public void Integrate(double duration)
{
if (duration == 0.0)
{
throw new InvalidDurationException("Duration can not be zero");
}
// Start by using gravity - this is already an acceleration so don't convert from a force
var resultingAcceleration = new Vector3(GravityAcceleration);
// Work out the acceleration from the force
resultingAcceleration.AddScaledVector(AccumulatedForce, InverseMass);
// Update position - for the moment we are using full equation - make accn bit configurable?
Position.AddScaledVector(Velocity, duration);
Position.AddScaledVector(resultingAcceleration, (duration * duration) / 2.0f);
// Update the velocity
Velocity.AddScaledVector(resultingAcceleration, duration);
// Impose drag if there is damping - we are using the full equation for now - make configurable?
if (Damping != 1.0f)
{
Velocity *= Math.Pow(Damping, duration);
}
// Clear the forces
ClearAccumulatedForce();
}
/// <summary>
/// Integrates the particle forward in time by the given amount.
/// This function uses a Newton-Euler integration method, which is a
/// Linear approximation of the correct integral. For this reason it
/// May be inaccurate in some cases.
///
/// We integrate, because we want to figure out what the next position
/// Should be in time given the current velocity.
///
/// We also want to figure velocity based on current acceleration, with
/// Some damping added to make the physics simulation more stable.
/// </summary>
/// <param name="timeDuration">Time since last frame in seconds</param>
public void Integrate(float timeDuration)
{
// Zero out stuff
ForceAccum = new Vector3();
// Update linear position
Position.AddScaledVector(Velocity, timeDuration);
// Update velocity
Vector3 resulintAcc = Acceleration;
resulintAcc.AddScaledVector(ForceAccum, InverseMass);
Velocity.AddScaledVector(resulintAcc, timeDuration);
Velocity *= (float)Math.Pow(Damping, timeDuration);
// Update linked mesh
LinkedMesh.Position = new vec3(Position.X, Position.Y, Position.Z);
}