/// <summary>
/// Creates a new PickResult.
/// </summary>
/// <param name="ray">Ray used in the test</param>
/// <param name="target">Target object</param>
/// <param name="boundingIntersection">The bounding intersection record.</param>
public PickResult(Ray ray, IPickable target, BoundingIntersectionRecord boundingIntersection)
{
_ray = ray;
_target = target;
_boundRecord = boundingIntersection;
_primRecord = null;
}
/// <summary>
/// Tests where on the volume the ray intersects, if it does. Uses the
/// Liang-Barsky clipping algorithm as described by David Eberly.
/// </summary>
/// <param name="ray">Ray to test</param>
/// <param name="result">The intersection result</param>
public override void IntersectsWhere(ref Ray ray, out BoundingIntersectionRecord result)
{
Vector3 rDir = ray.Direction;
Vector3 rOrigin = ray.Origin;
Vector3 diff;
Vector3.Subtract(ref rOrigin, ref m_center, out diff);
float t0 = float.NegativeInfinity;
float t1 = float.PositiveInfinity;
bool notCulled = Clip(rDir.X, -diff.X - m_extents.X, ref t0, ref t1) &&
Clip(-rDir.X, diff.X - m_extents.X, ref t0, ref t1) &&
Clip(rDir.Y, -diff.Y - m_extents.Y, ref t0, ref t1) &&
Clip(-rDir.Y, diff.Y - m_extents.Y, ref t0, ref t1) &&
Clip(rDir.Z, -diff.Z - m_extents.Z, ref t0, ref t1) &&
Clip(-rDir.Z, diff.Z - m_extents.Z, ref t0, ref t1);
if (notCulled && (!float.IsNegativeInfinity(t0) || !float.IsPositiveInfinity(t1)))
{
if (t1 > t0)
{
Vector3 p0;
Vector3.Multiply(ref rDir, t0, out p0);
Vector3.Add(ref p0, ref rOrigin, out p0);
IntersectionRecord rec1 = new IntersectionRecord(p0, t0);
Vector3 p1;
Vector3.Multiply(ref rDir, t1, out p1);
Vector3.Add(ref p1, ref rOrigin, out p1);
IntersectionRecord rec2 = new IntersectionRecord(p1, t1);
result = new BoundingIntersectionRecord(rec1, rec2);
return;
}
Vector3 p;
Vector3.Multiply(ref rDir, t0, out p);
Vector3.Add(ref p, ref rOrigin, out p);
IntersectionRecord rec = new IntersectionRecord(p, t0);
result = new BoundingIntersectionRecord(rec);
return;
}
result = new BoundingIntersectionRecord();
}
/// <summary>
/// Adds a ray and target to test an intersection. If the target is pickable,
/// and an intersection exists, the records are added to the query.
/// </summary>
/// <param name="ray">Ray to test with</param>
/// <param name="pickable">Target to test against</param>
/// <returns>True if an intersection was found, false otherwise.</returns>
public bool AddPick(Ray ray, IPickable pickable)
{
if (pickable == null)
{
return(false);
}
if (pickable.IsPickable)
{
BoundingVolume bv = pickable.WorldBounding;
BoundingIntersectionRecord bvRecord = new BoundingIntersectionRecord();
PrimitiveIntersectionRecord primRecord = new PrimitiveIntersectionRecord();
if (bv != null)
{
bv.IntersectsWhere(ref ray, out bvRecord);
}
else
{
return(false);
}
if (bvRecord.IntersectionCount > 0 && _primitivePickingEnabled)
{
primRecord = pickable.IntersectsPrimitivesWhere(ray);
if (primRecord.IntersectionCount > 0)
{
_results.Add(new PickResult(ray, pickable, bvRecord, primRecord));
_sorted = false;
return(true);
}
}
else if (bvRecord.IntersectionCount > 0)
{
_results.Add(new PickResult(ray, pickable, bvRecord));
_sorted = false;
return(true);
}
}
return(false);
}
public override void IntersectsWhere(ref Ray ray, out BoundingIntersectionRecord result)
{
throw new System.NotImplementedException();
}
/// <summary> /// Tests where on the volume the ray intersects, if it does. /// </summary> /// <param name="ray">Ray to test</param> /// <param name="result">The intersection result</param> public abstract void IntersectsWhere(ref Ray ray, out BoundingIntersectionRecord result);
/// <summary>
/// Tests where on the sphere the ray intersects, if it does.
/// </summary>
/// <param name="ray">Ray to test</param>
/// <param name="result">The intersection result</param>
public override void IntersectsWhere(ref Ray ray, out BoundingIntersectionRecord result)
{
Vector3 diff;
Vector3 rOrigin = ray.Origin;
Vector3 rDir = ray.Direction;
Vector3.Subtract(ref rOrigin, ref m_center, out diff);
float a, a1, discr, sqrt;
Vector3.Dot(ref diff, ref diff, out a);
a -= m_radius * m_radius;
//Check if we're inside the sphere, if so then the result must have
//one exit point
if (a <= 0.0f)
{
Vector3.Dot(ref rDir, ref diff, out a1);
discr = (a1 * a1) - a;
sqrt = MathHelper.Sqrt(discr);
//Calc the distance and exit point
float dist = sqrt - a1;
Vector3 p;
Vector3.Multiply(ref rDir, dist, out p);
Vector3.Add(ref p, ref rOrigin, out p);
IntersectionRecord rec = new IntersectionRecord(p, dist);
result = new BoundingIntersectionRecord(rec);
return;
}
Vector3.Dot(ref rDir, ref diff, out a1);
if (a1 >= 0.0f)
{
//No intersections
result = new BoundingIntersectionRecord();
return;
}
discr = a1 * a1 - a;
if (discr < 0.0f)
{
//No intersections
result = new BoundingIntersectionRecord();
return;
}
else if (discr >= MathHelper.ZeroTolerance)
{
//Entry and exit exist
sqrt = MathHelper.Sqrt(discr);
float dist1 = System.Math.Abs(-a1 - sqrt);
float dist2 = System.Math.Abs(-a1 + sqrt);
Vector3 p1;
Vector3.Multiply(ref rDir, dist1, out p1);
Vector3.Add(ref p1, ref rOrigin, out p1);
IntersectionRecord rec1 = new IntersectionRecord(p1, dist1);
Vector3 p2;
Vector3.Multiply(ref rDir, dist2, out p2);
Vector3.Add(ref p2, ref rOrigin, out p2);
IntersectionRecord rec2 = new IntersectionRecord(p2, dist2);
result = new BoundingIntersectionRecord(rec1, rec2);
return;
}
//The ray intersects the sphere at exactly one point.
float dis = -a1;
Vector3 point;
Vector3.Multiply(ref rDir, dis, out point);
Vector3.Add(ref point, ref rOrigin, out point);
IntersectionRecord rec0 = new IntersectionRecord(point, dis);
result = new BoundingIntersectionRecord(rec0);
return;
}
