A[2], Real B[2]) |
| { |
| if( (A[1] < B[1]) || (A[1]==B[1] && A[0]<B[0])) |
| return -1; |
| else if |
| ( A[1] == B[1] && A[0] == B[0]) return 0; |
| else |
| return 1; |
| } |
| |
| /*v is a vertex: the head of en edge, |
| *e is an edge, |
| *return 1 if e is below v: assume v1 and v2 are the two endpoints of e: |
| * v1<= v, v2<=v. |
| */ |
| Int isBelow(directedLine *v, directedLine *e) |
| { |
| Real* vert = v->head(); |
| if( compVertInY(e->head(), vert) != 1 |
| && compVertInY(e->tail(), vert) != 1 |
| ) |
| return 1; |
| else |
| return 0; |
| } |
| |
| /*v is a vertex: the head of en edge, |
| *e is an edge, |
| *return 1 if e is below v: assume v1 and v2 are the two endpoints of e: |
| * v1>= v, v2>=v. |
| */ |
| Int isAbove(directedLine *v, directedLine *e) |
| { |
| Real* vert = v->head(); |
| if( compVertInY(e->head(), vert) != -1 |
| && compVertInY(e->tail(), vert) != -1 |
| ) |
| return 1; |
| else |
| return 0; |
| } |
| |
| Int isCusp(directedLine *v) |
| { |
| Real *A=v->getPrev()->head(); |
| Real *B=v->head(); |
| Real *C=v->tail(); |
| if(A[1] < B[1] && B[1] < C[1]) |
| return 0; |
| else if(A[1] > B[1] && B[1] > C[1]) |
| return 0; |
| else if(A[1] < B[1] && C[1] < B[1]) |
| return 1; |
| else if(A[1] > B[1] && C[1] > B[1]) |
| return 1; |
| |
| if(isAbove(v, v) && isAbove(v, v->getPrev()) || |
| isBelow(v, v) && isBelow(v, v->getPrev())) |
| return 1; |
| else |
| return 0; |
| } |
| |
| /*crossproduct is strictly less than 0*/ |
| Int isReflex(directedLine *v) |
| { |
| Real* A = v->getPrev()->head(); |
| Real* B = v->head(); |
| Real* C = v->tail(); |
| Real Bx,By, Cx, Cy; |
| Bx = B[0] - A[0]; |
| By = B[1] - A[1]; |
| Cx = C[0] - A[0]; |
| Cy = C[1] - A[1]; |
| |
| if(Bx*Cy - Cx*By < 0) return 1; |
| else return 0; |
| } |
| |
| /*return |
| *0: not-cusp |
| *1: interior cusp |
| *2: exterior cusp |
| */ |
| Int cuspType(directedLine *v) |
| { |
| if(! isCusp(v)) return 0; |
| else if(isReflex(v)) return 1; |
| else |
| return 2; |
| } |
| |
| sweepRange* sweepRangeMake(directedLine* left, Int leftType, |
| directedLine* right, Int rightType) |
| { |
| sweepRange* ret = (sweepRange*)malloc(sizeof(sweepRange)); |
| assert(ret); |
| ret->left = left; |
| ret->leftType = leftType; |
| ret->right = right; |
| ret->rightType = rightType; |
| return ret; |
| } |
| |
| void sweepRangeDelete(sweepRange* range) |
| { |
| free(range); |
| } |
| |
| Int sweepRangeEqual(sweepRange* src1, sweepRange* src2) |
| { |
| Int leftEqual; |
| Int rightEqual; |
| |
| |
| /*The case when both are vertices should not happen*/ |
| assert(! (src1->leftType == 0 && src2->leftType == 0)); |
| if(src1->leftType == 0 && src2->leftType == 1){ |
| if(src1->left == src2->left || |
| src1->left->getPrev() == src2->left |
| ) |
| leftEqual = 1; |
| else |
| leftEqual = 0; |
| } |
| else if(src1->leftType == 1 && src2->leftType == 1){ |
| if(src1->left == src2->left) |
| leftEqual = 1; |
| else |
| leftEqual = 0; |
| } |
| else /*src1->leftType == 1 && src2->leftType == 0*/{ |
