diff --git a/Makefile b/Makefile
index 0d9bf706..004eb426 100644
--- a/Makefile
+++ b/Makefile
@@ -156,7 +156,7 @@ makeh$(EXE_EXTENSION): makeh.cpp
 	$(CXX) -O2 makeh.cpp -o $@
 
 autohdr.h: makeh$(EXE_EXTENSION) language-data.cpp *.cpp
-	./makeh classes.cpp locations.cpp colors.cpp hyperpoint.cpp geometry.cpp goldberg.cpp init.cpp floorshapes.cpp cell.cpp multi.cpp shmup.cpp pattern2.cpp mapeditor.cpp graph.cpp textures.cpp hprint.cpp language.cpp util.cpp complex.cpp *.cpp > autohdr.h
+	./makeh classes.cpp locations.cpp colors.cpp hyperpoint.cpp geometry.cpp goldberg.cpp init.cpp floorshapes.cpp cell.cpp multi.cpp shmup.cpp pattern2.cpp mapeditor.cpp graph.cpp textures.cpp hprint.cpp language.cpp util.cpp complex.cpp multigame.cpp *.cpp > autohdr.h
 
 language-data.cpp: langen$(EXE_EXTENSION)
 	./langen > language-data.cpp
diff --git a/cell.cpp b/cell.cpp
index b5206338..c93dc500 100644
--- a/cell.cpp
+++ b/cell.cpp
@@ -1450,7 +1450,7 @@ EX int valence() {
 /** portalspaces are not defined outside of a boundary */
 EX bool is_boundary(cell *c) {
   if(c == &out_of_bounds) return true;
-  return (cgflags & qPORTALSPACE) && isWall(c->wall);
+  return ((cgflags & qPORTALSPACE) || intra::in) && isWall(c->wall);
   }
 
 /** compute the distlimit for a tessellation automatically */
diff --git a/geometry.cpp b/geometry.cpp
index 49019560..95d3ca18 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -1196,7 +1196,7 @@ EX void check_cgi() {
   if(fake::in()) fake::underlying_cgip->timestamp = ntimestamp;
   if(arcm::alt_cgip) arcm::alt_cgip->timestamp = ntimestamp;
   
-  if(isize(cgis) > 4) {
+  if(isize(cgis) > 4 && !intra::in) {
     vector<pair<int, string>> timestamps;
     for(auto& t: cgis) timestamps.emplace_back(-t.second.timestamp, t.first);
     sort(timestamps.begin(), timestamps.end());
diff --git a/graph.cpp b/graph.cpp
index 2a82b320..4002fc52 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -4014,6 +4014,11 @@ EX subcellshape& generate_subcellshape_if_needed(cell *c, int id) {
     ss.walltester.push_back(w);
     }
 
+  if(hybri || WDIM == 2) {
+    ss.walltester.push_back(C0);
+    ss.walltester.push_back(C0);
+    }
+
   for(int i=0; i<c1->type; i++)
     ss.faces.push_back({hybrid::get_corner(c1, i, 0, -1), hybrid::get_corner(c1, i, 0, +1), hybrid::get_corner(c1, i, 1, +1), hybrid::get_corner(c1, i, 1, -1)});
 
diff --git a/hyper.cpp b/hyper.cpp
index 81ff951f..5184ce25 100644
--- a/hyper.cpp
+++ b/hyper.cpp
@@ -123,6 +123,7 @@
 #include "inforder.cpp"
 #include "dpgen.cpp"
 #include "vr.cpp"
+#include "intra.cpp"
 
