[postgis-commits] svn - r3424 - in trunk: . cunit liblwgeom
postgis-commits at postgis.refractions.net
postgis-commits at postgis.refractions.net
Tue Dec 16 14:29:42 PST 2008
Author: pramsey
Date: 2008-12-16 14:29:42 -0800 (Tue, 16 Dec 2008)
New Revision: 3424
Added:
trunk/cunit/
trunk/cunit/Makefile
trunk/cunit/cu_algorithm.c
trunk/cunit/cu_algorithm.h
trunk/cunit/cu_tester.c
trunk/liblwgeom/lwalgorithm.c
trunk/liblwgeom/lwalgorithm.h
Modified:
trunk/liblwgeom/Makefile.in
trunk/liblwgeom/liblwgeom.h
Log:
First cut of line crossing function, and associated cunit tests.
Added: trunk/cunit/Makefile
===================================================================
--- trunk/cunit/Makefile 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/cunit/Makefile 2008-12-16 22:29:42 UTC (rev 3424)
@@ -0,0 +1,25 @@
+
+LWGEOM=../liblwgeom
+LIBCUNIT=/usr/local/lib/libcunit.a
+LIBLWGEOM=$(LWGEOM)/liblwgeom.a
+
+OBJS = cu_tester.o \
+ cu_algorithm.o
+
+#---------------------------------------------------------------
+
+INCLUDES = -I/usr/local/include -I$(LWGEOM)
+CFLAGS = -g $(MSDEFINES) $(INCLUDES)
+LIBS = $(LIBCUNIT) $(LIBLWGEOM)
+LDFLAGS =
+
+cu_tester: $(OBJS) $(LIBS)
+
+test: cu_tester
+ ./cu_tester
+
+check: test
+
+clean:
+ @rm $(OBJS)
+ @rm cu_tester
Added: trunk/cunit/cu_algorithm.c
===================================================================
--- trunk/cunit/cu_algorithm.c 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/cunit/cu_algorithm.c 2008-12-16 22:29:42 UTC (rev 3424)
@@ -0,0 +1,476 @@
+
+#include "cu_algorithm.h"
+
+/*
+** Called from test harness to register the tests in this file.
+*/
+CU_pSuite register_cg_suite(void)
+{
+ CU_pSuite pSuite;
+ pSuite = CU_add_suite("PostGIS Computational Geometry Suite", init_cg_suite, clean_cg_suite);
+ if (NULL == pSuite)
+ {
+ CU_cleanup_registry();
+ return NULL;
+ }
+
+ if (
+ (NULL == CU_add_test(pSuite, "testSegmentSide()", testSegmentSide)) ||
+ (NULL == CU_add_test(pSuite, "testSegmentIntersects()", testSegmentIntersects)) ||
+ (NULL == CU_add_test(pSuite, "testLineCrossingShortLines()", testLineCrossingShortLines)) ||
+ (NULL == CU_add_test(pSuite, "testLineCrossingLongLines()", testLineCrossingLongLines))
+ )
+ {
+ CU_cleanup_registry();
+ return NULL;
+ }
+ return pSuite;
+}
+
+
+/*
+** Global variables used by tests below
+*/
+POINT2D *p1 = NULL;
+POINT2D *p2 = NULL;
+POINT2D *q1 = NULL;
+POINT2D *q2 = NULL;
+POINT4D *p = NULL;
+/* Two-point objects */
+POINTARRAY *pa21 = NULL;
+POINTARRAY *pa22 = NULL;
+LWLINE *l21 = NULL;
+LWLINE *l22 = NULL;
+/* Five-point objects */
+POINTARRAY *pa51 = NULL;
+POINTARRAY *pa52 = NULL;
+LWLINE *l51 = NULL;
+LWLINE *l52 = NULL;
+
+
+/*
+** The suite initialization function.
+** Create any re-used objects.
