main()
{
tPointi a,b,c,d;
tPointd p;
char code;
char ans;
do {
printf("\na,b,c,d=\n");
scanf("%d %d", &a[X],&a[Y]);
scanf("%d %d", &b[X],&b[Y]);
scanf("%d %d", &c[X],&c[Y]);
scanf("%d %d", &d[X],&d[Y]);
printf("(%d,%d) ", a[X],a[Y]);
printf("(%d,%d) ", b[X],b[Y]);
printf("(%d,%d) ", c[X],c[Y]);
printf("(%d,%d) ", d[X],d[Y]);
putchar('\n');
code = SegSegInt(a,b,c,d,p);
printf("code=%c; p=(%lf,%lf)\n", code, p[X], p[Y]);
printf("Continue(y/n)? "); ans = getchar(); ans = getchar();
} while (ans == 'y');
}
void merge2Holes(c_diagonal& cut,vector<c_diagonal>& allCuts,
vector<c_diagonal>::iterator tmpIte, c_ply* result_ply, bool& p1hasmorecut,bool& p2hasmorecut)
{
ply_vertex * v1, *v2;
v1 = cut.getV1();
v2 = cut.getV2();
ply_vertex* v1n = v1->getNext();
ply_vertex* v2n = v2->getNext();
addDiagnal(v1,v2);
ply_vertex* fakeV1 = v2->getNext();
ply_vertex* fakeV2 = v1->getNext();
c_polygon* initPolygon = v1->getExtra().parentPolygon;
fakeV1->getExtra().parentPly = result_ply;
fakeV2->getExtra().parentPly = result_ply;
fakeV1->getExtra().parentPolygon = v1->getExtra().parentPolygon;
fakeV2->getExtra().parentPolygon = v1->getExtra().parentPolygon;
v1->getExtra().parentPly = result_ply;
v2->getExtra().parentPly = result_ply;
result_ply->set(result_ply->getType(), v1);
result_ply->doInit();
result_ply->re_triangulate();
markParentPly(result_ply, initPolygon);
//fakeV1->getExtra().parentPly = v1->
//update the rest diagonals
vector<c_diagonal>::iterator dIte = tmpIte;
dIte++;
for (;dIte!=allCuts.end();++dIte)
{
c_diagonal& tmpDiag = *dIte;
ply_vertex* s = tmpDiag.getV1();
ply_vertex* e = tmpDiag.getV2();
if(s->getExtra().parentPolygon != initPolygon)
{
assert(e->getExtra().parentPolygon != initPolygon);
continue;
}
if(tmpDiag.getV1()==v1)
{
ply_vertex* otherVert = tmpDiag.getV2();
//if (v1,otherVert) intersects with (v2,v1n)
if(SegSegInt(v1->getPos().get(),otherVert->getPos().get(),
v2->getPos().get(),v1n->getPos().get()))
{
(*dIte).setEndPoints(fakeV1,otherVert);
}
}
if(tmpDiag.getV2()==v1)
{
ply_vertex* otherVert = tmpDiag.getV1();
//if (v1,otherVert) intersects with (v2,v1n)
if(SegSegInt(v1->getPos().get(),otherVert->getPos().get(),
v2->getPos().get(),v1n->getPos().get()))
{
(*dIte).setEndPoints(otherVert, fakeV1);
}
}
if(tmpDiag.getV1()==v2)
{
ply_vertex* otherVert = tmpDiag.getV2();
//if (v2,otherVert) intersects with (v1,v2n)
if (SegSegInt(v2->getPos().get(),otherVert->getPos().get(),
v1->getPos().get(),v2n->getPos().get()))
{
(*dIte).setEndPoints(fakeV2,otherVert);
}
}
if(tmpDiag.getV2()==v2)
{
ply_vertex* otherVert = tmpDiag.getV1();
//if ((v2,otherVert) intersects with (v1,v2n)
if (SegSegInt(v2->getPos().get(),otherVert->getPos().get(),
v1->getPos().get(),v2n->getPos().get()))
{
(*dIte).setEndPoints(otherVert, fakeV2);
}
}
assert(tmpDiag.getV1()->getExtra().parentPolygon == tmpDiag.getV2()->getExtra().parentPolygon);
}
}
/*---------------------------------------------------------------------
---------------------------------------------------------------------*/