 #if CAP_ROGUEVIZ
 #include "rogueviz/rogueviz-all.cpp"
diff --git a/hypgraph.cpp b/hypgraph.cpp
index d619484e..421a82cf 100644
--- a/hypgraph.cpp
+++ b/hypgraph.cpp
@@ -2902,6 +2902,17 @@ EX transmatrix get_shift_view_of(const hyperpoint H, const transmatrix V) {
 /** shift the view according to the given tangent vector */
 EX void shift_view(hyperpoint H) {
   if(callhandlers(false, hooks_shift_view, H)) return;
+  static bool recursive = false;
+  if(!recursive && intra::in) {
+    H /= 10;
+    recursive = true;
+    for(int i=0; i<10; i++) {
+      shift_view(H);
+      intra::check_portal_movement();
+      }
+    recursive = false;
+    return;
+    }
   auto oView = View;
   View = get_shift_view_of(H, View);
   auto& wc = current_display->which_copy;
diff --git a/intra.cpp b/intra.cpp
new file mode 100644
index 00000000..93cd1455
--- /dev/null
+++ b/intra.cpp
@@ -0,0 +1,297 @@
+#include "hyper.h"
+
+namespace hr {
+
+EX namespace intra {
+
+EX bool in;
+
+#if HDR
+/** information per every space connected with intra-portals */
+struct intra_data {
+  gamedata gd;
+  geometryinfo gi;
+  int wallindex;  
+  };
+#endif
+
+EX vector<intra_data> data;
+
+/** index of the space we are currently in */
+EX int intra_current;
+
+/** map cells to their intra spaces */
+EX map<cell*, int> intra_id;
+
+#if HDR
+/** information about portal (one side) */
+struct portal_data {
+  int kind;
+  hyperpoint v0;
+  ld d;
+  transmatrix T;
+  transmatrix iT;
+  hyperpoint co0;
+  hyperpoint co1;
+  ld scale;
+  /* convert h to portal coordinates ('poco') to usual coordinates */
+  hyperpoint to_poco(hyperpoint h) const;
+  /* convert h from portal coordinates ('poco') to usual coordinates */
+  hyperpoint from_poco(hyperpoint h) const;
+  };
+#endif
+
+hyperpoint portal_data::to_poco(hyperpoint h) const {
+  if(prod && kind == 1) {
+    auto dec = product_decompose(h);
+    h = dec.second;
+    h[0] /= h[2];
+    h[1] /= h[2];
+    h[2] = dec.first - d;
+    h[3] = 1;
+    return h;
+    }
+  else if(prod && kind == 0) {
+    h = T * h;
+    ld z = product_decompose(h).first;
+    h /= exp(z);
+    auto h1 = h;
+    h[0] = asin_auto(h1[1]);
+    h[1] = z;
+    h[2] = asin_auto_clamp(h1[0] / cos_auto(h[0]));
+    h[3] = 1;
+    return h;
+    }
+  else {
+    h = T * h;
+    h /= h[3];
+    return h;
+    }
+  }
+
+hyperpoint portal_data::from_poco(hyperpoint h) const {
+  if(prod && kind == 1) {
+    ld d = h[2];
+    h[2] = 1;
+    auto z = product_decompose(h).first;
+    return h * exp(d+d-z);
+    }
+  else if(prod && kind == 0) {
+    auto h0 = h;
+    h[0] = sin_auto(h0[2]) * cos_auto(h0[0]);
+    h[1] = sin_auto(h0[0]);
+    h[2] = cos_auto(h0[0]) * cos_auto(h0[2]);
+    h[3] = 1;
+    return iT * h * exp(h0[1]);
+    }
+  else {
+    h[3] = 1;
+    return normalize(iT * h);
+    }
+  }
+
+EX portal_data make_portal(cellwalker cw) {
+  auto& ss = currentmap->get_cellshape(cw.at);
+  auto& fac = ss.faces[cw.spin];
+  portal_data id;
+  id.scale = 1;
+  if(prod && cw.spin == cw.at->type - 1) {
+    id.kind = 1;
+    id.d = product_decompose(fac[0]).first;
+    id.v0 = C0 * exp(id.d);
+    }
+  else if(prod && cw.spin == cw.at->type - 2) {
+    throw hr_exception("cannot construct a portal in this direction");
+    }
+  else if(prod) {
+    id.kind = 0;
+    id.v0 = Hypc;
+    id.scale = cgi.plevel;
+    for(auto p: fac) id.v0 += p;
+    id.v0 /= sqrt(abs(intval(id.v0, Hypc)));
+    id.T = cpush(0, -hdist0(id.v0)) * spintox(id.v0);
+    for(int i=0; i<3; i++) id.T[3][i] = id.T[i][3] = i==3;
+    if(debugflags & DF_GEOM)
+    for(int a=0; a<4; a++) {
+      hyperpoint h = fac[a];
+      println(hlog, kz(h), " -> ", kz(spintox(id.v0)*h), " -> ", kz(cpush(0, -hdist0(id.v0))) * kz(spintox(id.v0) * h), " -> ", kz(id.to_poco(h)));
+      }
+    }
+  else {
+    id.kind = 0;
+    id.v0 = Hypc;
+    for(auto p: fac) id.v0 += p;
+    id.v0 = normalize(id.v0);
+    id.T = cpush(2, -hdist0(id.v0)) * cspin(2, 0, 90*degree) * spintox(id.v0);
+    }
+  id.iT = inverse(id.T);
+  if(MDIM == 3) for(int i=0; i<4; i++) id.iT[3][i] = id.iT[i][3] = i==3;
+  id.co0 = id.to_poco(fac[(in_s2xe() || sphere) ? 2 : 0]);
+  id.co1 = id.to_poco(fac[1]);
+  return id;
+  }
+
+#if HDR
+/** information about connection (portal-to-portal) */
+struct connection_data {
+  int source_world;
+  int target_world;
+  cellwalker scw, tcw;
+  portal_data id1;
+  portal_data id2;
+  transmatrix T;
+  };
+#endif
+
+EX map<cellwalker, connection_data> connections;
+
+EX connection_data* find_connection(int a, int b) {
+  for(auto& p: connections)
+    if(intra_id[p.first.at] == a && p.second.target_world == b)
+      return &p.second;
+  return nullptr;
+  }
+
+EX void switch_to(int id) {
