public TriangleD[] GetMeshTrianglesD()
{
var triangles = new TriangleD[TriangleIndicies.Count / 3];
for (int i = 0; i < triangles.Length; i++)
{
var triangle = new TriangleD(
Vertices[TriangleIndicies[i * 3 + 0]].ToVector3d(),
Vertices[TriangleIndicies[i * 3 + 1]].ToVector3d(),
Vertices[TriangleIndicies[i * 3 + 2]].ToVector3d()
);
triangles[i] = triangle;
}
return(triangles);
}
public static bool Intersects(this TriangleD triangle, SphereD sphere)
{
// from http://realtimecollisiondetection.net/bLog/?p=103
var A = triangle.a - sphere.center;
var B = triangle.b - sphere.center;
var C = triangle.c - sphere.center;
var rr = sphere.radius * sphere.radius;
var V = (B - A).Cross(C - A);
var d = A.Dot(V);
var e = V.Dot(V);
var sep1 = (d * d > rr * e);
var aa = A.Dot(A);
var ab = A.Dot(B);
var ac = A.Dot(C);
var bb = B.Dot(B);
var bc = B.Dot(C);
var cc = C.Dot(C);
var sep2 = (aa > rr) & (ab > aa) & (ac > aa);
var sep3 = (bb > rr) & (ab > bb) & (bc > bb);
var sep4 = (cc > rr) & (ac > cc) & (bc > cc);
var AB = B - A;
var BC = C - B;
var CA = A - C;
var d1 = ab - aa;
var d2 = bc - bb;
var d3 = ac - cc;
var e1 = AB.Dot(AB);
var e2 = BC.Dot(BC);
var e3 = CA.Dot(CA);
var Q1 = A * e1 - d1 * AB;
var Q2 = B * e2 - d2 * BC;
var Q3 = C * e3 - d3 * CA;
var QC = C * e1 - Q1;
var QA = A * e2 - Q2;
var QB = B * e3 - Q3;
var sep5 = (Q1.Dot(Q1) > rr * e1 * e1) & (Q1.Dot(QC) > 0);
var sep6 = (Q2.Dot(Q2) > rr * e2 * e2) & (Q2.Dot(QA) > 0);
var sep7 = (Q3.Dot(Q3) > rr * e3 * e3) & (Q3.Dot(QB) > 0);
return(!(sep1 | sep2 | sep3 | sep4 | sep5 | sep6 | sep7));
// or this, but i failed to convert it into shere x triangle http://www.phatcode.net/articles.php?id=459
}
public static bool Intersects(this SphereD sphere, TriangleD triangle) => Intersects(triangle, sphere);
// Thomas Moller ray triangle intersection
// or http://www.lighthouse3d.com/tutorials/maths/ray-triangle-intersection/
// release 0.054317 us
// debug 0.602176 us
public static RayDHitInfo CastRay(this RayD ray, TriangleD triangle)
{
// TODO
/*
* Zde doplòte kód pro testování existence prùseèíku parsku s trojúhelníkem.
* Vypoètený parametr t spoleènì s trojúhelníkem triangle vložte ma konci této metody
* do metody ray.closest_hit, napø. takto
*
* return ray.closest_hit( t, triangle );
*
* Tato metoda vrátí true v pøípadì, že zadaný parametr t je menší než pøedchozí a zapíše
* do paprsku i ukazatel na zasažený trojúhelník, pøes který (metoda target) je možno následnì zjistit
* normálu (target.normal()) nebo materiál v bodì zásahu.
*/
const double ____EPSILON = 0.000001f;
Vector3d V1 = triangle.a;
Vector3d V2 = triangle.b;
Vector3d V3 = triangle.c;
Vector3d O = ray.origin; //RayD origin
Vector3d D = ray.direction; //RayD direction
Vector3d e1, e2; //Edge1, Edge2
Vector3d P, Q, T;
double det, inv_det, u, v;
double t;
//Find vectors for two edges sharing V1
e1 = V2 - V1;
e2 = V3 - V1;
//Begin calculating determinant - also used to calculate u parameter
P = D.Cross(e2);
//if determinant is near zero, ray lies in plane of triangle
det = e1.Dot(P);
//NOT CULLING
if (det > -____EPSILON && det < ____EPSILON)
{
return(RayDHitInfo.NoHit);
}
inv_det = 1.0f / det;
//calculate distance from V1 to ray origin
T = O - V1;
//Calculate u parameter and test bound
u = T.Dot(P) * inv_det;
//The intersection lies outside of the triangle
if (u < 0.0f || u > 1.0f)
{
return(RayDHitInfo.NoHit);
}
//Prepare to test v parameter
Q = T.Cross(e1);
//Calculate V parameter and test bound
v = D.Dot(Q) * inv_det;
//The intersection lies outside of the triangle
if (v < 0.0f || u + v > 1.0f)
{
return(RayDHitInfo.NoHit);
}
t = e2.Dot(Q) * inv_det;
if (t > ____EPSILON)
{ //ray intersection
return(RayDHitInfo.HitAtRayDistance(t));
}
return(RayDHitInfo.NoHit); // trojúhelník nenalezen
}
