private static VECTOR3 _Extrude(ICoreScene3D dc, ReadOnlySpan <PointNode> nodes, bool closed, int divisions, ColorStyle color, bool flipFaces)
{
Span <POINT3> aa = stackalloc POINT3[divisions];
Span <POINT3> bb = stackalloc POINT3[divisions];
var maixAxis = _GetMainAxis(nodes);
if (closed)
{
var n = nodes[nodes.Length - 1];
n._FillSection(aa, divisions, maixAxis + n.Axis);
// aa.Reverse();
}
for (int s = 0; s < nodes.Length; ++s)
{
var n = nodes[s];
n._FillSection(bb, divisions, maixAxis + n.Axis);
if (s > 0 || closed)
{
for (int i = 0; i < bb.Length; ++i)
{
var j = (i + 1) % bb.Length;
if (flipFaces)
{
dc.DrawConvexSurface(POINT3.Array(aa[i], aa[j], bb[j], bb[i]), color);
}
else
{
dc.DrawConvexSurface(POINT3.Array(aa[j], aa[i], bb[i], bb[j]), color);
}
}
}
bb.CopyTo(aa);
}
return(maixAxis);
}
private readonly void _DrawCap(ICoreScene3D dc, ColorStyle fillColor, LineCapStyle cap, Span <POINT3> corners, bool dir)
{
var axis = Direction * (Diameter * 0.5f);
if (dir)
{
axis = -axis;
}
switch (cap)
{
case LineCapStyle.Round:
for (int i = 0; i < corners.Length; ++i)
{
var j = (i + 1) % corners.Length;
var i0 = corners[i].XYZ;
var j0 = corners[j].XYZ;
var i1 = VECTOR3.Lerp(Point, i0 + axis, 0.7f);
var j1 = VECTOR3.Lerp(Point, j0 + axis, 0.7f);
dc.DrawConvexSurface(POINT3.Array(i0, j0, j1, i1), fillColor);
dc.DrawConvexSurface(POINT3.Array(Point + axis, i1, j1), fillColor);
}
break;
case LineCapStyle.Triangle:
for (int i = 0; i < corners.Length; ++i)
{
var j = (i + 1) % corners.Length;
dc.DrawConvexSurface(POINT3.Array(Point + axis, corners[i], corners[j]), fillColor);
}
break;
default: dc.DrawConvexSurface(corners, fillColor); break;
}
}