Short circuit the edge intersection test when the gboxes are disjoint

git-svn-id: http://svn.osgeo.org/postgis/trunk@4612 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/liblwgeom/lwgeodetic.c b/liblwgeom/lwgeodetic.c
index d0cae18eae647868e269a4cfbac5e294304e5129..ff488451108e9db4d6d50cfce472f8f89ac40292 100644 (file)
--- a/liblwgeom/lwgeodetic.c
+++ b/liblwgeom/lwgeodetic.c
@@ -1330,7 +1330,7 @@ int ptarray_point_in_ring(POINTARRAY *pa, POINT2D pt_outside, POINT2D pt_to_test
 }
 
 
-static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double tolerance)
+static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double tolerance, int check_intersection)
 {
        GEOGRAPHIC_EDGE e1, e2;
        GEOGRAPHIC_POINT g1, g2;
@@ -1417,7 +1417,7 @@ static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double t
                        LWDEBUGF(4, "e2.start == GPOINT(%.6g %.6g) ", e2.start.lat, e2.start.lon);
                        LWDEBUGF(4, "e2.end == GPOINT(%.6g %.6g) ", e2.end.lat, e2.end.lon);
 
-                       if ( edge_intersection(e1, e2, &g) )
+                       if ( check_intersection && edge_intersection(e1, e2, &g) )
                        {
                                LWDEBUG(4,"edge intersection! returning 0.0");
                                return 0.0;
@@ -1444,6 +1444,7 @@ static double ptarray_distance_sphere(POINTARRAY *pa1, POINTARRAY *pa2, double t
 double lwgeom_distance_sphere(LWGEOM *lwgeom1, LWGEOM *lwgeom2, GBOX gbox1, GBOX gbox2, double tolerance)
 {
        int type1, type2;
+       int check_intersection = LW_FALSE;
        
        assert(lwgeom1);
        assert(lwgeom2);
@@ -1459,6 +1460,11 @@ double lwgeom_distance_sphere(LWGEOM *lwgeom1, LWGEOM *lwgeom2, GBOX gbox1, GBOX
        type1 = TYPE_GETTYPE(lwgeom1->type);
        type2 = TYPE_GETTYPE(lwgeom2->type);
        
+       
+       /* If the boxes aren't disjoint, we have to check for edge intersections */
+       if( gbox_overlaps(&gbox1, &gbox2) )
+               check_intersection = LW_TRUE;
+       
        /* Point/line combinations can all be handled with simple point array iterations */
        if( ( type1 == POINTTYPE || type1 == LINETYPE ) && 
            ( type2 == POINTTYPE || type2 == LINETYPE ) )
@@ -1475,7 +1481,7 @@ double lwgeom_distance_sphere(LWGEOM *lwgeom1, LWGEOM *lwgeom2, GBOX gbox1, GBOX
                else
                        pa2 = ((LWLINE*)lwgeom2)->points;
                
-               return ptarray_distance_sphere(pa1, pa2, tolerance);
+               return ptarray_distance_sphere(pa1, pa2, tolerance, check_intersection);
        }
        
        /* Point/Polygon cases, if point-in-poly, return zero, else return distance. */
@@ -1510,7 +1516,7 @@ double lwgeom_distance_sphere(LWGEOM *lwgeom1, LWGEOM *lwgeom2, GBOX gbox1, GBOX
                /* Not inside, so what's the actual distance? */
                for( i = 0; i < lwpoly->nrings; i++ )
                {
-                       double ring_distance = ptarray_distance_sphere(lwpoly->rings[i], lwpt->point, tolerance);
+                       double ring_distance = ptarray_distance_sphere(lwpoly->rings[i], lwpt->point, tolerance, check_intersection);
                        if( ring_distance < distance )
                                distance = ring_distance;
                        if( distance < tolerance )
@@ -1555,7 +1561,7 @@ double lwgeom_distance_sphere(LWGEOM *lwgeom1, LWGEOM *lwgeom2, GBOX gbox1, GBOX
                /* Not contained, so what's the actual distance? */
                for( i = 0; i < lwpoly->nrings; i++ )
                {
-                       double ring_distance = ptarray_distance_sphere(lwpoly->rings[i], lwline->points, tolerance);
+                       double ring_distance = ptarray_distance_sphere(lwpoly->rings[i], lwline->points, tolerance, check_intersection);
                        LWDEBUGF(4, "ring[%d] ring_distance = %.8g", i, ring_distance);
                        if( ring_distance < distance )
                                distance = ring_distance;
@@ -1592,7 +1598,7 @@ double lwgeom_distance_sphere(LWGEOM *lwgeom1, LWGEOM *lwgeom2, GBOX gbox1, GBOX
                {
                        for( j = 0; j < lwpoly2->nrings; j++ )
                        {
-                               double ring_distance = ptarray_distance_sphere(lwpoly1->rings[i], lwpoly2->rings[j], tolerance);
+                               double ring_distance = ptarray_distance_sphere(lwpoly1->rings[i], lwpoly2->rings[j], tolerance, check_intersection);
                                if( ring_distance < distance )
                                        distance = ring_distance;
                                if( distance < tolerance )