void ConvexIntersect( tPolygoni P, tPolygoni Q, int n, int m )
/* P has n vertices, Q has m vertices. */
{
int a, b; /* indices on P and Q (resp.) */
int a1, b1; /* a-1, b-1 (resp.) */
tPointi A, B; /* directed edges on P and Q (resp.) */
int cross; /* sign of z-component of A x B */
int bHA, aHB; /* b in H(A); a in H(b). */
tPointi Origin = {0,0}; /* (0,0) */
tPointd p; /* double point of intersection */
tPointd q; /* second point of intersection */
tInFlag inflag; /* {Pin, Qin, Unknown}: which inside */
int aa, ba; /* # advances on a & b indices (after 1st inter.) */
bool FirstPoint; /* Is this the first point? (used to initialize).*/
tPointd p0; /* The first point. */
int code; /* SegSegInt return code. */
/* Initialize variables. */
a = 0; b = 0; aa = 0; ba = 0;
inflag = Unknown; FirstPoint = TRUE;
do {
/*printf("%%Before Advances:a=%d, b=%d; aa=%d, ba=%d; inflag=%d\n", a, b, aa, ba, inflag);*/
/* Computations of key variables. */
a1 = (a + n - 1) % n;
b1 = (b + m - 1) % m;
SubVec( P[a], P[a1], A );
SubVec( Q[b], Q[b1], B );
cross = AreaSign( Origin, A, B );
aHB = AreaSign( Q[b1], Q[b], P[a] );
bHA = AreaSign( P[a1], P[a], Q[b] );
printf("%%cross=%d, aHB=%d, bHA=%d\n", cross, aHB, bHA );
/* If A & B intersect, update inflag. */
code = SegSegInt( P[a1], P[a], Q[b1], Q[b], p, q );
printf("%%SegSegInt: code = %c\n", code );
if ( code == '1' || code == 'v' ) {
if ( inflag == Unknown && FirstPoint ) {
aa = ba = 0;
FirstPoint = FALSE;
p0[X] = p[X]; p0[Y] = p[Y];
printf("%8.2lf %8.2lf moveto\n", p0[X], p0[Y] );
}
inflag = InOut( p, inflag, aHB, bHA );
printf("%%InOut sets inflag=%d\n", inflag);
}
/*-----Advance rules-----*/
/* Special case: A & B overlap and oppositely oriented. */
if ( ( code == 'e' ) && (Dot( A, B ) < 0) )
PrintSharedSeg( p, q ), exit(EXIT_SUCCESS);
/* Special case: A & B parallel and separated. */
if ( (cross == 0) && ( aHB < 0) && ( bHA < 0 ) )
printf("%%P and Q are disjoint.\n"), exit(EXIT_SUCCESS);
/* Special case: A & B collinear. */
else if ( (cross == 0) && ( aHB == 0) && ( bHA == 0 ) ) {
/* Advance but do not output point. */
if ( inflag == Pin )
b = Advance( b, &ba, m, inflag == Qin, Q[b] );
else
a = Advance( a, &aa, n, inflag == Pin, P[a] );
}
/* Generic cases. */
else if ( cross >= 0 ) {
if ( bHA > 0)
a = Advance( a, &aa, n, inflag == Pin, P[a] );
else
b = Advance( b, &ba, m, inflag == Qin, Q[b] );
}
else /* if ( cross < 0 ) */{
if ( aHB > 0)
b = Advance( b, &ba, m, inflag == Qin, Q[b] );
else
a = Advance( a, &aa, n, inflag == Pin, P[a] );
}
printf("%%After advances:a=%d, b=%d; aa=%d, ba=%d; inflag=%d\n", a, b, aa, ba, inflag);
/* Quit when both adv. indices have cycled, or one has cycled twice. */
} while ( ((aa < n) || (ba < m)) && (aa < 2*n) && (ba < 2*m) );
if ( !FirstPoint ) /* If at least one point output, close up. */
printf("%8.2lf %8.2lf lineto\n", p0[X], p0[Y] );
/* Deal with special cases: not implemented. */
if ( inflag == Unknown)
printf("%%The boundaries of P and Q do not cross.\n");
}