| if(src1->left == src2->left || |
| src1->left == src2->left->getPrev() |
| ) |
| leftEqual = 1; |
| else |
| leftEqual = 0; |
| } |
| |
| /*the same thing for right*/ |
| /*The case when both are vertices should not happen*/ |
| assert(! (src1->rightType == 0 && src2->rightType == 0)); |
| if(src1->rightType == 0 && src2->rightType == 1){ |
| if(src1->right == src2->right || |
| src1->right->getPrev() == src2->right |
| ) |
| rightEqual = 1; |
| else |
| rightEqual = 0; |
| } |
| else if(src1->rightType == 1 && src2->rightType == 1){ |
| if(src1->right == src2->right) |
| rightEqual = 1; |
| else |
| rightEqual = 0; |
| } |
| else /*src1->rightType == 1 && src2->rightType == 0*/{ |
| if(src1->right == src2->right || |
| src1->right == src2->right->getPrev() |
| ) |
| rightEqual = 1; |
| else |
| rightEqual = 0; |
| } |
| |
| return (leftEqual == 1 || rightEqual == 1); |
| } |
| |
| /*given (x_1, y_1) and (x_2, y_2), and y |
| *return x such that (x,y) is on the line |
| */ |
| inline/*static*/ Real intersectHoriz(Real x1, Real y1, Real x2, Real y2, Real y) |
| { |
| return ((y2==y1)? (x1+x2)*Real(0.5) : x1 + ((y-y1)/(y2-y1)) * (x2-x1)); |
| /* |
| if(y2 == y1) return (x1+x2)*0.5; |
| else return x1 + ((y-y1)/(y2-y1)) * (x2-x1); |
| */ |
| } |
| |
| /*compare two edges of a polygon. |
| *edge A < edge B if there is a horizontal line so that the intersection |
| *with A is to the left of the intersection with B. |
| *This function is used in sweepY for the dynamic search tree insertion to |
| *order the edges. |
| * Implementation: (x_1,y_1) and (x_2, y_2) |
| */ |
| static Int compEdges(directedLine *e1, directedLine *e2) |
| { |
| Real* head1 = e1->head(); |
| Real* tail1 = e1->tail(); |
| Real* head2 = e2->head(); |
| Real* tail2 = e2->tail(); |
| /* |
| Real h10 = head1[0]; |
| Real h11 = head1[1]; |
| Real t10 = tail1[0]; |
| Real t11 = tail1[1]; |
| Real h20 = head2[0]; |
| Real h21 = head2[1]; |
| Real t20 = tail2[0]; |
| Real t21 = tail2[1]; |
| */ |
| Real e1_Ymax, e1_Ymin, e2_Ymax, e2_Ymin; |
| /* |
| if(h11>t11) { |
| e1_Ymax= h11; |
| e1_Ymin= t11; |
| } |
| else{ |
| e1_Ymax = t11; |
| e1_Ymin = h11; |
| } |
| |
| if(h21>t21) { |
| e2_Ymax= h21; |
| e2_Ymin= t21; |
| } |
| else{ |
| e2_Ymax = t21; |
| e2_Ymin = h21; |
| } |
| */ |
| |
| if(head1[1]>tail1[1]) { |
| e1_Ymax= head1[1]; |
| e1_Ymin= tail1[1]; |
| } |
| else{ |
| e1_Ymax = tail1[1]; |
| e1_Ymin = head1[1]; |
| } |
| |
| if(head2[1]>tail2[1]) { |
| e2_Ymax= head2[1]; |
| e2_Ymin= tail2[1]; |
| } |
| else{ |
| e2_Ymax = tail2[1]; |
| e2_Ymin = head2[1]; |
| } |
| |
| |
| /*Real e1_Ymax = max(head1[1], tail1[1]);*/ /*max(e1->head()[1], e1->tail()[1]);*/ |
| /*Real e1_Ymin = min(head1[1], tail1[1]);*/ /*min(e1->head()[1], e1->tail()[1]);*/ |
| /*Real e2_Ymax = max(head2[1], tail2[1]);*/ /*max(e2->head()[1], e2->tail()[1]);*/ |
| /*Real e2_Ymin = min(head2[1], tail2[1]);*/ /*min(e2->head()[1], e2->tail()[1]);*/ |
| |
| Real Ymax = min(e1_Ymax, e2_Ymax); |
| Real Ymin = max(e1_Ymin, e2_Ymin); |
| |
