From 73c689211fc8613c8b02915c0d15a36af06de003 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Tue, 11 Oct 2022 19:56:37 +0200
Subject: [PATCH] shader flag to use no fog -- useful to display ultra-ideal
 points

---
 drawing.cpp | 3 +++
 shaders.cpp | 8 ++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drawing.cpp b/drawing.cpp
index 96921ec1..47a72229 100644
--- a/drawing.cpp
+++ b/drawing.cpp
@@ -39,6 +39,7 @@ static const int POLY_FAT = (1<<26);            // fatten this model in WRL expo
 static const int POLY_SHADE_TEXTURE = (1<<27);  // texture has 'z' coordinate for shading
 static const int POLY_ONE_LEVEL = (1<<28);      // only one level of the universal cover in SL(2,R)
 static const int POLY_APEIROGONAL = (1<<29);    // only vertices indexed up to she are drawn as the boundary
+static const int POLY_NO_FOG = (1<<30);         // disable fog for this
 
 /** \brief A graphical element that can be drawn. Objects are not drawn immediately but rather queued.
  *
@@ -679,6 +680,7 @@ void dqi_poly::gldraw() {
     else
       glhr::be_textured();
     if(flags & POLY_SHADE_TEXTURE) current_display->next_shader_flags |= GF_TEXTURE_SHADED;
+    if(flags & POLY_NO_FOG) current_display->next_shader_flags |= GF_NO_FOG;
     glBindTexture(GL_TEXTURE_2D, tinf->texture_id);
     if(isize(tinf->colors))
       glhr::vertices_texture_color(v, tinf->tvertices, tinf->colors, offset, offset_texture);
@@ -688,6 +690,7 @@ void dqi_poly::gldraw() {
     }
   else { 
     glhr::be_nontextured();
+    if(flags & POLY_NO_FOG) current_display->next_shader_flags |= GF_NO_FOG;
     glhr::vertices(v);
     }
   
diff --git a/shaders.cpp b/shaders.cpp
index ee56a1d4..51d63c4b 100644
--- a/shaders.cpp
+++ b/shaders.cpp
@@ -18,8 +18,9 @@ constexpr flagtype GF_VARCOLOR = 2;
 constexpr flagtype GF_LIGHTFOG = 4;
 constexpr flagtype GF_LEVELS   = 8;
 constexpr flagtype GF_TEXTURE_SHADED  = 16;
+constexpr flagtype GF_NO_FOG   = 32;
 
-constexpr flagtype GF_which    = 31;
+constexpr flagtype GF_which    = 63;
 
 constexpr flagtype SF_PERS3        = 256;
 constexpr flagtype SF_BAND         = 512;
@@ -393,7 +394,10 @@ shared_ptr<glhr::GLprogram> write_shader(flagtype shader_flags) {
   if(!skip_t) {
     vmain += "mediump vec4 t = uMV * aPosition;\n";
     vmain += coordinator;
-    if(GDIM == 3 && WDIM == 2 && hyperbolic && context_fog && pmodel == mdPerspective) {
+    if(shader_flags & GF_NO_FOG) {
+      vmain += "// no fog used";
+      }
+    else if(GDIM == 3 && WDIM == 2 && hyperbolic && context_fog && pmodel == mdPerspective) {
       vsh += 
         "uniform mediump mat4 uRadarTransform;\n"
         "uniform mediump sampler2D tAirMap;\n"