From 80b9d9533c4f9ccf430f2223c81b834eb78ca548 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Sat, 26 Feb 2022 09:49:46 +0100
Subject: [PATCH] intra:: fixed portals to/from S3 and H3

---
 intra.cpp     |  8 ++++++++
 raycaster.cpp | 10 ++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/intra.cpp b/intra.cpp
index 52a5ef35..ec417d61 100644
--- a/intra.cpp
+++ b/intra.cpp
@@ -91,6 +91,10 @@ hyperpoint portal_data::to_poco(hyperpoint h) const {
   else {
     h = T * h;
     h /= h[3];
+    if(sphere)
+      h[2] /= sqrt(1+h[0]*h[0]+h[1]*h[1]);
+    if(hyperbolic)
+      h[2] /= sqrt(1-h[0]*h[0]-h[1]*h[1]);
     return h;
     }
   }
@@ -126,6 +130,10 @@ hyperpoint portal_data::from_poco(hyperpoint h) const {
     }
   else {
     h[3] = 1;
+    if(sphere)
+      h[2] *= sqrt(1+h[0]*h[0]+h[1]*h[1]);
+    if(hyperbolic)
+      h[2] *= sqrt(1-h[0]*h[0]-h[1]*h[1]);
     return normalize(iT * h);
     }
   }
diff --git a/raycaster.cpp b/raycaster.cpp
index a0c5583d..0d304f7e 100644
--- a/raycaster.cpp
+++ b/raycaster.cpp
@@ -1575,22 +1575,28 @@ void raygen::add_functions() {
 
   add_if("to_poco_h3",
         "mediump vec4 to_poco_h3(mediump vec4 pos) {\n"
-        "  return pos / pos[3];\n"
+        "  pos = pos / pos[3];\n"
+        "  pos[2] /= sqrt(1.-pos.x*pos.x-pos.y*pos.y);\n"
+        "  return pos;\n"
         "  }\n\n");
 
   add_if("from_poco_h3",
         "mediump vec4 from_poco_h3(mediump vec4 pos) {\n"
+        "  pos[2] *= sqrt(1.-pos.x*pos.x-pos.y*pos.y);\n"
         "  float s = 1. - dot(pos.xyz, pos.xyz);\n"
         "  return pos / sqrt(s);\n"
         "  }\n\n");
 
   add_if("to_poco_s3",
         "mediump vec4 to_poco_s3(mediump vec4 pos) {\n"
-        "  return pos / pos[3];\n"
+        "  pos = pos / pos[3];\n"
+        "  pos[2] /= sqrt(1.+pos.x*pos.x+pos.y*pos.y);\n"
+        "  return pos;\n"
         "  }\n\n");
 
   add_if("from_poco_s3",
         "mediump vec4 from_poco_s3(mediump vec4 pos) {\n"
+        "  pos[2] *= sqrt(1.+pos.x*pos.x+pos.y*pos.y);\n"
         "  float s = 1. + dot(pos.xyz, pos.xyz);\n"
         "  return pos / sqrt(s);\n"
         "  }\n\n");