public bool HasCollision(ChunkInfo ci, int x, int y)
{
Vector2 worldPos = WorldMap.Chunk2World(ci, x, y);
Box2D worldBox = new Box2D(worldPos, 0.5f, 0.5f);
// Check against any player
Box2D playerBox = GameManager.Instance.MainPlayer.Box;
return(CollisionCode.TestBox2DBox2D(worldBox, playerBox));
}
public ItemInstance GetItemInstanceFromWorldPos(Vector2 worldPos)
{
// (O(n)) - No spatial partitioning, will probably be slow when many items are present.
foreach (ItemInstance item in ItemManager.Instance)
{
if (CollisionCode.TestPointBox2D(worldPos, item.Box))
{
return(item);
}
}
return(null);
}
public Enemy GetEnemyFromWorldPos(Vector2 worldPos)
{
foreach (Entity entity in EntityManager.Instance.Entities)
{
Enemy enemy = entity as Enemy;
if (enemy && CollisionCode.TestPointBox2D(worldPos, enemy.Box))
{
return(enemy);
}
}
return(null);
}
private void UpdatePositionInternal(Entity entity, Vector3 oldPosition, ref Vector3 newPosition, int step)
{
// Figure out sweep area
Vector2 oldPosition2D = new Vector2(oldPosition.x, oldPosition.y);
Vector2 newPosition2D = new Vector2(newPosition.x, newPosition.y);
float mostLeft = Math.Min(oldPosition2D.x, newPosition2D.x) - 0.5f;
float mostRight = Math.Max(oldPosition2D.x, newPosition2D.x) + 0.5f;
float mostUp = Math.Max(oldPosition2D.y, newPosition2D.y) + 0.5f;
float mostDown = Math.Min(oldPosition2D.y, newPosition2D.y) - 0.5f;
Vector2 topLeft = new Vector2(mostLeft, mostUp);
Vector2 bottomRight = new Vector2(mostRight, mostDown);
Box2D sweep = new Box2D(topLeft, bottomRight);
Box2D originalBox = new Box2D(oldPosition2D, 0.5f, 0.5f);
Box2D endBox = new Box2D(newPosition2D, 0.5f, 0.5f);
Vector2 displacement = endBox.Center - originalBox.Center;
// now get the list of tiles that we may have encountered during this sweep and return their boxes
CollisionInfo[] broadPhase = CollisionCode.BroadPhase(entity, sweep);
float bestT = 1.0f; // no collision
foreach (CollisionInfo ci in broadPhase)
{
// now for each collision potential collision, figure out at which 't' we hit the box, return the shortest t in case of multiple collision
float tFirst, tLast;
bool collide = CollisionCode.IntersectMovingBox2DBox2D(originalBox, ci.Box, displacement, new Vector2(0, 0), out tFirst, out tLast);
if (collide)
{
// Are we allowed to go through ?
if ((ci.Flags & CollisionFlags.Wall) == CollisionFlags.Wall)
{
// hard collision, prevent movement
bestT = Mathf.Min(tFirst, bestT);
}
else
{
// send OnTouchEvent on Entity
// Note: This will probably send multiple Touch events to the same pair. We should accumulate these TouchEvent and then sweep them if we get the bug.
Entity entity2 = ci.Entity;
// TODO - Since UpdateCollisionInternal is called multiple times per frame, also when checking potential collision detection, we need a way to turn it on and off
// to avoid sending false positive, also to avoid sending multiple touches on the same frame
if (entity2 != null)
{
entity.OnTouch(entity2);
entity2.OnTouch(entity);
}
}
}
}
if (bestT < 1.0f) // got at least one collision, reduce wanted velocity
{
displacement *= bestT;
newPosition2D = oldPosition2D + displacement;
}
if (bestT >= 0.999)
{
newPosition.x = newPosition2D.x;
newPosition.y = newPosition2D.y;
}
else if (step < 5)
{
// we were at oldPosition, we wanted to go at newPosition, we are currently stuck at newPosition2D
// if displacement was on a single-axis, forget it, there's nothing we do can
Vector3 wantedDisplacement = newPosition - oldPosition;
if (Mathf.Abs(wantedDisplacement.x) <= 0.001 || Mathf.Abs(wantedDisplacement.y) <= 0.001)
//if (true)
{
newPosition.x = newPosition2D.x;
newPosition.y = newPosition2D.y;
}
else
{
Vector3 subOldPosition = new Vector3(newPosition2D.x, newPosition2D.y, 0.0f);
Vector3 subNewPositionInX = newPosition;
subNewPositionInX.y = subOldPosition.y;
Vector3 subNewPositionInY = newPosition;
subNewPositionInY.x = subOldPosition.x;
// Try X-Axis only
UpdatePositionInternal(entity, subOldPosition, ref subNewPositionInX, step + 1);
// Try Y-Axis only
UpdatePositionInternal(entity, subOldPosition, ref subNewPositionInY, step + 1);
// Which one got us closer to our goal ?
if ((subNewPositionInX - newPosition).sqrMagnitude < (subNewPositionInY - newPosition).sqrMagnitude)
{
// TODO - Recurse again ?
// it was better to go in X only
newPosition.x = subNewPositionInX.x;
newPosition.y = subNewPositionInX.y;
}
else
{
newPosition.x = subNewPositionInY.x;
newPosition.y = subNewPositionInY.y;
}
}
}
}
