/// <summary>
/// Gets the anchor which belongs to the passed link target
/// </summary>
/// <param name="linkTarget">link target</param>
/// <returns>anchor instance</returns>
private AnchorShape GetAnchorFromLink(ShapeLink linkTarget)
{
// Get the anchor shape which is connected to the passed link
AnchorShape anchorShape = linkTarget.OwnerShape as AnchorShape;
Debug.Assert(anchorShape != null);
return(anchorShape);
}
/// <summary>
/// Gets the engine instance which belongs to the passed anchor, or NULL if the anchor
/// is not attached to an entity.
/// </summary>
/// <param name="linkTarget">link target</param>
/// <returns>Entity engine instance, or NULL if anchor is not attached to an entity</returns>
private EngineInstanceEntity GetEntityFromAnchor(AnchorShape anchorShape)
{
// Get the entity shape which holds the anchor
EntityShape entityShape = anchorShape.Parent as EntityShape;
if (entityShape == null)
{
return(null);
}
// Next get the engine instance of the entity shape
EngineInstanceEntity engineEntityInstance = entityShape._engineInstance as EngineInstanceEntity;
if (engineEntityInstance == null)
{
return(null);
}
return(engineEntityInstance);
}
/// <summary>
/// Performs the actual linking on engine instances
/// </summary>
/// <param name="src"></param>
/// <param name="target"></param>
public override void OnLink(ShapeLink src, ShapeLink target)
{
base.OnLink(src, target);
// Ignore links which don't belong to us
if (src.OwnerShape != this)
{
return;
}
// Get the anchor the target link points to
AnchorShape anchorShape = GetAnchorFromLink(target);
if (anchorShape == null || !HasEngineInstance())
{
return;
}
// Get the entity instance the target points to
EngineInstanceEntity entityInstance = GetEntityFromAnchor(anchorShape);
// Add the actor to the constraint
if (entityInstance != null)
{
// We have an anchor which belongs to an entity. Add the entity to the constraint
// and pass the anchor position, relative to the parent entity.
Vector3F anchorPositionLS = anchorShape.LocalSpacePosition;
bool bResult = EngineConstraintChainInstance.AddEntityAnchor(
(long)anchorShape.UniqueID, entityInstance, anchorPositionLS);
Debug.Assert(bResult == true);
}
else
{
// Our anchor is statically attached to the world.
// Add the static world anchor to the constraint. Pass the world space position of the anchor
// for this purpose.
Vector3F anchorPositionWS = anchorShape.Position;
bool bResult = EngineConstraintChainInstance.AddWorldAnchor((long)anchorShape.UniqueID, anchorShape);
Debug.Assert(bResult == true);
}
}
/// <summary>
/// unlinks a target from a source. Either src or target has this shape as owner
/// </summary>
/// <param name="src">the link source</param>
/// <param name="target">the link target</param>
public override void OnUnlink(ShapeLink src, ShapeLink target)
{
base.OnUnlink(src, target);
// Ignore links which don't belong to us
if (src.OwnerShape != this)
{
return;
}
// Get the anchor the target link points to
AnchorShape anchorShape = GetAnchorFromLink(target);
if (anchorShape == null || !HasEngineInstance())
{
return;
}
bool bResult = EngineConstraintChainInstance.RemoveAnchor((long)anchorShape.UniqueID);
Debug.Assert(bResult == true);
}
/// <summary>
/// Gets the engine instance which belongs to the passed anchor, or NULL if the anchor
/// is not attached to an entity.
/// </summary>
/// <param name="linkTarget">link target</param>
/// <returns>Entity engine instance, or NULL if anchor is not attached to an entity</returns>
private EngineInstanceEntity GetEntityFromAnchor(AnchorShape anchorShape)
{
// Get the entity shape which holds the anchor
EntityShape entityShape = anchorShape.Parent as EntityShape;
if (entityShape == null)
return null;
// Next get the engine instance of the entity shape
EngineInstanceEntity engineEntityInstance = entityShape._engineInstance as EngineInstanceEntity;
if (engineEntityInstance == null)
return null;
return engineEntityInstance;
}