+  if(intra_current == id) return;
+  data[intra_current].gd.storegame();
+  intra_current = id;
+  ginf[gProduct] = data[intra_current].gi;
+  data[intra_current].gd.restoregame();
+  }
+
+void connect_portal_1(cellwalker cw1, cellwalker cw2) {
+  auto& p = connections[cw1];
+  p.source_world = intra_id[cw1.at];
+  p.target_world = intra_id[cw2.at];
+  p.scw = cw1;
+  p.tcw = cw2;
+  switch_to(intra_id[cw1.at]);
+  p.id1 = make_portal(cw1);
+  switch_to(intra_id[cw2.at]);
+  p.id2 = make_portal(cw2);
+
+  if(1) {
+    dynamicval<eGeometry> g(geometry, gCubeTiling);
+    transmatrix T1;
+    set_column(T1, 0, p.id1.co0);
+    set_column(T1, 1, p.id1.co1);
+    set_column(T1, 2, hyperpoint(0,0,p.id1.scale,0));
+    set_column(T1, 3, C03);
+    transmatrix T2;
+    set_column(T2, 0, p.id2.co0);
+    set_column(T2, 1, p.id2.co1);
+    set_column(T2, 2, hyperpoint(0,0,-p.id2.scale,0));
+    set_column(T2, 3, C03);
+    if(debugflags & DF_GEOM) for(int i=0; i<4; i++)
+      println(hlog, "mapping ", get_column(T1, i), " to ", get_column(T2, i));
+    p.T = T2 * inverse(T1);
+    }
+  }
+
+EX vector<pair<int, cell*>> full_sample_list;
+
+EX void connect_portal(cellwalker cw1, cellwalker cw2) {
+  connect_portal_1(cw1, cw2);
+  connect_portal_1(cw2, cw1);
+  }
+
+/** make currentmap into one of the spaces in intra */
+EX void become() {
+  auto& ac = currentmap->allcells();
+  for(cell *c: ac)
+    intra_id[c] = intra_current;
+  for(cell *c: ac)
+    currentmap->wall_offset(c);
+  for(cell *c: ac) c->item = itNone;
+  data.emplace_back();
+  data.back().gd.storegame();
+  data.back().gi = ginf[gProduct];
+
+  auto v = hybrid::gen_sample_list();
+  int gi = 0;
+  if(full_sample_list.size()) {
+    gi = full_sample_list.back().first;
+    full_sample_list.pop_back();
+    }
+  data.back().wallindex = gi;
+  for(auto x: v)
+    full_sample_list.emplace_back(x.first + gi, x.second);
+  sightranges[geometry] = 10;
+  }
+
+/** after called become() on some spaces, actually start intra */
+EX void start(int id IS(0)) {
+  in = true;
+  intra_current = id;
+  data[intra_current].gd.restoregame();
+  ginf[gProduct] = data[intra_current].gi;
+  }
+
+#if HDR
+/** a convenience struct to switch back after a temporary switch_to */
+struct resetter {
+  int ic;
+  resetter() { ic = intra::intra_current; }
+  ~resetter() { if(intra::in) switch_to(ic); }
+  };
+#endif
+
+EX void may_switch_to(cell *c) {
+  if(in) switch_to(intra_id[c]);
+  }
+
+EX int full_wall_offset(cell *c) {
+  int wo = currentmap->wall_offset(c);
+  if(in) wo += data[intra_id[c]].wallindex;
+  return wo;
+  }
+
+EX void check_portal_movement() {
+  transmatrix iView = view_inverse(View);
+  ld dist = hdist0(iView * C0);
+  int nei = -1;
+  for(int i=0; i<centerover->type; i++) {
+    ld dist1 = hdist0(currentmap->ray_iadj(centerover, i) * iView * C0);
+    if(dist1 < dist) nei = i, dist = dist1;
+    }
+
+  auto cw1 = cellwalker(centerover, nei);
+  ld c = camera_speed;
+  auto p = at_or_null(connections, cw1);
+  if(p) {
+    ld eps = 1e-3;
+    c /= p->id1.scale;
+    anims::cycle_length /= p->id1.scale;
+
+    array<hyperpoint, 3> ds; /* camera, forward, upward */
+    ds[0] = inverse(View) * C0;
+    ds[1] = inverse(get_shift_view_of(ctangent(2, -eps), View)) * C0;
+    ds[2] = inverse(get_shift_view_of(ctangent(1, +eps), View)) * C0;
+
+    for(auto& h: ds) h = p->id1.to_poco(h);
+
+    /* reset the original */
+    View = Id; NLP = Id;
+
+    switch_to(p->target_world);
+    centerover = p->tcw.at;
+
+    if(1) {
+      dynamicval<eGeometry> g(geometry, gCubeTiling);
+      for(auto& h: ds) h = p->T * h;
+      }
+
+    for(auto& h: ds) h = p->id2.from_poco(h);
+
+    set_view(ds[0], ds[1], ds[2]);
+    
+    c *= p->id2.scale;
+    anims::cycle_length *= p->id2.scale;
+    camera_speed = c;
+    }
+  }
+
+EX }
+
+}
\ No newline at end of file
diff --git a/multigame.cpp b/multigame.cpp
index ec737784..7becd272 100644
--- a/multigame.cpp
+++ b/multigame.cpp
@@ -61,6 +61,8 @@ void gamedata_all(gamedata& gd) {
   gd.store(land_structure);
   gd.store(*current_display);
   gd.store(cgip);
+  gd.store(hybrid::underlying);
+  gd.store(hybrid::underlying_cgip);
   gd.store_ptr(vid);
   gd.store(sightrange_bonus);
   gd.store(genrange_bonus);
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index a0be2f24..529c32b6 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -1410,7 +1410,7 @@ EX namespace hybrid {
     vector<pair<int, cell*>> result;
     for(auto& v: cgi.walloffsets) if(v.first >= 0) result.push_back(v);
     sort(result.begin(), result.end());
-    result.emplace_back(isize(cgi.wallstart), nullptr);
+    result.emplace_back(isize(cgi.wallstart)-1, nullptr);
     return result;
     }
 
