// append "disc" verts/tris between vEnd1 and vEnd2
protected void append_2d_disc_segment(int iCenter, int iEnd1, int iEnd2, int nSteps, bool bCycle, ref int vtx_counter, ref int tri_counter, int groupid = -1, double force_r = 0)
{
Vector3d c = vertices[iCenter];
Vector3d e0 = vertices[iEnd1];
Vector3d e1 = vertices[iEnd2];
Vector3d v0 = (e0 - c);
double r0 = v0.Normalize();
if (force_r > 0)
{
r0 = force_r;
}
double tStart = Math.Atan2(v0.z, v0.x);
Vector3d v1 = (e1 - c);
double r1 = v1.Normalize();
if (force_r > 0)
{
r1 = force_r;
}
double tEnd = Math.Atan2(v1.z, v1.x);
// fix angles to handle sign. **THIS ONLY WORKS IF WE ARE GOING CCW!!**
if (tStart < 0)
{
tStart += MathUtil.TwoPI;
}
if (tEnd < 0)
{
tEnd += MathUtil.TwoPI;
}
if (tEnd < tStart)
{
tEnd += MathUtil.TwoPI;
}
int iPrev = iEnd1;
for (int i = 0; i < nSteps; ++i)
{
double t = (double)(i + 1) / (double)(nSteps + 1);
double angle = (1 - t) * tStart + (t) * tEnd;
Vector3d pos = c + new Vector3d(r0 * Math.Cos(angle), 0, r1 * Math.Sin(angle));
vertices.Set(vtx_counter, pos.x, pos.y, pos.z);
if (groupid >= 0)
{
groups[tri_counter] = groupid;
}
triangles.Set(tri_counter++, iCenter, iPrev, vtx_counter, bCycle);
iPrev = vtx_counter++;
}
if (groupid >= 0)
{
groups[tri_counter] = groupid;
}
triangles.Set(tri_counter++, iCenter, iPrev, iEnd2, bCycle);
}
/// <summary>
/// convert byte array to VectorArray3d
/// </summary>
static public VectorArray3d ToVectorArray3d(byte[] buffer)
{
int sz = sizeof(double);
int Nvals = buffer.Length / sz;
int Nvecs = Nvals / 3;
VectorArray3d v = new VectorArray3d(Nvecs);
for (int i = 0; i < Nvecs; i++)
{
double x = BitConverter.ToDouble(buffer, (3 * i) * sz);
double y = BitConverter.ToDouble(buffer, (3 * i + 1) * sz);
double z = BitConverter.ToDouble(buffer, (3 * i + 2) * sz);
v.Set(i, x, y, z);
}
return(v);
}