public char SegTriInt(tPointi T, tPointi q, tPointi r, tPointd p)
{
char code = '?';
m = -1;
code = SegPlaneInt(T, q, r, p, m);
System.Diagnostics.Debug.WriteLine("****M is now after segplaneint: " + m);
System.Diagnostics.Debug.WriteLine("SegPlaneInt code= " + code + " , m= " + m + "; p=()" + p.p[Xindex] + " , " + p.p[Yindex] + " , " + p.p[Zindex]);
if (code == '0')
{
return('0');
}
else if (code == 'q')
{
return(InTri3D(T, m, q));
}
else if (code == 'r')
{
return(InTri3D(T, m, r));
}
else if (code == 'p')
{
return(InPlane(T, m, q, r, p));
}
else if (code == '1')
{
return(SegTriCross(T, q, r));
}
else /* Error */
{
return(code);
}
}
/*---------------------------------------------------------------------
* Computes N & D and returns index m of largest component.
* ---------------------------------------------------------------------*/
public int PlaneCoeff(tPointi T, tPointd N, double D0)
{
int i;
double t; /* Temp storage */
double biggest = 0.0; /* Largest component of normal vector. */
m = 0; /* Index of largest component. */
NormalVec(Vertices[T.p[0]], Vertices[T.p[1]], Vertices[T.p[2]], N);
System.Diagnostics.Debug.WriteLine("PlaneCoeff: N=()" + N.p[Xindex] + " , " + N.p[Yindex] + " , " + N.p[Zindex]);
D = Dot(Vertices[T.p[0]], N);
System.Diagnostics.Debug.WriteLine("D should be in planecoeff" + D);
/* Find the largest component of N. */
for (i = 0; i < DIM; i++)
{
t = (float)(Math.Abs(N.p[i]));
if (t > biggest)
{
biggest = t;
m = i;
}
}
return(m);
}
/*---------------------------------------------------------------------
* Compute the cross product of (b-a)x(c-a) and place into N.
* ---------------------------------------------------------------------*/
public void NormalVec(tPointi a, tPointi b, tPointi c, tPointd N)
{
N.p[Xindex] = (c.p[Zindex] - a.p[Zindex]) * (b.p[Yindex] - a.p[Yindex]) -
(b.p[Zindex] - a.p[Zindex]) * (c.p[Yindex] - a.p[Yindex]);
N.p[Yindex] = (b.p[Zindex] - a.p[Zindex]) * (c.p[Xindex] - a.p[Xindex]) -
(b.p[Xindex] - a.p[Xindex]) * (c.p[Zindex] - a.p[Zindex]);
N.p[Zindex] = (b.p[Xindex] - a.p[Xindex]) * (c.p[Yindex] - a.p[Yindex]) -
(b.p[Yindex] - a.p[Yindex]) * (c.p[Xindex] - a.p[Xindex]);
}
/*---------------------------------------------------------------------
* Returns the dot product of the two input vectors.
* ---------------------------------------------------------------------*/
public double Dot(tPointi a, tPointd b)
{
int i;
double sum = 0.0;
for (i = 0; i < DIM; i++)
{
sum += a.p[i] * b.p[i];
}
return(sum);
}
public char InPlane(tPointi T, int m, tPointi q, tPointi r, tPointd p)
{
/* NOT IMPLEMENTED */
return('p');
}
/*---------------------------------------------------------------------
* 'p': The segment lies wholly within the plane.
* 'q': The q endpoint is on the plane (but not 'p').
* 'r': The r endpoint is on the plane (but not 'p').
* '0': The segment lies strictly to one side or the other of the plane.
* '1': The segement intersects the plane, and 'p' does not hold.
