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flightgear/tests/test-up.cxx

49 lines
1.4 KiB
C++

// 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;
}