void InitSpatialGrid()
{
spatialGrid = new List <GameObject> [flyingSpace, flyingSpace, flyingSpace];
for (int i = 0; i < numBoids; i++)
{
//initialize spatial grid again.
//if its null at hash make a list at the voxel.
currBoid = boidList[i].GetComponent <boids>();
position = currBoid.transform.position;
//if boid position outside of limits, kill and reinitialize
if (position.x < 0.0f || position.x > flyingSpace ||
position.y < 0.0f || position.y > flyingSpace ||
position.z < 0.0f || position.z > flyingSpace)
{
position = new Vector3
(Random.Range(0.0f + flyingSpace / 8, flyingSpace - flyingSpace / 8),
Random.Range(0.0f + flyingSpace / 8, flyingSpace - flyingSpace / 8),
Random.Range(0.0f + flyingSpace / 8, flyingSpace - flyingSpace / 8));
// calculateMedianPoint();
Destroy(boidList[i]);
boidList[i] = Instantiate(boidPrefab, position, Quaternion.identity);
}
if (spatialGrid[(int)Mathf.Floor(position.x), (int)Mathf.Floor(position.y), (int)Mathf.Floor(position.z)] == null)
{
spatialGrid[(int)Mathf.Floor(position.x),
(int)Mathf.Floor(position.y),
(int)Mathf.Floor(position.z)] = new List <GameObject>();
}
spatialGrid[(int)Mathf.Floor(position.x),
(int)Mathf.Floor(position.y),
(int)Mathf.Floor(position.z)].Add(boidList[i]);
}
}
//Update called once per update
void UpdateBoidPositions()
{
for (int i = 0; i < flyingSpace; i++)
{
for (int j = 0; j < flyingSpace; j++)
{
for (int k = 0; k < flyingSpace; k++)
{
if (spatialGrid[i, j, k] != null)
{
//for each boid in list at voxel
int count = spatialGrid[i, j, k].Count;
for (int boidInVoxelList = 0; boidInVoxelList < count; boidInVoxelList++)
{
currBoid = spatialGrid[i, j, k][boidInVoxelList].GetComponent <boids>();
//create interaction list
//everything in this voxel can be added
// interactionList.AddRange(spatialGrid[i, j, k]); //plus everything that is one voxel away on all sides
//this will add 27 boxes if 3x3x3 or greater. otherwise will add all 8.
for (int n = i - 1; n <= i + 1; n++)
{
//if its less than 0 we dont want that
if (n < 0)
{
continue;
}
if (n >= flyingSpace)
{
continue;
}
for (int p = j - 1; p <= j + 1; p++)
{
if (p < 0)
{
continue;
}
if (p >= flyingSpace)
{
continue;
}
for (int q = k - 1; q <= k + 1; q++)
{
if (q < 0)
{
continue;
}
if (q >= flyingSpace)
{
continue;
}
// Debug.Log("Would be adding boids from voxel [" + n + "," + p + "," + q + "]. /n/n");
if (spatialGrid[n, p, q] != null)
{
interactionList.AddRange(spatialGrid[n, p, q]);
}
}
}
}
Vector3 ourBoidPosition = spatialGrid[i, j, k][boidInVoxelList].transform.position;
//now we have interaction list with our ijk boid. iterate thru each in list and add up accelerations
int interactionCount = interactionList.Count;
for (int r = 0; r < interactionCount; r++)
{
if (interactionList[r].GetInstanceID() != currBoid.GetInstanceID())
{
boids otherBoid = interactionList[r].GetComponent <boids>();
//compute distance between our boid and the boid from the interaction list
distance = interactionList[r].transform.position - ourBoidPosition;
//compute ktheta
thetaOne = currBoid.GetThetaOne();
thetaTwo = currBoid.GetThetaTwo();
thetaMagnitude = Vector3.Angle(currBoid.getVelocity(), otherBoid.transform.position);
if ((-thetaOne / 2 <= thetaMagnitude) && thetaMagnitude <= thetaOne / 2)
{
ktheta = 1.0f;
}
else if (((thetaOne / 2) <= thetaMagnitude) && (thetaMagnitude <= (thetaTwo / 2)))
{
ktheta = ((thetaTwo / 2) - thetaMagnitude) / ((thetaTwo / 2) - (thetaOne / 2));
}
else
{
ktheta = 0.0f;
}
//compute kd
if (distance.magnitude < r1)
{
kd = 1.0f;
}
else if ((r1 <= distance.magnitude) && (distance.magnitude <= r2))
{
kd = (r2 - distance.magnitude) / (r2 - r1);
}
else
{
kd = 0.0f;
}
//pg 107 from House and Keyser's text
collision += ktheta * kd * (-1.0f * (kCollisionScale / (distance.magnitude + 0.01f)) * distance.normalized);
velocityMatch += ktheta * kd * (kVelocityScale * (otherBoid.getVelocity() - currBoid.getVelocity()));
centering += ktheta * kd * kCenteringScale * distance;
}
}
//prioritizing acceleration source (pg 108)
float ar = accelerationCap;
combinedAcceleration = Mathf.Min(ar, collision.magnitude) * collision.normalized;
ar = accelerationCap - combinedAcceleration.magnitude;
combinedAcceleration = combinedAcceleration + Mathf.Min(ar, velocityMatch.magnitude) * velocityMatch.normalized;
ar = accelerationCap - combinedAcceleration.magnitude;
combinedAcceleration = combinedAcceleration + Mathf.Min(ar, centering.magnitude) * centering.normalized;
//check walls. r2 is the far distance used in calculating kd
//check if our boid is nearing where X = 0
if (ourBoidPosition.x < (3 * flyingSpace / 7))
{
combinedAcceleration.x += accelerationCap / 2;
}
//check if our boid is nearing where X = max X bound
else if ((flyingSpace - ourBoidPosition.x) < 3 * flyingSpace / 7)
{
combinedAcceleration.x += -accelerationCap / 2;
}
//so if acceleration = 0 then reversing doesnt work
//check if our boid is nearing bound where Y = 0
if ((ourBoidPosition.y) < 3 * flyingSpace / 7)
{
combinedAcceleration.y += accelerationCap / 2;
}
//check if our boid is nearing where Y = max Y bound
else if ((flyingSpace - ourBoidPosition.y) < 3 * flyingSpace / 7)
{
combinedAcceleration.y -= accelerationCap / 2;
}
//check if our boid is nearing where Z = 0
if ((ourBoidPosition.z) < 3 * flyingSpace / 7)
{
combinedAcceleration.z += accelerationCap / 2;
}
//check if our boid is nearing where Z = max Z bound
else if ((flyingSpace - ourBoidPosition.z) < 3 * flyingSpace / 7)
{
combinedAcceleration.z += -accelerationCap / 2;
}
currBoid.setVelocity(combinedAcceleration * Time.deltaTime + currBoid.getVelocity());
//update position
temp = ourBoidPosition;
spatialGrid[i, j, k][boidInVoxelList].transform.position =
(2.0f * ourBoidPosition) - currBoid.getOldPosition() + ((Time.deltaTime * Time.deltaTime) * (combinedAcceleration));
currBoid.setOldPosition(temp);
interactionList.Clear();
}
}
}
}
}
System.Array.Clear(spatialGrid, 0, spatialGrid.GetLength(0) * spatialGrid.GetLength(1) * spatialGrid.GetLength(2));
}
// Start is called before the first frame update
void Start()
{
boid = GetComponent <boids>();
}