* ---------------------------------------------------------------------*/
public char SegPlaneInt(tPointi T, tPointi q, tPointi r, tPointd p, int m)
{
tPointd N;
int D0 = 0;
tPointi rq;
double num, denom, t;
int i;
N = new tPointd();
rq = new tPointi();
m = PlaneCoeff(T, N, D0);
System.Diagnostics.Debug.WriteLine("m= " + m + "; plane=( " + N.p[Xindex] + " , " + N.p[Yindex] + " , " + N.p[Zindex] + " , " + D + " )");
num = D - Dot(q, N);
SubVec(r, q, rq);
denom = Dot(rq, N);
System.Diagnostics.Debug.WriteLine("SegPlaneInt: num=" + num + " , denom= " + denom);
if (denom == 0.0)
{ /* Segment is parallel to plane. */
if (num == 0.0) /* q is on plane. */
{
return('p');
}
else
{
return('0');
}
}
else
{
t = num / denom;
}
System.Diagnostics.Debug.WriteLine("SegPlaneInt: t= " + t);
System.Diagnostics.Debug.WriteLine("p in seg plane int is: p=()");
for (i = 0; i < DIM; i++)
{
p.p[i] = q.p[i] + t * (r.p[i] - q.p[i]);
System.Diagnostics.Debug.WriteLine(p.p[i]);
}
if ((0.0 < t) && (t < 1.0))
{
return('1');
}
else if (num == 0.0) /* t == 0 */
{
return('q');
}
else if (num == denom) /* t == 1 */
{
return('r');
}
else
{
return('0');
}
}
//***********************
/*
* This function returns a char:
* 'V': the query point a coincides with a Vertex of polyhedron P.
* 'E': the query point a is in the relative interior of an Edge of polyhedron P.
* 'F': the query point a is in the relative interior of a Face of polyhedron P.
* 'i': the query point a is strictly interior to polyhedron P.
* 'o': the query point a is strictly exterior to( or outside of) polyhedron P.
*/
char InPolyhedron(int F, tPointi q, tPointi bmin, tPointi bmax, int radius)
{
tPointi r; /* Ray endpoint. */
tPointd p; /* Intersection point; not used. */
int f, k = 0, crossings = 0;
char code = '?';
r = new tPointi();
p = new tPointd();
/* If query point is outside bounding box, finished. */
if (!InBox(q, bmin, bmax))
{
return('o');
}
while (k++ < F)
{
crossings = 0;
RandomRay(r, radius);
AddVec(q, r);
System.Diagnostics.Debug.WriteLine("Ray endpoint: (" + r.p[0] + " , " + r.p[1] + " , " + r.p[2] + " )");
for (f = 0; f < F; f++)
{ /* Begin check each face */
if (BoxTest(f, q, r) == '0')
{
code = '0';
System.Diagnostics.Debug.WriteLine("BoxTest = 0!");
}
else
{
code = SegTriInt(Faces[f], q, r, p);
}
System.Diagnostics.Debug.WriteLine("Face = " + f + ": BoxTest/SegTriInt returns " + code);
/* If ray is degenerate, then goto outer while to generate another. */
if (code == 'p' || code == 'v' || code == 'e')
{
System.Diagnostics.Debug.WriteLine("Degenerate ray");
continue;
}
/* If ray hits face at interior point, increment crossings. */
else if (code == 'f')
{
crossings++;
System.Diagnostics.Debug.WriteLine("crossings = " + crossings);
}
/* If query endpoint q sits on a V/E/F, return that code. */
else if (code == 'V' || code == 'E' || code == 'F')
{
return(code);
}
/* If ray misses triangle, do nothing. */
else if (code == '0')
{
continue;
}
else
{
System.Diagnostics.Debug.WriteLine("Error");
return(' ');
}
} /* End check each face */
/* No degeneracies encountered: ray is generic, so finished. */
break;
} /* End while loop */
System.Diagnostics.Debug.WriteLine("Crossings at the end = " + crossings);
/* q strictly interior to polyhedron iff an odd number of crossings. */
if ((crossings % 2) == 1)
{
return('i');
}
else
{
return('o');
}
}