| Real y = Real(0.5)*(Ymax + Ymin); |
| |
| /* Real x1 = intersectHoriz(e1->head()[0], e1->head()[1], e1->tail()[0], e1->tail()[1], y); |
| Real x2 = intersectHoriz(e2->head()[0], e2->head()[1], e2->tail()[0], e2->tail()[1], y); |
| */ |
| /* |
| Real x1 = intersectHoriz(h10, h11, t10, t11, y); |
| Real x2 = intersectHoriz(h20, h21, t20, t21, y); |
| */ |
| Real x1 = intersectHoriz(head1[0], head1[1], tail1[0], tail1[1], y); |
| Real x2 = intersectHoriz(head2[0], head2[1], tail2[0], tail2[1], y); |
| |
| if(x1<= x2) return -1; |
| else return 1; |
| } |
| |
| /*used by sort precedures |
| */ |
| static Int compInY(directedLine* v1, directedLine* v2) |
| { |
| return v1->compInY(v2); |
| } |
| |
| void findDiagonals(Int total_num_edges, directedLine** sortedVertices, sweepRange** ranges, Int& num_diagonals, directedLine** diagonal_vertices) |
| { |
| Int i,j,k; |
| |
| k=0; |
| |
| for(i=0; i<total_num_edges; i++) |
| { |
| directedLine* vert =sortedVertices[i]; |
| directedLine* thisEdge = vert; |
| directedLine* prevEdge = vert->getPrev(); |
| /* |
| printf("find i=%i\n", i); |
| printf("the vertex is\n"); |
| vert->printSingle(); |
| */ |
| if(isBelow(vert, thisEdge) && isBelow(vert, prevEdge) && compEdges(prevEdge, thisEdge)<0) |
| { |
| /*this is an upward interior cusp*/ |
| diagonal_vertices[k++] = vert; |
| |
| for(j=i+1; j<total_num_edges; j++) |
| if(sweepRangeEqual(ranges[i], ranges[j])) |
| { |
| diagonal_vertices[k++] = sortedVertices[j]; |
| break; |
| } |
| assert(j<total_num_edges); |
| |
| |
| } |
| else if(isAbove(vert, thisEdge) && isAbove(vert, prevEdge) && compEdges(prevEdge, thisEdge)>0) |
| { |
| /*this is an downward interior cusp*/ |
| diagonal_vertices[k++] = vert; |
| for(j=i-1; j>=0; j--) |
| if(sweepRangeEqual(ranges[i], ranges[j])) |
| { |
| diagonal_vertices[k++] = sortedVertices[j]; |
| break; |
| } |
| /* printf("j=%i\n", j);*/ |
| assert(j>=0); |
| |
| |
| |
| } |
| } |
| num_diagonals = k/2; |
| } |
| |
| /*get rid of repeated diagonlas so that each diagonal appears only once in the array |
| */ |
| Int deleteRepeatDiagonals(Int num_diagonals, directedLine** diagonal_vertices, directedLine** new_vertices) |
| { |
| Int i,k; |
| Int j,l; |
| Int index; |
| index=0; |
| for(i=0,k=0; i<num_diagonals; i++, k+=2) |
| { |
| Int isRepeated=0; |
| /*check the diagonla (diagonal_vertice[k], diagonal_vertices[k+1]) |
| *is repeated or not |
| */ |
| for(j=0,l=0; j<index; j++, l+=2) |
| { |
| if( |
| (diagonal_vertices[k] == new_vertices[l] && |
| diagonal_vertices[k+1] == new_vertices[l+1] |
| ) |
| || |
| ( |
| diagonal_vertices[k] == new_vertices[l+1] && |
| diagonal_vertices[k+1] == new_vertices[l] |
| ) |
| ) |
| { |
| isRepeated=1; |
| break; |
| } |
| } |
| if(! isRepeated) |
| { |
| new_vertices[index+index] = diagonal_vertices[k]; |
| new_vertices[index+index+1] = diagonal_vertices[k+1]; |
| index++; |
| } |
| } |
| return index; |
| } |
| |
| /*for debug only*/ |
| directedLine** DBGfindDiagonals(directedLine *polygons, Int& num_diagonals) |
