public void Particle_InfiniteMass()
{
Particle part = new Particle(Vector3.Zero);
part.InverseMass = 0f; //infinite mass
Vector3 force = Vector3.Up;
part.addForce(force);
part.integrate(1); // first one only applies last frame's accumulators
part.integrate(1);
Assert.AreEqual(Vector3.Zero, part.Position);
}
public void Particle_Ideal_Nudge()
{
Particle part = new Particle(Vector3.Zero);
part.Mass = 1f;
Vector3 force = Vector3.Up;
part.addForce(force);
part.integrate(1); // first one only applies last frame's accumulators
part.integrate(1);
Assert.AreEqual(Vector3.Up, part.Position, "Position");
Assert.AreEqual(Vector3.Up, part.Velocity, "Velocity");
// This maybe be bug....
Assert.AreEqual(Vector3.Zero, part.Acceleration, "Acceleration");
}
public void Particle_NoBackInTime()
{
Particle part = new Particle(Vector3.Zero);
part.Mass = 1f;
Vector3 force = Vector3.Up;
part.integrate(-1f);
}
public void Particle_Linear_Damping()
{
Particle part = new Particle(Vector3.Zero);
part.Mass = 1f;
part.LinearDamping = 0.5f; //major damping factor
part.setVelocity(Vector3.Up * 2f);
part.integrate(0.5f);
Assert.AreEqual(Vector3.Up * (float)Math.Sqrt(2D), part.Velocity);
}
public void Particle_Zero_Case()
{
Particle part = new Particle(Vector3.Zero);
Assert.AreEqual(Vector3.Zero, part.Position);
Assert.AreEqual(Vector3.Zero, part.Velocity);
Assert.AreEqual(Vector3.Zero, part.Acceleration);
Assert.AreEqual(1f, part.LinearDamping);
Assert.AreEqual(0f, part.InverseMass);
Assert.AreEqual(0f, part.Mass);
// Check that N times is cool
part.integrate(1000); //integrate particle for 1 second
part.integrate(1000); //integrate particle for 1 second
part.integrate(1000); //integrate particle for 1 second
part.integrate(1000); //integrate particle for 1 second
// it should not have changed state
Assert.AreEqual(Vector3.Zero, part.Position);
Assert.AreEqual(Vector3.Zero, part.Velocity);
Assert.AreEqual(Vector3.Zero, part.Acceleration);
Assert.AreEqual(1f, part.LinearDamping);
Assert.AreEqual(0f, part.InverseMass);
Assert.AreEqual(0f, part.Mass);
}