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Overview
| Comment: | Fix the name of the trig function approximation in geopoly. No functional changes to the code. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
33576b12b450a37b467ba012e77b297e |
| User & Date: | drh 2018-11-29 12:00:02 |
Context
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2018-11-30
| ||
| 20:59 | Fix a typo in a comment. No changes to code. check-in: 23684cb8 user: drh tags: trunk | |
| 18:22 | Merge the pre-3.26.0 fixes from trunk. check-in: 2c76ce4f user: drh tags: apple-osx | |
|
2018-11-29
| ||
| 12:00 | Fix the name of the trig function approximation in geopoly. No functional changes to the code. check-in: 33576b12 user: drh tags: trunk | |
|
2018-11-28
| ||
| 19:23 | Fix a typo in a comment used to generate documentation. No changes to code. check-in: 62360cea user: drh tags: trunk | |
Changes
Changes to ext/rtree/geopoly.c.
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4+8*p->nVertex, SQLITE_TRANSIENT);
sqlite3_free(p);
}
}
#define GEOPOLY_PI 3.1415926535897932385
/* Fast approximation for cosine(X) for X between -0.5*pi and 2*pi
*/
static double geopolyCosine(double r){
assert( r>=-0.5*GEOPOLY_PI && r<=2.0*GEOPOLY_PI );
if( r>=1.5*GEOPOLY_PI ){
r -= 2.0*GEOPOLY_PI;
}
if( r>=0.5*GEOPOLY_PI ){
return -geopolyCosine(r-GEOPOLY_PI);
}else{
double r2 = r*r;
double r3 = r2*r;
double r5 = r3*r2;
return 0.9996949*r - 0.1656700*r3 + 0.0075134*r5;
}
}
................................................................................
i = 1;
p->hdr[0] = *(unsigned char*)&i;
p->hdr[1] = 0;
p->hdr[2] = (n>>8)&0xff;
p->hdr[3] = n&0xff;
for(i=0; i<n; i++){
double rAngle = 2.0*GEOPOLY_PI*i/n;
p->a[i*2] = x - r*geopolyCosine(rAngle-0.5*GEOPOLY_PI);
p->a[i*2+1] = y + r*geopolyCosine(rAngle);
}
sqlite3_result_blob(context, p->hdr, 4+8*n, SQLITE_TRANSIENT);
sqlite3_free(p);
}
/*
** If pPoly is a polygon, compute its bounding box. Then:
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4+8*p->nVertex, SQLITE_TRANSIENT);
sqlite3_free(p);
}
}
#define GEOPOLY_PI 3.1415926535897932385
/* Fast approximation for sine(X) for X between -0.5*pi and 2*pi
*/
static double geopolySine(double r){
assert( r>=-0.5*GEOPOLY_PI && r<=2.0*GEOPOLY_PI );
if( r>=1.5*GEOPOLY_PI ){
r -= 2.0*GEOPOLY_PI;
}
if( r>=0.5*GEOPOLY_PI ){
return -geopolySine(r-GEOPOLY_PI);
}else{
double r2 = r*r;
double r3 = r2*r;
double r5 = r3*r2;
return 0.9996949*r - 0.1656700*r3 + 0.0075134*r5;
}
}
................................................................................
i = 1;
p->hdr[0] = *(unsigned char*)&i;
p->hdr[1] = 0;
p->hdr[2] = (n>>8)&0xff;
p->hdr[3] = n&0xff;
for(i=0; i<n; i++){
double rAngle = 2.0*GEOPOLY_PI*i/n;
p->a[i*2] = x - r*geopolySine(rAngle-0.5*GEOPOLY_PI);
p->a[i*2+1] = y + r*geopolySine(rAngle);
}
sqlite3_result_blob(context, p->hdr, 4+8*n, SQLITE_TRANSIENT);
sqlite3_free(p);
}
/*
** If pPoly is a polygon, compute its bounding box. Then:
|