/// <summary>
/// Desire to move toward members of a group represented as a vector
/// </summary>
public static Vector3 CohesionForce(IAgent agent, IAgent otherAgent, SteerParameters steerParams)
{
Vector3 cohesion = agent.Position == otherAgent.Position ? Vector3.Zero :
Vector3.Normalize(otherAgent.Position - agent.Position);
return(cohesion * steerParams.CohesionWeight);
}
/// <summary>
/// Desire to maintain distance from other agents represented as a vector
/// </summary>
public static Vector3 SeparationForce(IAgent agent, IAgent otherAgent, SteerParameters steerParams, float agentSeparation)
{
Vector3 separation = (agent.Position - otherAgent.Position) / agentSeparation;
float magnitude = 1 - agentSeparation / steerParams.SeparationRange;
return(separation * magnitude * steerParams.SeparationWeight);
}
/// <summary>
/// Desire to randomly adjust current direction
/// </summary>
public static Vector3 WanderForce(IAgent agent, ref SteerParameters steerParams)
{
Vector3 wanderFocus = agent.Direction * 1.4f;
// the current angle of the wander should be offset slightly
steerParams.WanderCurrentAngle += (float)(rand.NextDouble() - 0.5f) * 2 * steerParams.TurningWeight;
Vector3 offset = new Vector3((float)Math.Cos(steerParams.WanderCurrentAngle), 0, (float)Math.Sin(steerParams.WanderCurrentAngle));
return Vector3.Normalize(wanderFocus + offset) * steerParams.WanderWeight;
}
/// <summary>
/// Desire to maintain distance from other agents represented as a vector
/// </summary>
public static Vector3 SeparationForce(IAgent agent, IAgent otherAgent, SteerParameters steerParams)
{
return SeparationForce(agent, otherAgent, steerParams, Vector3.Distance(agent.Position, otherAgent.Position));
}
/// <summary>
/// Keeps agents inside the world and above the surface of the terrain
/// </summary>
public static Vector3 WorldBoundsForce(IAgent agent, SteerParameters steerParams)
{
Vector3 force = Vector3.Zero;
float minY = steerParams.World.Terrain.CalculateHeight(agent.Position.X, agent.Position.Z) + 120;
float maxY = minY * 4;
float minX = 0;
float maxX = steerParams.World.Terrain.Width;
float minZ = 0;
float maxZ = steerParams.World.Terrain.Length;
if (agent.Position.X > maxX)
force += Vector3.UnitX * (maxX - agent.Position.X) / steerParams.SeparationRange;
else if (agent.Position.X < minX)
force += Vector3.UnitX * (minX - agent.Position.X) / steerParams.SeparationRange;
if (agent.Position.Y > maxY)
force += Vector3.UnitY * (maxY - agent.Position.Y) / steerParams.SeparationRange;
else if (agent.Position.Y < minY)
force += Vector3.UnitY * (minY - agent.Position.Y) / steerParams.SeparationRange;
if (agent.Position.Z > maxZ)
force += Vector3.UnitZ * (maxZ - agent.Position.Z) / steerParams.SeparationRange;
else if (agent.Position.Z < minZ)
force += Vector3.UnitZ * (minZ - agent.Position.Z) / steerParams.SeparationRange;
return force;
}
/// <summary>
/// Desire to move toward a specific point
/// </summary>
public static Vector3 GoalForce(IAgent agent, SteerParameters steerParams)
{
return (steerParams.GoalPosition - agent.Position) * steerParams.GoalWeight;
}
/// <summary>
/// Desire to align direction with another agent
/// </summary>
public static Vector3 AlignmentForce(IAgent otherAgent, SteerParameters steerParams)
{
return otherAgent.Direction * steerParams.AlignmentWeight;
}
/// <summary>
/// Desire to move toward members of a group represented as a vector
/// </summary>
public static Vector3 CohesionForce(IAgent agent, IAgent otherAgent, SteerParameters steerParams)
{
Vector3 cohesion = agent.Position == otherAgent.Position ? Vector3.Zero :
Vector3.Normalize(otherAgent.Position - agent.Position);
return cohesion * steerParams.CohesionWeight;
}
/// <summary>
/// Desire to maintain distance from other agents represented as a vector
/// </summary>
public static Vector3 SeparationForce(IAgent agent, IAgent otherAgent, SteerParameters steerParams, float agentSeparation)
{
Vector3 separation = (agent.Position - otherAgent.Position) / agentSeparation;
float magnitude = 1 - agentSeparation / steerParams.SeparationRange;
return separation * magnitude * steerParams.SeparationWeight;
}
