static ArrayList Triangulate(ref Vec3D[] v, Face f)
{
//verdeel Face f in meerdere kleine faces van 3 vertices
//Er wordt vanuit gegaan dat een face meer dan drie vertices heeft als deze in deze methode komt.
//en geef deze in een arraylist terug, MOGELIJK in een array.
//BEGIN Naive/Simple implementation, ONLY works on convex polygons.
ArrayList q = new ArrayList();
for (int i = 1; i < f.numberOfVertices - 1; i++)
{
int[] verts = new int[3];
verts[0] = f.vertices[0];
verts[1] = f.vertices[i];
verts[2] = f.vertices[i + 1];
Vec3D a, b, c;
a = v[verts[0]];
b = v[verts[1]];
c = v[verts[2]];
Vec3D norm = (b.subtract(a)).cross(c.subtract(a));
double area = 0.5 * System.Math.Abs((c.subtract(a).cross(b.subtract(a)).length()));
q.Add(new Face(verts, norm,area));
}
return q;
//END Naive/Simple implementation
}
/**
* Methode die het punt bepaald waarop een ray, gerepresenteerd door a en b in een array, in een face f.
* De vertices van de Face f zitten in de model waar f in zit.
*/
static double RayTriangleIntersection(ref unitVector direction, ref Model3D model, ref Face f)
{
double r = 0.0;
Vec3D[] v = model.vertices;
Vec3D h = f.normal;// v[f.vertices[1]].subtract(v[f.vertices[0]]).cross(v[f.vertices[2]].subtract(v[f.vertices[0]]));
if (h.length() > double.Epsilon)
{
Vec3D normal = f.normal.normalize();
//normalize the normal, then dot it with the direction vector
double NU = System.Math.Abs(normal.dot(direction.vector));
if (NU > double.Epsilon)
{
double d = (normal.dot(v[f.vertices[0]])) / NU;
if (d > r)
{
Vec3D P = direction.vector.times(d);
//is P on the triangle?
if ((v[f.vertices[0]].subtract(P).cross(v[f.vertices[1]].subtract(P))).dot(f.normal) >= 0 &&
(v[f.vertices[1]].subtract(P).cross(v[f.vertices[2]].subtract(P))).dot(f.normal) >= 0 &&
(v[f.vertices[2]].subtract(P).cross(v[f.vertices[0]].subtract(P))).dot(f.normal) >= 0)
return d;
}
}
}
//the ray will not intersect with the triangle
return double.NaN;
}
/**
* Methode die het punt bepaald waarop een ray, gerepresenteerd door a en b in een array, in een face f.
* De vertices van de Face f zitten in de model waar f in zit.
*/
static double RayTriangleIntersection2(ref unitVector direction, ref Model3D model, ref Face f)
{
double r = 0.0;
double d = 0.0;
Vec3D[] v = model.vertices;
Vec3D u = direction.vector;
Vec3D A = v[f.vertices[0]];
Vec3D B = v[f.vertices[1]];
Vec3D C = v[f.vertices[2]];
Vec3D CA = A.subtract(C);
Vec3D CB = B.subtract(C);
Vec3D p = u.cross(CB);
double det = CA.dot(p);
if (det > double.Epsilon)
{
double AlphaS = C.times(-1.0).dot(p);
if (AlphaS >= 0 && AlphaS <= det)
{
Vec3D q = CA.cross(C);
double BetaS = u.dot(q);
if (BetaS >= 0 && AlphaS + BetaS <= det)
d = (CB.dot(q)) / det;
}
}
else if(det < 0-Double.Epsilon)
{
double AlphaS = C.times(-1).dot(p);
if (AlphaS <= 0 && AlphaS >= det)
{
Vec3D q = CA.cross(C);
double BetaS = u.dot(q);
if (BetaS <= 0 && AlphaS + BetaS >= det)
d = (CB.dot(q)) / det;
}
}
if (d > r)
r = d;
//the ray will not intersect with the triangle
return r;
}
static double[] getMinMaxPhiTheta(ref Face f, ref Vec3D[] v, ref Model3D model)
{
/* int minPhi = phiTheta[0];
int minTheta = phiTheta[1];
int maxPhi = phiTheta[2];
int maxTheta = phiTheta[3]; */
double[] minmax = new double[4];
minmax[0] = double.MaxValue;
minmax[1] = double.MaxValue;
minmax[2] = double.MinValue;
minmax[3] = double.MinValue;
double minX = double.MaxValue, maxX = double.MinValue, minY = double.MaxValue,
maxY = double.MinValue, minZ = double.MaxValue, maxZ = double.MinValue, meanX = 0, meanY = 0, meanZ = 0;
for(int k=0; k < f.numberOfVertices; k++)
{
Vec3D vec = v[f.vertices[k]];
updateMinMaxMeanXYZ(ref minX,ref maxX,ref meanX,vec.x,ref minY,ref maxY,ref meanY,vec.y,ref minZ,ref maxZ,ref meanZ,vec.z,k);
double phi, theta;
phi = System.Math.Atan2(vec.y, vec.x);
theta = System.Math.Acos((vec.z) / (vec.length()));
if (minmax[0] > phi)
minmax[0] = phi;
if (minmax[1] > theta)
minmax[1] = theta;
if (minmax[2] < phi)
minmax[2] = phi;
if (minmax[3] < theta)
minmax[3] = theta;
}
/*
//Because of the possibility of an polygon lying on all equal or close theta, the correct theta may not be found with only the points.
//Trying to solve this here.
Vec3D dotPoint = new Vec3D(double.NaN,double.NaN,double.NaN);
double dotDist = double.MaxValue;
for (int k = 0; k < f2.numberOfVertices; k++)
{
Vec3D a, b, edge;
a = v[f.vertices[k]].copy().normalize();
b = v[f.vertices[(k + 1) % f.numberOfVertices]].copy().normalize();
edge = a.subtract(b).normalize();
double dotO = b.dot(edge);
if (dotO < 0.0)
{
Vec3D tempPoint = b.addition(edge.times(dotO));
double tempDist = tempPoint.squaredLength();
if (dotDist > tempDist)
{
dotDist = tempDist;
dotPoint = tempPoint;
}
}
}
minmax[3] = System.Math.Acos((dotPoint.z) / (dotPoint.length()));
*/
//Check om te bepalen of de polygon in het xy vlak (z is up),
//zo ja, check of erboven of eronder is en pas theta aan om volledig door te lopen.
if (minX < 0 && maxX > 0 && minY < 0 && maxY > 0)
if (meanZ > 0)
minmax[1] = 0;
else
minmax[3] = System.Math.PI;
return minmax;
}
