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Overview
| Comment: | Resolve issues with floating-point round-off error in the geopoly_overlap() routine. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | geojson |
| Files: | files | file ages | folders |
| SHA3-256: | a3c6696f2f39554e968dcd86c87296b0 |
| User & Date: | drh 2018-05-12 23:31:55 |
Context
|
2018-05-12
| ||
| 23:56 | Merge changes from trunk. check-in: 715740e3 user: drh tags: geojson | |
| 23:31 | Resolve issues with floating-point round-off error in the geopoly_overlap() routine. check-in: a3c6696f user: drh tags: geojson | |
| 21:09 | Add the geopoly_svg() SQL function. check-in: 318ba5f0 user: drh tags: geojson | |
Changes
Changes to ext/misc/geopoly.c.
497 498 499 500 501 502 503 504 505 506 507 508 509 510 ... 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 ... 702 703 704 705 706 707 708 709 710 711 712 713 714 715 ... 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 ... 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 |
int eType; /* 0 for ADD, 1 for REMOVE */
GeoSegment *pSeg; /* The segment to be added or removed */
GeoEvent *pNext; /* Next event in the sorted list */
};
struct GeoSegment {
double C, B; /* y = C*x + B */
double y; /* Current y value */
unsigned char side; /* 1 for p1, 2 for p2 */
unsigned int idx; /* Which segment within the side */
GeoSegment *pNext; /* Next segment in a list sorted by y */
};
struct GeoOverlap {
GeoEvent *aEvent; /* Array of all events */
GeoSegment *aSegment; /* Array of all segments */
................................................................................
t = y0;
y0 = y1;
y1 = t;
}
pSeg = p->aSegment + p->nSegment;
p->nSegment++;
pSeg->C = (y1-y0)/(x1-x0);
pSeg->B = y0 - x0*pSeg->C;
pSeg->side = side;
pSeg->idx = idx;
pEvent = p->aEvent + p->nEvent;
p->nEvent++;
pEvent->x = x0;
pEvent->eType = 0;
pEvent->pSeg = pSeg;
................................................................................
while( pThisEvent ){
if( pThisEvent->x!=rX ){
GeoSegment *pPrev = 0;
int iMask = 0;
GEODEBUG(("Distinct X: %g\n", pThisEvent->x));
rX = pThisEvent->x;
if( needSort ){
pActive = geopolySortSegmentsByYAndC(pActive);
needSort = 0;
}
for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
if( pPrev ){
if( pPrev->y!=pSeg->y ){
GEODEBUG(("MASK: %d\n", iMask));
................................................................................
}
pPrev = 0;
for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
double y = pSeg->C*rX + pSeg->B;
GEODEBUG(("Segment %d.%d %g->%g\n", pSeg->side, pSeg->idx, pSeg->y, y));
pSeg->y = y;
if( pPrev ){
if( pPrev->y>pSeg->y ){
rc = 1;
GEODEBUG(("Crossing: %d.%d and %d.%d\n",
pPrev->side, pPrev->idx,
pSeg->side, pSeg->idx));
goto geopolyOverlapDone;
}else if( pPrev->y!=pSeg->y ){
GEODEBUG(("MASK: %d\n", iMask));
................................................................................
pThisEvent->eType ? "RM " : "ADD",
pThisEvent->pSeg->side, pThisEvent->pSeg->idx,
pThisEvent->pSeg->C,
pThisEvent->pSeg->B));
if( pThisEvent->eType==0 ){
/* Add a segment */
pSeg = pThisEvent->pSeg;
pSeg->y = pSeg->C*rX + pSeg->B;
pSeg->pNext = pActive;
pActive = pSeg;
needSort = 1;
}else{
/* Remove a segment */
if( pActive==pThisEvent->pSeg ){
pActive = pActive->pNext;
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int eType; /* 0 for ADD, 1 for REMOVE */
GeoSegment *pSeg; /* The segment to be added or removed */
GeoEvent *pNext; /* Next event in the sorted list */
};
struct GeoSegment {
double C, B; /* y = C*x + B */
double y; /* Current y value */
float y0; /* Initial y value */
unsigned char side; /* 1 for p1, 2 for p2 */
unsigned int idx; /* Which segment within the side */
GeoSegment *pNext; /* Next segment in a list sorted by y */
};
struct GeoOverlap {
GeoEvent *aEvent; /* Array of all events */
GeoSegment *aSegment; /* Array of all segments */
................................................................................
t = y0;
y0 = y1;
y1 = t;
}
pSeg = p->aSegment + p->nSegment;
p->nSegment++;
pSeg->C = (y1-y0)/(x1-x0);
pSeg->B = y1 - x1*pSeg->C;
pSeg->y0 = y0;
pSeg->side = side;
pSeg->idx = idx;
pEvent = p->aEvent + p->nEvent;
p->nEvent++;
pEvent->x = x0;
pEvent->eType = 0;
pEvent->pSeg = pSeg;
................................................................................
while( pThisEvent ){
if( pThisEvent->x!=rX ){
GeoSegment *pPrev = 0;
int iMask = 0;
GEODEBUG(("Distinct X: %g\n", pThisEvent->x));
rX = pThisEvent->x;
if( needSort ){
GEODEBUG(("SORT\n"));
pActive = geopolySortSegmentsByYAndC(pActive);
needSort = 0;
}
for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
if( pPrev ){
if( pPrev->y!=pSeg->y ){
GEODEBUG(("MASK: %d\n", iMask));
................................................................................
}
pPrev = 0;
for(pSeg=pActive; pSeg; pSeg=pSeg->pNext){
double y = pSeg->C*rX + pSeg->B;
GEODEBUG(("Segment %d.%d %g->%g\n", pSeg->side, pSeg->idx, pSeg->y, y));
pSeg->y = y;
if( pPrev ){
if( pPrev->y>pSeg->y && pPrev->side!=pSeg->side ){
rc = 1;
GEODEBUG(("Crossing: %d.%d and %d.%d\n",
pPrev->side, pPrev->idx,
pSeg->side, pSeg->idx));
goto geopolyOverlapDone;
}else if( pPrev->y!=pSeg->y ){
GEODEBUG(("MASK: %d\n", iMask));
................................................................................
pThisEvent->eType ? "RM " : "ADD",
pThisEvent->pSeg->side, pThisEvent->pSeg->idx,
pThisEvent->pSeg->C,
pThisEvent->pSeg->B));
if( pThisEvent->eType==0 ){
/* Add a segment */
pSeg = pThisEvent->pSeg;
pSeg->y = pSeg->y0;
pSeg->pNext = pActive;
pActive = pSeg;
needSort = 1;
}else{
/* Remove a segment */
if( pActive==pThisEvent->pSeg ){
pActive = pActive->pNext;
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