diff --git a/raycaster.cpp b/raycaster.cpp
index 64eb126b..6ffaa818 100644
--- a/raycaster.cpp
+++ b/raycaster.cpp
@@ -57,11 +57,13 @@ EX int max_cells = 2048;
 EX bool rays_generate = true;
 
 EX ld& exp_decay_current() {
+  if(intra::in) return exp_decay_exp;
   if(fake::in()) return *FPIU(&exp_decay_current());
   return (sn::in() || hyperbolic || sl2) ? exp_decay_exp : exp_decay_poly;
   }
 
 EX int& max_iter_current() {
+  if(intra::in) return max_iter_iso;
   if(nonisotropic || stretch::in()) return max_iter_sol;
   else if(is_eyes()) return max_iter_eyes;
   else return max_iter_iso;
@@ -93,6 +95,7 @@ ld& maxstep_current() {
 eGeometry last_geometry;
 
 vector<pair<int, cell*>> used_sample_list() {
+  if(intra::in) return intra::full_sample_list;
   return hybrid::gen_sample_list();
   }
 
@@ -322,7 +325,8 @@ struct raygen {
   void compute_which_and_dist();
   void apply_reflect();
   void move_forward();
-  void emit_iterate();
+  void emit_intra_portal(int gid1, int gid2);
+  void emit_iterate(int gid1);
   void create();
   };
 
@@ -336,7 +340,7 @@ void raygen::compute_which_and_dist() {
     fmain +=
       "  if(which == -1) {\n";
 
-    fmain += "for(int i="+its(flat1)+"; i<"+(prod ? "sides-2" : (WDIM == 2 || is_subcube_based(variation)) ? "sides" : its(flat2))+"; i++) {\n";
+    fmain += "for(int i="+its(flat1)+"; i<"+(prod ? "sides-2" : (WDIM == 2 || is_subcube_based(variation) || intra::in) ? "sides" : its(flat2))+"; i++) {\n";
 
     // fmain += "int woi = walloffset+i;\n";
 
