From f4f6a7db5d2ae2afd7da808f020b6a0dfb19da07 Mon Sep 17 00:00:00 2001
From: Chris Hodapp <hodapp87@gmail.com>
Date: Sun, 16 Feb 2020 18:15:29 -0500
Subject: [PATCH] Sorta fix curve_horn_start

---
 README.md   |  3 ++-
 src/main.rs | 57 ++++++++++++++---------------------------------------
 2 files changed, 17 insertions(+), 43 deletions(-)

diff --git a/README.md b/README.md
index ca6f8aa..6ef06b3 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,8 @@
 
 ## Highest priority:
 
-- Continue converting `curve_horn_*`.
+- Fix issue with `curve_horn_*` that prevents geometry being joined in
+  middle.
 - Consider trampolining `to_mesh`.  My call stack seems needlessly
   deep in spots.  Can I make tail-recursive?
 - 
diff --git a/src/main.rs b/src/main.rs
index ce0a803..a01a7eb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -275,51 +275,23 @@ fn cube() -> OpenMesh {
     }.transform(geometry::Translation3::new(-0.5, -0.5, -0.5).to_homogeneous())
 }
 
-/*
 fn curve_horn_start() -> RuleStep {
-    // Seed is a square in XY, sidelength 1, centered at (0,0,0):
-    let seed = {
-        let m = OpenMesh {
-            verts: vec![
-                vertex(0.0, 0.0, 0.0),
-                vertex(1.0, 0.0, 0.0),
-                vertex(1.0, 1.0, 0.0),
-                vertex(0.0, 1.0, 0.0),
-            ],
-            faces: vec![
-                0, 1, 2,
-                0, 2, 3,
-            ],
-            idxs_entrance: vec![0],
-            idxs_exit: vec![0],
-            idxs_body: (0, 0),
-        };
-        let xform = nalgebra::geometry::Translation3::new(-0.5, -0.5, 0.0).to_homogeneous();
-        m.transform(xform)
-    };
-    vec![
-        // Since neither of the other two rules *start* with geometry:
-        RuleStep { geom: seed.clone(),
-                   rule: Box::new(Rule::EmptyRule),
-                   xform: nalgebra::geometry::Transform3::identity().to_homogeneous(),
-        },
-        // Recurse in both directions:
-        RuleStep { geom: seed.clone(),
-                   rule: Box::new(Rule::Recurse(curve_horn_thing_rule)),
-                   xform: nalgebra::geometry::Transform3::identity().to_homogeneous(),
-        },
-        RuleStep { geom: seed.clone(),
-                   rule: Box::new(Rule::Recurse(curve_horn_thing_rule)),
-                   xform: nalgebra::geometry::Rotation3::from_axis_angle(
-                       &nalgebra::Vector3::y_axis(),
-                       std::f32::consts::FRAC_PI_2).to_homogeneous(),
-        },
-    ]
+    let id = nalgebra::geometry::Transform3::identity().to_homogeneous();
+    let flip180 = nalgebra::geometry::Rotation3::from_axis_angle(
+        &nalgebra::Vector3::y_axis(),
+        std::f32::consts::PI).to_homogeneous();
+    RuleStep {
+        geom: empty_mesh(),
+        final_geom: empty_mesh(),
+        children: vec![
+            (Rule::Recurse(curve_horn_thing_rule), id),
+            (Rule::Recurse(curve_horn_thing_rule), flip180),
+        ],
+    }
+    // TODO: This has duplicate geometry in the middle because four
+    // vertices of each start point never technically connect.
 }
 
-//use std::convert::TryFrom;
-*/
-
 fn curve_horn_thing_rule() -> RuleStep {
 
     let y = &Vector3::y_axis();
@@ -442,4 +414,5 @@ fn main() {
 
     run_test(Rule::Recurse(cube_thing_rule), 3, "cube_thing");
     run_test(Rule::Recurse(curve_horn_thing_rule), 100, "curve_horn_thing");
+    run_test(Rule::Recurse(curve_horn_start), 100, "curve_horn2");
 }