X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=src%2Fgrits-util.c;h=ab795f9b15ae41c7e1c86884e2655ca8383371c1;hb=5c17e7d79895982036139dcffb5c17cefb1d4d9f;hp=a792014b97335570d61f89d8325d049443352a9f;hpb=f383c18c9f85a1b439c6bfb2a27d652278ed019a;p=grits

diff --git a/src/grits-util.c b/src/grits-util.c
index a792014..ab795f9 100644
--- a/src/grits-util.c
+++ b/src/grits-util.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009-2010 Andy Spencer <andy753421@gmail.com>
+ * Copyright (C) 2009-2011 Andy Spencer <andy753421@gmail.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -70,12 +70,13 @@
 
 #include <glib.h>
 #include <math.h>
+#include <stdio.h>
 
 #include "grits-util.h"
 
-/************
+/**************
  * GritsPoint *
- ************/
+ **************/
 /**
  * grits_point_set_lle:
  * @point: the point to modify
@@ -235,3 +236,153 @@ gdouble lon_avg(gdouble a, gdouble b)
 	}
 	return avg;
 }
+
+/**
+ * crossd3:
+ * @a:   the left   point
+ * @b:   the center point
+ * @c:   the right  point
+ * @out: the cross product
+ *
+ * Calculate the cross product of three points
+ */
+void crossd3(gdouble *a, gdouble *b, gdouble *c, gdouble *out)
+{
+	double ba[3], bc[3];
+
+	ba[0] = a[0] - b[0];
+	ba[1] = a[1] - b[1];
+	ba[2] = a[2] - b[2];
+
+	bc[0] = c[0] - b[0];
+	bc[1] = c[1] - b[1];
+	bc[2] = c[2] - b[2];
+
+	crossd(ba, bc, out);
+}
+
+/**
+ * crossd:
+ * @a: the first vector
+ * @b: the second vector
+ * @c: the cross product
+ *
+ * Calculate the cross product of two vectors
+ */
+void crossd(gdouble *a, gdouble *b, gdouble *out)
+{
+	out[0] = a[1] * b[2] - a[2] * b[1];
+	out[1] = a[2] * b[0] - a[0] * b[2];
+	out[2] = a[0] * b[1] - a[1] * b[0];
+}
+
+/**
+ * lengthd:
+ * @a: the vector
+ *
+ * Calculate the length (magnitude) of a vector.
+ *
+ * Returns: the length
+ */
+gdouble lengthd(gdouble *a)
+{
+	return sqrt(a[0] * a[0] +
+	            a[1] * a[1] +
+	            a[2] * a[2]);
+}
+
+/**
+ * normd:
+ * @a: the first longitude
+ *
+ * Normalize a vector to a mangitude of 1
+ */
+void normd(gdouble *a)
+{
+	gdouble total = lengthd(a);
+	a[0] = a[0] / total;
+	a[1] = a[1] / total;
+	a[2] = a[2] / total;
+}
+
+/**
+ * parse_points:
+ * @string:    String representation of the points
+ * @group_sep: Group separator
+ * @point_sep: Point separator
+ * @coord_sep: Coordinate separator
+ * @bounds:    The bounding box of all the points, or NULL
+ * @center:    The center of the @bounds, or NULL
+ *
+ * Parse a string of the form:
+ *   string -> group [@group_sep group] ...
+ *   group  -> point [@point_sep point] ...
+ *   point  -> latitude @coord_sep longitude [@coord_sep elevation]
+ *
+ * For example
+ *   parse_points("30,-80 30,-120 50,-120 50,-80", "\t", " ", ",");
+ *
+ * Returns: zero-terminated array of groups of points
+ */
+GritsPoints *parse_points(const gchar *string,
+		const gchar *group_sep, const gchar *point_sep, const gchar *coord_sep,
+		GritsBounds *bounds, GritsPoint *center)
+{
+	/* Split and count groups */
+	gchar **sgroups = g_strsplit(string, group_sep, -1);
+	int     ngroups = g_strv_length(sgroups);
+
+	GritsBounds _bounds = {-90, 90, -180, 180};
+	gdouble (**groups)[3] = (gpointer)g_new0(double*, ngroups+1);
+	for (int pi = 0; pi < ngroups; pi++) {
+		/* Split and count coordinates */
+		gchar **scoords = g_strsplit(sgroups[pi], point_sep, -1);
+		int     ncoords = g_strv_length(scoords);
+
+		/* Create binary coords */
+		gdouble (*coords)[3] = (gpointer)g_new0(gdouble, 3*(ncoords+1));
+		for (int ci = 0; ci < ncoords; ci++) {
+			gdouble lat, lon;
+			sscanf(scoords[ci], "%lf,%lf", &lat, &lon);
+			if (bounds || center) {
+				if (lat > _bounds.n) _bounds.n = lat;
+				if (lat < _bounds.s) _bounds.s = lat;
+				if (lon > _bounds.e) _bounds.e = lon;
+				if (lon < _bounds.w) _bounds.w = lon;
+			}
+			lle2xyz(lat, lon, 0,
+					&coords[ci][0],
+					&coords[ci][1],
+					&coords[ci][2]);
+		}
+
+		/* Insert coords into line array */
+		groups[pi] = coords;
+		g_strfreev(scoords);
+	}
+	g_strfreev(sgroups);
+
+	/* Output */
+	if (bounds)
+		*bounds = _bounds;
+	if (center) {
+		center->lat  = (_bounds.n + _bounds.s)/2;
+		center->lon  = lon_avg(_bounds.e, _bounds.w);
+		center->elev = 0;
+	}
+	return groups;
+}
+
+/**
+ * free_points:
+ * @points: Array of points allocated by parse_points()
+ *
+ * Frees all data allocated by parse_points
+ */
+void free_points(GritsPoints *points)
+{
+	gdouble (**_points)[3] = points;
+	for (int i = 0; _points[i]; i++)
+		g_free(_points[i]);
+	g_free(_points);
+}