//agent move in the same direction of the neighbours
public static Vector3d Alignment(List <IFlockAgent> neighbours, Vector3d desiredVelocity,
FlockSystem flockSystem)
{
Vector3d alignment = Vector3d.Zero;
foreach (IFlockAgent neighbour in neighbours)
{
alignment += neighbour.Velocity;
}
// We divide by the number of neighbours to actually get their average velocity
alignment /= neighbours.Count;
desiredVelocity += flockSystem.AlignmentStrength * alignment;
return(desiredVelocity);
}
//agent move towards the center of the neighbours
public static Vector3d Cohesion(List <IFlockAgent> neighbours, Point3d Position, Vector3d desiredVelocity,
FlockSystem flockSystem)
{
Point3d centre = Point3d.Origin;
foreach (IFlockAgent neighbour in neighbours)
{
centre += neighbour.Position;
}
// We divide by the number of neighbours to actually get their centre of mass
centre /= neighbours.Count;
Vector3d cohesion = centre - Position;
desiredVelocity += flockSystem.CohesionStrength * cohesion;
return(desiredVelocity);
}
//agent move away from neighbours if it gets too close
public static Vector3d Separation(List <IFlockAgent> neighbours, Point3d Position, Vector3d desiredVelocity,
FlockSystem flockSystem)
{
Vector3d separation = Vector3d.Zero;
foreach (IFlockAgent neighbour in neighbours)
{
double distanceToNeighbour = Position.DistanceTo(neighbour.Position);
if (distanceToNeighbour < flockSystem.SeparationDistance)
{
Vector3d getAway = Position - neighbour.Position;
/* We scale the getAway vector by inverse of distanceToNeighbour to make
* the getAway vector bigger as the agent gets closer to its neighbour */
separation += getAway / (getAway.Length * distanceToNeighbour);
}
}
desiredVelocity += flockSystem.SeparationStrength * separation;
return(desiredVelocity);
}
protected override void SolveInstance(IGH_DataAccess DA)
{
// ===============================================================================================
// Read input parameters
// ===============================================================================================
bool iReset = true;
bool iPlay = false;
bool i3D = false;
int iCount = 0;
double iTimestep = 0.0;
double iNeighbourhoodRadius = 0.0;
double iAlignment = 0.0;
double iCohesion = 0.0;
double iSeparation = 0.0;
double iSeparationDistance = 0.0;
List <Circle> iRepellers = new List <Circle>();
bool iUseParallel = false;
bool iUseRTree = false;
//bool iUseKDTree = false;
//Brep AgentBox = new Brep();
if (!DA.GetData("Reset", ref iReset))
{
return;
}
if (!DA.GetData("Play", ref iPlay))
{
return;
}
if (!DA.GetData("3D", ref i3D))
{
return;
}
if (!DA.GetData("Count", ref iCount))
{
return;
}
if (!DA.GetData("Timestep", ref iTimestep))
{
return;
}
if (!DA.GetData("Neighbourhood Radius", ref iNeighbourhoodRadius))
{
return;
}
if (!DA.GetData("Alignment", ref iAlignment))
{
return;
}
if (!DA.GetData("Cohesion", ref iCohesion))
{
return;
}
if (!DA.GetData("Separation", ref iSeparation))
{
return;
}
if (!DA.GetData("Separation Distance", ref iSeparationDistance))
{
return;
}
if (!DA.GetDataList("Repellers", iRepellers))
{
return;
}
if (!DA.GetData("Use Parallel", ref iUseParallel))
{
return;
}
if (!DA.GetData("Use R-Tree", ref iUseRTree))
{
return;
}
//if (!DA.GetData("Use KD-Tree", ref iUseKDTree)) return;
//if (!DA.GetData("BoundingBox", ref AgentBox)) return;
// ===============================================================================================
// Validate Data
// ===============================================================================================
if (iAlignment < 0.0)
{
AddRuntimeMessage(GH_RuntimeMessageLevel.Remark, "Cohesion>Seperation for flocking");
return;
}
if (iCohesion < 0.0)
{
AddRuntimeMessage(GH_RuntimeMessageLevel.Remark, "Cohesion>Seperation for flocking");
return;
}
if (iSeparation < 0.0)
{
AddRuntimeMessage(GH_RuntimeMessageLevel.Remark, "Cohesion>Seperation for flocking");
return;
}
// ===============================================================================================
// Read input parameters
// ===============================================================================================
if (iReset || flockSystem == null)
{
flockSystem = new FlockSystem(iCount, i3D);
}
else
{
// ===============================================================================================
// Assign the input parameters to the corresponding variables in the "flockSystem" object
// ===============================================================================================
flockSystem.Timestep = iTimestep;
flockSystem.NeighbourhoodRadius = iNeighbourhoodRadius;
flockSystem.AlignmentStrength = iAlignment;
flockSystem.CohesionStrength = iCohesion;
flockSystem.SeparationStrength = iSeparation;
flockSystem.SeparationDistance = iSeparationDistance;
flockSystem.Repellers = iRepellers;
flockSystem.UseParallel = iUseParallel;
flockSystem.UseRTree = iUseRTree;
// ===============================================================================
// Update the flock
// ===============================================================================
if (iUseRTree)
{
flockSystem.UpdateUsingRTree();
}
else
{
flockSystem.Update();
}
if (iPlay)
{
ExpireSolution(true);
}
}
// ===============================================================================
// Output the agent positions and velocities so we can see them on display
// ===============================================================================
List <GH_Point> positions = new List <GH_Point>();
List <GH_Vector> velocities = new List <GH_Vector>();
foreach (FlockAgent agent in flockSystem.Agents)
{
positions.Add(new GH_Point(agent.Position));
velocities.Add(new GH_Vector(agent.Velocity));
}
DA.SetDataList("Positions", positions);
DA.SetDataList("Velocities", velocities);
}
