From 4f88775ef9de4256e84b06afdea6f147b2b779cd Mon Sep 17 00:00:00 2001
From: Garth Minette <gminette@gmail.com>
Date: Thu, 24 Sep 2020 17:09:06 -0700
Subject: [PATCH] Changed circle_point_tangents() to return just a list of 2D
 tangent points.

---
 geometry.scad            |  6 +++---
 tests/test_geometry.scad | 18 +++++++++++-------
 version.scad             |  2 +-
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/geometry.scad b/geometry.scad
index 97564db..b09c05b 100644
--- a/geometry.scad
+++ b/geometry.scad
@@ -1342,7 +1342,7 @@ function find_circle_3points(pt1, pt2, pt3) =
 //   tangents = circle_point_tangents(r|d, cp, pt);
 // Description:
 //   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:
 //   r = Radius 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.
 // Example:
 //   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("cyan") for(tp=tanpts) {stroke([tp,pt]); stroke([tp,cp]);}
 //   color("red") move_copies(tanpts) circle(d=3,$fn=12);
@@ -1368,7 +1368,7 @@ function circle_point_tangents(r, d, cp, pt) =
     let(
         relang = acos(r/dist),
         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()
diff --git a/tests/test_geometry.scad b/tests/test_geometry.scad
index 84dd814..bf49f0f 100644
--- a/tests/test_geometry.scad
+++ b/tests/test_geometry.scad
@@ -601,13 +601,17 @@ module test_find_circle_3points() {
 
 
 module test_circle_point_tangents() {
-    tangs = circle_point_tangents(r=50,cp=[0,0],pt=[50*sqrt(2),0]);
-    assert(approx(subindex(tangs,0), [45,-45]));
-    expected = [for (ang=subindex(tangs,0)) polar_to_xy(50,ang)];
-    got = subindex(tangs,1);
-    if (!approx(flatten(got), flatten(expected))) {
-        echo("TAN_PTS:", got=got, expected=expected, delta=got-expected);
-        assert(approx(flatten(got), flatten(expected)));
+    testvals = [
+        // cp    r   pt                 expect
+        [[0,0],  50, [50*sqrt(2),0],    [polar_to_xy(50,45), polar_to_xy(50,-45)]],
+        [[5,10], 50, [5+50*sqrt(2),10], [[5,10]+polar_to_xy(50,45), [5,10]+polar_to_xy(50,-45)]],
+        [[0,0],  50, [0,50*sqrt(2)],    [polar_to_xy(50,135), polar_to_xy(50,45)]],
+        [[5,10], 50, [5,10+50*sqrt(2)], [[5,10]+polar_to_xy(50,135), [5,10]+polar_to_xy(50,45)]]
+    ];
+    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();
diff --git a/version.scad b/version.scad
index 975eb67..ba38fd3 100644
--- a/version.scad
+++ b/version.scad
@@ -8,7 +8,7 @@
 //////////////////////////////////////////////////////////////////////
 
 
-BOSL_VERSION = [2,0,428];
+BOSL_VERSION = [2,0,429];
 
 
 // Section: BOSL Library Version Functions