From 0c34e9fd34a9f20aa795dbc6c266ef9762666214 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Sun, 7 Jan 2024 09:13:31 +0100
Subject: [PATCH] 'cylidrical' stereo mode

---
 config.cpp  |  3 ++-
 graph.cpp   |  2 +-
 hyper.h     |  2 +-
 shaders.cpp | 11 +++++++++++
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/config.cpp b/config.cpp
index e546d085..c3b2b1b8 100644
--- a/config.cpp
+++ b/config.cpp
@@ -1385,7 +1385,8 @@ EX void initConfig() {
     {"ODS", "for rendering 360° VR videos (implemented only in raycaster and some other parts)"},
     {"Panini", "Projection believed to be used by Italian painters. Allows very high FOV angles while rendering more straight lines as straight than the stereographic projection."},
     {"stereographic", "Stereographic projection allows very high FOV angles."},
-    {"equirectangular", "for rendering 360° videos (implemented only in raycaster)"}
+    {"equirectangular", "for rendering 360° videos (implemented only in raycaster)"},
+    {"cylindrical", "full vertical (not implemented in raycaster)"}
     }, "stereo/high-FOV mode", 'm')
   ->set_reaction(reset_all_shaders);
 
diff --git a/graph.cpp b/graph.cpp
index 2d7609e2..ab6aff13 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -4119,7 +4119,7 @@ EX ld threshold, xyz_threshold;
 EX bool clip_checked = false;
 
 EX bool other_stereo_mode() {
-  return among(vid.stereo_mode, sODS, sPanini, sStereographic, sEquirectangular);
+  return vid.stereo_mode != sOFF;
   }
 
 void make_clipping_planes() {
diff --git a/hyper.h b/hyper.h
index 8fbbea2f..c04163c3 100644
--- a/hyper.h
+++ b/hyper.h
@@ -250,7 +250,7 @@ struct charstyle {
   bool lefthanded;
   };
 
-enum eStereo { sOFF, sAnaglyph, sLR, sODS, sPanini, sStereographic, sEquirectangular };
+enum eStereo { sOFF, sAnaglyph, sLR, sODS, sPanini, sStereographic, sEquirectangular, sCylindrical };
 
 enum eModel : int;
 
diff --git a/shaders.cpp b/shaders.cpp
index 31f73db7..f4d705b7 100644
--- a/shaders.cpp
+++ b/shaders.cpp
@@ -82,6 +82,12 @@ EX string panini_shader() {
     "t.w = 1.;\n";
   }
 
+EX string cylindrical_shader() {
+  return
+    "t /= t.w;\n"
+    "t.y = atan2(t.y, length(t.xz)) * length(t.xz) * 2. / PI;\n";
+  }
+
 EX string stereo_shader() {
   return
     "t.w += 1.; t *= 2. / t.w; t.w -= 1.;\n"
@@ -521,6 +527,11 @@ shared_ptr<glhr::GLprogram> write_shader(flagtype shader_flags) {
       vmain += panini_shader();
       shader_flags |= SF_ORIENT;
       }
+    else if((shader_flags & SF_PERS3) && vid.stereo_mode == sCylindrical && !vrhr::rendering_eye()) {
+      vmain += "t = uPP * t;", vsh += "uniform mediump mat4 uPP;";
+      vmain += cylindrical_shader();
+      shader_flags |= SF_ORIENT;
+      }
     else if((shader_flags & SF_PERS3) && vid.stereo_mode == sStereographic && !vrhr::rendering_eye()) {
       vmain += "t = uPP * t;", vsh += "uniform mediump mat4 uPP;";
       vmain += stereo_shader();