+*/
+int init_cg_suite(void)
+{
+ p = lwalloc(sizeof(POINT4D));
+ p1 = lwalloc(sizeof(POINT2D));
+ p2 = lwalloc(sizeof(POINT2D));
+ q1 = lwalloc(sizeof(POINT2D));
+ q2 = lwalloc(sizeof(POINT2D));
+ pa21 = ptarray_construct(0, 0, 2);
+ pa22 = ptarray_construct(0, 0, 2);
+ l21 = lwline_construct(-1, NULL, pa21);
+ l22 = lwline_construct(-1, NULL, pa22);
+ pa51 = ptarray_construct(0, 0, 5);
+ pa52 = ptarray_construct(0, 0, 5);
+ l51 = lwline_construct(-1, NULL, pa51);
+ l52 = lwline_construct(-1, NULL, pa52);
+ return 0;
+}
+
+/*
+** The suite cleanup function.
+** Frees any global objects.
+*/
+int clean_cg_suite(void)
+{
+ lwfree(p);
+ lwfree(p1);
+ lwfree(p2);
+ lwfree(q1);
+ lwfree(q2);
+ lwfree(pa21);
+ lwfree(pa22);
+ lwfree(pa51);
+ lwfree(pa52);
+ lwfree(l21);
+ lwfree(l22);
+ lwfree(l51);
+ lwfree(l52);
+ return 0;
+}
+
+/*
+** Test left/right side.
+*/
+void testSegmentSide(void)
+{
+ double rv = 0.0;
+ POINT2D *q = NULL;
+ q = lwalloc(sizeof(POINT2D));
+
+ /* Vertical line at x=0 */
+ p1->x = 0.0;
+ p1->y = 0.0;
+ p2->x = 0.0;
+ p2->y = 1.0;
+
+ /* On the left */
+ q->x = -2.0;
+ q->y = 1.5;
+ rv = segmentSide(p1, p2, q);
+ //printf("left %g\n",rv);
+ CU_ASSERT(rv < 0.0);
+
+ /* On the right */
+ q->x = 2.0;
+ rv = segmentSide(p1, p2, q);
+ //printf("right %g\n",rv);
+ CU_ASSERT(rv > 0.0);
+
+ /* On the line */
+ q->x = 0.0;
+ rv = segmentSide(p1, p2, q);
+ //printf("on line %g\n",rv);
+ CU_ASSERT_EQUAL(rv, 0.0);
+
+ lwfree(q);
+
+}
+
+/*
+** Test crossings side.
+*/
+void testSegmentIntersects(void)
+{
+
+ /* P: Vertical line at x=0 */
+ p1->x = 0.0;
+ p1->y = 0.0;
+ p2->x = 0.0;
+ p2->y = 1.0;
+
+ /* Q: Horizontal line crossing left to right */
+ q1->x = -0.5;
+ q1->y = 0.5;
+ q2->x = 0.5;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_CROSS_RIGHT );
+
+ /* Q: Horizontal line crossing right to left */
+ q1->x = 0.5;
+ q1->y = 0.5;
+ q2->x = -0.5;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_CROSS_LEFT );
+
+ /* Q: Horizontal line not crossing right to left */
+ q1->x = 0.5;
+ q1->y = 1.5;
+ q2->x = -0.5;
+ q2->y = 1.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_NO_INTERSECTION );
+
+ /* Q: Horizontal line crossing at vertex right to left */
+ q1->x = 0.5;
+ q1->y = 1.0;
+ q2->x = -0.5;
+ q2->y = 1.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_CROSS_LEFT );
+
+ /* Q: Diagonal line with large range crossing at vertex right to left */
+ q1->x = 0.5;
+ q1->y = 10.0;
+ q2->x = -0.5;
+ q2->y = -10.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_CROSS_LEFT );
+
+ /* Q: Diagonal line with large range crossing at vertex right to left */
+ q1->x = 0.5;
+ q1->y = 11.0;
+ q2->x = -0.5;
+ q2->y = -9.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_CROSS_LEFT );
+
+ /* Q: Horizontal touching from left */
+ q1->x = -0.5;
+ q1->y = 0.5;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_LEFT );
+
+ /* Q: Horizontal touching from right */
+ q1->x = 0.5;
+ q1->y = 0.5;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_RIGHT );
+
+ /* Q: Horizontal touching from left and far below*/
+ q1->x = -0.5;
+ q1->y = -10.5;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_LEFT );
+
+ /* Q: Horizontal touching from right and far above */
+ q1->x = 0.5;
+ q1->y = 10.5;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_RIGHT );
+
+ /* Q: Co-linear from top */
+ q1->x = 0.0;
+ q1->y = 10.0;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_COLINEAR );
