Add spoly_is_convex

Author: ggnmstr

Diff for: expected/init_test.out.in

@@ -24,12 +24,13 @@ psql:pg_sphere.test.sql:158: NOTICE:  argument type spath is only a shell
 psql:pg_sphere.test.sql:177: NOTICE:  type "sbox" is not yet defined
 DETAIL:  Creating a shell type definition.
 psql:pg_sphere.test.sql:184: NOTICE:  argument type sbox is only a shell
-psql:pg_sphere.test.sql:8568: NOTICE:  type "spherekey" is not yet defined
+psql:pg_sphere.test.sql:8582: NOTICE:  type "spherekey" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:pg_sphere.test.sql:8575: NOTICE:  argument type spherekey is only a shell
-psql:pg_sphere.test.sql:8589: NOTICE:  type "pointkey" is not yet defined
+psql:pg_sphere.test.sql:8589: NOTICE:  argument type spherekey is only a shell
+psql:pg_sphere.test.sql:8603: NOTICE:  type "pointkey" is not yet defined
 DETAIL:  Creating a shell type definition.
-psql:pg_sphere.test.sql:8596: NOTICE:  argument type pointkey is only a shell
-psql:pg_sphere.test.sql:8602: NOTICE:  argument type pointkey is only a shell
-psql:pg_sphere.test.sql:8608: NOTICE:  argument type pointkey is only a shell
-psql:pg_sphere.test.sql:8614: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8588: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8594: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:8600: NOTICE:  argument type pointkey is only a shell
+psql:pg_sphere.test.sql:9167: NOTICE:  return type smoc is only a shell
+psql:pg_sphere.test.sql:9173: NOTICE:  argument type smoc is only a shell

Diff for: expected/init_test_healpix.out.in

@@ -1,2 +1,2 @@
-psql:pg_sphere.test.sql:9181: NOTICE:  return type smoc is only a shell
-psql:pg_sphere.test.sql:9187: NOTICE:  argument type smoc is only a shell
+psql:pg_sphere.test.sql:9167: NOTICE:  return type smoc is only a shell
+psql:pg_sphere.test.sql:9173: NOTICE:  argument type smoc is only a shell

Diff for: expected/poly.out

@@ -1760,3 +1760,22 @@ SELECT npoints( spoly '{
        4
 (1 row)
 
+-- spoly is convex
+SELECT spoly_is_convex(spoly'{(53d 45m 35.0s, 37d 6m 30.0s), (52d 21m 36.0s, 41d 36m 7.0s), (54d 14m 18.0s, 45d 1m 35.0s), (51d 23m 3.0s, 45d 22m 49.0s), (51d 2m 12.0s, 41d 52m 1.0s), (50d 41m 47.0s, 38d 22m 0s) }');
+ spoly_is_convex 
+-----------------
+ f
+(1 row)
+
+SELECT spoly_is_convex(spoly'{(12d,32d),(34d,12d),(59d,21d),(69d,21d)}');
+ spoly_is_convex 
+-----------------
+ f
+(1 row)
+
+SELECT spoly_is_convex(spoly'{(12d,32d),(34d,12d),(59d,21d),(34d,40d)}');
+ spoly_is_convex 
+-----------------
+ t
+(1 row)
+

Diff for: pgs_polygon.sql.in

@@ -955,3 +955,17 @@ CREATE AGGREGATE spoly (
     stype     = spoly,
     finalfunc = spoly_add_points_fin_aggr
 );
+
+
+--
+-- polygon is convex
+--
+
+CREATE FUNCTION spoly_is_convex(spoly)
+   RETURNS BOOL
+   AS 'MODULE_PATHNAME', 'spherepoly_is_convex'
+   LANGUAGE 'c'
+   IMMUTABLE STRICT PARALLEL SAFE;
+
+COMMENT ON FUNCTION spoly_is_convex(spoly) IS
+  'true if spherical polygon is convex';

Diff for: sql/poly.sql

@@ -603,3 +603,8 @@ SELECT npoints( spoly '{
   (1.5121581120647 , -1.93925472462553e-05),
   (1.51214841579108 , -1.93925472462553e-05)
 }');
+
+-- spoly is convex
+SELECT spoly_is_convex(spoly'{(53d 45m 35.0s, 37d 6m 30.0s), (52d 21m 36.0s, 41d 36m 7.0s), (54d 14m 18.0s, 45d 1m 35.0s), (51d 23m 3.0s, 45d 22m 49.0s), (51d 2m 12.0s, 41d 52m 1.0s), (50d 41m 47.0s, 38d 22m 0s) }');
+SELECT spoly_is_convex(spoly'{(12d,32d),(34d,12d),(59d,21d),(69d,21d)}');
+SELECT spoly_is_convex(spoly'{(12d,32d),(34d,12d),(59d,21d),(34d,40d)}');

Diff for: src/polygon.c

@@ -57,6 +57,7 @@ PG_FUNCTION_INFO_V1(spheretrans_poly);
 PG_FUNCTION_INFO_V1(spheretrans_poly_inverse);
 PG_FUNCTION_INFO_V1(spherepoly_add_point);
 PG_FUNCTION_INFO_V1(spherepoly_add_points_finalize);
+PG_FUNCTION_INFO_V1(spherepoly_is_convex);
 
 
  /*
@@ -1478,3 +1479,53 @@ spherepoly_add_points_finalize(PG_FUNCTION_ARGS)
 	}
 	PG_RETURN_POINTER(poly);
 }
+
+
+Datum
+spherepoly_is_convex(PG_FUNCTION_ARGS)
+{
+	Vector3D	u,
+				v,
+				vsu,
+				wsv,
+				crs;
+	float8		cur = 0,
+				prev = 0;
+	SPOLY		*poly = (SPOLY *) PG_GETARG_POINTER(0);
+
+	if (poly == NULL)
+	{
+		PG_RETURN_BOOL(false);
+	}
+
+	poly = PG_GETARG_SPOLY(0);
+	if (poly->npts == 3)
+	{
+		PG_RETURN_BOOL(true);
+	}
+
+	for (int i = 0; i < poly->npts; i++)
+	{
+		const int j = (i - 1 + poly->npts) % poly->npts;
+		const int k = (i + 1) % poly->npts;
+
+		spoint_vector3d(&u, &poly->p[i]);
+		spoint_vector3d(&v, &poly->p[j]);
+		spoint_vector3d(&vsu, &poly->p[j]);
+		spoint_vector3d(&wsv, &poly->p[k]);
+
+		vector3d_addwithscalar(&vsu, -1, &u);
+		vector3d_addwithscalar(&wsv, -1, &v);
+
+		vector3d_cross(&crs, &vsu, &wsv);
+
+		cur = vector3d_scalar(&crs, &v);
+		if (cur * prev < 0)
+		{
+			PG_RETURN_BOOL(false);
+		}
+		prev = cur;
+	}
+
+	PG_RETURN_BOOL(true);
+}

Diff for: src/polygon.h

@@ -348,4 +348,9 @@ Datum	spherepoly_add_point(PG_FUNCTION_ARGS);
  */
 Datum	spherepoly_add_points_finalize(PG_FUNCTION_ARGS);
 
+/*
+ * Checks whether a polygon is convex
+ */
+Datum spherepoly_is_convex(PG_FUNCTION_ARGS);
+
 #endif