/// <summary>
/// Pass in the game object's position to check if it's within
/// the specified boundary space.
/// </summary>
/// <param name="gameObjectPosition">The position of the GameObject to check.</param>
/// <param name="boundaryType">The type of the boundary. Use PlayArea for the inscribed rectangle or TrackedArea for the bounds containing the whole space.</param>
/// <returns>True if the point is in the boundary type's bounds.</returns>
public bool ContainsObject(Vector3 gameObjectPosition, UnityEngine.Experimental.XR.Boundary.Type boundaryType)
{
gameObjectPosition = CameraCache.Main.transform.parent.InverseTransformPoint(gameObjectPosition);
if (gameObjectPosition.y < boundaryFloor || gameObjectPosition.y > boundaryHeight)
{
return(false);
}
if (boundaryType == UnityEngine.Experimental.XR.Boundary.Type.PlayArea)
{
if (inscribedRectangle == null || !inscribedRectangle.IsRectangleValid)
{
return(false);
}
return(inscribedRectangle.IsPointInRectangleBounds(new Vector2(gameObjectPosition.x, gameObjectPosition.z)));
}
else if (boundaryType == UnityEngine.Experimental.XR.Boundary.Type.TrackedArea)
{
// Check if the supplied game object's position is within the bounds volume.
return(EdgeHelpers.IsInside(boundaryGeometryEdges, new Vector2(gameObjectPosition.x, gameObjectPosition.z)));
}
return(false);
}
/// <summary>
/// Finds a large inscribed rectangle. Tries to be maximal but this is
/// best effort. The algorithm used was inspired by the blog post
/// https://d3plus.org/blog/behind-the-scenes/2014/07/08/largest-rect/
/// Random points within the polygon are chosen, and then 2 lines are
/// drawn through those points. The midpoints of those lines are
/// used as the center of various rectangles, using a binary search to
/// vary the size, until the largest fit-able rectangle is found.
/// This is then repeated for predefined angles (0-180 in steps of 15)
/// and aspect ratios (1 to 15 in steps of 0.5).
/// </summary>
private void FindInscribedRectangle(Edge[] edges, int randomSeed, out Vector2 center, out float angle, out float width, out float height)
{
center = EdgeHelpers.InvalidPoint;
angle = width = height = 0;
// Find min x, min y, max x, max y and generate random
// points in this range until we have randomPointCount
// random starting points
float minX = largeValue;
float minY = largeValue;
float maxX = smallValue;
float maxY = smallValue;
foreach (var edge in edges)
{
if (edge.Ax < minX || edge.Bx < minX)
{
minX = Math.Min(edge.Ax, edge.Bx);
}
if (edge.Ay < minY || edge.By < minY)
{
minY = Math.Min(edge.Ay, edge.By);
}
if (edge.Ax > maxX || edge.Bx > maxX)
{
maxX = Math.Max(edge.Ax, edge.Bx);
}
if (edge.Ay > maxY || edge.By > maxY)
{
maxY = Math.Max(edge.Ay, edge.By);
}
}
// Generate random points
Vector2[] startingPoints = new Vector2[randomPointCount];
{
var random = new System.Random(randomSeed);
for (int pointIndex = 0; pointIndex < randomPointCount; ++pointIndex)
{
Vector2 candidatePoint;
do
{
candidatePoint.x = ((float)random.NextDouble() * (maxX - minX)) + minX;
candidatePoint.y = ((float)random.NextDouble() * (maxY - minY)) + minY;
}while (!EdgeHelpers.IsInside(edges, candidatePoint));
startingPoints[pointIndex] = candidatePoint;
}
}
float[] angles = { 0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165 };
foreach (var candidateAngle in angles)
{
// For each randomly generated starting point
foreach (var startingPoint in startingPoints)
{
// Find the collision point of a cross through the given point at the given angle
// Ignore the return value. A return value of false indicates one of the points is bad.
// We will check each point's validity ourselves anyway.
Vector2 topCollisionPoint;
Vector2 bottomCollisionPoint;
Vector2 leftCollisionPoint;
Vector2 rightCollisionPoint;
FindSurroundingCollisionPoints(edges, startingPoint, DegreesToRadians(candidateAngle),
out topCollisionPoint, out bottomCollisionPoint, out leftCollisionPoint, out rightCollisionPoint);
// Now calculate the midpoint between top and bottom (the "vertical midpoint") and left and right (the "horizontal midpoint")
if (EdgeHelpers.IsValidPoint(topCollisionPoint) && EdgeHelpers.IsValidPoint(bottomCollisionPoint))
{
var verticalMidpoint = new Vector2((topCollisionPoint.x + bottomCollisionPoint.x) / 2,
(topCollisionPoint.y + bottomCollisionPoint.y) / 2);
float aspectRatio;
float w;
float h;
if (TryFitMaximumRectangleAtAngle(edges, verticalMidpoint, DegreesToRadians(candidateAngle), width * height, out aspectRatio, out w, out h))
{
center = verticalMidpoint;
angle = candidateAngle;
width = w;
height = h;
}
}
if (EdgeHelpers.IsValidPoint(leftCollisionPoint) && EdgeHelpers.IsValidPoint(rightCollisionPoint))
{
var horizontalMidpoint = new Vector2((leftCollisionPoint.x + rightCollisionPoint.x) / 2,
(leftCollisionPoint.y + rightCollisionPoint.y) / 2);
float aspectRatio;
float w;
float h;
if (TryFitMaximumRectangleAtAngle(edges, horizontalMidpoint, DegreesToRadians(candidateAngle), width * height, out aspectRatio, out w, out h))
{
center = horizontalMidpoint;
angle = candidateAngle;
width = w;
height = h;
}
}
}
}
}
/// <summary>
/// Given a point inside of the boundary, finds the points on the
/// boundary directly above, below, left and right of the point,
/// with respect to the given angle.
