// Return all times from start to stop. Also return the indexes of the times at which the earth elevation reaches a minima
void GetLowEarthTimes(DateTime outer_start, DateTime outer_stop, out List <DateTime> all_times, out List <int> indices_of_minima_earth_elevation)
{
var center = new Point(Region.Left + Region.Width / 2, Region.Top + Region.Height / 2);
var centerPatch = ViperEnvironment.GetPatch(TerrainPatch.LineSampleToId(center));
centerPatch.FillMatrices(ViperEnvironment.Terrain);
// Generate the time / elevation pairs
all_times = new List <DateTime>();
for (var time = outer_start; time <= outer_stop; time += Step)
{
all_times.Add(time);
}
var earth_elevations = all_times.Select(t =>
{
centerPatch.GetAzEl(CSpice.EarthPosition(t), 0, 0, out float _, out float earth_elevation_rad);
return(earth_elevation_rad);
}).ToList();
// Find minima
indices_of_minima_earth_elevation = new List <int>();
for (var i = 1; i < earth_elevations.Count - 1; i++)
{
if (Start <= all_times[i] && all_times[i] <= Stop && earth_elevations[i - 1] > earth_elevations[i] && earth_elevations[i] < earth_elevations[i + 1])
{
indices_of_minima_earth_elevation.Add(i);
}
}
}
/// <summary>
/// Map over the fraction of the sun's disk visible times Cos(theta) - theta is the angle between the sun and normal
/// </summary>
/// <param name="line"></param>
/// <param name="sample"></param>
/// <param name="start"></param>
/// <param name="stop"></param>
/// <param name="step"></param>
/// <param name="action"></param>
/// <returns></returns>
public bool MapOverSunContribution(int line, int sample, DateTime start, DateTime stop, TimeSpan step, Action <DateTime, float> action)
{
var id = TerrainPatch.LineSampleToId(line, sample);
var patch = GetPatch(id);
if (patch == null)
{
return(false);
}
var cross = GetSurfaceNormal(line, sample);
var y_offset = line - patch.Line;
var x_offset = sample - patch.Sample;
var mat = patch.Matrices[y_offset][x_offset];
var horizon = patch.Horizons[y_offset][x_offset];
if (!horizon.IsDegrees)
{
lock (horizon)
horizon.ConvertSlopeToDegrees();
}
var cache = SunVectorCache.GetSingleton();
var temp = new Vector3d();
for (var time = start; time <= stop; time += step)
{
var sunvec = cache.SunPosition(time);
TerrainPatch.Transform(ref sunvec, ref mat, ref temp);
var sun_x = temp[0];
var sun_y = temp[1];
var sun_z = temp[2];
var azimuth_rad = Math.Atan2(sun_y, sun_x) + Math.PI; // [0,2PI]
var azimuth_deg = (float)(azimuth_rad * 180d / Math.PI);
var alen = Math.Sqrt(sun_x * sun_x + sun_y * sun_y);
var slope = sun_z / alen;
var elevation_deg = ((float)Math.Atan(slope)) * 180f / 3.141592653589f;
var sunfrac = horizon.SunFraction2(azimuth_deg, elevation_deg);
//if (line == 17522 && sample == 12388)
//{
// Console.WriteLine($"{line},{sample}, time={time} elevation_deg={elevation_deg} sun={sunfrac}");
//}
sunvec.NormalizeFast(); // Normalize before calculating surface temp
var dot = Vector3d.Dot(sunvec, cross);
var sun_contrib = dot < 0d ? 0d : sunfrac * dot;
//if (sun_contrib > 0)
// Console.WriteLine(sun_contrib);
action(time, (float)sun_contrib);
}
return(true);
}
public void MapOverLightCurve(int line, int sample, DateTime start, DateTime stop, TimeSpan step, Action <DateTime, float> action)
{
var id = TerrainPatch.LineSampleToId(line, sample);
var patch = GetPatch(id);
if (patch == null)
{
return;
}
var y_offset = line - patch.Line;
var x_offset = sample - patch.Sample;
var mat = patch.Matrices[y_offset][x_offset];
var horizon = patch.Horizons[y_offset][x_offset];
if (!horizon.IsDegrees)
{
lock (horizon)
horizon.ConvertSlopeToDegrees();
}
var cache = SunVectorCache.GetSingleton();
var temp = new Vector3d();
for (var time = start; time <= stop; time += step)
{
var sunvec = cache.SunPosition(time);
TerrainPatch.Transform(ref sunvec, ref mat, ref temp);
var sun_x = temp[0];
var sun_y = temp[1];
var sun_z = temp[2];
var azimuth_rad = Math.Atan2(sun_y, sun_x) + Math.PI; // [0,2PI]
var azimuth_deg = (float)(azimuth_rad * 180d / Math.PI);
var alen = Math.Sqrt(sun_x * sun_x + sun_y * sun_y);
var slope = sun_z / alen;
var elevation_deg = ((float)Math.Atan(slope)) * 180f / 3.141592653589f;
var sun = horizon.SunFraction2(azimuth_deg, elevation_deg);
//Console.WriteLine($"time={time} elevation_deg={elevation_deg} sun={sun}");
action(time, sun);
}
}
private void UpdateSunCache()
{
lock (_horizonCache)
{
var keys = _sunCache.Keys.ToList();
foreach (var probe in keys)
{
var pt = new Point((int)probe.Location.X, (int)probe.Location.Y);
var id = TerrainPatch.LineSampleToId(pt);
if (!LunarHorizon.Singleton.PatchCache.TryGetValue(id, out TerrainPatch patch))
{
continue;
}
var ptInPatch = patch.PointInPatch(pt);
_sunCache[probe] = GetSunCurve(patch, ptInPatch, LunarHorizon.Singleton.MapView.SunVector, probe.Color);
}
}
UpdatePlots();
}
// Cache by id
private bool HorizonsHaveBeenCalculated(ConsolidatedLine consolidated)
{
var pixel = consolidated.Pixel;
var id = TerrainPatch.LineSampleToId(pixel.Y, pixel.X);
lock (_precache)
{
if (_precache.TryGetValue(id, out bool hasHorizons))
{
return(hasHorizons);
}
var patch = TerrainPatch.FromId(id);
var horizons_path = patch.Path;
var result = File.Exists(horizons_path);
if (result)
{
_cache.Add(id, patch);
}
_precache.Add(id, result);
return(result);
}
}
private Point?GetRequestedId(LocationProbe probe)
{
var pt = GetRequest(probe);
return(pt.HasValue ? (Point?)TerrainPatch.LineSampleToId(pt.Value) : null);
}
