From 8557d19b02c7b368137d2aff142e777cd8717929 Mon Sep 17 00:00:00 2001
From: Bob <rsheldiii@gmail.com>
Date: Sat, 21 Mar 2020 13:45:49 -0400
Subject: [PATCH] fix negative top tilt keytop tucking

---
 src/shapes/rounded_square.scad | 11 -----------
 src/shapes/square.scad         | 11 ++++++++---
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/src/shapes/rounded_square.scad b/src/shapes/rounded_square.scad
index bdeeb9e..4152239 100644
--- a/src/shapes/rounded_square.scad
+++ b/src/shapes/rounded_square.scad
@@ -6,17 +6,6 @@ module rounded_square_shape(size, delta, progress, center = true) {
   }
 }
 
-module square_shape(size, delta, progress) {
-  alpha = sin($top_tilt) * (top_total_key_height() - $corner_radius * 2) * 0.5;
-  gamma = ($width_difference * alpha) / ($total_depth+alpha);
-  polygon(points=[
-    [-size.x /2 + delta.x * progress/2 , -size.y / 2 + delta.y * progress/2],
-    [size.x / 2 - delta.x * progress/2,-size.y / 2 + delta.y * progress/2],
-    [size.x / 2 - delta.x * progress/2 + gamma * progress, size.y / 2 - delta.y * progress/2],
-    [-size.x / 2 + delta.x * progress/2 - gamma * progress, size.y / 2 - delta.y * progress/2]
-  ]);
-}
-
 // for skin
 
 function skin_rounded_square(size, delta, progress) =
diff --git a/src/shapes/square.scad b/src/shapes/square.scad
index d615e5d..39f9c4c 100644
--- a/src/shapes/square.scad
+++ b/src/shapes/square.scad
@@ -8,11 +8,16 @@ module square_shape_old(size, delta, progress){
 [-size.x / 2, size.y / 2] */
 
 module square_shape(size, delta, progress) {
+  // vertical inclination due to top tilt
   alpha = sin($top_tilt) * (top_total_key_height() - $corner_radius * 2) * 0.5;
-  gamma = ($width_difference * alpha) / ($total_depth+alpha);
+
+  // how much we have to tuck in the top and bottom of the keytop to make the sides parallel
+  gamma = min((($width_difference * alpha) / ($total_depth+alpha)), 0);
+  nega_gamma = max((($width_difference * alpha) / ($total_depth-alpha)), 0);
+
   polygon(points=[
-    [-size.x /2 + delta.x * progress/2 , -size.y / 2 + delta.y * progress/2],
-    [size.x / 2 - delta.x * progress/2,-size.y / 2 + delta.y * progress/2],
+    [-size.x /2 + delta.x * progress/2 + nega_gamma * progress , -size.y / 2 + delta.y * progress/2],
+    [size.x / 2 - delta.x * progress/2  - nega_gamma * progress ,-size.y / 2 + delta.y * progress/2],
     [size.x / 2 - delta.x * progress/2 + gamma * progress, size.y / 2 - delta.y * progress/2],
     [-size.x / 2 + delta.x * progress/2 - gamma * progress, size.y / 2 - delta.y * progress/2]
   ]);