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add sf_thicken_tri

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Justin Lin 2021-06-26 18:35:53 +08:00
parent 507c7ec226
commit 536128227b
1 changed files with 123 additions and 0 deletions
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src/surface/sf_thicken_tri.scad Normal file
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use <../util/sort.scad>;
use <../util/find_index.scad>;
use <../util/slice.scad>;
use <../util/sum.scad>;
use <../surface/sf_solidify_tri.scad>;
module sf_thicken_tri(points, triangles, thickness, direction = "BOTH") {
ascending = function(e1, e2) e1 - e2;
function connected_tris(leng_pts, triangles) =
let(
leng = len(triangles),
cnt_tris = [for(i = [0:leng_pts - 1]) []]
)
_connected_tris(triangles, leng, cnt_tris);
function _connected_tris(triangles, leng, cnt_tris, i = 0) =
i == leng ? cnt_tris :
let(
tri = sort(triangles[i], by = ascending),
b0 = cnt_tris[tri[0]],
b1 = cnt_tris[tri[1]],
b2 = cnt_tris[tri[2]],
nb0 = concat(b0, [triangles[i]]),
nb1 = concat(b1, [triangles[i]]),
nb2 = concat(b2, [triangles[i]]),
n_cnt_tris = concat(
slice(cnt_tris, 0, tri[0]),
[nb0],
slice(cnt_tris, tri[0] + 1, tri[1]),
[nb1],
slice(cnt_tris, tri[1] + 1, tri[2]),
[nb2],
slice(cnt_tris, tri[2] + 1)
)
)
_connected_tris(triangles, leng, n_cnt_tris, i + 1);
function tri_normal(tri) =
let(v = cross(tri[2] - tri[0], tri[1] - tri[0])) v / norm(v);
leng_pts = len(points);
cnn_tris = connected_tris(leng_pts, triangles);
if(is_list(direction)) {
dir_v = direction / norm(direction);
mid = sort(points)[leng_pts / 2];
tri = cnn_tris[find_index(points, function(p) p == mid)][0];
nv = tri_normal([points[tri[0]], points[tri[1]], points[tri[2]]]);
pts = [for(p = points) p + dir_v * thickness];
if(nv * dir_v > 0) {
sf_solidify_tri(pts, points, triangles);
}
else {
sf_solidify_tri(points, pts, triangles);
}
}
else {
vertex_normals = [
for(i = [0:leng_pts - 1])
let(
normals = [
for(tri = cnn_tris[i])
tri_normal([
points[tri[0]],
points[tri[1]],
points[tri[2]]]
)
]
)
sum(normals) / len(normals)
];
if(direction == "BOTH") {
half_thickness = thickness / 2;
pts1 = points + vertex_normals * half_thickness;
pts2 = points - vertex_normals * half_thickness;
sf_solidify_tri(pts1, pts2, triangles);
}
else if(direction == "FORWARD") {
pts1 = points + vertex_normals * thickness;
pts2 = points;
sf_solidify_tri(pts1, pts2, triangles);
}
else {
pts1 = points;
pts2 = points - vertex_normals * thickness;
sf_solidify_tri(pts1, pts2, triangles);
}
}
}
/*
use <triangle/tri_delaunay.scad>;
use <triangle/tri_delaunay_indices.scad>;
use <triangle/tri_delaunay_shapes.scad>;
use <surface/sf_thicken_tri.scad>;
points = [for(i = [0:50]) rands(-200, 200, 2)];
delaunay = tri_delaunay(points, ret = "DELAUNAY");
// count-clockwise (dotSCAD 2D polygon convention)
indices = tri_delaunay_indices(delaunay);
shapes = tri_delaunay_shapes(delaunay);
for(tri = shapes) {
offset(-1)
polygon(tri);
}
// triangles: clockwise (openscad 3D face convention)
triangles = [for(tri = indices) [tri[2], tri[1], tri[0]]];
pts = [for(p = points) [p[0], p[1], rands(100, 120, 1)[0]]];
thickness = 5;
sf_thicken_tri(pts, triangles, thickness);
*/