public IEnumerable<ISide> GetSides(Direction direction, Range positionRange, Range boundsRange, bool ascending = true)
{
return _directionSidesMap[(int) direction]
.Where(s =>
positionRange.Contains(s.Position) &&
boundsRange.IsIntersect(new Range(s.Begin, true, s.End, true)))
.OrderBy(s => ascending ? s.Position : -s.Position);
}
private IEnumerable<CollisionEvent> GetSideCollisions(IBody movingBody, Direction movingSideDirection, Vector2 path)
{
var axis = movingSideDirection.ToAxis();
var sidePosition = movingBody.GetBound(movingSideDirection);
var counterDirection = movingSideDirection.AtBack();
var pathForward = path.GetComponent(movingSideDirection);
if (pathForward == 0)
return Enumerable.Empty<CollisionEvent>();
var pathStartInclusive = pathForward > 0;
var pathEndInclusive = pathForward < 0;
var pathLeft = path.GetComponent(movingSideDirection.AtLeft());
var sideStartInclusive = pathLeft < 0;
var sideEndInclusive = pathLeft > 0;
var pathAlong = path.GetComponent(axis);
var pathAcross = path.GetComponent(axis.Orthogonal());
var collisionType = pathForward >= 0 ? CollisionType.Entering : CollisionType.Leaving;
var incidenceTangent = pathLeft/pathForward; //todo maybe pathLeft negate....
var movedSidePositionRange = new Range(sidePosition, pathStartInclusive, sidePosition + pathAlong, pathEndInclusive);
var movedSideRange = movingBody.GetBoundRange(movingSideDirection, sideStartInclusive, sideEndInclusive);
var counterSides = _sideRepository.GetSides(counterDirection, movedSidePositionRange, movedSideRange, pathAlong > 0);
return (from counterSide in counterSides //todo query bodyBounds more optimal!!! use special sorted structs
where counterSide.Body != movingBody && movedSidePositionRange.Contains(counterSide.Position)
let pathAlongToCounterSide = counterSide.Position - sidePosition
let pathAcrossToCounterSide = pathAcross * pathAlongToCounterSide / pathAlong
where movedSideRange.IsIntersect(new Range(counterSide.Begin, sideStartInclusive, counterSide.End, sideEndInclusive))
group counterSide.Body by pathAlongToCounterSide into g
select new CollisionEvent
{
Collision = new Collision
{
Bodies = g.ToArray(),
Type = collisionType,
NormalDirection = counterDirection,
IncidenceTangent = incidenceTangent
},
Traversed = g.Key / pathAlong,
});
}