static private void TestProjectionAgainstAABB(AABBProjection projection, AABB aabb, out List <ProjectionsSideCollisionInfo> collisionInfo)
{
collisionInfo = new List <ProjectionsSideCollisionInfo>();
foreach (AABBProjection.AABBProjectionSegment projectionSegment in projection.PathSegments.Values)
{
for (int i = 0; i < 4; i++)
{
AABB.AABBSide currentSide = (AABB.AABBSide)i;
LineSegment aabbSegment = aabb.Sides[i];
Vector2f[] collisionPoints = null;
if (projectionSegment.Path.CollidesWith(aabbSegment, out collisionPoints))
{
foreach (Vector2f collisionPoint in collisionPoints)
{
ProjectionsSideCollisionInfo info = new ProjectionsSideCollisionInfo();
info.ProjectionSegment = projectionSegment;
info.CollisionPoint = collisionPoint;
info.Side = currentSide;
info.Length = Helpers.DistanceBetweenTwoPoints(projectionSegment.Path.Start, collisionPoint);
collisionInfo.Add(info);
}
}
}
}
}
static public CollisionResults TestCollisions(CollisionObject object1, CollisionObject object2)
{
CollisionResults results = new CollisionResults()
{
Object1 = object1, Object2 = object2
};
//Are they already colliding?
if (object1.BoundingBox.Overlaps(object2.BoundingBox))
{
results.Type = CollisionType.enAbsolute;
return(results);
}
//If both items are stationary, then there's no reason for projections. Return
if ((object1.Velocity.X == 0.0f && object1.Velocity.Y == 0.0f) && (object2.Velocity.X == 0.0f && object2.Velocity.Y == 0.0f))
{
return(results);
}
AABBProjection object1Projection = new AABBProjection(object1.BoundingBox, object1.Velocity);
AABBProjection object2Projection = new AABBProjection(object2.BoundingBox, object2.Velocity);
results.Object1Projection = object1Projection;
results.Object2Projection = object2Projection;
List <AABBProjection.AABBProjectionCollisionResult> projectionResults = null;
bool collisions = (object1Projection.CollidesWith(object2Projection, out projectionResults) &&
((object1.Velocity.X != 0.0f || object1.Velocity.Y != 0.0f) && (object2.Velocity.X != 0.0f || object2.Velocity.Y != 0.0f)));
if (collisions)
{
List <AABBProjection.AABBProjectionCollisionResult> sorted = projectionResults.OrderBy(x => x.Length).ToList();
AABBProjection.AABBProjectionCollisionResult shortestResult = sorted[0];
AABBProjection.AABBProjectionSegmentEnum[] adjacentSegments = AABBProjection.GetAdjacentSegments(shortestResult.LocalSide);
List <AABBProjection.AABBProjectionCollisionResult> adjacentSegmentResults = sorted.Where(x => x.OtherSide == shortestResult.OtherSide && adjacentSegments.Contains(x.LocalSide)).OrderBy(x => x.Length).ToList();
if (adjacentSegmentResults.Count > 0)
{
float shortestLength = adjacentSegmentResults[0].Length;
//There could be multiples if we hit a corner
adjacentSegmentResults = adjacentSegmentResults.Where(x => x.Length == shortestLength).ToList();
//Verify collision by projecting the AABB's to this point-in-time in their movement.
float totalMovementDistance = Helpers.DistanceBetweenTwoPoints(object1.BoundingBox.Position, object1Projection.End.Position);
//This is when the collision *MIGHT* happen for THIS collision object
float pointInTime = shortestLength / totalMovementDistance;
SFML.Window.Vector2f object1Position = object1.BoundingBox.Position + (object1.Velocity * pointInTime);
AABB localCollisionResultProjection = new AABB(object1Position, object1.BoundingBox.Extents, SFML.Graphics.Color.Green);
//Now, see where the OTHER collision object will be at this point in time.
