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Update geometry.scad

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RonaldoCMP 2021-10-14 11:48:41 -03:00
parent 4d9a1d36ac
commit 6b542191ce
1 changed files with 11 additions and 7 deletions
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geometry.scad
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@ -1616,7 +1616,8 @@ function point_in_polygon(point, poly, nonzero=false, eps=EPSILON) =
// simple polygons with the same winding. These polygons may have "touching" vertices
// (two vertices having the same coordinates, but distinct adjacencies) and "contact" edges
// (edges whose vertex pairs have the same pairwise coordinates but are in reversed order) but has
// no self-crossing. See examples bellow. If all polygon edges are contact edges, returns an empty list.
// no self-crossing. See examples bellow. If all polygon edges are contact edges,
// it returns an empty list for 2d polygons and issues an error for 3d polygons.
// .
// Self-crossing polygons have no consistent winding and usually produce an error but
// when an error is not issued the outputs are not correct triangulations. The function
@ -1630,18 +1631,21 @@ function point_in_polygon(point, poly, nonzero=false, eps=EPSILON) =
// poly = star(id=10, od=15,n=11);
// tris = polygon_triangulate(poly);
// color("lightblue") for(tri=tris) polygon(select(poly,tri));
// color("blue") up(1) for(tri=tris) { stroke(select(poly,tri),.15,closed=true); }
// color("magenta") up(2) stroke(poly,.25,closed=true);
// color("black") up(3) vnf_debug([poly,[]],faces=false,size=1);
// Example(2D,NoAxes): a polygon with a hole and one "contact" edge
// poly = [ [-10,0], [10,0], [0,10], [-10,0], [-4,4], [4,4], [0,2], [-4,4] ];
// tris = polygon_triangulate(poly);
// color("lightblue") for(tri=tris) polygon(select(poly,tri));
// color("blue") up(1) for(tri=tris) { stroke(select(poly,tri),.15,closed=true); }
// color("magenta") up(2) stroke(poly,.25,closed=true);
// color("black") up(3) vnf_debug([poly,[]],faces=false,size=1);
// Example(2D,NoAxes): a polygon with "touching" vertices and no holes
// poly = [ [0,0], [5,5], [-5,5], [0,0], [-5,-5], [5,-5] ];
// tris = polygon_triangulate(poly);
// color("lightblue") for(tri=tris) polygon(select(poly,tri));
// color("blue") up(1) for(tri=tris) { stroke(select(poly,tri),.15,closed=true); }
// color("magenta") up(2) stroke(poly,.25,closed=true);
// color("black") up(3) vnf_debug([poly,[]],faces=false,size=1);
// Example(2D,NoAxes): a polygon with "contact" edges and no holes
@ -1649,6 +1653,7 @@ function point_in_polygon(point, poly, nonzero=false, eps=EPSILON) =
// [7,7], [7,3], [3,3] ];
// tris = polygon_triangulate(poly); // see from the top
// color("lightblue") for(tri=tris) polygon(select(poly,tri));
// color("blue") up(1) for(tri=tris) { stroke(select(poly,tri),.15,closed=true); }
// color("magenta") up(2) stroke(poly,.25,closed=true);
// color("black") up(3) vnf_debug([poly,[]],faces=false,size=1);
// Example(3D):
@ -1666,7 +1671,7 @@ function polygon_triangulate(poly, ind, eps=EPSILON) =
let( ind = is_undef(ind) ? count(len(poly)) : ind )
len(ind) == 3
? _is_degenerate([poly[ind[0]], poly[ind[1]], poly[ind[2]]], eps) ? [] :
// no zero area
// non zero area
assert( norm(scalar_vec3(cross(poly[ind[1]]-poly[ind[0]], poly[ind[2]]-poly[ind[0]]))) > 2*eps,
"The polygon vertices are collinear.")
[ind]
@ -1675,12 +1680,11 @@ function polygon_triangulate(poly, ind, eps=EPSILON) =
let(
ind = deduplicate_indexed(poly, ind, eps)
)
len(ind)<3 ? [] :
assert(len(ind)>=3 , "The polygon vertices are collinear.")
let(
pts = select(poly,ind),
nrm = polygon_normal(pts)
)
// here, instead of an error, it might return [] or undef
assert( nrm!=undef,
"The polygon has self-intersections or its vertices are collinear or non coplanar.")
let(