From 87052bb1723dc58e7b060e32b475a376897f1d91 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Mon, 29 Apr 2019 15:26:50 +0800
Subject: [PATCH] required by path_extrude

---
 src/rotate_p.scad | 50 +++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 46 insertions(+), 4 deletions(-)

diff --git a/src/rotate_p.scad b/src/rotate_p.scad
index fb91f02d..7480cfcb 100644
--- a/src/rotate_p.scad
+++ b/src/rotate_p.scad
@@ -14,6 +14,37 @@
 include <__private__/__to2d.scad>;
 include <__private__/__to3d.scad>;
 
+
+function _q_rotate_p_3d(p, a, v) = 
+    let(
+        half_a = a / 2,
+        axis = v / norm(v),
+        s = sin(half_a),
+        x = s * axis[0],
+        y = s * axis[1],
+        z = s * axis[2],
+        w = cos(half_a),
+        
+        x2 = x + x,
+        y2 = y + y,
+        z2 = z + z,
+
+        xx = x * x2,
+        yx = y * x2,
+        yy = y * y2,
+        zx = z * x2,
+        zy = z * y2,
+        zz = z * z2,
+        wx = w * x2,
+        wy = w * y2,
+        wz = w * z2        
+    )
+    [
+        [1 - yy - zz, yx - wz, zx + wy] * p,
+        [yx + wz, 1 - xx - zz, zy - wx] * p,
+        [zx - wy, zy + wx, 1 - xx - yy] * p
+    ];
+
 function _rotx(pt, a) = 
     let(cosa = cos(a), sina = sin(a))
     [
@@ -48,10 +79,21 @@ function to_avect(a) =
          ) 
      );
 
-function rotate_p(point, a) =
+function _rotate_p(p, a) =
     let(angle = to_avect(a))
-    len(point) == 3 ? 
-        _rotate_p_3d(point, angle) :
+    len(p) == 3 ? 
+        _rotate_p_3d(p, angle) :
         __to2d(
-            _rotate_p_3d(__to3d(point), angle)
+            _rotate_p_3d(__to3d(p), angle)
         );
+
+
+function _q_rotate_p(p, a, v) =
+    len(p) == 3 ? 
+        _q_rotate_p_3d(p, a, v) :
+        __to2d(
+            _q_rotate_p_3d(__to3d(p), a, v)
+        );
+
+function rotate_p(point, a, v) =
+    v == undef ? _rotate_p(point, a) : _q_rotate_p(point, a, v);