| { |
| Int total_num_edges = 0; |
| directedLine** array = polygons->toArrayAllPolygons(total_num_edges); |
| quicksort( (void**)array, 0, total_num_edges-1, (Int (*)(void*, void*)) compInY); |
| sweepRange** ranges = (sweepRange**) malloc(sizeof(sweepRange*) * total_num_edges); |
| assert(ranges); |
| |
| sweepY(total_num_edges, array, ranges); |
| |
| directedLine** diagonal_vertices = (directedLine**) malloc(sizeof(directedLine*) * total_num_edges); |
| assert(diagonal_vertices); |
| findDiagonals(total_num_edges, array, ranges, num_diagonals, diagonal_vertices); |
| |
| num_diagonals=deleteRepeatDiagonals(num_diagonals, diagonal_vertices, diagonal_vertices); |
| return diagonal_vertices; |
| |
| } |
| |
| |
| /*partition into Y-monotone polygons*/ |
| directedLine* partitionY(directedLine *polygons, sampledLine **retSampledLines) |
| { |
| Int total_num_edges = 0; |
| directedLine** array = polygons->toArrayAllPolygons(total_num_edges); |
| |
| quicksort( (void**)array, 0, total_num_edges-1, (Int (*)(void*, void*)) compInY); |
| |
| sweepRange** ranges = (sweepRange**) malloc(sizeof(sweepRange*) * (total_num_edges)); |
| assert(ranges); |
| |
| |
| |
| sweepY(total_num_edges, array, ranges); |
| |
| |
| |
| /*the diagonal vertices are stored as: |
| *v0-v1: 1st diagonal |
| *v2-v3: 2nd diagonal |
| *v5-v5: 3rd diagonal |
| *... |
| */ |
| |
| |
| Int num_diagonals; |
| /*number diagonals is < total_num_edges*total_num_edges*/ |
| directedLine** diagonal_vertices = (directedLine**) malloc(sizeof(directedLine*) * total_num_edges*2/*total_num_edges*/); |
| assert(diagonal_vertices); |
| |
| |
| |
| findDiagonals(total_num_edges, array, ranges, num_diagonals, diagonal_vertices); |
| |
| |
| |
| directedLine* ret_polygons = polygons; |
| sampledLine* newSampledLines = NULL; |
| Int i,k; |
| |
| num_diagonals=deleteRepeatDiagonals(num_diagonals, diagonal_vertices, diagonal_vertices); |
| |
| |
| |
| Int *removedDiagonals=(Int*)malloc(sizeof(Int) * num_diagonals); |
| for(i=0; i<num_diagonals; i++) |
| removedDiagonals[i] = 0; |
| |
| |
| |
| |
| |
| for(i=0,k=0; i<num_diagonals; i++,k+=2) |
| { |
| |
| |
| directedLine* v1=diagonal_vertices[k]; |
| directedLine* v2=diagonal_vertices[k+1]; |
| directedLine* ret_p1; |
| directedLine* ret_p2; |
| |
| /*we ahve to determine whether v1 and v2 belong to the same polygon before |
| *their structure are modified by connectDiagonal(). |
| */ |
| /* |
| directedLine *root1 = v1->findRoot(); |
| directedLine *root2 = v2->findRoot(); |
| assert(root1); |
| assert(root2); |
| */ |
| |
| directedLine* root1 = v1->rootLinkFindRoot(); |
| directedLine* root2 = v2->rootLinkFindRoot(); |
| |
| if(root1 != root2) |
| { |
| |
| removedDiagonals[i] = 1; |
| sampledLine* generatedLine; |
| |
| |
| |
| v1->connectDiagonal(v1,v2, &ret_p1, &ret_p2, &generatedLine, ret_polygons); |
| |
| |
| |
| newSampledLines = generatedLine->insert(newSampledLines); |
| /* |
| ret_polygons = ret_polygons->cutoffPolygon(root1); |
| |
| ret_polygons = ret_polygons->cutoffPolygon(root2); |
