private PixelInformation getIlluminationDirectionPerRenderingPixel(SpacecraftState sc, uint x, uint y)
{
PixelInformation PixelOut = new PixelInformation();
Vector3D c_pos = sc.getPosition();
// STEP 1: Visibility Test
Vector3D rayDirection = (sc.getPOVDirection() + (((1 + Convert.ToDouble(this._height) - (2 * Convert.ToDouble(y))) / (2 * Convert.ToDouble(this._height))) * sc.getPOVUp()) - (((1 + Convert.ToDouble(this._width) - (2 * Convert.ToDouble(x))) / (2 * Convert.ToDouble(this._width))) * sc.getPOVRight())).unit();
double discriminant = 4 * Math.Pow(c_pos * rayDirection, 2) - 4 * (rayDirection * rayDirection) * (c_pos * c_pos) + 4 * (rayDirection * rayDirection) * Math.Pow(_moon_radius, 2);
bool encounter = false;
Vector3D p_surf = new Vector3D();
if (discriminant < 0)
{
// no encounter
}
else if (discriminant == 0)
{
// one intersection
encounter = true;
double t = (-2 * (c_pos * rayDirection)) / (2 * (rayDirection * rayDirection));
p_surf = c_pos + rayDirection * t;
}
else
{
// two intersections
encounter = true;
double t1 = (-2 * (c_pos * rayDirection) + Math.Sqrt(discriminant)) / (2 * (rayDirection * rayDirection));
double t2 = (-2 * (c_pos * rayDirection) - Math.Sqrt(discriminant)) / (2 * (rayDirection * rayDirection));
Vector3D ray_point1 = c_pos + rayDirection * t1;
Vector3D ray_point2 = c_pos + rayDirection * t2;
double ray_norm1 = (ray_point1 - c_pos).norm();
double ray_norm2 = (ray_point2 - c_pos).norm();
if (ray_norm1 < ray_norm2)
{
p_surf = ray_point1;
}
else
{
p_surf = ray_point2;
}
}
if (encounter)
{
/*
Pixel shows the Moon's surface: Continue with executing steps 2 - 8.
*/
double x1 = Convert.ToDouble(x);
double y1 = Convert.ToDouble(y);
// STEP 2: Obtaining the Surface Hit Point
PixelOut.lat = tools.rad2deg((Math.PI / 2) - Math.Acos(p_surf.z() / _moon_radius));
PixelOut.lon = tools.rad2deg(Math.Atan2(p_surf.y(), p_surf.x()));
// STEP 3: Calculation of the Sun's direction
Vector3D hat_p_surf = p_surf.unit();
Vector3D hat_d_sun = (sc.getSunPosition() - p_surf).unit();
// STEP 4: Derivation of the Local Tangent Plane of the Surface Hit Point (nothing to do here)
// STEP 5: Determination of a Subsurface Point of the Solar Illumination Direction on the Local Tangent Plane
double lambda_5 = -(1000 * (hat_d_sun.x() * hat_p_surf.x() + hat_d_sun.y() * hat_p_surf.y() + hat_d_sun.z() * hat_p_surf.z())) / (hat_p_surf.x() * hat_p_surf.x() + hat_p_surf.y() * hat_p_surf.y() + hat_p_surf.z() * hat_p_surf.z());
Vector3D p_local = p_surf + 1000 * hat_d_sun + lambda_5 * hat_p_surf;
// STEP 6: Local Illumination Direction
Vector3D hat_d_local = (p_local - c_pos).unit();
/// STEP 7: Projection of the Local Illumination Point to the Image Plane
Vector3D k = c_pos + sc.getPOVDirection();
Vector3D c_up = sc.getPOVUp();
Vector3D c_right = sc.getPOVRight();
double w = Convert.ToDouble(this._width);
double h = Convert.ToDouble(this._height);
double x2 =
(
-2 * w * c_pos.y() * c_up.z() * hat_d_local.x() - c_right.y() * c_up.z() * hat_d_local.x() - w * c_right.y() * c_up.z() * hat_d_local.x()
+ 2 * w * c_pos.x() * c_up.z() * hat_d_local.y() + c_right.x() * c_up.z() * hat_d_local.y() + w * c_right.x() * c_up.z() * hat_d_local.y()
+ 2 * w * c_pos.z() * (c_up.y() * hat_d_local.x() - c_up.x() * hat_d_local.y())
