From 07343e9e37b97374dfee5c70380de277f28f6d78 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Sat, 16 Apr 2022 12:59:58 +0800
Subject: [PATCH] refactor

---
 src/__comm__/__in_line.scad   |  5 ++++-
 src/_impl/_in_shape_impl.scad | 17 +++++++----------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/__comm__/__in_line.scad b/src/__comm__/__in_line.scad
index db4ebf07..a595a5be 100644
--- a/src/__comm__/__in_line.scad
+++ b/src/__comm__/__in_line.scad
@@ -5,4 +5,7 @@ function __in_line(line_pts, pt, epsilon = 0.0001) =
         v1 = pts[0] - pt3d, 
         v2 = pts[1] - pt3d
     )
-    (norm(cross(v1, v2)) < epsilon) && ((v1 * v2) <= epsilon);
\ No newline at end of file
+    v1 * v2 <= epsilon && (
+        let(v = cross(v1, v2)) 
+        v * v < (epsilon ^ 2)
+    );
\ No newline at end of file
diff --git a/src/_impl/_in_shape_impl.scad b/src/_impl/_in_shape_impl.scad
index 9e177a92..614447a1 100644
--- a/src/_impl/_in_shape_impl.scad
+++ b/src/_impl/_in_shape_impl.scad
@@ -2,11 +2,10 @@ use <__comm__/__in_line.scad>;
 
 function _in_shape_in_line_equation(edge, pt) = 
     let(
-        v = edge[1] - edge[0],
-        a = v.y / v.x,
-        b = edge[0].y - a * edge[0].x
+        p0 = edge[0],
+        v = edge[1] - p0
     )
-    (pt.y == a * pt.x + b);
+    pt.y == (v.y / v.x) * (pt.x - p0.x) + p0.y;
 
 function _in_shape_in_any_edges(edges, pt, epsilon) = 
     let(
@@ -16,15 +15,13 @@ function _in_shape_in_any_edges(edges, pt, epsilon) =
     is_undef(maybe_last);
 
 function _in_shape_interpolate_x(y, p1, p2) = 
-    p1.y == p2.y ? p1.x : (
-        p1.x + (p2.x - p1.x) * (y - p1.y) / (p2.y - p1.y)
-    );
+    p1.y == p2.y ? p1.x : 
+    let(v = p2 - p1) p1.x + v.x * (y - p1.y) / v.y;
     
 function _in_shape_does_pt_cross(pts, i, j, pt) = 
-    ((pts[i].y > pt.y) != (pts[j].y > pt.y)) &&
-    (pt.x < _in_shape_interpolate_x(pt.y, pts[i], pts[j]));
+    let(pi = pts[i], pj = pts[j])
+    ((pi.y - pt.y) * (pj.y - pt.y) < 0) && (pt.x < _in_shape_interpolate_x(pt.y, pi, pj));
     
-
 function _in_shape_sub(shapt_pts, leng, pt, cond, i, j) =
     j == leng ? cond : _in_shape_sub(shapt_pts, leng, pt,  _in_shape_does_pt_cross(shapt_pts, i, j, pt) ? !cond : cond, j, j + 1);
  
\ No newline at end of file