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add tri_delaunay

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Justin Lin
2020-02-25 15:41:06 +08:00
parent 364345ad7f
commit 906de42f7f
2 changed files with 66 additions and 0 deletions
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48
src/experimental/_impl/_tri_delaunay_impl.scad Normal file
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use <experimental/tri_circumcircle.scad>;
// [max, min, min, max]
function _tri_delaunay_boundIndices(points, leng, indices, i = 0) =
let(
bounds = i < leng - 1 ? _tri_delaunay_boundIndices(points, leng, indices, i + 1)
: [undef, undef, undef, undef],
p0 = points[indices[0]],
p1 = points[indices[1]],
p2 = points[i],
c_circle = tri_circumcircle([p0, p1, p2]),
r = c_circle[1],
cside = c_circle == [] ? undef : cross(p1 - p0, c_circle[0] - p1),
pside = cross(p1 - p0, p2 - p1),
pdot = (p2 - p0) * (p2 - p1)
)
pdot < 0 && 0 == pside ? [-1, 1, 1, -1] :
c_circle == [] ? bounds :
pside > 0 && cside > 0 ? [bounds[0], bounds[1], bounds[2], bounds[3] ? min(bounds[3], r) : r] :
pside > 0 && cside <= 0 ? [bounds[0], bounds[1], bounds[2] ? max(bounds[2], r) : r, bounds[3]] :
pside <= 0 && cside > 0 ? [bounds[0], bounds[1] ? max(bounds[1],r) : r, bounds[2], bounds[3]] :
[bounds[0] ? min(bounds[0], r) : r, bounds[1], bounds[2], bounds[3]]; // is_undef(cside) also returns this
function _tri_delaunay_try_triangle(points, indices_boundIndices, i) =
let(
indices = indices_boundIndices[0],
bounds = indices_boundIndices[1],
p0 = points[indices[0]],
p1 = points[indices[1]],
p2 = points[i],
c_circle = tri_circumcircle([p0, p1, p2]),
r = c_circle[1],
cside = c_circle == [] ? undef : cross(p1 - p0, c_circle[0] - p1)
)
c_circle == [] ? undef :
(cside > 1 && (!bounds[2] && (!bounds[1] || r>=bounds[1]) && (!bounds[3] || r<=bounds[3]))) ||
(cside <= 1 && (!bounds[1] && (!bounds[2] || r>=bounds[2]) && (!bounds[0] || r<=bounds[0]))) ? concat(indices, [i]) :
undef;
function _tri_delaunay_triangleIndices(points, leng, indices_boundIndices, triangles, i = 0) =
let(
indices = indices_boundIndices[0],
newtriangle = _tri_delaunay_try_triangle(points, indices_boundIndices, i),
newtriangles = newtriangle ? concat(triangles, [newtriangle]) : triangles
)
i <= indices[1] ? _tri_delaunay_triangleIndices(points, leng, indices_boundIndices, [], indices[1] + 1) :
i< leng - 1 ? _tri_delaunay_triangleIndices(points, leng, indices_boundIndices, newtriangles,i + 1) :
newtriangles;

18
src/experimental/tri_delaunay.scad Normal file
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use <experimental/_impl/_tri_delaunay_impl.scad>;
use <experimental/flat.scad>;
function tri_delaunay(points)=
let(
leng = len(points),
indices_lt = [for(i=[0:leng - 3]) for(j = [i + 1:leng - 2]) [i, j]],
indices_boundIndices_lt = [
for(indices = indices_lt)
[indices, _tri_delaunay_boundIndices(points, leng, indices)]
]
)
flat(
[
for(indices_boundIndices = indices_boundIndices_lt)
_tri_delaunay_triangleIndices(points, leng, indices_boundIndices, [])
]
);