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Changed RA/Dec display to show geocentric coordinates for stars 

and galaxies only. Show coordinates only when observer is within 1000km
of Earth to assure that coordinates of an object match it's apparent position
with respect to the equatorial grid.
ver1_5_1
Chris Laurel 2008-01-22 03:44:57 +00:00
parent df91a26387
commit 8a661c37a7
1 changed files with 137 additions and 56 deletions
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193
src/celestia/celestiacore.cpp
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@ -6,7 +6,7 @@
// keyboard events. CelestiaCore then turns those events into calls
// to Renderer and Simulation.
//
// Copyright (C) 2001, Chris Laurel <claurel@shatters.net>
// Copyright (C) 2001-2008, Chris Laurel <claurel@shatters.net>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
@ -2929,12 +2929,94 @@ static void displayRADec(Overlay& overlay, Vec3d v)
overlay << _("RA: ");
overlay << " ";
displayAngleInHourMinSec(overlay, ra);
overlay << "\n";
overlay << endl;
overlay << _("Dec: ");
displayAngle(overlay, dec);
overlay << endl;
}
// Display nicely formatted planetocentric/planetographic coordinates.
// The latitude and longitude parameters are angles in radians, altitude
// is in kilometers.
static void displayPlanetocentricCoords(Overlay& overlay,
const Body& body,
double longitude,
double latitude,
double altitude,
bool showAltitude)
{
char ewHemi = ' ';
char nsHemi = ' ';
double lon = 0.0;
double lat = 0.0;
// Terrible hack for Earth and Moon longitude conventions. Fix by
// adding a field to specify the longitude convention in .ssc files.
if (body.getName() == "Earth" || body.getName() == "Moon")
{
if (latitude < 0.0)
nsHemi = 'S';
else if (latitude > 0.0)
nsHemi = 'N';
if (longitude < 0.0)
ewHemi = 'W';
else if (longitude > 0.0f)
ewHemi = 'E';
lon = (float) abs(radToDeg(longitude));
lat = (float) abs(radToDeg(latitude));
}
else
{
// Swap hemispheres if the object is a retrograde rotator
Quatd q = ~body.getEclipticalToEquatorial(astro::J2000);
bool retrograde = (Vec3d(0.0, 1.0, 0.0) * q.toMatrix3()).y < 0.0;
if ((latitude < 0.0) ^ retrograde)
nsHemi = 'S';
else if ((latitude > 0.0) ^ retrograde)
nsHemi = 'N';
if (retrograde)
ewHemi = 'E';
else
ewHemi = 'W';
lon = -radToDeg(longitude);
if (lon < 0.0)
lon += 360.0;
lat = abs(radToDeg(latitude));
}
overlay.unsetf(ios::fixed);
overlay << setprecision(6);
overlay << lat << nsHemi << ' ' << lon << ewHemi;
if (showAltitude)
overlay << ' ' << altitude << _("km") << endl;
overlay << endl;
}
#if 0
// Show the planetocentric latitude, longitude, and altitude of a
// observer.
static void displayObserverPlanetocentricCoords(Overlay& overlay,
Body& body,
const UniversalCoord& observerPos,
double tdb)
{
// Get the observer position in body-centered ecliptical coordinates
Vec3d ecl = observerPos - Selection(&body).getPosition(tdb);
ecl *= astro::microLightYearsToKilometers(1.0);
Vec3d pc = body.eclipticToPlanetocentric(ecl, tdb);
displayPlanetocentricCoords(overlay, body, pc.x, pc.y, pc.z, true);
}
#endif
static void displayAcronym(Overlay& overlay, char* s)
{
if (strchr(s, ' ') != NULL)
@ -3131,54 +3213,8 @@ static void displayLocationInfo(Overlay& overlay,
{
Vec3f locPos = location.getPosition();
Vec3d lonLatAlt = body->cartesianToPlanetocentric(Vec3d(locPos.x, locPos.y, locPos.z));
char ewHemi = ' ';
char nsHemi = ' ';
float lon = 0.0f;
float lat = 0.0f;
// Terrible hack for Earth and Moon longitude conventions. Fix by
// adding a field to specify the longitude convention in .ssc files.