| ret_polygons = ret_p1->insertPolygon(ret_polygons); |
| root1->rootLinkSet(ret_p1); |
| root2->rootLinkSet(ret_p1); |
| ret_p1->rootLinkSet(NULL); |
| ret_p2->rootLinkSet(ret_p1); |
| */ |
| ret_polygons = ret_polygons->cutoffPolygon(root2); |
| |
| |
| |
| root2->rootLinkSet(root1); |
| ret_p1->rootLinkSet(root1); |
| ret_p2->rootLinkSet(root1); |
| |
| /*now that we have connected the diagonal v1 and v2, |
| *we have to check those unprocessed diagonals which |
| *have v1 or v2 as an end point. Notice that the head of v1 |
| *has the same coodinates as the head of v2->prev, and the head of |
| *v2 has the same coordinate as the head of v1->prev. |
| *Suppose these is a diagonal (v1, x). If (v1,x) is still a valid |
| *diagonal, then x should be on the left hand side of the directed line: *v1->prev->head -- v1->head -- v1->tail. Otherwise, (v1,x) should be |
| *replaced by (v2->prev, x), that is, x is on the left of |
| * v2->prev->prev->head, v2->prev->head, v2->prev->tail. |
| */ |
| Int ii, kk; |
| for(ii=0, kk=0; ii<num_diagonals; ii++, kk+=2) |
| if( removedDiagonals[ii]==0) |
| { |
| directedLine* d1=diagonal_vertices[kk]; |
| directedLine* d2=diagonal_vertices[kk+1]; |
| /*check d1, and replace diagonal_vertices[kk] if necessary*/ |
| if(d1 == v1) { |
| /*check if d2 is to left of v1->prev->head:v1->head:v1->tail*/ |
| if(! pointLeft2Lines(v1->getPrev()->head(), |
| v1->head(), v1->tail(), d2->head())) |
| { |
| /* |
| assert(pointLeft2Lines(v2->getPrev()->getPrev()->head(), |
| v2->getPrev()->head(), |
| v2->getPrev()->tail(), d2->head())); |
| */ |
| diagonal_vertices[kk] = v2->getPrev(); |
| } |
| } |
| if(d1 == v2) { |
| /*check if d2 is to left of v2->prev->head:v2->head:v2->tail*/ |
| if(! pointLeft2Lines(v2->getPrev()->head(), |
| v2->head(), v2->tail(), d2->head())) |
| { |
| /* |
| assert(pointLeft2Lines(v1->getPrev()->getPrev()->head(), |
| v1->getPrev()->head(), |
| v1->getPrev()->tail(), d2->head())); |
| */ |
| diagonal_vertices[kk] = v1->getPrev(); |
| } |
| } |
| /*check d2 and replace diagonal_vertices[k+1] if necessary*/ |
| if(d2 == v1) { |
| /*check if d1 is to left of v1->prev->head:v1->head:v1->tail*/ |
| if(! pointLeft2Lines(v1->getPrev()->head(), |
| v1->head(), v1->tail(), d1->head())) |
| { |
| /* assert(pointLeft2Lines(v2->getPrev()->getPrev()->head(), |
| v2->getPrev()->head(), |
| v2->getPrev()->tail(), d1->head())); |
| */ |
| diagonal_vertices[kk+1] = v2->getPrev(); |
| } |
| } |
| if(d2 == v2) { |
| /*check if d1 is to left of v2->prev->head:v2->head:v2->tail*/ |
| if(! pointLeft2Lines(v2->getPrev()->head(), |
| v2->head(), v2->tail(), d1->head())) |
| { |
| /* assert(pointLeft2Lines(v1->getPrev()->getPrev()->head(), |
| v1->getPrev()->head(), |
| v1->getPrev()->tail(), d1->head())); |
| */ |
| diagonal_vertices[kk+1] = v1->getPrev(); |
| } |
| } |
| } |
| }/*end if (root1 not equal to root 2)*/ |
| } |
| |
| /*second pass, now all diagoals should belong to the same polygon*/ |
| |
| |
| |
