From aa1b102b781e22d843e73a82c3b19627cd097b3e Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Tue, 4 Dec 2018 18:10:36 +0100
Subject: [PATCH] crystal::rug:: correct centering

---
 crystal.cpp  | 19 +++++++++++++++++++
 hyper.h      |  1 +
 hypgraph.cpp |  4 ++++
 3 files changed, 24 insertions(+)

diff --git a/crystal.cpp b/crystal.cpp
index fed8adbb..8bc2717b 100644
--- a/crystal.cpp
+++ b/crystal.cpp
@@ -755,6 +755,8 @@ ld crug_rotation[MAXDIM][MAXDIM];
 
 int ho = 1;
 
+ldcoord rug_center;
+
 void init_rotation() {
   for(int i=0; i<MAXDIM; i++)
   for(int j=0; j<MAXDIM; j++)
@@ -783,6 +785,7 @@ void next_home_orientation() {
 
 hyperpoint coord_to_flat(ldcoord co) {
   hyperpoint res = hpxyz(0, 0, 0);
+  co = co - rug_center;
   for(int a=0; a<MAXDIM; a++)
     for(int b=0; b<3; b++)
       res[b] += crug_rotation[b][a] * co[a];
@@ -807,6 +810,22 @@ void apply_rotation(const transmatrix t) {
     }
   }
 
+void centerrug(ld aspd) {
+  if(vid.sspeed >= 4.99) aspd = 1000;
+  
+  auto m = crystal_map();
+  ldcoord at = m->get_coord(cwt.at) - rug_center;
+  
+  ld R = sqrt(at|at);
+  
+  if(R < 1e-9) rug_center = m->get_coord(cwt.at);  
+  else {
+    aspd *= (2+3*R*R);
+    if(aspd > R) aspd = R;  
+    rug_center = rug_center + at * aspd / R;
+    }
+  }
+  
 void build_rugdata() {
   using namespace rug;
   rug::clear_model(); 
diff --git a/hyper.h b/hyper.h
index 2d74be3a..f67ad236 100644
--- a/hyper.h
+++ b/hyper.h
@@ -4164,6 +4164,7 @@ namespace crystal {
   ld compass_angle();
   string compass_help();
   void may_place_compass(cell *c);
+  void centerrug(ld aspd);
   }
 
 hyperpoint get_warp_corner(cell *c, int cid);
diff --git a/hypgraph.cpp b/hypgraph.cpp
index 3f05b5cc..c00a26b0 100644
--- a/hypgraph.cpp
+++ b/hypgraph.cpp
@@ -956,6 +956,10 @@ void spinEdge(ld aspd) {
   }
 
 void centerpc(ld aspd) { 
+  
+  if(geometry == gCrystal)
+    crystal::centerrug(aspd);
+  
   if(ors::mode == 2 && vid.sspeed < 5) return;
   if(vid.sspeed >= 4.99) aspd = 1000;
   DEBB(DF_GRAPH, (debugfile,"center pc\n"));