+ (1 + w) * c_right.z() * (c_up.y() * hat_d_local.x() - c_up.x() * hat_d_local.y())
+ 2 * w * c_pos.y() * c_up.x() * hat_d_local.z() + c_right.y() * c_up.x() * hat_d_local.z() + w * c_right.y() * c_up.x() * hat_d_local.z()
- 2 * w * c_pos.x() * c_up.y() * hat_d_local.z() - c_right.x() * c_up.y() * hat_d_local.z() - w * c_right.x() * c_up.y() * hat_d_local.z()
- 2 * w * c_up.z() * hat_d_local.y() * k.x() + 2 * w * c_up.y() * hat_d_local.z() * k.x() + 2 * w * c_up.z() * hat_d_local.x() * k.y() - 2 * w * c_up.x() * hat_d_local.z() * k.y()
- 2 * w * c_up.y() * hat_d_local.x() * k.z() + 2 * w * c_up.x() * hat_d_local.y() * k.z()
)/(
2 * (c_right.z() * (c_up.y() * hat_d_local.x() - c_up.x() * hat_d_local.y()) + c_right.y() * (-c_up.z() * hat_d_local.x() + c_up.x() * hat_d_local.z()) + c_right.x() * (c_up.z() * hat_d_local.y() - c_up.y() * hat_d_local.z()))
);
double y2 =
(
-c_right.z() * c_up.y() * hat_d_local.x() - h * c_right.z() * c_up.y() * hat_d_local.x() + c_right.y() * c_up.z() * hat_d_local.x()
+ h * c_right.y() * c_up.z() * hat_d_local.x() - 2 * h * c_pos.x() * c_right.z() * hat_d_local.y() + c_right.z() * c_up.x() * hat_d_local.y()
+ h * c_right.z() * c_up.x() * hat_d_local.y() - c_right.x() * c_up.z() * hat_d_local.y() - h * c_right.x() * c_up.z() * hat_d_local.y()
+ c_pos.z() * (-2 * h * c_right.y() * hat_d_local.x() + 2 * h * c_right.x() * hat_d_local.y()) + 2 * h * c_pos.x() * c_right.y() * hat_d_local.z()
- c_right.y() * c_up.x() * hat_d_local.z() - h * c_right.y() * c_up.x() * hat_d_local.z() + c_right.x() * c_up.y() * hat_d_local.z()
+ h * c_right.x() * c_up.y() * hat_d_local.z() + 2 * h * c_pos.y() * (c_right.z() * hat_d_local.x() - c_right.x() * hat_d_local.z())
+ 2 * h * c_right.z() * hat_d_local.y() * k.x() - 2 * h * c_right.y() * hat_d_local.z() * k.x() - 2 * h * c_right.z() * hat_d_local.x() * k.y()
+ 2 * h * c_right.x() * hat_d_local.z() * k.y() + 2 * h * c_right.y() * hat_d_local.x() * k.z() - 2 * h * c_right.x() * hat_d_local.y() * k.z()
)/(
2 * (c_right.z() * (-c_up.y() * hat_d_local.x() + c_up.x() * hat_d_local.y()) + c_right.y() * (c_up.z() * hat_d_local.x() - c_up.x() * hat_d_local.z()) + c_right.x() * (-c_up.z() * hat_d_local.y() + c_up.y() * hat_d_local.z()))
);
// STEP 8: The Local Solar Illumination Angle
Vector2D v1 = new Vector2D(0, 1000);
Vector2D v2 = new Vector2D(x2-x1, y2-y1);
if (v2.x() > 0)
{
PixelOut.IlluminationAngle = tools.rad2deg(Math.Acos((v1 * v2) / (v1.norm() * v2.norm())));
}
else
{
PixelOut.IlluminationAngle = tools.rad2deg(2 * Math.PI - Math.Acos((v1 * v2) / (v1.norm() * v2.norm())));
}
PixelOut.exists = true;
return PixelOut;
}
else
{
// next grid sample point
return PixelOut;
}
}
public void doCalculationsLogic(Spacecraft sc, double time)
{
int step = sc.addSpacecraftState(time);
SpacecraftState scState = sc.getSpacecraftState(step);
double simTime = sc.getSpacecraftState(step).getTime();
Vector3D position = sc.getSpacecraftState(step).getPosition();
Vector3D sun_position = sc.getSpacecraftState(step).getSunPosition();
Quaternion orientation = sc.getSpacecraftState(step).getOrientation();
Console.WriteLine(" Simulation time point #" + this.loopCount.ToString("D5") + ": " + simTime + " MJD (" + tools.MJDtoUTC(simTime).ToString("s") + " UTC)");