| for(i=0,k=0; i<num_diagonals; i++, k += 2) |
| if(removedDiagonals[i] == 0) |
| { |
| |
| |
| directedLine* v1=diagonal_vertices[k]; |
| directedLine* v2=diagonal_vertices[k+1]; |
| |
| |
| |
| directedLine* ret_p1; |
| directedLine* ret_p2; |
| |
| /*we ahve to determine whether v1 and v2 belong to the same polygon before |
| *their structure are modified by connectDiagonal(). |
| */ |
| directedLine *root1 = v1->findRoot(); |
| /* |
| directedLine *root2 = v2->findRoot(); |
| |
| |
| |
| assert(root1); |
| assert(root2); |
| assert(root1 == root2); |
| */ |
| sampledLine* generatedLine; |
| |
| |
| |
| v1->connectDiagonal(v1,v2, &ret_p1, &ret_p2, &generatedLine, ret_polygons); |
| newSampledLines = generatedLine->insert(newSampledLines); |
| |
| ret_polygons = ret_polygons->cutoffPolygon(root1); |
| |
| ret_polygons = ret_p1->insertPolygon(ret_polygons); |
| |
| ret_polygons = ret_p2->insertPolygon(ret_polygons); |
| |
| |
| |
| for(Int j=i+1; j<num_diagonals; j++) |
| { |
| if(removedDiagonals[j] ==0) |
| { |
| |
| directedLine* temp1=diagonal_vertices[2*j]; |
| directedLine* temp2=diagonal_vertices[2*j+1]; |
| if(temp1==v1 || temp1==v2 || temp2==v1 || temp2==v2) |
| if(! temp1->samePolygon(temp1, temp2)) |
| { |
| /*if temp1 and temp2 are in different polygons, |
| *then one of them must be v1 or v2. |
| */ |
| |
| |
| |
| assert(temp1==v1 || temp1 == v2 || temp2==v1 || temp2 ==v2); |
| if(temp1==v1) |
| { |
| diagonal_vertices[2*j] = v2->getPrev(); |
| } |
| if(temp2==v1) |
| { |
| diagonal_vertices[2*j+1] = v2->getPrev(); |
| } |
| if(temp1==v2) |
| { |
| diagonal_vertices[2*j] = v1->getPrev(); |
| } |
| if(temp2==v2) |
| { |
| diagonal_vertices[2*j+1] = v1->getPrev(); |
| } |
| } |
| } |
| } |
| |
| } |
| |
| /*clean up spaces*/ |
| free(array); |
| free(ranges); |
| free(diagonal_vertices); |
| free(removedDiagonals); |
| |
| *retSampledLines = newSampledLines; |
| return ret_polygons; |
| } |
| |
| /*given a set of simple polygons where the interior |
| *is decided by left-hand principle, |
| *return a range (sight) for each vertex. This is called |
| *Trapezoidalization. |
| */ |
| void sweepY(Int nVertices, directedLine** sortedVertices, sweepRange** ret_ranges) |
| { |
| Int i; |
| /*for each vertex in the sorted list, update the binary search tree. |
| *and store the range information for each vertex. |
| */ |
| treeNode* searchTree = NULL; |
| for(i=0; i<nVertices;i++) |
| { |
| |
| directedLine* vert = sortedVertices[i]; |
| |
| directedLine* thisEdge = vert; |
| directedLine* prevEdge = vert->getPrev(); |
| |
| if(isBelow(vert, thisEdge) && isAbove(vert, prevEdge)) |
| { |
| |
| /*case 1: this < v < prev |
| *the polygon is going down at v, the interior is to |
| *the right hand side. |
| * find the edge to the right of thisEdge for right range. |
| * delete thisEdge |
| * insert prevEdge |
| */ |
| treeNode* thisNode = TreeNodeFind(searchTree, thisEdge, ( Int (*) (void *, void *))compEdges); |
| assert(thisNode); |
| |
| treeNode* succ = TreeNodeSuccessor(thisNode); |
