// custom method to do some extra work after the collision check
protected override void UpdateEntityState( CollisionCheckResult result )
{
base.UpdateEntityState( result );
_againstWall = result.XAxis;
}
public CollisionCheckResult Check(Vector2 currentPosition, Vector2 positionDelta, Vector2 objectSize)
{
Result = new CollisionCheckResult()
{
Position = currentPosition
};
_currentPosition = currentPosition.Ceiling();
_positionDelta = positionDelta.Ceiling();
_objectSize = objectSize.Ceiling();
_finalPosition = new Vector2(_positionDelta.X, _positionDelta.Y);
// short-circuit if there is nothing to do
if (positionDelta == Vector2.Zero)
{
return(Result);
}
// determine if we need to perform multiple checks, e.g. the entitys proposed
// position is more than one tile away.
var steps = (float)Math.Ceiling(Math.Max(Math.Abs(_positionDelta.X), Math.Abs(_positionDelta.Y)) / _map.TileSize);
if (steps > 1)
{
var stepDelta = _positionDelta / steps;
if (stepDelta.X > 0 || stepDelta.Y > 0)
{
for (var i = 0; i < steps; i++)
{
PeekStep(stepDelta, i);
// if the trace finds a collision anywhere along the way, zero out the offending part of the vector
if (Result.XAxis)
{
stepDelta.X = 0;
positionDelta.X = 0;
}
if (Result.YAxis)
{
stepDelta.Y = 0;
positionDelta.Y = 0;
}
}
}
}
else
{
PeekStep(positionDelta, 0f);
}
return(Result);
}
public CollisionCheckResult Check( Vector2 currentPosition, Vector2 positionDelta, Vector2 objectSize )
{
Result = new CollisionCheckResult() { Position = currentPosition };
_currentPosition = currentPosition.Ceiling();
_positionDelta = positionDelta.Ceiling();
_objectSize = objectSize.Ceiling();
_finalPosition = new Vector2( _positionDelta.X, _positionDelta.Y );
// short-circuit if there is nothing to do
if( positionDelta == Vector2.Zero )
return Result;
// determine if we need to perform multiple checks, e.g. the entitys proposed
// position is more than one tile away.
var steps = (float)Math.Ceiling( Math.Max( Math.Abs( _positionDelta.X ), Math.Abs( _positionDelta.Y ) ) / _map.TileSize );
if( steps > 1 )
{
var stepDelta = _positionDelta / steps;
if( stepDelta.X > 0 || stepDelta.Y > 0 )
{
for( var i = 0; i < steps; i++ )
{
PeekStep( stepDelta, i );
// if the trace finds a collision anywhere along the way, zero out the offending part of the vector
if( Result.XAxis )
{
stepDelta.X = 0;
positionDelta.X = 0;
}
if( Result.YAxis )
{
stepDelta.Y = 0;
positionDelta.Y = 0;
}
}
}
}
else
{
PeekStep( positionDelta, 0f );
}
return Result;
}
protected virtual void UpdateEntityState( CollisionCheckResult result )
{
IsStanding = false;
if( result.YAxis )
{
IsStanding = Velocity.Y > 0;
Velocity = new Vector2( Velocity.X, 0 );
}
if( result.XAxis )
Velocity = new Vector2( 0, Velocity.Y );
Position = result.Position;
}
