public override float getNearestIntersection(ref Ray ray, ref Vector3 collisionPoint, ref Vector3 surfaceNormal)
{
if(UseTree)
{
Sphere primHit;
_tree.PrintDebugMessages = PrintDebugMessages;
return _tree.getNearestIntersection(ref ray, out primHit);
}
else
{
return base.getNearestIntersection(ref ray, ref collisionPoint, ref surfaceNormal);
}
}
public virtual float getNearestIntersection(ref Ray r, ref Vector3 collisionPoint, ref Vector3 surfaceNormal)
{
float nearestIntersection = float.PositiveInfinity;
foreach (Sphere s in _spheres)
{
float intersection = r.intersects(s, ref collisionPoint, ref surfaceNormal);
if (intersection < nearestIntersection)
{
nearestIntersection = intersection;
}
}
return nearestIntersection;
}
public override float getNearestIntersection(ref Ray ray, ref Vector3 collisionPoint, ref Vector3 surfaceNormal, ref Material mat)
{
// Use KD-Tree to check for intersection
Sphere primHit;
float t = _tree.getNearestIntersection(ref ray, out primHit);
if ( !float.IsPositiveInfinity(t) )
{
ray.Direction.Normalize();
collisionPoint = ray.Origin + (Vector3)(t * ray.Direction);
surfaceNormal = Vector3.Subtract(collisionPoint, primHit.Position);
surfaceNormal.Normalize();
collisionPoint = primHit.Position + primHit.Radius * surfaceNormal;
mat = primHit.Material;
}
return t;
}
// Code from: http://web.archive.org/web/20040629174917/http://www.acm.org/jgt/papers/MollerTrumbore97/code.html
public float rayTriIntersect(Ray ray)
{
float EPSILON = 10e-5f;
Vector3 dir = ray.Direction;
Vector3 orig = ray.Origin;
Vector3 vert0 = new Vector3(p0);
Vector3 vert1 = new Vector3(p1);
Vector3 vert2 = new Vector3(p2);
//double edge1[3], edge2[3], tvec[3], pvec[3], qvec[3];
//double det,inv_det;
/* find vectors for two edges sharing vert0 */
Vector3 edge1 = vert1 - vert0; //SUB(edge1, vert1, vert0);
Vector3 edge2 = vert2 - vert0; //SUB(edge2, vert2, vert0);
/* begin calculating determinant - also used to calculate U parameter */
Vector3 pvec = Vector3.Cross(dir, edge2); //CROSS(pvec, dir, edge2);
/* if determinant is near zero, ray lies in plane of triangle */
float det = Vector3.Dot(edge1, pvec); //det = DOT(edge1, pvec);
if (det > -EPSILON && det < EPSILON)
return 0;
float inv_det = 1.0f / det;
/* calculate distance from vert0 to ray origin */
Vector3 tvec = orig - vert0; //SUB(tvec, orig, vert0);
/* calculate U parameter and test bounds */
float u = Vector3.Dot(tvec, pvec) * inv_det; //*u = DOT(tvec, pvec) * inv_det;
if (u < 0.0 || u > 1.0)
return 0;
/* prepare to test V parameter */
Vector3 qvec = Vector3.Cross(tvec, edge1); //CROSS(qvec, tvec, edge1);
/* calculate V parameter and test bounds */
float v = Vector3.Dot(dir, qvec) * inv_det; //*v = DOT(dir, qvec) * inv_det;
if (v < 0.0 || u + v > 1.0)
return 0;
/* calculate t, ray intersects triangle */
float t = Vector3.Dot(edge2, qvec) * inv_det; //*t = DOT(edge2, qvec) * inv_det;
Vector3 collisionPoint = ray.Origin + t * ray.Direction;
Vector3 surfaceNormal = Vector3.Cross(edge1, edge2);
surfaceNormal.Normalize();
return t;
}
public abstract float intersects(ref Ray r, ref Vector3 collisionPoint, ref Vector3 surfaceNormal);
