/// <summary>
/// Performs a ray cast on the polygon given an optional tmax value
/// Only process the information in the rayHit structure if Intersection = true,
/// which is specified in the gxtRayHit instance and the return value. If the ray origin is
/// inside the Polygon it is not considered an intersection
/// </summary>
/// <param name="ray">Ray</param>
/// <param name="polygon">Polygon</param>
/// <param name="rayHit">Ray Hit Info</param>
/// <param name="tmax">Max T Value</param>
/// <returns>If Intersecting</returns>
public virtual bool RayCast(gxtRay ray, ref gxtPolygon polygon, out gxtRayHit rayHit, float tmax = float.MaxValue)
{
rayHit = new gxtRayHit();
rayHit.Distance = tmax;
// if a crossing is within tmax
bool intersection = false;
// temp holder for segment distance
float distance;
// number of crossings, regardless of tmax
int crossings = 0;
// log a message when we run a raycast on a very detailed polygon
// to indicate that the results may not be perfect
int testIterations = polygon.NumVertices;
if (MaxIterations < polygon.NumVertices)
{
gxtLog.WriteLineV(gxtVerbosityLevel.WARNING, "Polygon vertices exceeds max collider iterations. Not all segments will be tested!");
testIterations = MaxIterations;
}
for (int j = polygon.NumVertices - 1, i = 0; i < testIterations; j = i, i++)
{
if (RayIntersectsSegment(ray, polygon.v[j], polygon.v[i], out distance))
{
crossings++;
if (distance <= rayHit.Distance)
{
intersection = true;
rayHit.Distance = distance;
rayHit.Point = ray.GetPoint(distance);
// right perp assumes CCW polygon winding
Vector2 edge = polygon.v[j] - polygon.v[i];
rayHit.Normal = Vector2.Normalize(gxtMath.RightPerp(edge));
}
}
}
// raycast algorithm
rayHit.Intersection = intersection && crossings > 0 && crossings % 2 == 0;
return rayHit.Intersection;
}
public static bool RayCast(gxtRay ray, gxtPolygon polygon, float tmax, out float t, out Vector2 pt, out Vector2 normal)
{
t = float.MaxValue;
pt = ray.Origin;
normal = ray.Direction;
bool intersection = false;
// temp holder for segment distance
float distance;
int crossings = 0;
for (int j = polygon.NumVertices - 1, i = 0; i < polygon.NumVertices; j = i, i++)
{
if (RayIntersectsSegment(ray, polygon.v[j], polygon.v[i], float.MaxValue, out distance))
{
crossings++;
if (distance < t && distance <= tmax)
{
intersection = true;
t = distance;
pt = ray.GetPoint(t);
Vector2 edge = polygon.v[i] - polygon.v[j];
normal = Vector2.Normalize(gxtMath.RightPerp(edge));
//normal = gxtMath.GetReflection(ray.Direction, edgeNormal);
}
}
}
return intersection && crossings > 0 && crossings % 2 == 0;
}