@@ -961,15 +965,132 @@ void raygen::apply_reflect() {
     }
   }
 
-void raygen::emit_iterate() {
+void raygen::emit_intra_portal(int gid1, int gid2) {
+
+  int they_curvature = false;
+  if(1) {
+    intra::resetter ir;
+    intra::switch_to(gid2);
+    they_curvature = hyperbolic ? -1 : sphere ? 1 : 0;
+    /* product also has 0 */
+    }
+
+  if(prod && they_curvature) {
+    string fn = in_h2xe() ? "to_poco_h2xr_h" : "to_poco_s2xr_s";
+    fmain +=
+      "    mediump vec4 nposition = position + tangent * xspeed * 1e-3;\n"
+      "    position = "+fn+"(position);\n"
+      "    position.z = 0.;\n" // zpos - uPLevel;\n"
+      "    nposition = "+fn+"(nposition);\n"
+      "    nposition.z = zspeed * 1e-3;\n";
+    }
+  else if(prod) {
+    string fn = in_h2xe() ? "to_poco_h2xr_e" : "to_poco_s2xr_e";
+    fmain +=
+      "    mediump vec4 nposition = position + tangent * xspeed * 1e-3;\n"
+      "    mediump mat4 tkt = " + getM("mid+1") + ";\n"
+      "    position = "+fn+"(tkt * position);\n"
+      "    position.y = zpos;\n"
+      "    nposition = "+fn+"(tkt * nposition);\n"
+      "    nposition.y = zpos + zspeed * 1e-3;\n";
+    }
+  else {
+    fmain +=
+      "    mediump vec4 nposition = position + tangent * 1e-3;\n"
+      "    mediump mat4 tkt = " + getM("mid+1") + ";\n";
+    if(hyperbolic) fmain +=
+      "    position = to_poco_h3(tkt * position);\n"
+      "    nposition = to_poco_h3(tkt * nposition);\n";
+    else if(sphere) fmain +=
+      "    position = to_poco_s3(tkt * position);\n"
+      "    nposition = to_poco_s3(tkt * nposition);\n";
+    else fmain +=
+      "    position = tkt * position;\n"
+      "    nposition = tkt * nposition;\n";
+    }
+
+  fmain +=
+    "    mediump mat4 m = " + getM("mid") + ";\n"
+    "    position = m * position;\n"
+    "    nposition = m * nposition;\n";
+
+  int we_curvature = hyperbolic ? -1 : sphere ? 1 : 0;
+
+  intra::resetter ir;
+  intra::switch_to(gid2);
+
+  if(prod && we_curvature) {
+    string sgn = in_h2xe() ? "-" : "+";
+    string fn = in_h2xe() ? "from_poco_h2xr_h" : "from_poco_s2xr_s";
+    ld their_plevel = cgi.plevel / 2;
+    fmain +=
+    "    zspeed = (nposition.z - position.z) * 1e3;\n"
+    "    zpos = position.z + " + glhr::to_glsl(their_plevel) + ";\n"
+    "    position = "+fn+"(position);\n"
+    "    nposition = "+fn+"(nposition);\n"
+    "    tangent = (nposition - position) * 1e3;\n"
+    "    mediump float pnorm = tangent.z * position.z "+sgn+" tangent.x * position.x "+sgn+" tangent.y * position.y;\n"
+    "    tangent -= position * pnorm;\n"
+    "    xspeed = sqrt(tangent.x * tangent.x + tangent.y * tangent.y "+sgn+" tangent.z * tangent.z);\n"
+    "    tangent /= xspeed;\n";
+    }
+  else if(prod) {
+    string sgn = in_h2xe() ? "-" : "+";
+    string fn = in_h2xe() ? "from_poco_h2xr_e" : "from_poco_s2xr_e";
+    fmain +=
+    "    mediump mat4 itkt = " + getM("mid+2") + ";\n";
+    fmain +=
+    "    zpos = position.y;\n"
+    "    zspeed = (nposition.y - zpos) * 1e3;\n"
+    "    position = itkt * "+fn+"(position);\n"
+    "    nposition = itkt * "+fn+"(nposition);\n"
+    "    tangent = (nposition - position) * 1e3;\n"
+    "    mediump float pnorm = tangent.z * position.z "+sgn+" dot(position.xy, tangent.xy);\n"
+    "    tangent -= position * pnorm;\n"
+    "    xspeed = sqrt(dot(tangent.xy, tangent.xy) "+sgn+" tangent.z * tangent.z);\n"
+    "    tangent /= xspeed;\n"
+    "    mediump float l = xspeed*xspeed+zspeed*zspeed;\n"
+    "    xspeed /= sqrt(l); zspeed /= sqrt(l);\n";
+    }
+  else {
+    string sgn = hyperbolic ? "-" : "+";
+    string he = hyperbolic ? "from_poco_h3" : "from_poco_s3";
+    fmain +=
+    "    mediump mat4 itkt = " + getM("mid+2") + ";\n";
+
+    if(hyperbolic || sphere) fmain +=
+    "    position = itkt * "+he+"(position);\n"
+    "    nposition = itkt * "+he+"(nposition);\n"
+    "    tangent = (nposition - position) * 1e3;\n"
+    "    mediump float pnorm = position.w * position.w "+sgn+" dot(position.xyz, position.xyz);\n"
+    "    position /= sqrt(pnorm);\n"
+    "    pnorm = tangent.w * position.w "+sgn+" dot(position.xyz, tangent.xyz);\n"
+    "    tangent -= position * pnorm;\n"
+    "    mediump float xspeed = sqrt(dot(tangent.xyz, tangent.xyz) "+sgn+" tangent.w * tangent.w);\n"
+    "    tangent /= xspeed;\n";
+
+    else fmain +=
+    "    position = itkt * position;\n"
+    "    nposition = itkt * nposition;\n"
+    "    tangent = (nposition - position) * 1e3;\n"
+    "    tangent /= dot(tangent.xyz, tangent.xyz);\n";
+    }
+  }
+
+void raygen::emit_iterate(int gid1) {
   using glhr::to_glsl;
 
+  if(intra::in && prod)
+    fmain += "  const mediump float uPLevel = " + to_glsl(cgi.plevel/2) + ";\n";
+
   fmain +=
     "  mediump float dist = 100.;\n";
 
   fmain +=
     "  int which = -1;\n";
 
+  if(hyperbolic && intra::in) fmain += "iter +=8;\n";
+
   if(in_e2xe() && !eyes) fmain += "tangent.w = position.w = 0.;\n";
 
   if(IN_ODS) fmain +=
@@ -1183,7 +1304,111 @@ void raygen::emit_iterate() {
     "  m[0][1] = -m[0][1]; m[1][0] = -m[1][0];\n" // inverse
     "  toOrig = toOrig * m;\n";
 
