private void FindIntersection(Vector3 origin, Vector3 dir, ref float tmin, ref Trig triangle, ref Vector3 barycentric)
{
foreach (var trig in trigs)
{
if (Geometry.ThereIsIntersection(origin, dir, trig, out var t, out var bary))
{
if (t > 0.01f && tmin > t)
{
tmin = t;
triangle = trig;
barycentric = bary;
}
}
}
}
public static int CompareByPosition(Trig t1, Trig t2, int axes)
{
var v1 = t1.Center.GetByIndex(axes);
var v2 = t2.Center.GetByIndex(axes);
if (v1 > v2)
{
return(1);
}
if (v1 < v2)
{
return(-1);
}
return(0);
}
public void Traverse(Ray ray, ref float tmin, ref Trig triangle, ref Vector3 barycentric)
{
if (isLeaf)
{
FindIntersection(ray.Origin, ray.Dir, ref tmin, ref triangle, ref barycentric);
return;
}
if (!GetIntersection(ray.Origin, ray.Dir, box))
{
return;
}
left?.Traverse(ray, ref tmin, ref triangle, ref barycentric);
middle?.Traverse(ray, ref tmin, ref triangle, ref barycentric);
right?.Traverse(ray, ref tmin, ref triangle, ref barycentric);
}
public static bool ThereIsIntersection(Vector3 rayOrigin, Vector3 rayVector, Trig inTriangle, out float t, out Vector3 barycentric)
{
t = int.MaxValue;
barycentric = Vector3.Zero;
var vertex0 = inTriangle.A;
var vertex1 = inTriangle.B;
var vertex2 = inTriangle.C;
var edge1 = vertex1 - vertex0;
var edge2 = vertex2 - vertex0;
var h = Vector3.Cross(rayVector, edge2);
var a = Vector3.Dot(edge1, h);
var EPSILON = 1e-10f;
if (a > -EPSILON && a < EPSILON)
{
return(false);
}
var f = 1 / a;
var s = rayOrigin - vertex0;
var u = f * Vector3.Dot(s, h);
if (u < 0.0 || u > 1.0)
{
return(false);
}
var q = Vector3.Cross(s, edge1);
var v = f * Vector3.Dot(rayVector, q);
if (v < 0.0 || u + v > 1.0)
{
return(false);
}
var w = 1 - v - u;
barycentric = new Vector3(u, v, w);
// At this stage we can compute t to find out where the intersection point is on the line.
t = f * Vector3.Dot(edge2, q);
return(t > EPSILON);
}
public void SetupTrigs()
{
Trigs = new Trig[Faces.Length];
for (var i = 0; i < Faces.Length; i++)
{
var face = Faces[i];
var aIndex = face[0].VertexIndex;
var bIndex = face[1].VertexIndex;
var cIndex = face[2].VertexIndex;
var anIndex = face[0].NormalIndex;
var bnIndex = face[1].NormalIndex;
var cnIndex = face[2].NormalIndex;
Trigs[i] = new Trig(Vertices[aIndex], Vertices[bIndex], Vertices[cIndex],
Normals[anIndex], Normals[bnIndex], Normals[cnIndex]);
}
}
public BoundingBox(Trig t)
{
SetBounds(t);
UpdateSize();
}
private void UpdateTriangleBoundBox(Trig t)
{
var newBox = new BoundingBox(t);
MergeBoundBox(newBox);
}
private bool IsMiddle(Trig t, float center)
{
return(t.Mins.GetByIndex(dimSplit) <= center && t.Maxs.GetByIndex(dimSplit) >= center);
}