public void Add(double size, int colorNumber, Flatbody body)
{
Ellipse newCircle = new Ellipse();
newCircle.Width = newCircle.Height = CircleSize(size);
newCircle.Fill = (SolidColorBrush)Application.Current.Resources[circleColorResourceBaseString + colorNumber.ToString()];
newCircle.RenderTransform = CircleTransform(body);
simCanvas.Children.Add(newCircle);
circles.Add(newCircle);
}
// Mapping point in simulation space to rendering space:
// simPt * scaleFactor + simulationCenterTranslation + circleCenterTranslation -> renderingOffset
public TranslateTransform CircleTransform(Flatbody body)
{
TranslateTransform t = new TranslateTransform();
double circleCenterTranslation = -CircleSize(body.Size) / 2.0;
t.X = body.Position.X * scaleFactor + simulationCenterTranslation.X + circleCenterTranslation;
t.Y = body.Position.Y * -scaleFactor + simulationCenterTranslation.Y + circleCenterTranslation;
return(t);
}
public Point BodyToBodyAccelerate(Flatbody otherBody)
{
const double rMinimum = 10.0; // we are not simulating collisions so don't let accelerations run away as bodies
// approach 0.0 separation
const double rMinSquared = rMinimum * rMinimum;
double rX = otherBody.position.X - this.position.X;
double rY = otherBody.position.Y - this.position.Y;
double rSquared = (rX * rX) + (rY * rY);
rSquared = Math.Max(rSquared, rMinSquared); // enforce minimum value of r
double r = Math.Sqrt(rSquared);
double a = otherBody.mass / rSquared;
return(new Point(a * rX / r, a * rY / r));
}