-  fmain += no_intra_portal;
+  if(!intra::in) fmain += no_intra_portal;
+  else {
+
+    if(hyperbolic) {
+      fsh +=
+        "mediump vec4 to_poco_h3(mediump vec4 pos) {\n"
+        "  return pos / pos[3];\n"
+        "  }\n\n";
+
+      fsh +=
+        "mediump vec4 from_poco_h3(mediump vec4 pos) {\n"
+        "  float s = 1. - dot(pos.xyz, pos.xyz);\n"
+        "  return pos / sqrt(s);\n"
+        "  }\n\n";
+      }
+
+    if(sphere) {
+      fsh +=
+        "mediump vec4 to_poco_s3(mediump vec4 pos) {\n"
+        "  return pos / pos[3];\n"
+        "  }\n\n";
+
+      fsh +=
+        "mediump vec4 from_poco_s3(mediump vec4 pos) {\n"
+        "  float s = 1. + dot(pos.xyz, pos.xyz);\n"
+        "  return pos / sqrt(s);\n"
+        "  }\n\n";
+      }
+
+    if(prod) {
+      if(in_h2xe()) {
+        fsh +=
+          "mediump vec4 from_poco_h2xr_h(mediump vec4 pos) {\n"
+          "  float s = 1. - pos.x*pos.x - pos.y * pos.y;\n"
+          "  pos.z = 1.;\n"
+          "  return pos / sqrt(s);\n"
+          "  }\n\n";
+
+        fsh +=
+          "mediump vec4 to_poco_h2xr_h(mediump vec4 pos) {\n"
+          "  pos /= pos[2];\n"
+          "  pos.w = 1.;\n"
+          "  return pos;\n"
+          "  }\n\n";
+
+        fsh +=
+          "mediump vec4 from_poco_h2xr_e(mediump vec4 pos) {\n"
+            "  return vec4(sinh(pos[2]) * cosh(pos[0]), sinh(pos[0]), cosh(pos[0]) * cosh(pos[2]), 0);\n"
+          "  }\n\n";
+
+        fsh +=
+          "mediump vec4 to_poco_h2xr_e(mediump vec4 pos) {\n"
+          "  mediump float x = asinh(pos[1]);\n"
+          "  return vec4(x, 0, asinh(pos[0] / cosh(x)), 1);\n"
+          "  }\n\n";
+        }
+      else {
+        fsh +=
+          "mediump vec4 from_poco_s2xr_s(mediump vec4 pos) {\n"
+          "  float s = 1. + pos.x*pos.x + pos.y * pos.y;\n"
+          "  pos.z = 1.;\n"
+          "  return pos / sqrt(s);\n"
+          "  }\n\n";
+
+        fsh +=
+          "mediump vec4 to_poco_s2xr_s(mediump vec4 pos) {\n"
+          "  pos /= pos[2];\n"
+          "  pos.w = 1.;\n"
+          "  return pos;\n"
+          "  }\n\n";
+
+        fsh +=
+          "mediump vec4 from_poco_s2xr_e(mediump vec4 pos) {\n"
+            "  return vec4(sin(pos[2]) * cos(pos[0]), sin(pos[0]), cos(pos[0]) * cos(pos[2]), 0);\n"
+          "  }\n\n";
+
+        fsh +=
+          "mediump vec4 to_poco_s2xr_e(mediump vec4 pos) {\n"
+          "  mediump float x = asin_clamp(pos[1]);\n"
+          "  return vec4(x, 0, asin_clamp(pos[0] / cos(x)), 1);\n"
+          "  }\n\n";
+        }
+      }
+
+    if(intra::in) {
+      int q = isize(intra::data);
+      for(int gid2=0; gid2<q; gid2++) {
+        if(gid2 == q-1)
+          fmain += "  {\n";
+        else  {
+          fmain += "  if(nwalloffset < " + its(intra::data[gid2+1].wallindex) + ") {\n";
+          }
+        if(gid1 == gid2)
+          fmain += no_intra_portal;
+        else
+          emit_intra_portal(gid1, gid2);
+        if(gid2 == q-1)
+          fmain += "  }\n";
+        else
+          fmain += "  } else\n";
+        }
+      }
+    else
+      fmain += no_intra_portal;
+    }
 
   if(many_cell_types) {
     fmain +=
@@ -1239,7 +1464,15 @@ void raygen::create() {
       "  gl_Position = aPosition; at = uProjection * aPosition; \n"
       "  }\n";
 
