From d2c20fee224503452f390446d915e7a81b7c92d4 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Mon, 13 May 2019 15:09:24 +0200
Subject: [PATCH] redone spinEdge so that fixed_yz works in gravity lands

---
 graph.cpp    | 15 +++++++--------
 hyper.h      |  4 +++-
 hypgraph.cpp | 28 +++++++++++++++++++++-------
 3 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/graph.cpp b/graph.cpp
index 1de34a39..42f94c2c 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -2644,8 +2644,9 @@ bool drawMonster(const transmatrix& Vparam, int ct, cell *c, color_t col) {
   return false;
   }
 
-double downspin;
 cell *straightDownSeek;
+hyperpoint straightDownPoint;
+ld straightDownSpeed;
 
 #define AURA 180
 
@@ -5958,12 +5959,10 @@ void drawcell(cell *c, transmatrix V, int spinv, bool mirrored) {
 
       if(usethis) {
         straightDownSeek = c;
-        downspin = atan2(V[1][GDIM], V[0][GDIM]);
-        downspin += (side-1) * M_PI/2;
-        downspin += conformal::rotation * degree;
-        while(downspin < -M_PI) downspin += 2*M_PI;
-        while(downspin > +M_PI) downspin -= 2*M_PI;
-        downspin = downspin * min(spd, (double)1);
+        straightDownPoint = tC0(V);
+        straightDownSpeed = spd;
+        if(side == 2) for(int i=0; i<3; i++) straightDownPoint[i] = -straightDownPoint[i];
+        if(side == 1) straightDownPoint = spin(-M_PI/2) * straightDownPoint;
         }
       }
       
@@ -6529,7 +6528,7 @@ void drawthemap() {
     multi::ccdist[i] = 1e20; multi::ccat[i] = NULL;
     }
 
-  straightDownSeek = NULL; downspin = 0;
+  straightDownSeek = NULL;
 
   #if ISMOBILE
   mouseovers = XLAT("No info about this...");
diff --git a/hyper.h b/hyper.h
index be5e720b..544ecfec 100644
--- a/hyper.h
+++ b/hyper.h
@@ -2678,7 +2678,9 @@ void preparesort();
 
 bool dodrawcell(cell *c);
 void drawcell(cell *c, transmatrix V, int spinv, bool mirrored);
-extern double downspin;
+extern cell* straightDownSeek;
+extern hyperpoint straightDownPoint;
+extern ld straightDownSpeed;
 
 extern int frameid;
 extern bool leftclick;
diff --git a/hypgraph.cpp b/hypgraph.cpp
index 6c5ca083..507d8b7a 100644
--- a/hypgraph.cpp
+++ b/hypgraph.cpp
@@ -1063,7 +1063,7 @@ transmatrix eumovedir(int d) {
   }
 
 void spinEdge(ld aspd) { 
-
+  ld downspin = 0;
   if(playerfound && vid.fixed_facing) {
     hyperpoint H = gpushxto0(playerV * C0) * playerV * xpush0(5);
     downspin = atan2(H[1], H[0]);
@@ -1073,14 +1073,28 @@ void spinEdge(ld aspd) {
     while(downspin > +M_PI) downspin -= 2*M_PI;
     aspd = (1 + 2 * abs(downspin)) * aspd;
     }
+  else if(WDIM == 2 && GDIM == 3 && vid.fixed_yz) {  
+    aspd = 999999;
+    if(straightDownSeek) {
+      if(straightDownPoint[0])
+        downspin = conformal::rotation * degree - atan2(straightDownPoint[0], straightDownPoint[1]);
+      }
+    else {
+      if(View[0][2]) 
+        downspin = -atan2(View[0][2], View[1][2]);
+      }
+    }
+  else if(straightDownSeek) {
+    downspin = atan2(straightDownPoint[1], straightDownPoint[0]);
+    downspin -= M_PI/2;
+    downspin += conformal::rotation * degree;
+    while(downspin < -M_PI) downspin += 2*M_PI;
+    while(downspin > +M_PI) downspin -= 2*M_PI;
+    downspin = downspin * min(straightDownSpeed, (double)1);
+    }
   if(downspin >  aspd) downspin =  aspd;
   if(downspin < -aspd) downspin = -aspd;
-  View = spin(downspin) * View;
-  
-  if(WDIM == 2 && GDIM == 3 && vid.fixed_yz && View[0][2]) {
-    ld d12 = atan2(View[0][2], View[1][2]);
-    View = cspin(1, 0, d12) * View;
-    }
+  View = spin(downspin) * View;  
   }
 
 void centerpc(ld aspd) {