+
+ /* Q: Co-linear from bottom */
+ q1->x = 0.0;
+ q1->y = -10.0;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_COLINEAR );
+
+ /* Q: Co-linear contained */
+ q1->x = 0.0;
+ q1->y = 0.4;
+ q2->x = 0.0;
+ q2->y = 0.5;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_COLINEAR );
+
+ /* Q: Horizontal touching at end point from left */
+ q1->x = -0.5;
+ q1->y = 1.0;
+ q2->x = 0.0;
+ q2->y = 1.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_LEFT );
+
+ /* Q: Horizontal touching at end point from right */
+ q1->x = 0.5;
+ q1->y = 1.0;
+ q2->x = 0.0;
+ q2->y = 1.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_RIGHT );
+
+ /* Q: Horizontal touching at start point from left */
+ q1->x = -0.5;
+ q1->y = 0.0;
+ q2->x = 0.0;
+ q2->y = 0.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_LEFT );
+
+ /* Q: Horizontal touching at start point from right */
+ q1->x = 0.5;
+ q1->y = 0.0;
+ q2->x = 0.0;
+ q2->y = 0.0;
+ CU_ASSERT( segmentIntersects(p1, p2, q1, q2) == SEG_TOUCH_RIGHT );
+
+}
+
+void testLineCrossingShortLines(void)
+{
+
+ int rv = 0;
+
+ /*
+ ** Simple test, two two-point lines
+ */
+
+ /* Vertical line from 0,0 to 1,1 */
+ p->x = 0.0;
+ p->y = 0.0;
+ setPoint4d(pa21, 0, p);
+ p->y = 1.0;
+ setPoint4d(pa21, 1, p);
+
+ /* Horizontal, crossing mid-segment */
+ p->x = -0.5;
+ p->y = 0.5;
+ setPoint4d(pa22, 0, p);
+ p->x = 0.5;
+ setPoint4d(pa22, 1, p);
+
+ CU_ASSERT( lineCrossingDirection(l21, l22) == LINE_CROSS_RIGHT );
+
+ /* Horizontal, crossing at top end vertex */
+ p->x = -0.5;
+ p->y = 1.0;
+ setPoint4d(pa22, 0, p);
+ p->x = 0.5;
+ setPoint4d(pa22, 1, p);
+
+ CU_ASSERT( lineCrossingDirection(l21, l22) == LINE_CROSS_RIGHT );
+
+ /* Horizontal, crossing at bottom end vertex */
+ p->x = -0.5;
+ p->y = 0.0;
+ setPoint4d(pa22, 0, p);
+ p->x = 0.5;
+ setPoint4d(pa22, 1, p);
+
+ CU_ASSERT( lineCrossingDirection(l21, l22) == LINE_CROSS_RIGHT );
+
+ /* Horizontal, no crossing */
+ p->x = -0.5;
+ p->y = 2.0;
+ setPoint4d(pa22, 0, p);
+ p->x = 0.5;
+ setPoint4d(pa22, 1, p);
+
+ CU_ASSERT( lineCrossingDirection(l21, l22) == LINE_NO_CROSS );
+
+ /* Vertical, no crossing */
+ p->x = -0.5;
+ p->y = 0.0;
+ setPoint4d(pa22, 0, p);
+ p->y = 1.0;
+ setPoint4d(pa22, 1, p);
+
+ CU_ASSERT( lineCrossingDirection(l21, l22) == LINE_NO_CROSS );
+
+}
+
+void testLineCrossingLongLines(void)
+{
+
+ /*
+ ** More complex test, longer lines and multiple crossings
+ */
+
+ /* Vertical line with vertices at y integers */
+ p->x = 0.0;
+ p->y = 0.0;
+ setPoint4d(pa51, 0, p);
+ p->y = 1.0;
+ setPoint4d(pa51, 1, p);
+ p->y = 2.0;
+ setPoint4d(pa51, 2, p);
+ p->y = 3.0;
+ setPoint4d(pa51, 3, p);
+ p->y = 4.0;
+ setPoint4d(pa51, 4, p);
+
+ /* Two crossings at segment midpoints */
+ p->x = 1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 0, p);
+ p->x = -1.0;
+ p->y = 1.5;
+ setPoint4d(pa52, 1, p);
+ p->x = 1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 2, p);
+ p->x = 1.0;
+ p->y = 4.0;
+ setPoint4d(pa52, 3, p);
+ p->x = 1.0;
+ p->y = 5.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_MULTICROSS_END_SAME_FIRST_LEFT );
+
+ /* One crossing at interior vertex */
+ p->x = 1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 0, p);
+ p->x = 0.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 1, p);
+ p->x = -1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 2, p);
+ p->x = -1.0;
+ p->y = 2.0;
+ setPoint4d(pa52, 3, p);