-    irays = isize(cgi.raywall);
+    if(intra::in) {
+      irays = 0;
+      intra::resetter ir;
+      for(int i=0; i<isize(intra::data); i++) {
+        intra::switch_to(i);
+        irays += isize(cgi.raywall);
+        }
+      }
+    else irays = isize(cgi.raywall);
     string rays = its(irays);
 
     fsh =
@@ -1481,6 +1714,11 @@ void raygen::create() {
         "  mediump vec4 position = vw * vec4(0., 0., 0., 1.);\n"
         "  mediump vec4 tangent = vw * at0;\n";
       }
+    if(intra::in && !prod) {
+      fmain += "  mediump float zspeed = 1.;\n";
+      fmain += "  mediump float xspeed = 1.;\n";
+      fmain += "  mediump float zpos = 0.;\n";
+      }
     
     if(eyes) {
       fsh += "mediump uniform mat4 uEyeShift;\n";
@@ -1522,7 +1760,25 @@ void raygen::create() {
       "  mediump vec2 cid = uStartid;\n"
       "  for(int iter=0; iter<" + its(max_iter_current()) + "; iter++) {\n";
 
-    emit_iterate();
+    if(intra::in) {
+      int gi = isize(intra::data);
+      for(int i=0; i<gi; i++) {
+        if(i == gi-1)
+          fmain += "  {\n";
+        else  {
+          fmain += "  if(walloffset < " + its(intra::data[i+1].wallindex) + ") {\n";
+          }
+        intra::resetter ir;
+        intra::switch_to(i);
+        emit_iterate(i);
+        if(i == gi-1)
+          fmain += "  }\n";
+        else
+          fmain += "  } else\n";
+        }
+      }
+    else
+      emit_iterate(-1);
 
     fmain +=
       "  }\n"
@@ -1644,9 +1900,12 @@ struct raycast_map {
     ms.clear();
     ms.resize(sa.back().first, Id);
     
+    intra::resetter ir;
+
     for(auto& p: sa) {
       int id = p.first;
       cell *c = p.second;
+      intra::may_switch_to(c);
       if(!c) continue;
       for(int j=0; j<c->type; j++)
         ms[id+j] = protect_prod(currentmap->ray_iadj(c, j));
@@ -1667,6 +1926,7 @@ struct raycast_map {
         int id = p.first;
         cell *c = p.second;
         if(!c) continue;
+        intra::may_switch_to(c);
         for(int j=0; j<c->type; j++)
           ms[mirror_shift+id+j] = protect_prod(mirrorize(ms[id+j]));
         if(WDIM == 2) for(int a: {0, 1}) {
@@ -1680,12 +1940,14 @@ struct raycast_map {
         }
       }    
 
-    if(prod) {
-      for(auto p: sa) {
-        int id =p.first;
-        if(id == 0) continue;
-        ms[id-2] = Id;
-        ms[id-1] = Id;
+    for(auto p: sa) {
+      cell *c = p.second;
+      if(!c) continue;
+      intra::may_switch_to(c);
+      int id =p.first;
+      if(prod) {
+        ms[id+c->type-2] = Id;
+        ms[id+c->type-1] = Id;
         }
       }
     }
@@ -1694,13 +1956,22 @@ struct raycast_map {
     manual_celllister cl;
     cl.add(cs);
     bool optimize = !isWall3(cs);
+    intra::resetter ir;
     // vector<int> legaldir = { -1 };
     for(int i=0; i<isize(cl.lst); i++) {
       cell *c = cl.lst[i];
+      intra::may_switch_to(c);
       if(racing::on && i > 0 && c->wall == waBarrier) continue;
       if(optimize && isWall3(c)) continue;
       forCellIdCM(c2, d, c) {
         // if(reflect_val == 0 && !((1<<d) & legaldir[i])) continue;
+
+        if(intra::in) {
+          cellwalker cw(c, d);
+          auto p = at_or_null(intra::connections, cw);
+          if(p) c2 = p->tcw.at;
+          }
+
         if(rays_generate) setdist(c2, 7, c);
         /* if(!cl.listed(c2))
           legaldir.push_back(legaldir[i] &~ (1<<((d+3)%6)) ); */
@@ -1722,6 +1993,7 @@ struct raycast_map {
     }
 
   void generate_connections(cell *c, int id) {
+    intra::may_switch_to(c);
     auto& vmap = volumetric::vmap;
     if(volumetric::on) {
       celldrawer dd;
@@ -1735,7 +2007,14 @@ struct raycast_map {
         vcolor = (backcolor << 8);
       volumetric[u] = glhr::acolor(vcolor);
       }
-    forCellIdEx(c1, i, c) {
+    forCellIdEx(c1_real, i, c) {
+      cell *c1 = c1_real;
+      const intra::connection_data *p = nullptr;
+      if(intra::in) {
+        cellwalker cw(c, i);
+        p = at_or_null(intra::connections, cw);
+        if(p) c1 = p->tcw.at;
+        }
       int u = (id/per_row*length) + (id%per_row * deg) + i;
       if(!ids.count(c1)) {
         wallcolor[u] = glhr::acolor(color_out_of_range | 0xFF);
@@ -1775,23 +2054,36 @@ struct raycast_map {
           }
         }
       
