void HelixObject::BuildShape(TimeValue t, PolyShape& ashape) {
// Set the object's interpolation parameters
ReadyInterpParams(t);
// Set the general interval to the one we just got
ivalid = interpValid;
ashape.NewShape();
// Start a PolyLine for our helix...
PolyLine *line = ashape.NewLine();
// Compute some helpful stuff...
int points = (int)(turns * (float)POINTS_PER_TURN);
if(points == 0)
points = 1;
float fPoints = (float)points;
numberOfPieces = 0;
for(int i = 0; i <= points; ++i) {
float pct = (float)i / fPoints;
float r = radius1 + deltaRadius * pct;
float hpct = pct;
if(bias > 0.0f)
hpct = 1.0f - (float)pow(1.0f - pct, power );
else
if(bias < 0.0f)
hpct = (float)pow(pct, power);
float z = height * hpct;
float angle = totalRadians * pct;
float x = r * (float)cos(angle);
float y = r * (float)sin(angle);
DWORD flags = POLYPT_SMOOTH;
if((i % 10) == 0 || i == points) {
flags |= POLYPT_KNOT; // Let it know the piece boundary
if(i > 0)
numberOfPieces++;
}
line->Append(PolyPt(Point3(x,y,z), flags));
}
perPiece = 1.0f / (float)numberOfPieces;
ashape.UpdateSels(); // Make sure it readies the selection set info
ashape.InvalidateGeomCache(FALSE);
lengthOfCurve = ashape.lines[0].CurveLength();
}
