public static double Dot(Vector v1, Vector v2)
{
Debug.Assert(v1.IsRational());
Debug.Assert(v2.IsRational());
return v1.X * v2.X + v1.Y * v2.Y;
}
public static bool Animate(
Point currentValue, Vector currentVelocity, Point targetValue,
double attractionFator, double dampening,
double terminalVelocity, double minValueDelta, double minVelocityDelta,
out Point newValue, out Vector newVelocity)
{
Debug.Assert(currentValue.IsRational());
Debug.Assert(currentVelocity.IsRational());
Debug.Assert(targetValue.IsRational());
Debug.Assert(dampening.IsRational());
Debug.Assert(dampening > 0 && dampening < 1);
Debug.Assert(attractionFator.IsRational());
Debug.Assert(attractionFator > 0);
Debug.Assert(terminalVelocity > 0);
Debug.Assert(minValueDelta > 0);
Debug.Assert(minVelocityDelta > 0);
Vector diff = targetValue - currentValue;
if (diff.Length > minValueDelta || currentVelocity.Length > minVelocityDelta)
{
newVelocity = currentVelocity * (1 - dampening);
newVelocity += diff * attractionFator;
newVelocity *= (currentVelocity.Length > terminalVelocity) ? terminalVelocity / currentVelocity.Length : 1;
newValue = currentValue + newVelocity;
return true;
}
else
{
newValue = targetValue;
newVelocity = new Vector();
return false;
}
}
public static bool Animate(
Point currentValue, Vector currentVelocity, Vector force,
double dampening, double terminalVelocity, double minValueDelta, double minVelocityDelta,
out Point newValue, out Vector newVelocity)
{
Debug.Assert(currentValue.IsRational());
Debug.Assert(currentVelocity.IsRational());
Debug.Assert(dampening.IsRational());
Debug.Assert(dampening > 0 && dampening < 1);
Debug.Assert(terminalVelocity > 0);
Debug.Assert(minValueDelta > 0);
Debug.Assert(minVelocityDelta > 0);
if (force.Length > minValueDelta || currentVelocity.Length > minVelocityDelta)
{
newVelocity = currentVelocity * (1 - dampening);
newVelocity += force;
newVelocity *= (currentVelocity.Length > terminalVelocity) ? terminalVelocity / currentVelocity.Length : 1;
newValue = currentValue + newVelocity;
return true;
}
else
{
newValue = currentValue;
newVelocity = new Vector();
return false;
}
}
public static double AngleRad(Vector v1, Vector v2)
{
Debug.Assert(v1.IsRational());
Debug.Assert(v2.IsRational());
double dot = Dot(v1, v2);
double dotNormalize = dot / (v1.Length * v2.Length);
double acos = Math.Acos(dotNormalize);
return acos;
}