-      int wo = currentmap->wall_offset(c);
+      int wo = intra::full_wall_offset(c);
       if(wo >= our_raygen.irays) {
         println(hlog, "wo=", wo, " irays = ", our_raygen.irays);
         reset_raycaster();
         return;
         }
-      transmatrix T = currentmap->iadj(c, i) * inverse(ms[wo + i]);
-      if(in_e2xe() && i >= c->type-2)
-        T = Id;
-      T = protect_prod(T);
-      for(int k=0; k<=isize(ms); k++) {
-        if(k < isize(ms) && !eqmatrix(ms[k], T, 1e-5)) continue;
-        if(k == isize(ms)) ms.push_back(T);
+      if(p) {
+        int k = isize(ms);
+        auto bak = geometry;
+        ms.push_back(p->T);
+        geometry = bak;
+        ms.push_back(p->id1.T);
+        ms.push_back(p->id2.iT);
         connections[u][2] = (k+.5) / 1024.;
-        break;
         }
-      auto wo1 = currentmap->wall_offset(c1);
+      else {
+        transmatrix T = currentmap->iadj(c, i) * inverse(ms[wo + i]);
+        if(in_e2xe() && i >= c->type-2)
+          T = Id;
+        T = protect_prod(T);
+        for(int k=0; k<=isize(ms); k++) {
+          if(k < isize(ms) && !eqmatrix(ms[k], T, 1e-5)) continue;
+          if(k == isize(ms)) ms.push_back(T);
+          connections[u][2] = (k+.5) / 1024.;
+          break;
+          }
+        }
+      intra::resetter ir;
+      intra::may_switch_to(c1);
+      int wo1 = intra::full_wall_offset(c1);
       if(wo1 >= max_wall_offset)
         println(hlog, "error: wall_offset ", wo1, " exceeds ", max_wall_offset);
       if(c1->type >= max_celltype)
@@ -1815,6 +2107,7 @@ struct raycast_map {
   
   void generate_connections() {
     int id = 0;
+    intra::resetter ir;
     for(cell* c: lst) if(!reset_rmap)
       generate_connections(c, id++);
     }
@@ -2012,14 +2305,22 @@ EX void cast() {
     }
   
   if(o->uWallOffset != -1) {
-    glUniform1i(o->uWallOffset, currentmap->wall_offset(cs));
+    glUniform1i(o->uWallOffset, intra::full_wall_offset(cs));
     glUniform1i(o->uSides, cs->type + (WDIM == 2 ? 2 : 0));
     }
 
   vector<glvertex> wallx, wally;
   vector<GLint> wallstart;
 
-  load_walls(wallx, wally, wallstart);
+  if(intra::in) {
+    intra::resetter ir;
+    for(int i=0; i<isize(intra::data); i++) {
+      intra::switch_to(i);
+      load_walls(wallx, wally, wallstart);
+      }
+    }
+  else
+    load_walls(wallx, wally, wallstart);
 
   if(wall_via_texture) {
     int wlength = next_p2(isize(wallx));
diff --git a/screenshot.cpp b/screenshot.cpp
index d7bb090d..c8d67714 100644
--- a/screenshot.cpp
+++ b/screenshot.cpp
@@ -801,21 +801,23 @@ EX void take(string fname, const function<void()>& what IS(default_screenshot_co
       #if CAP_WRL
       wrl::take(fname);
       #endif
-      return;
+      break;
     
     case screenshot_format::svg:
       #if CAP_SVG
       svg::render(fname, what);
       #endif
-      return;
+      break;
     
     case screenshot_format::png:
     case screenshot_format::rawfile:
       #if CAP_PNG
       render_png(fname, what);
       #endif
-      return;
+      break;
     }
+
+  v.backup.plevel_factor = vid.plevel_factor;
   }
 
 #if CAP_COMMANDLINE
diff --git a/shaders.cpp b/shaders.cpp
index 63f350e9..18dbe621 100644
--- a/shaders.cpp
+++ b/shaders.cpp
@@ -751,6 +751,7 @@ EX void add_fixed_functions(string& shader) {
 
   add_if(shader, "tanh", "mediump float tanh(mediump float x) { return sinh(x) / cosh(x); }\n");
   add_if(shader, "sinh", "mediump float sinh(mediump float x) { return (exp(x) - exp(-x)) / 2.0; }\n");
+  add_if(shader, "asin_clamp", "mediump float asin_clamp(mediump float x) { return x > 1. ? PI/2. : x < -1. ? -PI/2. : asin(x); }\n");
   add_if(shader, "cosh", "mediump float cosh(mediump float x) { return (exp(x) + exp(-x)) / 2.0; }\n");
   add_if(shader, "asinh", "mediump float asinh(mediump float x) { return log(sqrt(x*x + 1.0) + x); }\n");
   add_if(shader, "acosh", "mediump float acosh(mediump float x) { return log(sqrt(x*x - 1.0) + x); }\n");