private void TwoBodyJointConstraint(Func <KinematicsSystem, IConstraintSolver> solver)
{
var a = new PhysicalParticle();
var b = new PhysicalParticle();
var c = new JointConstraint(a, Vector2.UnitX, b, -Vector2.UnitX);
b.Position = 2 * Vector2.UnitX;
b.Velocity.X = 10;
system.AddParticles(a, b);
system.AddConstraints(c);
var constraintSolver = solver(system);
var integrator = new KinematicsIntegrator(system, constraintSolver)
{
MaximumTimeStep = 0.01f,
MaxStepsPerFrame = 500
};
integrator.Integrate(1);
a.Position.X.Should().BeApproximately(5, tolerance);
b.Position.X.Should().BeApproximately(7, tolerance);
a.Velocity.X.Should().BeApproximately(5, tolerance);
b.Velocity.X.Should().BeApproximately(5, tolerance);
}
public KinematicsSystem Initialize(Size area)
{
system = new KinematicsSystem();
const int boxSize = 20;
for (int i = 0; i < rows; i++)
{
double y = area.Height - boxSize * (i + 0.5);
for (int j = 0; j < rows - i; j++)
{
int x = (area.Width - boxSize * 2 * rows) / 2 + boxSize * 2 * j + boxSize * i;
var particle = new PhysicalParticle
{
Position = new Vector2(x, y),
Polygon = new Rectangle(-boxSize, -boxSize / 2, boxSize * 2, boxSize).ToPolygon(),
InertialMoment = boxSize * boxSize
};
system.AddParticles(particle);
}
}
system.AddForceField(new ConstantGravityField());
system.AddConstraints(new TwoBodyConstraint(new CollisionConstraint(), new AllPairs()));
system.AddConstraints(new RectangleBoundaryConstraint(new Rectangle(Point.Zero, area)));
return(system);
}
public KinematicsSystem Initialize(Size area)
{
circleRadius = area.Height * 0.375f;
circlePosition = new Vector2(area.Width * .5f, area.Height * .5f);
var particlePosition = circlePosition
+ Vector2.FromPolarDegrees(circleRadius, -60)
+ new Vector2(boxSize * .5f, boxSize * .5f)
; //+ new Vector2(0, boxSize * .5f);
system = new KinematicsSystem();
system.AddParticles(new PhysicalParticle
{
Position = particlePosition,
//Angle = -(float)Math.PI / 4,
InertialMoment = boxSize * boxSize / 12f,
});
system.AddConstraints(new CirclePerimeterOffcenterConstraint(
system.Particles[0], circlePosition, circleRadius, new Vector2(-boxSize * .5f, -boxSize * .5f)));
system.AddForceField(new ConstantGravityField());
return(system);
}
public static void CreateChain(KinematicsSystem system, int boxCount, float boxSize, Vector2 particlePosition)
{
for (int i = 0; i < boxCount; i++)
{
particlePosition += new Vector2(boxSize, 0);
system.AddParticles(
new PhysicalParticle
{
Position = particlePosition,
InertialMoment = boxSize * boxSize / 12f,
}
);
if (i > 0)
{
PhysicalParticle last = system.Particles[i - 1];
PhysicalParticle current = system.Particles[i];
// Use the sign to alternate which corner is attached. This allows the chain to spread out diagonally.
int sign = 2 * (i % 2) - 1;
system.AddConstraints(new JointConstraint(
last, new Vector2(boxSize * .5f, sign * boxSize * .5f),
current, new Vector2(-boxSize * .5f, sign * boxSize * .5f)));
}
}
}
public KinematicsSystem Initialize(Size area)
{
screenArea = area;
ParticleGenerator generator = new ParticleGenerator();
system = new KinematicsSystem();
system.AddParticles(generator.Generate(particleCount, new Vector2(screenArea.Width / 2, 100), Vector2.Zero));
system.AddForceField(new ConstantGravityField());
system.AddConstraints(new RectangleBoundaryConstraint(new Rectangle(Point.Zero, area)));
return(system);
}
public KinematicsSystem Initialize(Size area)
{
boxes.Clear();
system = new KinematicsSystem();
for (int i = 0; i < BoxCount; i++)
{
boxes.Add(new PhysicalParticle
{
Polygon = new Rectangle(-boxSize / 2, -boxSize / 2, boxSize, boxSize).ToPolygon(),
Position = new Vector2(
area.Width * 0.5 + (BoxCount / 2 - i) * boxSize,
area.Height * 0.3
),
Velocity = new Vector2(0, (BoxCount / 2 - i) * 100)
});
if (i > 0)
{
var constraint = new JointConstraint(boxes[i - 1], new Vector2(-boxSize * 0.5, 0),
boxes[i], new Vector2(boxSize * 0.5, 0));
system.AddConstraints(constraint);
}
}
sphere = new PhysicalParticle
{
Position = new Vector2(area.Width * 0.5, area.Height * 0.25)
};
var constraintBox = boxes[boxes.Count / 2];
system.AddConstraints(
new CirclePerimeterOffcenterConstraint(constraintBox,
sphere.Position, 40, constraintBox.Polygon[0]));
system.AddParticles(boxes.ToArray());
system.AddForceField(new ConstantGravityField());
return(system);
}
public KinematicsSystem Initialize(Size area)
{
screenArea = area;
ParticleGenerator generator = new ParticleGenerator();
system = new KinematicsSystem();
system.AddParticles(generator.Generate(particleCount,
i => new Vector2(50 + 200 * i, 200),
i => Vector2.Zero));
system.AddConstraints(new TwoBodyConstraint(new CollisionConstraint(), new AllPairs()));
system.Particles.First().Velocity.X = 100;
return(system);
}
public KinematicsSystem Initialize(Size area)
{
system = new KinematicsSystem();
var planet = new PhysicalParticle
{
Position = (Vector2)area / 2,
Polygon = new RegularPolygonBuilder().BuildPolygon(6, 60),
Mass = 10,
InertialMoment = 5 * 60 * 60,
};
system.AddParticles(planet);
GenerateParticles(planet);
system.AddConstraints(new TwoBodyConstraint(new CollisionConstraint(), new AllPairs()));
system.AddForceField(new PlanetGravity(planet, 4000000));
return(system);
}
public KinematicsSystem Initialize(Size area)
{
circleRadius = area.Height * 0.375f;
circlePosition = new Vector2(area.Width * 0.5f, area.Height * 0.5f);
var particlePosition = circlePosition + Vector2.FromPolarDegrees(circleRadius, -60);
system = new KinematicsSystem();
system.AddParticles(new PhysicalParticle
{
Position = particlePosition,
Angle = 1.5f,
AngularVelocity = 20f,
});
system.AddConstraints(new CirclePerimeterConstraint(system.Particles[0], circlePosition, circleRadius));
system.AddForceField(new ConstantGravityField());
return(system);
}
private void GenerateParticles(PhysicalParticle planet)
{
system.AddParticles(new ParticleGenerator().Generate(particles,
i => planet.Position + Vector2.FromPolar(300, 2 * Math.PI * i / particles),
i => Vector2.FromPolar(50, 2 * Math.PI * i / particles + Math.PI * 0.5)));
}