+ p->x = -1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_CROSS_LEFT );
+
+ /* Two crossings at interior vertices */
+ p->x = 1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 0, p);
+ p->x = 0.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 1, p);
+ p->x = -1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 2, p);
+ p->x = 0.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 3, p);
+ p->x = 1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_MULTICROSS_END_SAME_FIRST_LEFT );
+
+ /* Two crossings, one at the first vertex on at interior vertex */
+ p->x = 1.0;
+ p->y = 0.0;
+ setPoint4d(pa52, 0, p);
+ p->x = 0.0;
+ p->y = 0.0;
+ setPoint4d(pa52, 1, p);
+ p->x = -1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 2, p);
+ p->x = 0.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 3, p);
+ p->x = 1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_MULTICROSS_END_SAME_FIRST_LEFT );
+
+ /* Two crossings, one at the first vertex on the next interior vertex */
+ p->x = 1.0;
+ p->y = 0.0;
+ setPoint4d(pa52, 0, p);
+ p->x = 0.0;
+ p->y = 0.0;
+ setPoint4d(pa52, 1, p);
+ p->x = -1.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 2, p);
+ p->x = 0.0;
+ p->y = 1.0;
+ setPoint4d(pa52, 3, p);
+ p->x = 1.0;
+ p->y = 2.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_MULTICROSS_END_SAME_FIRST_LEFT );
+
+ /* Two crossings, one at the last vertex on the next interior vertex */
+ p->x = 1.0;
+ p->y = 4.0;
+ setPoint4d(pa52, 0, p);
+ p->x = 0.0;
+ p->y = 4.0;
+ setPoint4d(pa52, 1, p);
+ p->x = -1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 2, p);
+ p->x = 0.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 3, p);
+ p->x = 1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_MULTICROSS_END_SAME_FIRST_LEFT );
+
+ /* Three crossings, two at midpoints, one at vertex */
+ p->x = 0.5;
+ p->y = 1.0;
+ setPoint4d(pa52, 0, p);
+ p->x = -1.0;
+ p->y = 0.5;
+ setPoint4d(pa52, 1, p);
+ p->x = 1.0;
+ p->y = 2.0;
+ setPoint4d(pa52, 2, p);
+ p->x = -1.0;
+ p->y = 2.0;
+ setPoint4d(pa52, 3, p);
+ p->x = -1.0;
+ p->y = 3.0;
+ setPoint4d(pa52, 4, p);
+ CU_ASSERT( lineCrossingDirection(l51, l52) == LINE_MULTICROSS_END_LEFT );
+
+}
+
Added: trunk/cunit/cu_algorithm.h
===================================================================
--- trunk/cunit/cu_algorithm.h 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/cunit/cu_algorithm.h 2008-12-16 22:29:42 UTC (rev 3424)
@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "CUnit/Basic.h"
+
+#include "lwalgorithm.h"
+
+/***********************************************************************
+** for Computational Geometry Suite
+*/
+
+/* Set-up / clean-up functions */
+CU_pSuite register_cg_suite(void);
+int init_cg_suite(void);
+int clean_cg_suite(void);
+
+/* Test functions */
+void testSegmentSide(void);
+void testSegmentIntersects(void);
+void testLineCrossingShortLines(void);
+void testLineCrossingLongLines(void);
+
+
Added: trunk/cunit/cu_tester.c
===================================================================
--- trunk/cunit/cu_tester.c 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/cunit/cu_tester.c 2008-12-16 22:29:42 UTC (rev 3424)
@@ -0,0 +1,56 @@
+
+#include <stdio.h>
+#include <string.h>
+#include "CUnit/Basic.h"
+
+#include "cu_algorithm.h"
+
+
+/*
+** Set up liblwgeom to run in stand-alone mode using the
+** usual system memory handling functions.
