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Fixes for point_in_region(). Fixed assemble_path_fragments() to detect and shortcut self intersecting path fragment sets.

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Revar Desmera 2019-07-04 23:47:42 -07:00
parent 7d1edc2fba
commit baae135ab3
1 changed files with 25 additions and 7 deletions
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32
geometry.scad
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@ -46,11 +46,11 @@ function point_left_of_segment2d(point, edge) =
// Internal non-exposed function.
function _point_above_below_segment(point, edge, eps=EPSILON) =
edge[0].y <= point.y+eps? (
(edge[1].y > point.y-eps && point_left_of_segment2d(point, edge) > eps)? 1 : 0
function _point_above_below_segment(point, edge) =
edge[0].y <= point.y? (
(edge[1].y > point.y && point_left_of_segment2d(point, edge) > 0)? 1 : 0
) : (
(edge[1].y <= point.y+eps && point_left_of_segment2d(point, edge) < eps)? -1 : 0
(edge[1].y <= point.y && point_left_of_segment2d(point, edge) < 0)? -1 : 0
);
@ -427,6 +427,23 @@ function assemble_path_fragments(subpaths,eps=EPSILON,_finished=[]) =
eps=eps,
_finished=concat(_finished, [matches[0][1]])
)
) : let(
subpath = matches[0][1],
splen = len(subpath),
conn1 = [for (i=[1:splen-1]) if (approx(subpath[0],subpath[i])) i],
conn2 = [for (i=[0:splen-2]) if (approx(subpath[splen-1],subpath[i])) i]
) (conn1 != [] || conn2 != [])? let(
finpath = select(subpath, 0, conn1!=[]? conn1[0] : conn2[0]),
subpath2 = select(subpath, conn1!=[]? conn1[0] : conn2[0], -1)
) (
assemble_path_fragments(
concat(
[subpath2],
[for (i = [1:1:len(subpaths)-1]) if(i != matches[0][0]) subpaths[i]]
),
eps=eps,
_finished=concat(_finished, [finpath])
)
) : (
assemble_path_fragments(
concat(
@ -489,10 +506,11 @@ function simplify_path_indexed(points, path, eps=EPSILON) =
// path = The list of 2D path points forming the perimeter of the polygon.
// eps = Acceptable variance. Default: `EPSILON` (1e-9)
function point_in_polygon(point, path, eps=EPSILON) =
// Original algorithm from http://geomalgorithms.com/a03-_inclusion.html
// Does the point lie on any edges? If so return 0.
sum([for(i=[0:1:len(path)-1]) point_on_segment2d(point, select(path, i, i+1), eps=eps)?1:0])>0 ? 0 :
sum([for(i=[0:1:len(path)-1]) let(seg=select(path,i,i+1)) if(!approx(seg[0],seg[1],eps=eps)) point_on_segment2d(point, seg, eps=eps)?1:0]) > 0? 0 :
// Otherwise compute winding number and return 1 for interior, -1 for exterior
sum([for(i=[0:1:len(path)-1]) _point_above_below_segment(point, select(path, i, i+1), eps=eps)]) != 0 ? 1 : -1;
sum([for(i=[0:1:len(path)-1]) let(seg=select(path,i,i+1)) if(!approx(seg[0],seg[1],eps=eps)) _point_above_below_segment(point, seg)]) != 0? 1 : -1;
// Function: point_in_region()
@ -510,7 +528,7 @@ function point_in_polygon(point, path, eps=EPSILON) =
function point_in_region(point, region, eps=EPSILON, _i=0, _cnt=0) =
(_i >= len(region))? ((_cnt%2==1)? 1 : -1) : let(
pip = point_in_polygon(point, region[_i], eps=eps)
) approx(pip,0,eps=eps)? 0 : point_in_region(point, region, eps=eps, _i=_i+1, _cnt = _cnt + (pip>eps? 1 : 0));
) pip==0? 0 : point_in_region(point, region, eps=eps, _i=_i+1, _cnt = _cnt + (pip>0? 1 : 0));
// Function: pointlist_bounds()