private static int[] GetFieldCircle(Point point, double radiusX, double radiusY, FluidField2D field)
{
// Get the box that contains the return circle
var center = GetFieldPoint_XY(point, field);
var min = GetFieldPoint_XY(new Point(point.X - radiusX, point.Y - radiusY), field);
var max = GetFieldPoint_XY(new Point(point.X + radiusX, point.Y + radiusY), field);
// Get points that are inside the circle
List <int> retVal = new List <int>();
double maxDistance = ((radiusX * field.XSize) + (radiusY * field.YSize)) * .5d; // just take the average. TODO: see if inside the ellipse
double maxDistanceSquared = maxDistance * maxDistance;
for (int x = min.Item1; x <= max.Item1; x++)
{
for (int y = min.Item2; y <= max.Item2; y++)
{
double dx = x - center.Item1;
double dy = y - center.Item2;
double distanceSquared = (dx * dx) + (dy * dy);
if (distanceSquared <= maxDistanceSquared)
{
retVal.Add(field.GetK(x, y));
}
}
}
// Exit Function
return(retVal.ToArray());
}
private static Tuple <int, double>[] GetFieldCircle(Point point, double radiusX, double radiusY, double valueCenter, double valueEdge, FluidField2D field)
{
// Get the box that contains the return circle
var center = GetFieldPoint_XY(new Point(point.X, point.Y), field);
var min = GetFieldPoint_XY(new Point(point.X - radiusX, point.Y - radiusY), field);
var max = GetFieldPoint_XY(new Point(point.X + radiusX, point.Y + radiusY), field);
// Get points that are inside the circle
List <Tuple <int, double> > retVal = new List <Tuple <int, double> >();
Vector radius = new Vector(radiusX * field.XSize, radiusY * field.YSize);
double maxDistance = ((radiusX * field.XSize) + (radiusY * field.YSize)) * .5d; // just take the average. TODO: see if inside the ellipse
double maxDistanceSquared = maxDistance * maxDistance;
for (int x = min.Item1; x <= max.Item1; x++)
{
for (int y = min.Item2; y <= max.Item2; y++)
{
double dx = x - center.Item1;
double dy = y - center.Item2;
double distanceSquared = (dx * dx) + (dy * dy);
if (distanceSquared <= maxDistanceSquared)
{
double distance = Math.Sqrt(distanceSquared);
retVal.Add(Tuple.Create(
field.GetK(x, y), // coordinates that the field wants
UtilityCore.GetScaledValue(valueCenter, valueEdge, 0, maxDistance, distance) // LERP
));
}
}
}
// Exit Function
return(retVal.ToArray());
}
/// <summary>
/// This takes a point from 0 to 1, and returns the corresponding position in the field (what the field calls k)
/// </summary>
private static int GetFieldPoint(Point point, FluidField2D field)
{
var xy = GetFieldPoint_XY(point, field);
return(field.GetK(xy.Item1, xy.Item2));
}
public void Update()
{
const int NUMSAMPLES = 20;
double width = this.ActualWidth;
double height = this.ActualHeight;
if (double.IsNaN(width) || double.IsInfinity(width))
{
// This control isn't visible yet
return;
}
DrawingContext drawing = _visual.RenderOpen();
double[] xVel, yVel;
xVel = _field.XVel;
yVel = _field.YVel;
int xSize = _field.XSize;
int ySize = _field.YSize;
double cellWidth = width / xSize;
double cellHeight = height / ySize;
double cellHalfWidth = cellWidth / 2d;
double cellHalfHeight = cellHeight / 2d;
double scale = (width + height) / 2d;
double dotRadius = (cellWidth + cellHeight) / 5d;
// Always include 0 and size - 1. The rest should be evenly distributed
double incX = Convert.ToDouble(xSize - 1) / (NUMSAMPLES - 1); // subtracting 1 to guarantee the edges get one
double incY = Convert.ToDouble(ySize - 1) / (NUMSAMPLES - 1);
for (double xd = 0; xd < xSize; xd += incX)
{
for (double yd = 0; yd < ySize; yd += incY)
{
int x = Convert.ToInt32(Math.Round(xd));
if (x > xSize - 1)
{
x = xSize - 1;
}
int y = Convert.ToInt32(Math.Round(yd));
if (y > ySize - 1)
{
y = ySize - 1;
}
// Figure out the center of this cell
Point center = new Point((cellWidth * x) + cellHalfWidth, (cellHeight * y) + cellHalfHeight);
// Add the velocity at this cell
int index = FluidField2D.GetK(xSize, x, y);
Point end = new Point(center.X + (xVel[index] * scale), center.Y + (yVel[index] * scale));
drawing.DrawLine(_pen, center, end);
//drawing.DrawEllipse(Brushes.Gold, _pen, center, dotRadius, dotRadius); // too expensive
}
}
drawing.Close();
this.InvalidateVisual();
}