/// <summary>
/// Calculates the required force to separate the two agents
/// </summary>
public void ApplyCollisionForce(int i, SpatialMapData target)
{
// calculate the distance bewteen the two agents
float3 direction = agents[i].position - target.position;
direction.y = 0; // clamp the y-axis to create a 2D force
// exit if the agents are within the minimum distance
// this helps prevent excessive collision forces
float distance = math.length(direction);
if (distance <= minDistance)
{
return;
}
// calculate the mass difference between the two agents
float mass = movementConfigs[movement[i]].mass;
float massRatio = target.mass / mass;
// calcuate the collision force for this agent and skip
// if it does not exceed the minForce, creating a deadband
float combinedRadius = collision.radius + target.radius;
float penetration = combinedRadius / distance;
float forceScale = penetration * massRatio;
if (forceScale <= minForce)
{
return;
}
// apply the collision to this agents steering force
direction = math.normalizesafe(direction, float3.zero);
steering[i] += direction * forceScale;
}
public void Execute(int i, TransformAccess transform)
{
AgentBehaviors mask = AgentBehaviors.Active;
if ((behaviors[i] & mask) == 0)
{
return;
}
float mass = movementConfigs[movement[i]].mass;
int3 grid = GridPosition(transform.position);
int3 bucket = new int3(
grid.x / size.x,
grid.y / size.y,
grid.z / size.z
);
Agents.AgentKinematics agent = agents[i];
agent.position = transform.position;
agents[i] = agent;
SpatialMapData data = new SpatialMapData();
data.position = transform.position;
data.height = collision.height;
data.radius = collision.radius;
data.mass = mass;
spatialMap.Add(bucket, data);
}
/// <summary>
/// Checks if there is a collision between two agents
/// using their collision radius and height
/// </summary>
public bool Collision(AgentKinematics self, SpatialMapData target)
{
// skip if the target agent is the same as the source agent
if (self.position.Equals(target.position))
{
return(false);
}
// find the distance between the two agents
// clamp y-axis to test 2D circle intersection
float3 delta = self.position - target.position;
float deltaY = delta.y;
delta.y = 0;
// use the combined radius of the two agents to
// test if their collision radius intersect
float distance = math.length(delta);
float radius = collision.radius + target.radius;
bool intersectCircle = distance <= radius;
// compare the two agent's height and offset for collisions
// use delta Y to test that the agents are colliding with each other
bool intersectHeight;
if (deltaY >= 0) // target is above the agent
{
intersectHeight = deltaY - collision.height < 0;
}
else // target is below the agent
{
intersectHeight = -deltaY - target.height < 0;
}
// agents must be intersecting the 2D circle
// and height to be considered a collision
return(intersectCircle && intersectHeight);
}
