bool SiblingFromRay(OctPositionVector subjectPos, VOBoundsDepthNode parent, Ray3f ray, out VOBoundsDepthNode sibling, out Vector3f escapeMagnitudes)
{
sibling = new VOBoundsDepthNode(null, default(Bounds));
Bounds subjectBounds = subjectPos.octant(parent.bounds);
escapeMagnitudes = EscapeVector.GetCornerMagnitudes(subjectBounds, ray) + new Vector3f(magNudge, magNudge, magNudge);
OctPositionVector siblingPosVector;
var cardinalDirection = ray.direction.GetDirection(escapeMagnitudes.IndexOfAbsMin);
if (subjectPos.Shift(cardinalDirection, out siblingPosVector))
{
sibling = new VOBoundsDepthNode(parent.node[siblingPosVector.flatIndex], siblingPosVector.octant(parent.bounds), parent.depth + 1);
return(true);
}
return(false);
}
//
// Get's the first leaf hit by a ray, if any.
// TODO: revisit the logic. Exiting when we exit tree bounds feels like it shouldn't be necessary
//
public bool GetFirstRayhit(Ray3f ray, out T leaf, out List <DBUGColorBounds> debugTraversal, out List <Ray3f> rayStepsDebug)
{
debugTraversal = new List <DBUGColorBounds>();
rayStepsDebug = new List <Ray3f>();
leaf = default(T);
var node = new VOBoundsDepthNode(root, bounds, 0);
var ancestors = new Stack <VOBoundsDepthNode>();
Vector3f pos;
if (!EscapeVector.EnterPosition(bounds, ray, out pos))
{
return(false);
}
ray.origin = pos;
int iterSafety = 0;
while (true && iterSafety++ < (int)(Mathf.Pow(8, _maxDepth) / 4))
{
if (!bounds.Contains(ray.origin))
{
return(false);
}
if (node.node.isLeaf)
{
leaf = node.node.data;
return(true);
}
OctPositionVector nextChildPosVector;
var nextChild = node.node.GetAt(ray.origin, node.bounds.center, out nextChildPosVector);
if (nextChild != null)
{
ancestors.Push(node);
node = new VOBoundsDepthNode(nextChild, nextChildPosVector.octant(node.bounds), node.depth + 1);
continue;
}
// else find a sibling or pop to parent
int doIterSafety = 0;
VOBoundsDepthNode sibling;
do
{
// while the ray origin is still within the parent bounds, see if there's a sibling along the ray
Vector3f escapeMagnitudes;
var subjectPosVector = OctPositionVector.FromPosition(ray.origin, node.bounds.center);
var validRayMove = SiblingFromRay(subjectPosVector, node, ray, out sibling, out escapeMagnitudes);
ray.origin += ray.direction * escapeMagnitudes.MinAbs;
if (validRayMove)
{
if (sibling.node != null)
{
ancestors.Push(node);
node = sibling;
}
}
else
{
if (ancestors.Count > 0)
{
node = ancestors.Pop();
break;
}
else
{
return(false);
}
}
if (doIterSafety++ > 20)
{
Debug.LogWarning("problems: hit inner do-while iter safety"); break;
}
} while (sibling.node == null);
}
Debug.LogWarning("We didn't want to get here. ray traversing octree ");
return(false);
}