Console.WriteLine(" --------------------------------------------------------------------------------------------------------------");
Console.WriteLine();
Console.WriteLine(" Calculating spacecraft position at given simulation time...");
Console.WriteLine(" Result:");
Console.WriteLine(" x = " + position.x().ToString(Program.scientificFormat) + " m (" + tools.m2AU(position.x()).ToString(Program.scientificFormat) + " AU)");
Console.WriteLine(" y = " + position.y().ToString(Program.scientificFormat) + " m (" + tools.m2AU(position.y()).ToString(Program.scientificFormat) + " AU)");
Console.WriteLine(" z = " + position.z().ToString(Program.scientificFormat) + " m (" + tools.m2AU(position.z()).ToString(Program.scientificFormat) + " AU)");
Console.WriteLine();
if (sc.isOrientationGiven())
{
Console.WriteLine(" Calculating spacecraft orientation at given simulation time...");
Console.WriteLine(" Result (Quaternion):");
Console.WriteLine(" q_0 = " + orientation.r().ToString(Program.scientificFormat));
Console.WriteLine(" q_1 = " + orientation.v().x().ToString(Program.scientificFormat));
Console.WriteLine(" q_2 = " + orientation.v().y().ToString(Program.scientificFormat));
Console.WriteLine(" q_3 = " + orientation.v().z().ToString(Program.scientificFormat));
Console.WriteLine();
}
Console.WriteLine(" Calculating Sun position at given simulation time...");
Console.WriteLine(" Result:");
Console.WriteLine(" x = " + sun_position.x().ToString(Program.scientificFormat) + " m (" + tools.m2AU(sun_position.x()).ToString(Program.scientificFormat) + " AU)");
Console.WriteLine(" y = " + sun_position.y().ToString(Program.scientificFormat) + " m (" + tools.m2AU(sun_position.y()).ToString(Program.scientificFormat) + " AU)");
Console.WriteLine(" z = " + sun_position.z().ToString(Program.scientificFormat) + " m (" + tools.m2AU(sun_position.z()).ToString(Program.scientificFormat) + " AU)");
Console.WriteLine();
string filename = this.getOutputPath() + "MoonSurfIllumSim_step_" + this.loopCount.ToString("D5");
Console.WriteLine(" Ray tracing scene (Dynamical Surface Pattern Selection Algorithm - DSPSA)...");
this.generatePOVRayFile(sc.getSpacecraftState(step), filename);
Console.WriteLine(" POV-Ray file written to \"" + filename + ".pov\"");
Console.WriteLine(" Rendering using POV-Ray...");
Process pov = new Process();
pov.StartInfo.FileName = this._pov_path + "pvengine64.exe";
pov.StartInfo.Arguments = "/EXIT Quality=11 Antialias_Depth=3 Antialias=On Antialias_Threshold=0.1 Jitter_Amount=0.5 Jitter=On Width=" + this._width + " Height=" + this._height + " Antialias=On Antialias_Threshold=0.3 /RENDER \"" + filename + ".pov\"";
pov.Start();
pov.WaitForExit();
if (Program.writeAnnotation)
{
Console.WriteLine(" Regenerating rendering with annotations...");
FileStream myStream = new FileStream(filename + ".png", FileMode.Open);
Image myBitmap = Image.FromStream(myStream);
myStream.Close();
myStream.Dispose();
Graphics g = Graphics.FromImage(myBitmap);
//g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
float fontSize = (float)Convert.ToDouble(this._width) * 0.0095F;
Font myFont = new Font("Consolas", fontSize);
Quaternion rotQuat;
if (sc.isOrientationGiven())
{
rotQuat = scState.getOrientation();
}
else
{
double phi = Math.Atan2(scState.getPosition().y(), scState.getPosition().x());