+*/
+void cunit_lwerr(const char *fmt, va_list ap) {
+ printf("Got an LWERR.\n");
+}
+
+void cunit_lwnotice(const char *fmt, va_list ap) {
+ printf("Got an LWNOTICE.\n");
+}
+
+void lwgeom_init_allocators(void) {
+ /* liblwgeom callback - install PostgreSQL handlers */
+ lwalloc_var = malloc;
+ lwrealloc_var = realloc;
+ lwfree_var = free;
+ lwerror_var = default_errorreporter;
+ lwnotice_var = default_noticereporter;
+}
+
+/*
+** The main() function for setting up and running the tests.
+** Returns a CUE_SUCCESS on successful running, another
+** CUnit error code on failure.
+*/
+int main()
+{
+
+ /* initialize the CUnit test registry */
+ if (CUE_SUCCESS != CU_initialize_registry())
+ return CU_get_error();
+
+ /* Add the PostGIS suite to the registry */
+ if (NULL == register_cg_suite())
+ {
+ CU_cleanup_registry();
+ return CU_get_error();
+ }
+
+ /* Run all tests using the CUnit Basic interface */
+ CU_basic_set_mode(CU_BRM_VERBOSE);
+ CU_basic_run_tests();
+ CU_cleanup_registry();
+
+ return CU_get_error();
+
+}
Modified: trunk/liblwgeom/Makefile.in
===================================================================
--- trunk/liblwgeom/Makefile.in 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/liblwgeom/Makefile.in 2008-12-16 22:29:42 UTC (rev 3424)
@@ -35,6 +35,7 @@
lwmcurve.o \
lwmsurface.o \
lwutil.o \
+ lwalgorithm.o \
lwgunparse.o \
lwgparse.o \
lwsegmentize.o \
Modified: trunk/liblwgeom/liblwgeom.h
===================================================================
--- trunk/liblwgeom/liblwgeom.h 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/liblwgeom/liblwgeom.h 2008-12-16 22:29:42 UTC (rev 3424)
@@ -22,7 +22,10 @@
#define FP_CONTAINS_INCL(A, X, B) (FP_LTEQ(A, X) && FP_LTEQ(X, B))
#define FP_CONTAINS_EXCL(A, X, B) (FP_LT(A, X) && FP_LT(X, B))
#define FP_CONTAINS(A, X, B) FP_CONTAINS_EXCL(A, X, B)
+#define LW_TRUE 1
+#define LW_FALSE 0
+
/*
* Memory management function types
*/
Added: trunk/liblwgeom/lwalgorithm.c
===================================================================
