[GRASS-SVN] r55860 - grass/branches/releasebranch_6_4/lib/vector/Vlib
svn_grass at osgeo.org
svn_grass at osgeo.org
Wed Apr 17 14:56:11 PDT 2013
Author: mmetz
Date: 2013-04-17 14:56:11 -0700 (Wed, 17 Apr 2013)
New Revision: 55860
Modified:
grass/branches/releasebranch_6_4/lib/vector/Vlib/intersect.c
Log:
Vlib: fix Vect_segment_intersection() (backport from trunk)
Modified: grass/branches/releasebranch_6_4/lib/vector/Vlib/intersect.c
===================================================================
--- grass/branches/releasebranch_6_4/lib/vector/Vlib/intersect.c 2013-04-17 21:55:35 UTC (rev 55859)
+++ grass/branches/releasebranch_6_4/lib/vector/Vlib/intersect.c 2013-04-17 21:56:11 UTC (rev 55860)
@@ -113,8 +113,8 @@
double *y2, double *z2, int with_z)
{
static int first_3d = 1;
- double d, d1, d2, r1, r2, dtol, t;
- int switched = 0;
+ double d, d1, d2, r1, dtol, t;
+ int switched;
/* TODO: Works for points ? */
@@ -128,7 +128,7 @@
first_3d = 0;
}
- /* Check identical lines */
+ /* Check identical segments */
if ((ax1 == bx1 && ay1 == by1 && ax2 == bx2 && ay2 == by2) ||
(ax1 == bx2 && ay1 == by2 && ax2 == bx1 && ay2 == by1)) {
G_debug(2, " -> identical segments");
@@ -141,36 +141,48 @@
return 5;
}
- /* 'Sort' lines by x1, x2, y1, y2 */
- if (bx1 < ax1)
+ /* 'Sort' lines by x, y
+ * MUST happen before D, D1, D2 are calculated */
+ switched = 0;
+ if (bx2 < bx1)
switched = 1;
- else if (bx1 == ax1) {
- if (bx2 < ax2)
+ else if (bx2 == bx1) {
+ if (by2 < by1)
switched = 1;
- else if (bx2 == ax2) {
- if (by1 < ay1)
- switched = 1;
- else if (by1 == ay1) {
- if (by2 < ay2)
- switched = 1; /* by2 != ay2 (would be identical */
- }
- }
}
+
if (switched) {
- t = ax1;
- ax1 = bx1;
- bx1 = t;
- t = ay1;
- ay1 = by1;
- by1 = t;
- t = ax2;
- ax2 = bx2;
+ t = bx1;
+ bx1 = bx2;
bx2 = t;
- t = ay2;
- ay2 = by2;
+ t = by1;
+ by1 = by2;
by2 = t;
+ t = bz1;
+ bz1 = bz2;
+ bz2 = t;
}
+ switched = 0;
+ if (ax2 < ax1)
+ switched = 1;
+ else if (ax2 == ax1) {
+ if (ay2 < ay1)
+ switched = 1;
+ }
+
+ if (switched) {
+ t = ax1;
+ ax1 = ax2;
+ ax2 = t;
+ t = ay1;
+ ay1 = ay2;
+ ay2 = t;
+ t = az1;
+ az1 = az2;
+ az2 = t;
+ }
+
d = D;
d1 = D1;
d2 = D2;
@@ -182,16 +194,23 @@
* Can it be a problem to set the tolerance to 0.0 ? */
dtol = 0.0;
if (fabs(d) > dtol) {
- r1 = D1 / d;
- r2 = D2 / d;
- G_debug(2, " -> not parallel/collinear: r1 = %f, r2 = %f", r1, r2);
-
- if (r1 < 0 || r1 > 1 || r2 < 0 || r2 > 1) {
- G_debug(2, " -> no intersection");
- return 0;
+ G_debug(2, " -> not parallel/collinear: d1 = %f, d2 = %f", d1, d2);
+ if (d > 0) {
+ if (d1 < 0 || d1 > d || d2 < 0 || d2 > d) {
+ G_debug(2, " -> no intersection");
+ return 0;
+ }
}
+ else {
+ if (d1 < d || d1 > 0 || d2 < d || d2 > 0) {
+ G_debug(2, " -> no intersection");
