//--------------------------------------------------------------------
public SimModel(GameModel model, float mass, SimObjectType simObjectType)
: base(mass, simObjectType)
{
this.model = model;
this.currPosition = model.Translate;
this.prevPosition = currPosition;
}
public ChainSim(Game game, GameModel[] ropeSegmentModels, float totalMass, float stiffness, float damping)
: base(game)
{
//create sim data
float sphereMass = totalMass / ropeSegmentModels.Length;
SimModel[] simObjs = new SimModel[ropeSegmentModels.Length];
for (int i = 0; i < ropeSegmentModels.Length; i++)
{
simObjs[i] = new SimModel(ropeSegmentModels[i], sphereMass, SimObjectType.ACTIVE);
this.AddSimObject(simObjs[i]);
}
//attach springs between the sim objects
for (int i = 1; i < ropeSegmentModels.Length; i++)
{
this.AddSpring(stiffness, damping, simObjs[i - 1], simObjs[i]);
this.Constraints.Add(new LengthConstraint((simObjs[i - 1].Model.Translate - simObjs[i].Model.Translate).Length(), simObjs[i - 1], simObjs[i]));
}
}
private void InitChainScene()
{
//chain attributes
int numSegments = 30;
float separation = 0.65f;
//load in segments
GameModel[] segments = new GameModel[numSegments];
for (int i = 0; i < numSegments; i++)
{
segments[i] = modelComponent.LoadGameModel("chainSegment");
//reduce the size of each segment
segments[i].Scale = 0.3f * Vector3.One;
//position each segment downwards incrementally to form the chain
segments[i].TranslateY = -i * separation;
//rotate the even segments by 90 degrees in Y axis
segments[i].RotateY = (i % 2) * 90.0f;
}
//create a chain sim
float totalMass = 1.0f;
float stiffness = 0.3f;
float damping = 0.01f;
chainSim = new ChainSim(this, segments, totalMass, stiffness, damping);
//add in a global force generator: gravity
Gravity gravity = new Gravity(new Vector3(0, -9.81f * 5, 0));
chainSim.AddGlobalForceGenerator(gravity);
//constrain the head point so that we can control it
chainHeadPoint = new PointConstraint(Vector3.Zero, chainSim.SimObjects[0]);
chainSim.Constraints.Add(chainHeadPoint);
//create a integrator and assign it to the sim
float drag = 0.005f;
Integrator integrator = new VerletNoVelocityIntegrator(this, drag);
chainSim.Integrator = integrator;
}