| assert(succ); |
| searchTree = TreeNodeDeleteSingleNode(searchTree, thisNode); |
| searchTree = TreeNodeInsert(searchTree, TreeNodeMake(prevEdge), ( Int (*) (void *, void *))compEdges); |
| |
| |
| ret_ranges[i] = sweepRangeMake(vert, 0, (directedLine*) (succ->key), 1); |
| |
| } |
| else if(isAbove(vert, thisEdge) && isBelow(vert, prevEdge)) |
| { |
| |
| /*case 2: this > v > prev |
| *the polygon is going up at v, the interior is to |
| *the left hand side. |
| * find the edge to the left of thisEdge for left range. |
| * delete prevEdge |
| * insert thisEdge |
| */ |
| treeNode* prevNode = TreeNodeFind(searchTree, prevEdge, ( Int (*) (void *, void *))compEdges); |
| assert(prevNode); |
| treeNode* pred = TreeNodePredecessor(prevNode); |
| searchTree = TreeNodeDeleteSingleNode(searchTree, prevNode); |
| searchTree = TreeNodeInsert(searchTree, TreeNodeMake(thisEdge), ( Int (*) (void *, void *))compEdges); |
| ret_ranges[i] = sweepRangeMake((directedLine*)(pred->key), 1, vert, 0); |
| } |
| else if(isAbove(vert, thisEdge) && isAbove(vert, prevEdge)) |
| { |
| |
| /*case 3: insert both edges*/ |
| treeNode* thisNode = TreeNodeMake(thisEdge); |
| treeNode* prevNode = TreeNodeMake(prevEdge); |
| searchTree = TreeNodeInsert(searchTree, thisNode, ( Int (*) (void *, void *))compEdges); |
| searchTree = TreeNodeInsert(searchTree, prevNode, ( Int (*) (void *, void *))compEdges); |
| if(compEdges(thisEdge, prevEdge)<0) /*interior cusp*/ |
| { |
| |
| treeNode* leftEdge = TreeNodePredecessor(thisNode); |
| treeNode* rightEdge = TreeNodeSuccessor(prevNode); |
| ret_ranges[i] = sweepRangeMake( (directedLine*) leftEdge->key, 1, |
| (directedLine*) rightEdge->key, 1 |
| ); |
| } |
| else /*exterior cusp*/ |
| { |
| |
| ret_ranges[i] = sweepRangeMake( prevEdge, 1, thisEdge, 1); |
| } |
| } |
| else if(isBelow(vert, thisEdge) && isBelow(vert, prevEdge)) |
| { |
| |
| /*case 4: delete both edges*/ |
| treeNode* thisNode = TreeNodeFind(searchTree, thisEdge, ( Int (*) (void *, void *))compEdges); |
| treeNode* prevNode = TreeNodeFind(searchTree, prevEdge, ( Int (*) (void *, void *))compEdges); |
| if(compEdges(thisEdge, prevEdge)>0) /*interior cusp*/ |
| { |
| treeNode* leftEdge = TreeNodePredecessor(prevNode); |
| treeNode* rightEdge = TreeNodeSuccessor(thisNode); |
| ret_ranges[i] = sweepRangeMake( (directedLine*) leftEdge->key, 1, |
| (directedLine*) rightEdge->key, 1 |
| ); |
| } |
| else /*exterior cusp*/ |
| { |
| ret_ranges[i] = sweepRangeMake( thisEdge, 1, prevEdge, 1); |
| } |
| searchTree = TreeNodeDeleteSingleNode(searchTree, thisNode); |
| searchTree = TreeNodeDeleteSingleNode(searchTree, prevNode); |
| } |
| else |
| { |
| fprintf(stderr,"error in partitionY.C, invalid case\n"); |
| printf("vert is\n"); |
| vert->printSingle(); |
| printf("thisEdge is\n"); |
| thisEdge->printSingle(); |
| printf("prevEdge is\n"); |
| prevEdge->printSingle(); |
| |
| exit(1); |
| } |
| } |
| |
| /*finaly clean up space: delete the search tree*/ |
| TreeNodeDeleteWholeTree(searchTree); |
| } |