double theta = Math.Acos(scState.getPosition().z() / (scState.getPosition().norm()));
rotQuat = new RotationQuaternion(new Vector3D(0, 1, 0), theta) * new RotationQuaternion(new Vector3D(0, 0, 1), -phi);
}
// Local Solar Illumination Angle
Pen pen = new Pen(Color.Red, 2);
pen.StartCap = LineCap.SquareAnchor;
pen.EndCap = LineCap.Round;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
SolidBrush redBrush = new SolidBrush(Color.Red);
foreach (var pixel in scState.PixelInfo)
{
double x1 = pixel.Key.x();
double y1 = pixel.Key.y();
Vector2D endPoint = new Vector2D(x1, y1) + new Vector2D(0, this.gridH/2).rotate(tools.deg2rad(pixel.Value.IlluminationAngle));
g.DrawLine(pen, new Point(Convert.ToInt32(x1), Convert.ToInt32(y1)), new Point(Convert.ToInt32(endPoint.x()), Convert.ToInt32(endPoint.y())));
g.FillEllipse(redBrush, (float)x1 - 3F, (float)y1 - 3F, 6, 6);
}
// Annotations to be written
g.DrawString("Simulation Timecode: " + scState.getTime().ToString(Program.scientificFormat) + " MJD (" + tools.MJDtoUTC(simTime).ToString("s") + "Z UTC)", myFont, Brushes.White, new PointF(2 * fontSize, 1 * 1.8F * fontSize));
g.DrawString("S/C Position: [" + scState.getPosition().x().ToString(Program.scientificFormat) + "," + scState.getPosition().y().ToString(Program.scientificFormat) + "," + scState.getPosition().z().ToString(Program.scientificFormat) + "] m", myFont, Brushes.White, new PointF(2 * fontSize, 2 * 1.8F * fontSize));
g.DrawString("S/C Orientation Quaternion: [" + rotQuat.v().x().ToString(Program.scientificFormat) + "," + rotQuat.v().y().ToString(Program.scientificFormat) + "," + rotQuat.v().z().ToString(Program.scientificFormat) + "," + rotQuat.r().ToString(Program.scientificFormat) + "]", myFont, Brushes.White, new PointF(2 * fontSize, 3 * 1.8F * fontSize));
g.DrawString("Sun Position: [" + scState.getSunPosition().x().ToString(Program.scientificFormat) + "," + scState.getSunPosition().y().ToString(Program.scientificFormat) + "," + scState.getSunPosition().z().ToString(Program.scientificFormat) + "] m", myFont, Brushes.White, new PointF(2 * fontSize, 4 * 1.8F * fontSize));
g.DrawString("Flight Altitude over MMR: " + (scState.getPosition().norm() - 1.73715E6).ToString(Program.scientificFormat) + " m", myFont, Brushes.White, new PointF(2 * fontSize, 5 * 1.8F * fontSize));
g.DrawString("Surface Mesh Resolution: " + this._res.ToString() + " px/deg", myFont, Brushes.White, new PointF(2 * fontSize, 6 * 1.8F * fontSize));
g.DrawString("FOV: " + this._FOV.ToString() + " deg (hor. & vert.), optics: perspective camera", myFont, Brushes.White, new PointF(2 * fontSize, 7 * 1.8F * fontSize));
g.DrawString("Moon Surface Illumination Simulation Framework (MSISF), v" + Program.VERSION, new Font("Tahoma", fontSize), Brushes.White, new PointF(2 * fontSize, (float)Convert.ToDouble(this._height) - 3 * 1.8F * fontSize));
g.DrawString("B.Eng. René Schwarz (rene-schwarz.com), more Information: http://go.rene-schwarz.com/masters-thesis", new Font("Tahoma", fontSize), Brushes.White, new PointF(2 * fontSize, (float)Convert.ToDouble(this._height) - 2 * 1.8F * fontSize));
myBitmap.Save(filename + ".annotated.png");
myBitmap.Dispose();
}
Console.WriteLine();
Console.WriteLine();
this.loopCount++;
}