From b7a4997509d8de82a5b5389841371f3187416769 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Sat, 7 Jan 2023 12:22:14 +0100
Subject: [PATCH] fixed camera movement in euc_in_sl2

---
 hyperpoint.cpp |  4 ++--
 hypgraph.cpp   | 25 +++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/hyperpoint.cpp b/hyperpoint.cpp
index 4c635f62..453957a8 100644
--- a/hyperpoint.cpp
+++ b/hyperpoint.cpp
@@ -1765,7 +1765,7 @@ EX bool asign(ld y1, ld y2) { return signum(y1) != signum(y2); }
 EX ld xcross(ld x1, ld y1, ld x2, ld y2) { return x1 + (x2 - x1) * y1 / (y1 - y2); }
 
 #if HDR
-enum eShiftMethod { smProduct, smIsotropic, smEmbedded, smLie, smGeodesic };
+enum eShiftMethod { smProduct, smIsotropic, smEmbedded, smLie, smGeodesic, smESL2 };
 enum eEmbeddedShiftMethodChoice { smcNone, smcBoth, smcAuto };
 enum eShiftMethodApplication { smaManualCamera, smaAutocenter, smaObject, smaWallRadar };
 #endif
@@ -1785,7 +1785,7 @@ EX bool use_embedded_shift(eShiftMethodApplication sma) {
 EX eShiftMethod shift_method(eShiftMethodApplication sma) {
   if(gproduct) return smProduct;
   if(embedded_plane && sma == smaObject) return geom3::same_in_same() ? smIsotropic : smEmbedded;
-  if(embedded_plane && use_embedded_shift(sma)) return (nonisotropic && !sl2) ? smLie : smEmbedded;
+  if(embedded_plane && use_embedded_shift(sma)) return sl2 ? smESL2 : nonisotropic ? smLie : smEmbedded;
   if(!nonisotropic && !stretch::in() && !(!nisot::geodesic_movement && hyperbolic && bt::in())) return smIsotropic;
   if(!nisot::geodesic_movement && !embedded_plane) return smLie;
   return smGeodesic;
diff --git a/hypgraph.cpp b/hypgraph.cpp
index b9e1c725..ec8496b2 100644
--- a/hypgraph.cpp
+++ b/hypgraph.cpp
@@ -3306,7 +3306,7 @@ EX void shift_view(hyperpoint H, eShiftMethod sm IS(shift_method(smaManualCamera
   wc = get_shift_view_of(H, wc, sm);
   }
 
-/** works in embedded_plane (except embedded product where shift_view works) */
+/** works in embedded_plane (except embedded product where shift_view works, and euc_in_sl2) */
 EX transmatrix get_shift_view_embedded_of(const transmatrix V, const transmatrix T) {
   transmatrix IV = view_inverse(V);
   transmatrix rot = V * map_relative_push(IV * C0);
@@ -3324,6 +3324,22 @@ void shift_view_embedded(const transmatrix T) {
   wc = R * wc;
   }
 
+EX transmatrix get_shift_view_embedded_of_esl2(const transmatrix V, const hyperpoint h) {
+  transmatrix IV = view_inverse(V);
+  transmatrix rot = V * map_relative_push(IV * C0);
+  transmatrix V1 = gpushxto0(h) * gpushxto0(IV*C0);
+  transmatrix IV1 = view_inverse(V1);
+  transmatrix rot1 = V1 * map_relative_push(IV1 * C0);
+  return rot * inverse(rot1) * V1 * inverse(V);
+  }
+
+void shift_view_esl2(hyperpoint h) {
+  transmatrix R = get_shift_view_embedded_of_esl2(View, h);
+  View = R * View;
+  auto& wc = current_display->which_copy;
+  wc = R * wc;
+  }
+
 /** works in isotropic and product spaces */
 void shift_view_mmul(const transmatrix T) {
   View = T * View;
@@ -3394,6 +3410,9 @@ EX void shift_view_to(shiftpoint H, eShiftMethod sm IS(shift_method(smaManualCam
     case smProduct:
       shift_view_by_matrix(gpushxto0(unshift(H)), sm);
       return;
+    case smESL2:
+      shift_view_esl2(lp_iapply(unshift(H)));
+      return;
     case smLie:
       shift_view(-lie_log(H), sm);
       return;
@@ -3409,9 +3428,11 @@ EX void shift_view_towards(shiftpoint H, ld l, eShiftMethod sm IS(shift_method(s
   switch(sm) {
     case smIsotropic:
     case smEmbedded:
-      if(sl2) shift_view_to(H, sm); // shift_view_by_matrix(rgpushxto0(unshift(lie_exp(tangent_length(lie_log(H), -l)))), smEmbedded);
       shift_view_by_matrix(rspintox(unshift(H)) * xpush(-l) * spintox(unshift(H)), sm);
       return;
+    case smESL2:
+      shift_view_esl2(esl2_ita0(tangent_length(esl2_ati(lp_iapply(unshift(H))), l)));
+      return;
     case smLie:
       shift_view(tangent_length(lie_log(H), -l), sm);
       return;