--- trunk/liblwgeom/lwalgorithm.c 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/liblwgeom/lwalgorithm.c 2008-12-16 22:29:42 UTC (rev 3424)
@@ -0,0 +1,262 @@
+#include "lwalgorithm.h"
+
+/*
+** segmentSide()
+**
+** Return < 0.0 if point Q is left of segment P
+** Return > 0.0 if point Q is right of segment P
+** Return = 0.0 if point Q in on segment P
+*/
+double segmentSide(POINT2D *p1, POINT2D *p2, POINT2D *q)
+{
+ return ( (q->x - p1->x) * (p2->y - p1->y) - (p2->x - p1->x) * (q->y - p1->y) );
+}
+
+int segmentEnvelopeIntersects(POINT2D *p1, POINT2D *p2, POINT2D *q1, POINT2D *q2) {
+ double minq=LW_MIN(q1->x,q2->x);
+ double maxq=LW_MAX(q1->x,q2->x);
+ double minp=LW_MIN(p1->x,p2->x);
+ double maxp=LW_MAX(p1->x,p2->x);
+
+ if(minp>maxq || maxp<minq)
+ return LW_FALSE;
+
+ minq=LW_MIN(q1->y,q2->y);
+ maxq=LW_MAX(q1->y,q2->y);
+ minp=LW_MIN(p1->y,p2->y);
+ maxp=LW_MAX(p1->y,p2->y);
+
+ if(minp>maxq || maxp<minq)
+ return LW_FALSE;
+
+ return LW_TRUE;
+}
+
+/*
+** segmentIntersects()
+**
+** Returns one of
+** SEG_ERROR = -1,
+** SEG_NO_INTERSECTION = 0,
+** SEG_COLINEAR = 1,
+** SEG_CROSS_LEFT = 2,
+** SEG_CROSS_RIGHT = 3,
+** SEG_TOUCH_LEFT = 4,
+** SEG_TOUCH_RIGHT = 5
+*/
+int segmentIntersects(POINT2D *p1, POINT2D *p2, POINT2D *q1, POINT2D *q2) {
+
+ double pq1, pq2, qp1, qp2;
+
+ /* No envelope interaction => we are done. */
+ if (!segmentEnvelopeIntersects(p1, p2, q1, p2)) {
+ return SEG_NO_INTERSECTION;
+ }
+
+ /* Are the start and end points of q on the same side of p? */
+ pq1=segmentSide(p1,p2,q1);
+ pq2=segmentSide(p1,p2,q2);
+ if ((pq1>0 && pq2>0) || (pq1<0 && pq2<0)) {
+ return SEG_NO_INTERSECTION;
+ }
+
+ /* Are the start and end points of p on the same side of q? */
+ qp1=segmentSide(q1,q2,p1);
+ qp2=segmentSide(q1,q2,p2);
+ if ((qp1>0 && qp2>0) || (qp1<0 && qp2<0)) {
+ return SEG_NO_INTERSECTION;
+ }
+
+ /* Nobody is on one side or another? Must be colinear. */
+ if (pq1 == 0.0 && pq2 == 0.0 && qp1 == 0.0 && qp2 == 0.0) {
+ return SEG_COLINEAR;
+ }
+
+ /*
+ ** When one end-point touches, the sidedness is determined by the
+ ** location of the other end-point.
