/// <summary>
/// Converts a given point to RA-Dec coordinate space.
/// </summary>
/// <param name="point">
/// Point between 1 and 0 inclusive.
/// </param>
/// <returns>
/// Point in RA-Dec coordinates.
/// </returns>
public Vector2d PointToRaDec(Vector2d point)
{
int indexX = (int)(point.X / this.subDivSize);
int indexY = (int)(point.Y / this.subDivSize);
if (indexX > ((int)Math.Pow(2, this.subDivisions) - 1))
{
indexX = ((int)Math.Pow(2, this.subDivisions) - 1);
}
if (indexY > ((int)Math.Pow(2, this.subDivisions) - 1))
{
indexY = ((int)Math.Pow(2, this.subDivisions) - 1);
}
double distX = (point.X - ((double)indexX * this.subDivSize)) / this.subDivSize;
double distY = (point.Y - ((double)indexY * this.subDivSize)) / this.subDivSize;
Vector2d interpolatedTop = Vector2d.Lerp(this.mapRaDec[indexX, indexY], this.mapRaDec[indexX + 1, indexY], distX);
Vector2d interpolatedBottom = Vector2d.Lerp(this.mapRaDec[indexX, indexY + 1], this.mapRaDec[indexX + 1, indexY + 1], distX);
Vector2d result = Vector2d.Lerp(interpolatedTop, interpolatedBottom, distY);
return result;
}
/// <summary>
/// Maps image pixels to lat-long values.
/// </summary>
/// <param name="tileMap">Tile mapper.</param>
/// <param name="hasData">Boolean indicates whether the coordinates maps to valid color.</param>
/// <returns>List of color values.</returns>
private List<Color> MapToColors(OctTileMap tileMap, out bool hasData)
{
List<Color> colors = new List<Color>(Constants.TileSize * Constants.TileSize);
Vector2d point = new Vector2d();
hasData = false;
for (int pixelY = 0; pixelY < Constants.TileSize; pixelY++)
{
point.Y = ((double)pixelY + 0.5) / Constants.TileSize;
for (int pixelX = 0; pixelX < Constants.TileSize; pixelX++)
{
point.X = ((double)pixelX + 0.5) / Constants.TileSize;
var v = tileMap.PointToRaDec(point);
Color color = (this.colorMap.GetColor(v.X, v.Y));
if (color != Color.Transparent)
{
hasData = true;
}
colors.Add(color);
}
}
return colors;
}
/// <summary>
/// Interpolates the two vectors.
/// </summary>
/// <param name="left">
/// First vector.
/// </param>
/// <param name="right">
/// Second vector.
/// </param>
/// <param name="interpolater">
/// Interpolater factor.
/// </param>
/// <returns>
/// Lerp-ed vector.
/// </returns>
public static Vector2d Lerp(Vector2d left, Vector2d right, double interpolater)
{
if (Math.Abs(left.X - right.X) > 180)
{
if (left.X > right.X)
{
right.X += 360;
}
else
{
left.X += 360;
}
}
return new Vector2d(left.X * (1 - interpolater) + right.X * interpolater, left.Y * (1 - interpolater) + right.Y * interpolater);
}
/// <summary>
/// Creates the tile specified by level.
/// </summary>
/// <param name="level">
/// Zoom level.
/// </param>
/// <param name="tileX">
/// X tile coordinate.
/// </param>
/// <param name="tileY">
/// Y tile coordinate.
/// </param>
public void Create(int level, int tileX, int tileY)
{
// Pick the set of vertices where elevation will be computed.
int[] verticesX = backslashVerticesX;
int[] verticesY = backslashVerticesY;
if (IsSlashQuadrant(level, tileX, tileY))
{
verticesX = slashVerticesX;
verticesY = slashVerticesY;
}
// Compute required elevations.
short[] h = new short[verticesX.Length];
Vector2d pt = new Vector2d();
OctTileMap tileMap = new OctTileMap(level, tileX, tileY);
for (int i = 0; i < verticesX.Length; i++)
{
pt.X = ((double)verticesX[i]) / VertexInterval;
pt.Y = ((double)verticesY[i]) / VertexInterval;
Vector2d v = tileMap.PointToRaDec(pt);
h[i] = this.elevationMap.GetElevation(v.X - 180.0, v.Y);
}
// Save elevations.
this.tileSerializer.Serialize(h, level, tileX, tileY);
}