From d48a506721e6122df2506b7b703ec3e8ee345303 Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Wed, 31 Jan 2001 22:57:22 +0000
Subject: [PATCH] Added a test-up program to test the concept of "up".

---
 tests/Makefile.am |  5 ++++-
 tests/test-up.cxx | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 tests/test-up.cxx

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 8f773fc06..cbb62fa1c 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -1,4 +1,4 @@
-bin_PROGRAMS = est-epsilon gl-info test-mktime
+bin_PROGRAMS = est-epsilon gl-info test-mktime test-up
 
 est_epsilon_SOURCES = est-epsilon.c
 est_epsilon_LDADD = $(base_LIBS)
@@ -8,3 +8,6 @@ gl_info_LDADD = $(opengl_LIBS)
 
 test_mktime_SOURCES = test-mktime.cxx
 test_mktime_LDADD = $(base_LIBS)
+
+test_up_SOURCES = test-up.cxx
+test_up_LDADD = -lsgmath -lsgdebug -lplibsg $(base_LIBS)
diff --git a/tests/test-up.cxx b/tests/test-up.cxx
new file mode 100644
index 000000000..362384784
--- /dev/null
+++ b/tests/test-up.cxx
@@ -0,0 +1,49 @@
+// do some test relating to the concept of "up"
+
+#include <iostream>
+
+#include <plib/sg.h>
+
+#include <simgear/constants.h>
+#include <simgear/math/sg_geodesy.hxx>
+
+int main() {
+    // for each lat/lon given in goedetic coordinates, calculate
+    // geocentric coordinates, cartesian coordinates, the local "up"
+    // vector (based on original geodetic lat/lon), as well as the "Z"
+    // intercept (for which 0 = center of earth)
+
+
+    double lon = 0;
+    double alt = 0;
+
+    for ( double lat = 0; lat <= 90; lat += 5.0 ) {
+	cout << "lon = " << lon << "  geod lat = " << lat;
+
+	double sl_radius, lat_geoc;
+	sgGeodToGeoc( lat * DEG_TO_RAD, alt, &sl_radius, &lat_geoc );
+	cout << "  geoc lat = " << lat_geoc * RAD_TO_DEG << endl;
+
+	Point3D pgd( lon * DEG_TO_RAD, lat * DEG_TO_RAD, 0.0 );
+	Point3D pc = sgGeodToCart( pgd );
+	cout << "  cartesian = " << pc << endl;
+
+	sgMat4 UP;
+	sgVec3 geod_up;
+	sgMakeRotMat4( UP, lon, 0.0, -lat );
+	sgSetVec3( geod_up, UP[0][0], UP[0][1], UP[0][2] );
+	cout << "  geod up = " << geod_up[0] << ", " << geod_up[1] << ", "
+	     << geod_up[2] << endl;
+
+	double slope = geod_up[2] / geod_up[0];
+	double intercept = pc.z() - slope * pc.x();
+	cout << "  Z intercept (based on geodetic up) = " << intercept << endl;
+
+	slope = pc.z() / pc.x();
+	intercept = pc.z() - slope * pc.x();
+	cout << "  Z intercept (based on geocentric up) = " << intercept << endl;
+
+   }
+
+    return 0;
+}