+ */
+ if ( pq2 == 0.0 ) {
+ if ( pq1 < 0.0 )
+ return SEG_TOUCH_LEFT;
+ else
+ return SEG_TOUCH_RIGHT;
+ }
+ if ( pq1 == 0.0 ) {
+ if ( pq2 < 0.0 )
+ return SEG_TOUCH_LEFT;
+ else
+ return SEG_TOUCH_RIGHT;
+ }
+
+ /* The segments cross, what direction is the crossing? */
+ if ( pq1 < pq2 )
+ return SEG_CROSS_RIGHT;
+ else
+ return SEG_CROSS_LEFT;
+
+ /* This should never happen! */
+ return SEG_ERROR;
+
+}
+
+/*
+** lineCrossingDirection()
+**
+** Returns one of
+** LINE_NO_CROSS = 0
+** LINE_CROSS_LEFT = -1
+** LINE_CROSS_RIGHT = 1
+** LINE_MULTICROSS_END_LEFT = -2
+** LINE_MULTICROSS_END_RIGHT = 2
+** LINE_MULTICROSS_END_SAME_FIRST_LEFT = -3
+** LINE_MULTICROSS_END_SAME_FIRST_RIGHT = 3
+** LINE_TOUCH_LEFT = -4
+** LINE_TOUCH_RIGHT = 4
+**
+*/
+int lineCrossingDirection(LWLINE *l1, LWLINE *l2) {
+
+ int i = 0, j = 0, rv = 0;
+ POINT2D *p1;
+ POINT2D *p2;
+ POINT2D *q1;
+ POINT2D *q2;
+ POINTARRAY *pa1;
+ POINTARRAY *pa2;
+ int cross_left = 0;
+ int cross_right = 0;
+ int first_cross = 0;
+ int final_cross = 0;
+ int this_cross = 0;
+ int vertex_touch = -1;
+ int vertex_touch_type = 0;
+
+ pa1 = (POINTARRAY*)l1->points;
+ pa2 = (POINTARRAY*)l2->points;
+
+ p1 = lwalloc(sizeof(POINT2D));
+ p2 = lwalloc(sizeof(POINT2D));
+ q1 = lwalloc(sizeof(POINT2D));
+ q2 = lwalloc(sizeof(POINT2D));
+
+ /* One-point lines can't intersect (and shouldn't exist). */
+ if( pa1->npoints < 2 || pa2->npoints < 2 )
+ return LINE_NO_CROSS;
+
+ LWDEBUGF(5, "lineCrossingDirection: l1 = %s", lwgeom_to_ewkt((LWGEOM*)l1,0));
+ LWDEBUGF(5, "lineCrossingDirection: l2 = %s", lwgeom_to_ewkt((LWGEOM*)l2,0));
+
+ for ( i = 1; i < pa2->npoints; i++ ) {
+
+ rv = getPoint2d_p(pa2, i-1, q1);
+ rv = getPoint2d_p(pa2, i, q2);
+
+ for ( j = 1; j < pa1->npoints; j++ ) {
+
+ rv = getPoint2d_p(pa1, j-1, p1);
+ rv = getPoint2d_p(pa1, j, p2);
+
+ LWDEBUGF(5, "lineCrossingDirection: i=%d, j=%d", i, j);
+
+ this_cross = segmentIntersects(p1, p2, q1, q2);
+
+ if( ! first_cross && this_cross )
+ first_cross = this_cross;
+ if( this_cross )
+ final_cross = this_cross;
+
+ if( this_cross == SEG_CROSS_LEFT ) {
+ cross_left++;
+ break;
+ }
+
+ if( this_cross == SEG_CROSS_RIGHT ) {
+ cross_right++;
+ break;
+ }
+
+ /*
+ ** Crossing-at-vertex will cause four segment touch interactions, two at
+ ** j-1 and two at j. We avoid incrementing our cross count by ignoring the
+ ** second pair.
+ */
+ if( this_cross == SEG_TOUCH_LEFT ) {
+ if ( vertex_touch == (i-1) && vertex_touch_type == SEG_TOUCH_RIGHT ) {
+ cross_left++;
+ vertex_touch = -1;
+ vertex_touch_type = 0;
+ }
+ else {
+ vertex_touch = i;
+ vertex_touch_type = this_cross;
+ }
+ break;
+ }
+ if( this_cross == SEG_TOUCH_RIGHT ) {
+ if ( vertex_touch == (i-1) && vertex_touch_type == SEG_TOUCH_LEFT ) {
+ cross_right++;
+ vertex_touch = -1;
+ vertex_touch_type = 0;
+ }
+ else {
+ vertex_touch = i;
+ vertex_touch_type = this_cross;
+ }
+ break;
+ }
+
+ /*
+ ** TODO Handle co-linear cases.
