/*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);
}
public void VelocityFriction(double a, double b, double c)
{
// The force of pressure affects velocity
for (int iterate = 0; iterate < 1; iterate++)
{
// NOTE: We include the border cells in global friction
for (int x = 0; x < t_width; x++)
{
for (int y = 0; y < t_height; y++)
{
int cell = CellOffset(x, y, t_width);
Engine.Calc.Vector v = new Engine.Calc.Vector(mp_xv0[cell], mp_yv0[cell]);
double len2 = v.MagnitudeSquared();
double len = System.Math.Sqrt(len2);
if (len < 0.0f)
{
len = -len;
}
len -= m_dt * (a * len2 + b * len + c);
if (len < 0.0d)
{
len = 0.0d;
}
if (len < 0.0f)
{
len = 0.0f;
}
v.Normalize();
v.SetMagnitude(len);
mp_xv0[cell] = v.X;
mp_yv0[cell] = v.Y;
}
}
}
}
private int Threaded_GetParticles(int start, int end, Threading.ParamList paramlist)
{
Engine.Effects.Code.Particles.AutonomousParticle[] particles = (Engine.Effects.Code.Particles.AutonomousParticle[])paramlist.Get("particles").Value;
for (int x = start; x < end; x++)
{
for (int y = 0; y < t_cells.GetLength(1); y++)
{
int offset = Engine.Surface.Ops.GetGridOffset(x, y, t_cells.GetLength(0), t_cells.GetLength(1));
particles[offset] = new Effects.Code.Particles.AutonomousParticle(new Engine.Calc.Vector((x * t_gridCellWidth) + (t_gridCellWidth / 2),
(y * t_gridCellHeight) + (t_gridCellHeight / 2)));
Engine.Calc.Vector vel = t_cells[x, y].Pressure;
vel.Normalize();
vel.SetMagnitude(2);
particles[offset].Velocity = vel;
//t_cells[x, y].CalculateAveragePressure(t_flowField, x * t_gridCellWidth, y * t_gridCellHeight);
}
}
return(0);
}
