/// <summary>
/// convenience function to construct a IntrRay3Triangle3 object for a mesh triangle
/// </summary>
public static IntrRay3Triangle3 TriangleIntersection(DMesh3 mesh, int ti, Ray3d ray)
{
if (!mesh.IsTriangle(ti))
{
return(null);
}
Triangle3d tri = new Triangle3d();
mesh.GetTriVertices(ti, ref tri.V0, ref tri.V1, ref tri.V2);
IntrRay3Triangle3 q = new IntrRay3Triangle3(ray, tri);
q.Find();
return(q);
}
public static int FindHitTriangle_LinearSearch(DMesh3 mesh, Ray3d ray)
{
int tNearestID = DMesh3.InvalidID;
double fNearestT = double.MaxValue;
var tri = new Triangle3d();
foreach (int ti in mesh.TriangleIndices())
{
// [TODO] optimize this
mesh.GetTriVertices(ti, ref tri.V0, ref tri.V1, ref tri.V2);
var ray_tri_hit = new IntrRay3Triangle3(ray, tri);
if (ray_tri_hit.Find())
{
if (ray_tri_hit.RayParameter < fNearestT)
{
fNearestT = ray_tri_hit.RayParameter;
tNearestID = ti;
}
}
}
return(tNearestID);
}
void find_hit_triangle(int iBox, ref Ray3d ray, ref double fNearestT, ref int tID)
{
int idx = box_to_index[iBox];
if (idx < triangles_end) // triange-list case, array is [N t1 t2 ... tN]
{
Triangle3d tri = new Triangle3d();
int num_tris = index_list[idx];
for (int i = 1; i <= num_tris; ++i)
{
int ti = index_list[idx + i];
// [TODO] optimize this
mesh.GetTriVertices(ti, ref tri.V0, ref tri.V1, ref tri.V2);
IntrRay3Triangle3 ray_tri_hit = new IntrRay3Triangle3(ray, tri);
if (ray_tri_hit.Find())
{
if (ray_tri_hit.RayParameter < fNearestT)
{
fNearestT = ray_tri_hit.RayParameter;
tID = ti;
}
}
}
}
else // internal node, either 1 or 2 child boxes
{
double e = MathUtil.ZeroTolerancef;
int iChild1 = index_list[idx];
if (iChild1 < 0) // 1 child, descend if nearer than cur min-dist
{
iChild1 = (-iChild1) - 1;
double fChild1T = box_ray_intersect_t(iChild1, ray);
if (fChild1T <= fNearestT + e)
{
find_hit_triangle(iChild1, ref ray, ref fNearestT, ref tID);
}
}
else // 2 children, descend closest first
{
iChild1 = iChild1 - 1;
int iChild2 = index_list[idx + 1] - 1;
double fChild1T = box_ray_intersect_t(iChild1, ray);
double fChild2T = box_ray_intersect_t(iChild2, ray);
if (fChild1T < fChild2T)
{
if (fChild1T <= fNearestT + e)
{
find_hit_triangle(iChild1, ref ray, ref fNearestT, ref tID);
if (fChild2T <= fNearestT + e)
{
find_hit_triangle(iChild2, ref ray, ref fNearestT, ref tID);
}
}
}
else
{
if (fChild2T <= fNearestT + e)
{
find_hit_triangle(iChild2, ref ray, ref fNearestT, ref tID);
if (fChild1T <= fNearestT + e)
{
find_hit_triangle(iChild1, ref ray, ref fNearestT, ref tID);
}
}
}
}
}
}