/// <summary>
/// Checks all collisions within the entities known collision cells
/// </summary>
/// <param name="entity">Entity to check.</param>
protected override void Process(Entity entity)
{
var collision = entity.GetComponent <CollisionComponent>();
var sprite = entity.GetComponent <SpriteTransform>();
var center = Vector2.Zero;
if (sprite != null)
{
center = sprite.Target.Origin;
}
if (collision != null)
{
var neighbours = _map.GetCollisions(entity, collision);
var boxCount = collision.Boxes.Count;
// Check collisions for all of the entities AABB's for all neighbours
for (int b = 0; b < boxCount; b++)
{
var box = collision.Boxes[b];
// Move the box to align with the entities new position
if (sprite != null)
{
box.Width += sprite.Bounds.Width - box.Width;
box.Height += sprite.Bounds.Height - box.Height;
box.X += sprite.Target.Position.X - box.X - (sprite.Bounds.Width / 2);
box.Y += sprite.Target.Position.Y - box.Y - (sprite.Bounds.Height / 2);
collision.Boxes[b] = box;
}
// Do narrow phase checking for each neighbour
foreach (var n in neighbours)
{
var neighbourCollision = n.GetComponent <CollisionComponent>();
collision.Event = HandleCollisions(box, neighbourCollision);
if (collision.Event)
{
// Update collision information for other systems' use
collision.Collider = n;
neighbourCollision.Event = true;
neighbourCollision.Collider = entity;
break;
}
}
// Do tilemap collision checking
if (_tileMap != null)
{
var physics = entity.GetComponent <PhysicsComponent>();
var movement = entity.GetComponent <Movement>();
if (physics != null && movement != null)
{
// Get all tiles surrounding the entity
var top = (int)Math.Floor(box.Top / _tileMap.TileSize.Y);
var left = (int)Math.Floor(box.Left / _tileMap.TileSize.X);
var right = Math.Ceiling(box.Right / _tileMap.TileSize.X) - 1;
var bottom = Math.Ceiling(box.Bottom / _tileMap.TileSize.X) - 1;
int xSide = 1;
int ySide = 1;
// Check all the tiles around the entity, updating the negative velocity
// of their movement based on the direction a collision was found
for (int x = left; x <= right; x++)
{
for (int y = top; y <= bottom; y++)
{
var tileAABB = new Rectangle(
x * _tileMap.TileSize.X,
y * _tileMap.TileSize.Y,
_tileMap.TileSize.X,
_tileMap.TileSize.Y
);
// Check collision for that tile and alter velocity if collision was found
if (_tileMap[x, y].Flag == TileFlag.Impassable && box.Intersects(tileAABB))
{
physics.Velocity = new Vector2(xSide * 5, ySide * 5);
movement.Position = movement.LastPosition;
}
ySide -= 2;
}
xSide -= 2;
}
}
}
}
}
}