+ return 0;
+ }
+ }
+ r1 = d1 / d;
+
*x1 = ax1 + r1 * (ax2 - ax1);
*y1 = ay1 + r1 * (ay2 - ay1);
*z1 = 0;
@@ -203,7 +222,7 @@
/* segments are parallel or collinear */
G_debug(3, " -> parallel/collinear");
- if (D1 || D2) { /* lines are parallel */
+ if (d1 || d2) { /* lines are parallel */
G_debug(2, " -> parallel");
return 0;
}
@@ -213,18 +232,8 @@
/* Collinear vertical */
/* original code assumed lines were not both vertical
* so there is a special case if they are */
- if (ax1 == ax2 && bx1 == bx2 && ax1 == bx1) {
+ if (ax1 == ax2) {
G_debug(2, " -> collinear vertical");
- if (ay1 > ay2) {
- t = ay1;
- ay1 = ay2;
- ay2 = t;
- } /* to be sure that ay1 < ay2 */
- if (by1 > by2) {
- t = by1;
- by1 = by2;
- by2 = t;
- } /* to be sure that by1 < by2 */
if (ay1 > by2 || ay2 < by1) {
G_debug(2, " -> no intersection");
return 0;
@@ -232,21 +241,23 @@
/* end points */
if (ay1 == by2) {
+ G_debug(2, " -> connected by end points");
*x1 = ax1;
*y1 = ay1;
*z1 = 0;
- G_debug(2, " -> connected by end points");
+
return 1; /* endpoints only */
}
if (ay2 == by1) {
+ G_debug(2, " -> connected by end points");
*x1 = ax2;
*y1 = ay2;
*z1 = 0;
- G_debug(2, " -> connected by end points");
+
return 1; /* endpoints only */
}
- /* heneral overlap */
+ /* general overlap */
G_debug(3, " -> vertical overlap");
/* a contains b */
if (ay1 <= by1 && ay2 >= by2) {
@@ -257,10 +268,8 @@
*x2 = bx2;
*y2 = by2;
*z2 = 0;
- if (!switched)
- return 3;
- else
- return 4;
+
+ return 3;
}
/* b contains a */
if (ay1 >= by1 && ay2 <= by2) {
@@ -271,69 +280,54 @@
*x2 = ax2;
*y2 = ay2;
*z2 = 0;
- if (!switched)
- return 4;
- else
- return 3;
+
+ return 4;
}
/* general overlap, 2 intersection points */
G_debug(2, " -> partial overlap");
if (by1 > ay1 && by1 < ay2) { /* b1 in a */
- if (!switched) {
- *x1 = bx1;
- *y1 = by1;
- *z1 = 0;
- *x2 = ax2;
- *y2 = ay2;
- *z2 = 0;
- }
- else {
- *x1 = ax2;
- *y1 = ay2;
- *z1 = 0;
- *x2 = bx1;
- *y2 = by1;
- *z2 = 0;
- }
+ G_debug(2, " -> b1 in a");
+ *x1 = bx1;
+ *y1 = by1;
+ *z1 = 0;
+ *x2 = ax2;
+ *y2 = ay2;
+ *z2 = 0;
+
return 2;
}
if (by2 > ay1 && by2 < ay2) { /* b2 in a */
- if (!switched) {
- *x1 = bx2;
- *y1 = by2;
- *z1 = 0;
- *x2 = ax1;
- *y2 = ay1;
- *z2 = 0;
- }
- else {
- *x1 = ax1;
- *y1 = ay1;
- *z1 = 0;
- *x2 = bx2;
- *y2 = by2;
- *z2 = 0;
- }
+ G_debug(2, " -> b2 in a");
+ *x1 = ax1;
+ *y1 = ay1;
+ *z1 = 0;
+ *x2 = bx2;
+ *y2 = by2;
+ *z2 = 0;
+
return 2;
}
/* should not be reached */
G_warning(_("Vect_segment_intersection() ERROR (collinear vertical segments)"));
+ G_warning("a");
G_warning("%.15g %.15g", ax1, ay1);
G_warning("%.15g %.15g", ax2, ay2);
- G_warning("x");
+ G_warning("b");
G_warning("%.15g %.15g", bx1, by1);
G_warning("%.15g %.15g", bx2, by2);
return 0;
}