/// </summary>
private bool FindSurroundingCollisionPoints(
Edge[] edges,
Vector2 point, float angleRad, out Vector2 topCollisionPoint,
out Vector2 bottomCollisionPoint, out Vector2 leftCollisionPoint,
out Vector2 rightCollisionPoint)
{
topCollisionPoint = EdgeHelpers.InvalidPoint;
bottomCollisionPoint = EdgeHelpers.InvalidPoint;
leftCollisionPoint = EdgeHelpers.InvalidPoint;
rightCollisionPoint = EdgeHelpers.InvalidPoint;
bool isInside = EdgeHelpers.IsInside(edges, point);
if (!isInside)
{
return(false);
}
// Find the top and bottom collision points by creating a large line segment that goes through the point to MAX and MIN values on Y
var topEndpoint = new Vector2(point.x, largeValue);
var bottomEndpoint = new Vector2(point.x, smallValue);
topEndpoint = RotatePoint(point, angleRad, topEndpoint);
bottomEndpoint = RotatePoint(point, angleRad, bottomEndpoint);
var verticalLine = new Edge(topEndpoint, bottomEndpoint);
// Find the left and right collision points by creating a large line segment that goes through the point to MAX and Min values on X
var rightEndpoint = new Vector2(largeValue, point.y);
var leftEndpoint = new Vector2(smallValue, point.y);
rightEndpoint = RotatePoint(point, angleRad, rightEndpoint);
leftEndpoint = RotatePoint(point, angleRad, leftEndpoint);
var horizontalLine = new Edge(rightEndpoint, leftEndpoint);
// Loop the edges and find the nearest intersection point
foreach (var edge in edges)
{
Vector2 verticalIntersection = EdgeHelpers.GetIntersection(edge, verticalLine);
if (EdgeHelpers.IsValidPoint(verticalIntersection))
{
// Is this intersection above or below the point?
bool isAbove = RotatePoint(point, -angleRad, verticalIntersection).y > point.y;
if (isAbove)
{
// If this collision point is closer than the previous one
if (!EdgeHelpers.IsValidPoint(topCollisionPoint) ||
Vector2.SqrMagnitude(point - verticalIntersection) < Vector2.SqrMagnitude(point - topCollisionPoint))
{
topCollisionPoint = verticalIntersection;
}
}
else
{
if (!EdgeHelpers.IsValidPoint(bottomCollisionPoint) ||
Vector2.SqrMagnitude(point - verticalIntersection) < Vector2.SqrMagnitude(point - bottomCollisionPoint))
{
bottomCollisionPoint = verticalIntersection;
}
}
} // If vertical intersection found
Vector2 horizontalIntersection = EdgeHelpers.GetIntersection(edge, horizontalLine);
if (EdgeHelpers.IsValidPoint(horizontalIntersection))
{
// Is this intersection left or right of the point?
bool isLeft = RotatePoint(point, -angleRad, horizontalIntersection).x < point.x;
if (isLeft)
{
// Is it closer than the previous intersection?
if (!EdgeHelpers.IsValidPoint(leftCollisionPoint) ||
Vector2.SqrMagnitude(point - horizontalIntersection) < Vector2.SqrMagnitude(point - leftCollisionPoint))
{
leftCollisionPoint = horizontalIntersection;
}
}
else
{
// Is it closer than the previous intersection?
if (!EdgeHelpers.IsValidPoint(rightCollisionPoint) ||
Vector2.SqrMagnitude(point - horizontalIntersection) < Vector2.SqrMagnitude(point - rightCollisionPoint))
{
rightCollisionPoint = horizontalIntersection;
}
}
}
}
// Assert that any point inside should have intersection points on all sides with the polygon
if (!EdgeHelpers.IsValidPoint(topCollisionPoint) || !EdgeHelpers.IsValidPoint(bottomCollisionPoint) ||
!EdgeHelpers.IsValidPoint(leftCollisionPoint) || !EdgeHelpers.IsValidPoint(rightCollisionPoint))
{
return(false);
}
return(true);
}