public static void Draw(this Engine.Effects.Particles.ForceParticle fp, Engine.Surface.Canvas c, Engine.Color.Cell color)
{
// TODO a strange case where position is way out of bounds which causes LinearInterpolation to build a list that
// has so many items that it reaches "out of bounds (int)"
// this problem may have disappeared since I changed to Engine.Calc.Vector
if (double.IsNaN(fp.Position.X) || double.IsNaN(fp.Position.Y))
{
return;
}
// draw a line between last position and current position
List <MousePoint> points = Engine.Calc.Math.LinearInterpolate(new MousePoint(fp.PreviousPoint.X, fp.PreviousPoint.Y),
new MousePoint((int)fp.Position.X, (int)fp.Position.Y));
foreach (MousePoint p in points)
{
int x = p.X;
int y = p.Y;
if (c.IsOutOfBounds(x, y))
{
return;
}
Engine.Color.Cell bg = c.GetPixel(x, y, Surface.PixelRetrievalOptions.ReturnEdgePixel);
c.SetPixel(Engine.Calc.Color.FastAlphaBlend(color, bg), x, y, Surface.PixelSetOptions.Ignore);
}
}
/*public static Engine.Calc.Vector ExpressiveForce(this Engine.Effects.Particles.Attractor attractor,
* Engine.Effects.Particles.ForceParticle p)
* {
* float G = 4f;
*
* Engine.Calc.Vector relDistance = attractor.Distance(p);
*
* float distance = relDistance.Norm; // Norm seems the magnitude in Processing
*
* float force = G / distance;
*
* force = Engine.Calc.Math.Sigmoid(force);
*
* relDistance.Normalize();
* Engine.Calc.Vector.Multiply(relDistance, force);
*
* return relDistance;
* }*/
/// <summary>
///
/// </summary>
/// <param name="attractor"></param>
/// <param name="p"></param>
/// <param name="G">The "Gravitational constant" of the force (suggested value 1.3)</param>
/// <param name="expansion">Allows the force to be stronger or weaker on longer distances while remaining weak at very short distances.
/// suggested value 2.8</param>
/// <param name="direction">the direction of the force. positive makes the force attraction, negative makes the force repulsion. suggested value 0.5 or -0.5</param>
/// <returns></returns>
public static Engine.Calc.Vector ModularForce(this Engine.Effects.Particles.Attractor attractor,
Engine.Effects.Particles.ForceParticle p)
{
Engine.Calc.Vector relDistance = attractor.Distance(p);
double distance = System.Math.Sqrt(relDistance.X * relDistance.X + relDistance.Y * relDistance.Y);
double force = (attractor.Intensity * attractor.Force * distance) - 10d / System.Math.Pow(attractor.Expression, -1 * (distance / attractor.Force));
relDistance.Normalize();
relDistance *= force;
return(relDistance);
}