SFML.Window.Vector2f otherPosition = object2.BoundingBox.Position + (object2.Velocity * pointInTime);
AABB otherCollisionResultProjection = new AABB(otherPosition, object2.BoundingBox.Extents, SFML.Graphics.Color.Blue);
results.Object1CollisionAABB = localCollisionResultProjection;
results.Object2CollisionAABB = otherCollisionResultProjection;
results.CollisionTime = pointInTime;
//Do they overlap at the projection result?
if (!localCollisionResultProjection.Overlaps(otherCollisionResultProjection))
{
return(results);
}
foreach (AABBProjection.AABBProjectionCollisionResult collisionResult in adjacentSegmentResults)
{
AABB.AABBSide collisionSide = AABBProjection.GetSideFromProjectionSegments(shortestResult.LocalSide, collisionResult.LocalSide);
AABB.AABBSide otherCollisionSide = AABB.GetOppositeSide(collisionSide);
results.Object1CollisionAABB.Sides[(int)collisionSide].SetColor(SFML.Graphics.Color.Red);
results.Object2CollisionAABB.Sides[(int)otherCollisionSide].SetColor(SFML.Graphics.Color.Red);
results.Sides[collisionSide] = otherCollisionSide;
}
results.Type = CollisionType.enPrediction;
}
}
else
{
List <ProjectionsSideCollisionInfo> collisionInfo = null;
AABBProjection checkedObjectProjection = null;
if (object1.Velocity.X != 0.0f || object1.Velocity.Y != 0.0f)
{
//Test projection1 against projection2's End's segments
TestProjectionAgainstAABB(object1Projection, object2Projection.End, out collisionInfo);
checkedObjectProjection = object1Projection;
}
else if (object2.Velocity.X != 0.0f || object2.Velocity.Y != 0.0f)
{
//Test projection2 against projection1's End segments
TestProjectionAgainstAABB(object2Projection, object1Projection.End, out collisionInfo);
checkedObjectProjection = object2Projection;
}
if (collisionInfo != null)
{
if (collisionInfo.Count > 0)
{
collisionInfo = collisionInfo.OrderBy(x => x.Length).ToList();
ProjectionsSideCollisionInfo closestInfo = collisionInfo[0];
float shortestLength = closestInfo.Length;
//Verify collision by projecting the AABB's to this point-in-time in their movement.
float totalMovementDistance = Helpers.DistanceBetweenTwoPoints(checkedObjectProjection.Start.Position, checkedObjectProjection.End.Position);
//This is when the collision *MIGHT* happen for THIS collision object
float pointInTime = shortestLength / totalMovementDistance;
SFML.Window.Vector2f object1Position = object1.BoundingBox.Position + (object1.Velocity * pointInTime);
AABB localCollisionResultProjection = new AABB(object1Position, object1.BoundingBox.Extents, SFML.Graphics.Color.Green);
//Now, see where the OTHER collision object will be at this point in time.
SFML.Window.Vector2f otherPosition = object2.BoundingBox.Position + (object2.Velocity * pointInTime);
AABB otherCollisionResultProjection = new AABB(otherPosition, object2.BoundingBox.Extents, SFML.Graphics.Color.Blue);
//Do they overlap at the projection result?
//if (!localCollisionResultProjection.Overlaps(otherCollisionResultProjection))
//return results;
results.Object1CollisionAABB = localCollisionResultProjection;
results.Object2CollisionAABB = otherCollisionResultProjection;
AABB.AABBSide object1Side = AABB.GetOppositeSide(closestInfo.Side);
results.Object1CollisionAABB.Sides[(int)object1Side].SetColor(SFML.Graphics.Color.Red);
results.Object2CollisionAABB.Sides[(int)closestInfo.Side].SetColor(SFML.Graphics.Color.Red);
results.Type = CollisionType.enPrediction;
results.Sides[object1Side] = closestInfo.Side;
results.CollisionTime = pointInTime;
}
}
}
if (results.CollisionTime == (1.0f / 0.0f))
{
int i = 0;
}
return(results);
}