public bool HasCollisionBelow(IEntity entity)
{
Debug.Assert(entity != null);
Rect r = entity.CreateCollisionRectangle();
float initialMid = r.Top + r.Height / 2f;
r.X -= JUMP_X_TOLERANCE / 2f;
r.Width += JUMP_X_TOLERANCE;
r.Y += JUMP_Y_TOLERANCE; // move it down a bit
var tiles = World.Map.GetTouchedTiles(r);
foreach (var tile in tiles) {
if (tile.Key.Intersects(r) && // we have a collision
(tile.Value == CollisionType.Block ||
tile.Value == CollisionType.Platform) && // it is a blocking collision
tile.Key.Top >= initialMid) { // the block is below us (below our feet)
int x = World.Map.GetTileXIndex(tile.Key);
int y = World.Map.GetTileYIndex(tile.Key);
// If the tile above the current tile is passable, we may jump !
if (World.Map.IsValidXIndex(x) && World.Map.IsValidYIndex(y) &&
World.Map.GetCollision(x, y - 1) == CollisionType.Passable)
return true;
}
}
return false;
}
/// <summary>
/// Resolves the collisions between an entity and the world it is in.
/// </summary>
public void UndoCollisions(IEntity entity)
{
Debug.Assert(entity != null);
var collisions = World.GetTouchedObjects(entity.CreateCollisionRectangle());
HandleCollisionGroup(entity, collisions);
}
public bool HasCollisions(IEntity entity)
{
Debug.Assert(entity != null);
var rect = entity.CreateCollisionRectangle();
var collisions = World.GetTouchedObjects(rect);
foreach (var collision in collisions) {
if (collision.Value != CollisionType.Passable &&
rect.Intersects(collision.Key)) {
return true;
}
}
return false;
}
/// <summary>
/// Handles the collision of an object with multiple entities.
/// </summary>
void HandleCollisionGroup(
IEntity entity,
List<KeyValuePair<Rect, CollisionType>> collisions)
{
Debug.Assert(entity != null);
Debug.Assert(collisions != null);
foreach (KeyValuePair<Rect, CollisionType> collision in collisions)
{
// We recreate an entity rectangle on every loop
// because multiple collisions might affect the entity in the same frame.
Rect entityRect = entity.CreateCollisionRectangle();
Rect rect = collision.Key;
CollisionType type = collision.Value;
switch (type)
{
case CollisionType.Block:
UndoCollision(entity, entityRect, rect);
break;
case CollisionType.Passable: break; // do nothing then
default:
throw new NotImplementedException("Collision type not implemented.");
}
}
}
