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Changed circle_point_tangents() to return just a list of 2D tangent points.

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Garth Minette 2020-09-24 17:09:06 -07:00
parent 02b765aae0
commit 4f88775ef9
3 changed files with 15 additions and 11 deletions
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6
geometry.scad
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@ -1342,7 +1342,7 @@ function find_circle_3points(pt1, pt2, pt3) =
// tangents = circle_point_tangents(r|d, cp, pt); // tangents = circle_point_tangents(r|d, cp, pt);
// Description: // Description:
// Given a 2d circle and a 2d point outside that circle, finds the 2d tangent point(s) on the circle for a // Given a 2d circle and a 2d point outside that circle, finds the 2d tangent point(s) on the circle for a
// line passing through the point. Returns list of zero or more sublists of [ANG, TANGPT] // line passing through the point. Returns a list of zero or more 2D tangent points.
// Arguments: // Arguments:
// r = Radius of the circle. // r = Radius of the circle.
// d = Diameter of the circle. // d = Diameter of the circle.
@ -1350,7 +1350,7 @@ function find_circle_3points(pt1, pt2, pt3) =
// pt = The coordinates of the 2d external point. // pt = The coordinates of the 2d external point.
// Example: // Example:
// cp = [-10,-10]; r = 30; pt = [30,10]; // cp = [-10,-10]; r = 30; pt = [30,10];
// tanpts = subindex(circle_point_tangents(r=r, cp=cp, pt=pt),1); // tanpts = circle_point_tangents(r=r, cp=cp, pt=pt);
// color("yellow") translate(cp) circle(r=r); // color("yellow") translate(cp) circle(r=r);
// color("cyan") for(tp=tanpts) {stroke([tp,pt]); stroke([tp,cp]);} // color("cyan") for(tp=tanpts) {stroke([tp,pt]); stroke([tp,cp]);}
// color("red") move_copies(tanpts) circle(d=3,$fn=12); // color("red") move_copies(tanpts) circle(d=3,$fn=12);
@ -1368,7 +1368,7 @@ function circle_point_tangents(r, d, cp, pt) =
let( let(
relang = acos(r/dist), relang = acos(r/dist),
angs = [baseang + relang, baseang - relang] angs = [baseang + relang, baseang - relang]
) [for (ang=angs) [ang, cp + r*[cos(ang),sin(ang)]]]; ) [for (ang=angs) cp + r*[cos(ang),sin(ang)]];
// Function: circle_circle_tangents() // Function: circle_circle_tangents()

18
tests/test_geometry.scad
View file

@ -601,13 +601,17 @@ module test_find_circle_3points() {
module test_circle_point_tangents() { module test_circle_point_tangents() {
tangs = circle_point_tangents(r=50,cp=[0,0],pt=[50*sqrt(2),0]); testvals = [
assert(approx(subindex(tangs,0), [45,-45])); // cp r pt expect
expected = [for (ang=subindex(tangs,0)) polar_to_xy(50,ang)]; [[0,0], 50, [50*sqrt(2),0], [polar_to_xy(50,45), polar_to_xy(50,-45)]],
got = subindex(tangs,1); [[5,10], 50, [5+50*sqrt(2),10], [[5,10]+polar_to_xy(50,45), [5,10]+polar_to_xy(50,-45)]],
if (!approx(flatten(got), flatten(expected))) { [[0,0], 50, [0,50*sqrt(2)], [polar_to_xy(50,135), polar_to_xy(50,45)]],
echo("TAN_PTS:", got=got, expected=expected, delta=got-expected); [[5,10], 50, [5,10+50*sqrt(2)], [[5,10]+polar_to_xy(50,135), [5,10]+polar_to_xy(50,45)]]
assert(approx(flatten(got), flatten(expected))); ];
for (v = testvals) {
cp = v[0]; r = v[1]; pt = v[2]; expect = v[3];
info = str("cp=",cp, ", r=",r, ", pt=",pt);
assert_approx(circle_point_tangents(r=r,cp=cp,pt=pt), expect, info);
} }
} }
*test_circle_point_tangents(); *test_circle_point_tangents();

2
version.scad
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@ -8,7 +8,7 @@
////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////
BOSL_VERSION = [2,0,428]; BOSL_VERSION = [2,0,429];
// Section: BOSL Library Version Functions // Section: BOSL Library Version Functions