From b898365d6875c19ca99a77ab0acaed863cb2c929 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Wed, 31 Jul 2019 12:19:39 +0200
Subject: [PATCH] solv:: lazy version of inv_exp

---
 hyper.h      |  2 +-
 hypgraph.cpp |  2 +-
 sol.cpp      | 21 +++++++++++++--------
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/hyper.h b/hyper.h
index 234f9eb2..fdc8236b 100644
--- a/hyper.h
+++ b/hyper.h
@@ -5631,7 +5631,7 @@ namespace kite {
 namespace solv {
   extern transmatrix local_perspective;
   hrmap *new_map();
-  hyperpoint inverse_exp(hyperpoint h);
+  hyperpoint inverse_exp(hyperpoint h, bool lazy);
 
   transmatrix get_solmul(const transmatrix T, const transmatrix V);
   extern string solshader;
diff --git a/hypgraph.cpp b/hypgraph.cpp
index b2e7e3a9..142604b0 100644
--- a/hypgraph.cpp
+++ b/hypgraph.cpp
@@ -320,7 +320,7 @@ void applymodel(hyperpoint H, hyperpoint& ret) {
       }
 
     case mdSolPerspective: {
-      auto S = solv::inverse_exp(H);
+      auto S = solv::inverse_exp(H, false);
       ld ratio = vid.xres / current_display->tanfov / current_display->radius / 2;
       ret[0] = S[0]/S[2] * ratio;
       ret[1] = S[1]/S[2] * ratio;
diff --git a/sol.cpp b/sol.cpp
index a775b941..562ea97a 100644
--- a/sol.cpp
+++ b/sol.cpp
@@ -111,21 +111,26 @@ namespace solv {
   
     return 0.5 - atan((0.5-x) / y) / M_PI;
     }
-  
-  pt inverse_exp(pt h) {
+
+  pt inverse_exp(pt h, bool lazy) {
     load_table();
     
-    ld ix = h[0] >= 0. ? x_to_ix(h[0]) : -x_to_ix(-h[0]);
-    ld iy = h[1] >= 0. ? x_to_ix(h[1]) : -x_to_ix(-h[1]);
+    ld ix = h[0] >= 0. ? x_to_ix(h[0]) : x_to_ix(-h[0]);
+    ld iy = h[1] >= 0. ? x_to_ix(h[1]) : x_to_ix(-h[1]);
     ld iz = tanh(h[2]);
     
-    if(ix < 0.) ix = -ix;
-    if(iy < 0.) iy = -iy;
-    if(iz < 0.) { iz = -iz; ld s = ix; ix = iy; iy = s; }
+    if(h[2] < 0.) { iz = -iz; swap(ix, iy); }
     
     ix *= PRECX-1;
     iy *= PRECY-1;
     iz *= PRECZ-1;
+    
+    if(lazy) {
+      auto r = inverse_exp_table[(iz*PRECY+iy)*PRECX+ix];
+      hyperpoint res = C0;
+      for(int i=0; i<3; i++) res[i] = r[i];
+      return res;
+      }
 
     if(ix >= PRECX-1) ix = PRECX-2;
     if(iy >= PRECX-1) iy = PRECX-2;
@@ -135,7 +140,7 @@ namespace solv {
     int ay = iy, by = ay+1;
     int az = iz, bz = az+1;
     
-    pt res;
+    pt res = C0;
 
     #define S0(x,y,z) inverse_exp_table[(z*PRECY+y)*PRECX+x][t]
     #define S1(x,y) (S0(x,y,az) * (bz-iz) + S0(x,y,bz) * (iz-az))