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Code Issues Releases Wiki Activity

add in_shape

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This commit is contained in:
Justin Lin 2019-05-26 21:05:34 +08:00
parent d771a88642
commit 1fcf8b113f
2 changed files with 63 additions and 0 deletions
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7
src/__private__/__edges_from.scad Normal file
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function __edges_from(pts) =
let(leng = len(pts))
concat(
[for(i = [0:leng - 2]) [pts[i], pts[i + 1]]],
[[pts[len(pts) - 1], pts[0]]]
);

56
src/in_shape.scad Normal file
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include <__private__/__edges_from.scad>;
function _in_shape_in_line_equation(edge, pt) =
let(
x1 = edge[0][0],
y1 = edge[0][1],
x2 = edge[1][0],
y2 = edge[1][1],
a = (y2 - y1) / (x2 - x1),
b = y1 - a * x1
)
(pt[1] == a * pt[0] + b);
function _in_shape_in_edge(edge, pt) =
let(
maxx = max([edge[0][0], edge[1][0]]),
minx = min([edge[0][0], edge[1][0]]),
maxy = max([edge[0][1], edge[1][1]]),
miny = min([edge[0][1], edge[1][1]]),
vt = edge[1] - edge[0]
)
pt[0] >= minx && pt[0] <= maxx && pt[1] >= miny && pt[1] <= maxy &&
(vt[0] == 0 ? (pt[0] == edge[0][0]) : _in_shape_in_line_equation(edge, pt));
function _in_shape_in_any_edges_sub(edges, leng, pt, i) =
leng == i ? false : (
_in_shape_in_edge(edges[i], pt) ? true : _in_shape_in_any_edges_sub(edges, leng, pt, i + 1)
);
function _in_shape_in_any_edges(edges, pt) = _in_shape_in_any_edges_sub(edges, len(edges), pt, 0);
function _in_shape_interpolate_x(y, p1, p2) =
p1[1] == p2[1] ? p1[0] : (
p1[0] + (p2[0] - p1[0]) * (y - p1[1]) / (p2[1] - p1[1])
);
function _in_shape_does_pt_cross(pts, i, j, pt) =
((pts[i][1] > pt[1]) != (pts[j][1] > pt[1])) &&
(pt[0] < _in_shape_interpolate_x(pt[1], pts[i], pts[j]));
function _in_shape_sub(shapt_pts, leng, pt, cond, i, j) =
j == leng ? cond : (
_in_shape_does_pt_cross(shapt_pts, i, j, pt) ?
_in_shape_sub(shapt_pts, leng, pt, !cond, j, j + 1) :
_in_shape_sub(shapt_pts, leng, pt, cond, j, j + 1)
);
function in_shape(shapt_pts, pt, include_edge = false) =
let(
leng = len(shapt_pts),
edges = __edges_from(points)
)
_in_shape_in_any_edges(edges, pt) ? include_edge :
_in_shape_sub(shapt_pts, leng, pt, false, leng - 1, 0);