public static IList <FeatureHitTestResult> HitTestWithFeatures(this ARSCNView view, CGPoint point)
{
var results = new List <FeatureHitTestResult>();
var ray = view.HitTestRayFromScreenPosition(point);
if (ray.HasValue)
{
var result = view.HitTestFromOrigin(ray.Value.Origin, ray.Value.Direction);
if (result.HasValue)
{
results.Add(result.Value);
}
}
return(results);
}
public static SCNVector3?HitTestWithInfiniteHorizontalPlane(this ARSCNView view, CGPoint point, SCNVector3 pointOnPlane)
{
SCNVector3?result = null;
var ray = view.HitTestRayFromScreenPosition(point);
if (ray.HasValue)
{
// Do not intersect with planes above the camera or if the ray is almost parallel to the plane.
if (ray.Value.Direction.Y <= -0.03f)
{
// Return the intersection of a ray from the camera through the screen position with a horizontal plane
// at height (Y axis).
result = Utilities.RayIntersectionWithHorizontalPlane(ray.Value.Origin, ray.Value.Direction, pointOnPlane.Y);
}
}
return(result);
}
public static IList <FeatureHitTestResult> HitTestWithFeatures(this ARSCNView view,
CGPoint point,
float coneOpeningAngleInDegrees,
float minDistance = 0,
float maxDistance = float.MaxValue,
int maxResults = 1)
{
var results = new List <FeatureHitTestResult>();
ARPointCloud features = null;
using (var frame = view.Session.CurrentFrame)
{
features = frame?.RawFeaturePoints;
}
if (features != null)
{
var ray = view.HitTestRayFromScreenPosition(point);
if (ray.HasValue)
{
var maxAngleInDegrees = Math.Min(coneOpeningAngleInDegrees, 360f) / 2f;
var maxAngle = (maxAngleInDegrees / 180f) * Math.PI;
var points = features.Points;
for (nuint j = 0; j < features.Count; j++)
{
var feature = points[j];
var featurePosition = new SCNVector3((Vector3)feature);
var originToFeature = featurePosition - ray.Value.Origin;
var crossProduct = SCNVector3.Cross(originToFeature, ray.Value.Direction);
var featureDistanceFromResult = crossProduct.Length;
var hitTestResult = ray.Value.Origin + (ray.Value.Direction * SCNVector3.Dot(ray.Value.Direction, originToFeature));
var hitTestResultDistance = (hitTestResult - ray.Value.Origin).Length;
if (hitTestResultDistance < minDistance || hitTestResultDistance > maxDistance)
{
// Skip this feature - it is too close or too far away.
continue;
}
var originToFeatureNormalized = SCNVector3.Normalize(originToFeature);
var angleBetweenRayAndFeature = Math.Acos(SCNVector3.Dot(ray.Value.Direction, originToFeatureNormalized));
if (angleBetweenRayAndFeature > maxAngle)
{
// Skip this feature - is outside of the hit test cone.
continue;
}
// All tests passed: Add the hit against this feature to the results.
results.Add(new FeatureHitTestResult
{
Position = hitTestResult,
DistanceToRayOrigin = hitTestResultDistance,
FeatureHit = featurePosition,
FeatureDistanceToHitResult = featureDistanceFromResult
});
}
// Sort the results by feature distance to the ray.
results = results.OrderBy(result => result.DistanceToRayOrigin).ToList();
// Cap the list to maxResults.
var cappedResults = new List <FeatureHitTestResult>();
var i = 0;
while (i < maxResults && i < results.Count)
{
cappedResults.Add(results[i]);
i += 1;
}
results = cappedResults;
}
}
return(results);
}
