NopSCADlib/tests/bezier.scad

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2019-06-08 17:10:47 -04:00
//
// NopSCADlib Copyright Chris Palmer 2018
// nop.head@gmail.com
// hydraraptor.blogspot.com
//
// This file is part of NopSCADlib.
//
// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
// GNU General Public License as published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
//
// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along with NopSCADlib.
// If not, see <https://www.gnu.org/licenses/>.
//
include <../utils/core/core.scad>
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use <../utils/bezier.scad>
use <../utils/sweep.scad>
use <../utils/annotation.scad>
function find_min_z(path, i = 1, best_i = 0) =
i >= len(path) ? best_i
: find_min_z(path, i + 1, path[i].z < path[best_i].z ? i : best_i);
module beziers() {
//
// Make Bezier control points to give specified length
//
control_points = adjust_bezier_length([[0, 0, 100], [0, 0, 0], [200, 0, 20], [100, -100, 50]], 250);
//
// Draw control points
//
color("green")
for(p = control_points)
translate(p)
sphere(1);
//
// Lines joining the control points
//
color("red")
sweep(control_points, circle_points(0.5, $fn = 64));
//
// Bezier curve path from control points
//
curve = bezier_path(control_points);
//
// Draw the curve
//
sweep(curve, circle_points(2, $fn = 64));
//
// Length computed from control points
//
length = bezier_length(control_points);
//
// Length computed from curve
//
length2 = path_length(curve);
assert(str(length) == str(length2), str(length, " ", length2));
//
// Minimum Z
//
min_z = bezier_min_z(control_points);
i = find_min_z(curve);
assert(str(min_z) == str(curve[i].z));
color("blue") {
translate(curve[i] + [0, 0, 2])
arrow();
translate(curve[i] - [0, 0, 2])
vflip()
arrow();
}
translate(control_points[1] - [0, 0, 2])
label(str("bezier_length = ", length, ", bezier_min_z = ", bezier_min_z(curve)), valign = "top");
}
if($preview)
beziers();