From 72501c20f6c94bf7bc20565f81b77926f2833758 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Mon, 15 Jul 2024 13:30:27 +0200
Subject: [PATCH] sl2:: fixes to ggmatrix

---
 geometry2.cpp    |  5 +----
 nonisotropic.cpp | 14 +++++++-------
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/geometry2.cpp b/geometry2.cpp
index ad57307a..93518ec9 100644
--- a/geometry2.cpp
+++ b/geometry2.cpp
@@ -203,12 +203,9 @@ transmatrix hrmap_standard::relative_matrixh(heptagon *h2, heptagon *h1, const h
 EX shiftmatrix &ggmatrix(cell *c) {
   shiftmatrix& t = gmatrix[c];
   if(t[LDIM][LDIM] == 0) {
+    if(sl2) return t = twist::nmul(shiftless(actual_view_transform * View), twist::relative_shiftmatrix(c, centerover));
     t.T = actual_view_transform * View * calc_relative_matrix(c, centerover, C0);
     t.shift = 0;
-    if(sl2) {
-      ld d = twist::get_phase_difference(c, centerover);
-      t.shift = floor(d / TAU + .5) * TAU;
-      }
     }
   return t;
   }
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 88a97e68..4db79e41 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -2465,16 +2465,16 @@ EX namespace twist {
       return M = lift_matrix(PIU(currentmap->adj(cw, i)));      
       }
     
+    shiftmatrix relative_shiftmatrix(cell *c2, cell *c1) {
+      return nmul(ninverse(recorded_matrices[c1]), recorded_matrices[c2]);
+      }
+
     transmatrix relative_matrixc(cell *c2, cell *c1, const hyperpoint& hint) override { 
       if(c1 == c2) return Id;
       if(gmatrix0.count(c2) && gmatrix0.count(c1))
         return inverse_shift(gmatrix0[c1], gmatrix0[c2]);
       for(int i=0; i<c1->type; i++) if(c1->move(i) == c2) return adj(c1, i);
-      return inverse_shift(recorded_matrices[c2], recorded_matrices[c1]);
-      }
-
-    ld get_phase_difference(cell *c2, cell *c1) {
-      return recorded_matrices.at(c2).shift - recorded_matrices.at(c1).shift;
+      return inverse_shift(recorded_matrices[c1], recorded_matrices[c2]);
       }
 
     transmatrix ray_iadj(cell *c1, int i) override {
@@ -2514,9 +2514,9 @@ EX namespace twist {
       }
     }
 
-  EX ld get_phase_difference(cell *c2, cell *c1) {
+  EX shiftmatrix relative_shiftmatrix(cell *c2, cell *c1) {
     auto hmap = dynamic_cast<hrmap_twisted*> (currentmap);
-    return hmap->get_phase_difference(c2, c1);
+    return hmap->relative_shiftmatrix(c2, c1);
     }
 
   /** reinterpret the given point of rotspace as a rotation matrix in the underlying geometry (note: this is the inverse)