public Vector3 GetForce(Steering steering)
{
if (isResponsibleForNeighbourUpdate)
{
// TODO: figure out how to add or remove neighbours automatically here or in neighbours
neighbours.Update();
}
/*
* Avoid collisions by determining for each neighbor when their paths will be closest to each other
* and then steer laterally to avoid collision.
* https://www.red3d.com/cwr/steer/Unaligned.html
*/
float distanceToBeginReacting = 4f * (steering.GetSize() + steering.GetStoppingDistance());
//Debug.Log(doubleStopDistance);
foreach (Neighbour <Steering> neighbour in neighbours)
{
if (neighbour.dd > distanceToBeginReacting * distanceToBeginReacting)
{
break;
}
Steering otherUnit = neighbour.obj;
Vector3 offset = otherUnit.GetPosition() - steering.GetPosition();
Vector3 relativeVelocity = steering.GetVelocity() - otherUnit.GetVelocity();
// Decrease the timeToCollision so that closestOffset is nonZero.
float combinedSize = steering.GetSize() + otherUnit.GetSize();
float timeToCollision = (offset.magnitude - combinedSize) / SteeringUtilities.parallelComponent(relativeVelocity, offset).magnitude;
if (timeToCollision > 2 * steering.GetStoppingTime())
{
continue;
}
Vector3 closestOffset = (offset - (timeToCollision * relativeVelocity));
float preferredDistance = 1.5f * combinedSize;
if (closestOffset.sqrMagnitude > preferredDistance * preferredDistance)
{
continue;
}
SteeringUtilities.drawDebugVector(steering, timeToCollision * steering.GetVelocity(), Color.cyan);
SteeringUtilities.drawDebugPoint(steering.GetPosition() + timeToCollision * steering.GetVelocity(), Color.cyan);
SteeringUtilities.drawDebugVector(otherUnit, timeToCollision * otherUnit.GetVelocity(), Color.cyan);
SteeringUtilities.drawDebugPoint(otherUnit.GetPosition() + timeToCollision * otherUnit.GetVelocity(), Color.cyan);
// TODO: for head-on collisions steer to the right
// Steer in the direction of the component of the collision normal that is perpindicular to the current velocity.
// This way the unit will turn instead of just slowing down.
// TODO: use an amount of acceleration proportionate to the time until collision and the severity of the collision
return(SteeringUtilities.scaledVector(steering.GetAcceleration(), SteeringUtilities.perpindicularComponent(-closestOffset, steering.GetVelocity())));
//return SteeringUtilities.getForceForDirection(steering, -closestOffset);
}
return(Vector3.zero);
}
public Vector3 GetForce(Steering steering)
{
float raycastDistance = 2f * (2f * steering.GetSize()) + 2f * (steering.GetMaxSpeed() * steering.GetMaxSpeed() / steering.GetAcceleration());
// TODO: send out 3 rays and define static quaternions to determine the rotated direction vectors.
Vector3 directionVector = steering.GetVelocity();
// TODO: update the side raycast lengths based on steering's size, and the center raycast based on speed.
// TODO: constrain hit normals to the relevant plane in case the collider has a complicated shape
Vector3 hitNormal1 = RaycastNormal(steering, (Steering.UseXZ ? xzRotateLeft : xyRotateLeft) * directionVector, raycastDistance * 0.5f);
Vector3 hitNormal2 = RaycastNormal(steering, directionVector, raycastDistance);
Vector3 hitNormal3 = RaycastNormal(steering, (Steering.UseXZ ? xzRotateRight : xyRotateRight) * directionVector, raycastDistance * 0.5f);
// If multiple raycasts hit, sum the normals.
// TODO: weight the normals differently based on which collision point is closest.
Vector3 combinedNormal = SteeringUtilities.scaledDownVector(1f, hitNormal1 + hitNormal2 + hitNormal3);
if (combinedNormal.sqrMagnitude > 0f)
{
// For the normal of the wall ahead, steer to have a velocity that is perpindicular to it.
Vector3 leftVector = new Vector3(combinedNormal.y + combinedNormal.z, -Steering.YMult * combinedNormal.x, -Steering.ZMult * combinedNormal.x);
Vector3 rightVector = new Vector3((-combinedNormal.y) - combinedNormal.z, Steering.YMult * combinedNormal.x, Steering.ZMult * combinedNormal.x);
float rayLeftDistance = RaycastDistance(steering, leftVector, raycastDistance);
float rayRightDistance = RaycastDistance(steering, rightVector, raycastDistance);
// TODO: Consider updating the logic when approaching a corner.
// Currently the unit kind of turns toward the side that they are coming from even if the other turn is shorter.
// Case 1: Wall in front, wall on left, wall on right.
if (rayLeftDistance < raycastDistance && rayRightDistance < raycastDistance)
{
// Move towards the left/right wall that is closer. That should be moving away from the corner point.
if (rayLeftDistance < rayRightDistance)
{
return(SteeringUtilities.getForceForDirection(steering, leftVector));
}
else // rayRightDistance < rayLeftDistance
{
return(SteeringUtilities.getForceForDirection(steering, rightVector));
}
}
// Case 2: Wall in front, wall on left
else if (rayLeftDistance < raycastDistance)
{
return(SteeringUtilities.getForceForDirection(steering, rightVector));
}
// Case 3: Wall in front, wall on right
else if (rayRightDistance < raycastDistance)
{
return(SteeringUtilities.getForceForDirection(steering, leftVector));
}
// Case 4: Wall in front
else
{
// Move towards whichever of left or right is closer to the current velocity
Vector3 perpindicularVector = SteeringUtilities.perpindicularComponent(combinedNormal, steering.GetVelocity());
// Edge case: the normal is parallel to velocity. In this case, pick one of the two perpindicular vectors at random.
if (perpindicularVector == Vector3.zero)
{
Debug.Log("Exact perpindicular!");
int randomSign = Random.value < .5 ? 1 : -1;
perpindicularVector = new Vector3((-combinedNormal.y) - combinedNormal.z, Steering.YMult * combinedNormal.x * randomSign, Steering.ZMult * combinedNormal.x * randomSign);
}
return(SteeringUtilities.getForceForDirection(steering, perpindicularVector));
}
}
return(Vector3.zero);
}