public void UpdateCollisions()
{
foreach (var b in bodies)
{
//destroy objects outside of bounds
if ((b.position.X < -boundarySize || b.position.X > sceneWidth + boundarySize ||
b.position.Y < -boundarySize || b.position.Y > sceneHeight + boundarySize) &&
b.owner is Placeholder == false)
{
b.owner.health = 0;
}
}
//clean grid
for (int x = 0; x < gridSize; x++)
{
for (int y = 0; y < gridSize; y++)
{
colliderGrid[x][y].Clear();
}
}
//place objects into 2D grid
foreach (var body in bodies)
{
int tileX = Mathfp.Floor(body.position.X / gridCellWidth);
int tileY = Mathfp.Floor(body.position.Y / gridCellHeight);
body.occupiedTile = new Point(tileX, tileY);
//inject into grid, including adjacent tiles
for (int x = tileX - 1; x <= tileX + 1; x++)
{
for (int y = tileY - 1; y <= tileY + 1; y++)
{
if (x >= 0 && x < gridSize && y >= 0 && y < gridSize)
{
colliderGrid[x][y].PutIntoFreeSlot(body);
}
}
}
}
//check collisions
for (int i = 0; i < contactCapacity; i++)
{
contacts[i].confirmed = false;
}
foreach (var body in bodies)
{
int x = body.occupiedTile.x;
int y = body.occupiedTile.y;
//ignore objects outside grid
if (!(x >= 0 && x < gridSize && y > 0 && y < gridSize))
{
continue;
}
foreach (var other in colliderGrid[x][y])
{
if (other != null && other != body)
{
if (body.CanCollideWith(other) && PerformCollision(body, other))
{
int existing = FindExistingContact(body, other);
if (existing == -1)
{
var contact = new Connection(body, other);
if (AddContact(contact))
{
behaviorController.SendCollisionEnter(contact);
}
}
else
{
behaviorController.SendCollisionContinue(contacts[existing]);
contacts[existing].confirmed = true;
}
}
}
}
}
for (int i = 0; i < contactCapacity; i++)
{
if (contacts[i].alive && contacts[i].confirmed == false)
{
behaviorController.SendCollisionExit(contacts[i]);
contacts[i].alive = false;
}
}
}