From 4d64618600ccd7bedfcbbd714359fab0a4e035bc Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Tue, 6 Aug 2019 21:09:12 +0200
Subject: [PATCH] nilv:: geodesic wall surfaces

---
 nonisotropic.cpp | 7 +++++++
 polygons.cpp     | 4 ++++
 2 files changed, 11 insertions(+)

diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 308e111d..d84ff17e 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -526,6 +526,13 @@ namespace nilv {
       }
 
     };
+
+  hyperpoint on_geodesic(hyperpoint s0, hyperpoint s1, ld x) {
+    using namespace hyperpoint_vec;
+    hyperpoint local = inverse(nisot::translate(s0)) * s1;
+    hyperpoint h = get_inverse_exp(local, 100);
+    return nisot::translate(s0) * formula_exp(h * x);
+    }
   }
 
 namespace nisot {
diff --git a/polygons.cpp b/polygons.cpp
index cde85e41..032bbb35 100644
--- a/polygons.cpp
+++ b/polygons.cpp
@@ -717,6 +717,8 @@ void geometry_information::make_wall(int id, vector<hyperpoint> vertices, vector
     hyperpoint v2 = vertices[(a+1)%n] - center;
     texture_order([&] (ld x, ld y) {
       hyperpoint h = center + v1 * x + v2 * y;
+      if(nil && (x || y))
+        h = nilv::on_geodesic(center, nilv::on_geodesic(v1+center, v2+center, y / (x+y)), x + y);
       if(sol || !binarytiling) { hpcpush(normalize(h)); return; }
       hyperpoint res = binary::parabolic3(h[0], h[1]) * xpush0(yy*h[2]);
       hpcpush(res);
@@ -728,6 +730,8 @@ void geometry_information::make_wall(int id, vector<hyperpoint> vertices, vector
     int STEP = vid.texture_step;
     for(int a=0; a<n; a++) for(int y=0; y<STEP; y++) {
       hyperpoint h = (vertices[a] * (STEP-y) + vertices[(a+1)%n] * y)/STEP;
+      if(nil)
+        h = nilv::on_geodesic(vertices[a], vertices[(a+1)%n], y * 1. / STEP);
       if(sol || !binarytiling) { hpcpush(normalize(h)); continue; }
       hyperpoint res = binary::parabolic3(h[0], h[1]) * xpush0(yy*h[2]);
       hpcpush(res);