+ */
+
+ LWDEBUGF(5, "lineCrossingDirection: this_cross=%d, prev_cross=%d, vertex_touch=%d, vertex_touch_type=%d", this_cross, prev_cross, vertex_touch, vertex_touch_type);
+
+ }
+
+ }
+
+ LWDEBUGF(5, "first_cross=%d, final_cross=%d, cross_left=%d, cross_right=%d", first_cross, final_cross, cross_left, cross_right);
+
+ lwfree(p1);
+ lwfree(p2);
+ lwfree(q1);
+ lwfree(q2);
+
+ if( !cross_left && !cross_right && !first_cross && !final_cross )
+ return LINE_NO_CROSS;
+
+ if( !cross_left && !cross_right && ( first_cross == SEG_TOUCH_RIGHT || final_cross == SEG_TOUCH_RIGHT ) )
+ return LINE_TOUCH_RIGHT;
+
+ if( !cross_left && !cross_right && ( first_cross == SEG_TOUCH_LEFT || final_cross == SEG_TOUCH_LEFT ) )
+ return LINE_TOUCH_LEFT;
+
+ if( !cross_left && cross_right == 1 )
+ return LINE_CROSS_RIGHT;
+
+ if( !cross_right && cross_left == 1 )
+ return LINE_CROSS_LEFT;
+
+ if( cross_left - cross_right == 1 )
+ return LINE_MULTICROSS_END_LEFT;
+
+ if( cross_left - cross_right == -1 )
+ return LINE_MULTICROSS_END_RIGHT;
+
+ if( cross_left - cross_right == 0 && first_cross == SEG_CROSS_LEFT )
+ return LINE_MULTICROSS_END_SAME_FIRST_LEFT;
+
+ if( cross_left - cross_right == 0 && first_cross == SEG_CROSS_RIGHT )
+ return LINE_MULTICROSS_END_SAME_FIRST_RIGHT;
+
+ if( cross_left - cross_right == 0 && first_cross == SEG_TOUCH_LEFT )
+ return LINE_MULTICROSS_END_SAME_FIRST_RIGHT;
+
+ if( cross_left - cross_right == 0 && first_cross == SEG_TOUCH_RIGHT )
+ return LINE_MULTICROSS_END_SAME_FIRST_LEFT;
+
+ return LINE_NO_CROSS;
+
+}
+
Added: trunk/liblwgeom/lwalgorithm.h
===================================================================
--- trunk/liblwgeom/lwalgorithm.h 2008-12-16 21:21:57 UTC (rev 3423)
+++ trunk/liblwgeom/lwalgorithm.h 2008-12-16 22:29:42 UTC (rev 3424)
@@ -0,0 +1,30 @@
+#include "liblwgeom.h"
+
+enum CG_SEGMENT_INTERSECTION_TYPE {
+ SEG_ERROR = -1,
+ SEG_NO_INTERSECTION = 0,
+ SEG_COLINEAR = 1,
+ SEG_CROSS_LEFT = 2,
+ SEG_CROSS_RIGHT = 3,
+ SEG_TOUCH_LEFT = 4,
+ SEG_TOUCH_RIGHT = 5
+};
+
+double segmentSide(POINT2D *p1, POINT2D *p2, POINT2D *q);
+int segmentIntersects(POINT2D *p1, POINT2D *p2, POINT2D *q1, POINT2D *q2);
+int segmentEnvelopeIntersects(POINT2D *p1, POINT2D *p2, POINT2D *q1, POINT2D *q2);
+
+
+enum CG_LINE_CROSS_TYPE {
+ LINE_NO_CROSS = 0,
+ LINE_CROSS_LEFT = -1,
+ LINE_CROSS_RIGHT = 1,
+ LINE_MULTICROSS_END_LEFT = -2,
+ LINE_MULTICROSS_END_RIGHT = 2,
+ LINE_MULTICROSS_END_SAME_FIRST_LEFT = -3,
+ LINE_MULTICROSS_END_SAME_FIRST_RIGHT = 3,
+ LINE_TOUCH_LEFT = -4,
+ LINE_TOUCH_RIGHT = 4
+};
+
+int lineCrossingDirection(LWLINE *l1, LWLINE *l2);
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