if (body->getName() == "Earth" || body->getName() == "Moon")
{
if (lonLatAlt.y < 0.0f)
nsHemi = 'S';
else if (lonLatAlt.y > 0.0f)
nsHemi = 'N';
if (lonLatAlt.x < 0.0f)
ewHemi = 'W';
else if (lonLatAlt.x > 0.0f)
ewHemi = 'E';
lon = (float) abs(radToDeg(lonLatAlt.x));
lat = (float) abs(radToDeg(lonLatAlt.y));
}
else
{
// Swap hemispheres if the object is a retrograde rotator
Quatd q = ~body->getEclipticalToEquatorial(astro::J2000);
bool retrograde = (Vec3d(0.0, 1.0, 0.0) * q.toMatrix3()).y < 0.0;
if ((lonLatAlt.y < 0.0f) ^ retrograde)
nsHemi = 'S';
else if ((lonLatAlt.y > 0.0f) ^ retrograde)
nsHemi = 'N';
if (retrograde)
ewHemi = 'E';
else
ewHemi = 'W';
lon = (float) -radToDeg(lonLatAlt.x);
if (lon < 0.0f)
lon += 360.0f;
lat = (float) abs(radToDeg(lonLatAlt.y));
}
overlay << body->getName(true).c_str() << " ";
overlay.unsetf(ios::fixed);
overlay << setprecision(6);
overlay << lat << nsHemi << ' ' << lon << ewHemi << '\n';
displayPlanetocentricCoords(overlay, *body,
lonLatAlt.x, lonLatAlt.y, lonLatAlt.z, false);
}
}
@ -3306,9 +3342,9 @@ void CelestiaCore::renderOverlay()
// Time and date
glPushMatrix();
glColor4f(0.7f, 0.7f, 1.0f, 1.0f);
glTranslatef( width - dateStrWidth,
(float) (height - fontHeight),
0.0f);
glTranslatef( (float) (width - dateStrWidth),
(float) (height - fontHeight),
0.0f);
overlay->beginText();
overlay->print(dateStr);
@ -3543,9 +3579,54 @@ void CelestiaCore::renderOverlay()
break;
}
Vec3d vect = sel.getPosition(sim->getTime()) - sim->getObserver().getPosition();
vect = vect * Mat3d::xrotation(-astro::J2000Obliquity);
displayRADec(*overlay, vect);
// Display RA/Dec for the selection, but only when the observer is near
// the Earth.
Selection refObject = sim->getFrame().refObject;
if (refObject.body() && refObject.body()->getName() == "Earth")
{
Body* earth = refObject.body();
UniversalCoord observerPos = sim->getObserver().getPosition();
double distToEarth = (observerPos - refObject.getPosition(sim->getTime())).length();
distToEarth = astro::microLightYearsToKilometers(distToEarth) - earth->getRadius();
if (distToEarth < 1000.0)
{
#if 1
// Code to show the geocentric RA/Dec
// Only show the coordinates for stars and deep sky objects, where
// the geocentric values will match the apparent values for observers
// near the Earth.
if (sel.star() != NULL || sel.deepsky() != NULL)
{
Vec3d v = sel.getPosition(sim->getTime()) - Selection(earth).getPosition(sim->getTime());
v = v * Mat3d::xrotation(-astro::J2000Obliquity);
displayRADec(*overlay, v);
}
#else
// Code to display the apparent RA/Dec for the observer
// Don't show RA/Dec for the Earth itself
if (sel.body() != earth)
{
Vec3d vect = sel.getPosition(sim->getTime()) - observerPos;
vect = vect * Mat3d::xrotation(-astro::J2000Obliquity);
displayRADec(*overlay, vect);
}
// Show the geocentric coordinates of the observer, required for
// converting the selection RA/Dec from observer-centric to some
// other coordinate system.
// TODO: We should really show the planetographic (for Earth, geodetic)
// coordinates.
displayObserverPlanetocentricCoords(*overlay,
*earth,
observerPos,
sim->getTime());
#endif
}
}
overlay->endText();