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Add new sibling() helper to SGBucket

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- will replace sgBucketOffset eventually
- expand test coverage for both sibling() and offset function

(one test case is disabled since it fails)
This commit is contained in:
James Turner 2014-02-12 15:31:40 +00:00
parent 79c56c924f
commit 9a09a6a447
3 changed files with 93 additions and 0 deletions
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10
simgear/bucket/newbucket.cxx
View File

@ -254,6 +254,16 @@ double SGBucket::get_height_m() const {
return SG_BUCKET_SPAN * degree_height;
}
SGBucket SGBucket::sibling(int dx, int dy) const
{
double clat = get_center_lat() + dy * SG_BUCKET_SPAN;
// find the lon span for the new latitude
double span = sg_bucket_span( clat );
double tmp = get_center_lon() + dx * span;
tmp = SGMiscd::normalizePeriodic(-180.0, 180.0, tmp);
return SGBucket(tmp, clat);
}
// find the bucket which is offset by the specified tile units in the
// X & Y direction. We need the current lon and lat to resolve

5
simgear/bucket/newbucket.hxx
View File

@ -280,6 +280,11 @@ public:
*/
inline int get_y() const { return y; }
/**
* @return bucket offset from this by dx,dy
*/
SGBucket sibling(int dx, int dy) const;
// friends
friend std::ostream& operator<< ( std::ostream&, const SGBucket& );

78
simgear/bucket/test_bucket.cxx
View File

@ -74,6 +74,7 @@ void testPolar()
}
// test the tiles just below the pole (between 86 & 89 degrees N/S)
void testNearPolar()
{
SGBucket b1(1, 88.5);
@ -93,6 +94,81 @@ void testNearPolar()
void testOffset()
{
// bucket just below the 22 degree cutoff, so the next tile north
// is twice the width
SGBucket b1(-59.8, 21.9);
COMPARE(b1.get_chunk_lat(), 21);
COMPARE(b1.get_chunk_lon(), -60);
COMPARE(b1.get_x(), 1);
COMPARE(b1.get_y(), 7);
// offset vertically
SGBucket b2(b1.sibling(0, 1));
COMPARE(b2.get_chunk_lat(), 22);
COMPARE(b2.get_chunk_lon(), -60);
COMPARE(b2.get_x(), 0);
COMPARE(b2.get_y(), 0);
COMPARE(b2.gen_index(), sgBucketOffset(-59.8, 21.9, 0, 1));
// offset vertically and horizontally. We compute horizontal (x)
// movement at the target latitude, so this should move 0.25 * -3 degrees,
// NOT 0.125 * -3 degrees.
SGBucket b3(b1.sibling(-3, 1));
COMPARE(b3.get_chunk_lat(), 22);
COMPARE(b3.get_chunk_lon(), -61);
COMPARE(b3.get_x(), 1);
COMPARE(b3.get_y(), 0);
COMPARE(b3.gen_index(), sgBucketOffset(-59.8, 21.9, -3, 1));
}
void testPolarOffset()
{
SGBucket b1(-11.7, -89.6);
COMPARE(b1.get_chunk_lat(), -90);
COMPARE(b1.get_chunk_lon(), -12);
COMPARE(b1.get_x(), 0);
COMPARE(b1.get_y(), 3);
// offset horizontally
SGBucket b2(b1.sibling(-2, 0));
COMPARE(b2.get_chunk_lat(), -90);
COMPARE(b2.get_chunk_lon(), -36);
COMPARE(b2.get_x(), 0);
COMPARE(b2.get_y(), 3);
COMPARE(b2.gen_index(), sgBucketOffset(-11.7, -89.6, -2, 0));
#if 0
// offset vertically towards the pole
SGBucket b3(b1.sibling(0, -5));
COMPARE(b3.get_chunk_lat(), -90);
COMPARE(b3.get_chunk_lon(), -12);
COMPARE(b3.get_x(), 0);
COMPARE(b3.get_y(), 0);
COMPARE(b3.gen_index(), sgBucketOffset(-11.7, -89.6, 0, 0));
#endif
}
// test behaviour of bucket-offset near the anti-meridian (180-meridian)
void testOffsetWrap()
{
// near the equator
SGBucket b1(-179.8, 16.8);
COMPARE(b1.get_chunk_lat(), 16);
COMPARE(b1.get_chunk_lon(), -180);
COMPARE(b1.get_x(), 1);
COMPARE(b1.get_y(), 6);
SGBucket b2(b1.sibling(-2, 0));
COMPARE(b2.get_chunk_lat(), 16);
COMPARE(b2.get_chunk_lon(), 179);
COMPARE(b2.get_x(), 7);
COMPARE(b2.get_y(), 6);
COMPARE(b2.gen_index(), sgBucketOffset(-179.8, 16.8, -2, 0));
}
@ -125,6 +201,8 @@ int main(int argc, char* argv[])
testPolar();
testNearPolar();
testOffset();
testOffsetWrap();
testPolarOffset();
cout << "all tests passed OK" << endl;
return 0; // passed