+ /* Collinear non vertical */
+
G_debug(2, " -> collinear non vertical");
- /* Collinear non vertical */
- if ((bx1 > ax1 && bx2 > ax1 && bx1 > ax2 && bx2 > ax2) ||
- (bx1 < ax1 && bx2 < ax1 && bx1 < ax2 && bx2 < ax2)) {
+ /* b is to the left or right of a */
+ if ((bx1 > ax2) || (bx2 < ax1)) {
+ /* should not happen if segments are selected from rtree */
G_debug(2, " -> no intersection");
return 0;
}
@@ -342,38 +336,23 @@
G_debug(2, " -> overlap/connected end points");
/* end points */
- if ((ax1 == bx1 && ay1 == by1) || (ax1 == bx2 && ay1 == by2)) {
+ if (ax1 == bx2 && ay1 == by2) {
+ G_debug(2, " -> connected by end points");
*x1 = ax1;
*y1 = ay1;
*z1 = 0;
- G_debug(2, " -> connected by end points");
+
return 1;
}
- if ((ax2 == bx1 && ay2 == by1) || (ax2 == bx2 && ay2 == by2)) {
+ if (ax2 == bx1 && ay2 == by1) {
+ G_debug(2, " -> connected by end points");
*x1 = ax2;
*y1 = ay2;
*z1 = 0;
- G_debug(2, " -> connected by end points");
+
return 1;
}
- if (ax1 > ax2) {
- t = ax1;
- ax1 = ax2;
- ax2 = t;
- t = ay1;
- ay1 = ay2;
- ay2 = t;
- } /* to be sure that ax1 < ax2 */
- if (bx1 > bx2) {
- t = bx1;
- bx1 = bx2;
- bx2 = t;
- t = by1;
- by1 = by2;
- by2 = t;
- } /* to be sure that bx1 < bx2 */
-
/* a contains b */
if (ax1 <= bx1 && ax2 >= bx2) {
G_debug(2, " -> a contains b");
@@ -383,10 +362,8 @@
*x2 = bx2;
*y2 = by2;
*z2 = 0;
- if (!switched)
- return 3;
- else
- return 4;
+
+ return 3;
}
/* b contains a */
if (ax1 >= bx1 && ax2 <= bx2) {
@@ -397,58 +374,41 @@
*x2 = ax2;
*y2 = ay2;
*z2 = 0;
- if (!switched)
- return 4;
- else
- return 3;
+
+ return 4;
}
/* general overlap, 2 intersection points (lines are not vertical) */
G_debug(2, " -> partial overlap");
if (bx1 > ax1 && bx1 < ax2) { /* b1 is in a */
- if (!switched) {
- *x1 = bx1;
- *y1 = by1;
- *z1 = 0;
- *x2 = ax2;
- *y2 = ay2;
- *z2 = 0;
- }
- else {
- *x1 = ax2;
- *y1 = ay2;
- *z1 = 0;
- *x2 = bx1;
- *y2 = by1;
- *z2 = 0;
- }
+ G_debug(2, " -> b1 in a");
+ *x1 = bx1;
+ *y1 = by1;
+ *z1 = 0;
+ *x2 = ax2;
+ *y2 = ay2;
+ *z2 = 0;
+
return 2;
}
if (bx2 > ax1 && bx2 < ax2) { /* b2 is in a */
- if (!switched) {
- *x1 = bx2;
- *y1 = by2;
- *z1 = 0;
- *x2 = ax1;
- *y2 = ay1;
- *z2 = 0;
- }
- else {
- *x1 = ax1;
- *y1 = ay1;
- *z1 = 0;
- *x2 = bx2;
- *y2 = by2;
- *z2 = 0;
- }
+ G_debug(2, " -> b2 in a");
+ *x1 = ax1;
+ *y1 = ay1;
+ *z1 = 0;
+ *x2 = bx2;
+ *y2 = by2;
+ *z2 = 0;
+
return 2;
}
/* should not be reached */
G_warning(_("Vect_segment_intersection() ERROR (collinear non vertical segments)"));
+ G_warning("a");
G_warning("%.15g %.15g", ax1, ay1);
G_warning("%.15g %.15g", ax2, ay2);
- G_warning("x");
+ G_warning("b");
G_warning("%.15g %.15g", bx1, by1);
G_warning("%.15g %.15g", bx2, by2);
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