fractal geometry

cell.cpp

@@ -402,6 +402,141 @@ EX bool is_in_disk(cell *c) {
   return *it == c;
   }
 
+bool sierpinski3(gp::loc g) {
+  int x = g.first;
+  int y = g.second;
+  set<pair<int, int>> visited;
+  while(true) {
+    if(visited.count({x,y})) return false;
+    visited.insert({x,y});
+    // if(x == -1 && y == -2) return false;
+    // if(x == -2 && y == -3) return false;
+    if(x == 0 && y == 0) return true;
+    if((x&1) == 1 && (y&1) == 1) return false;
+    x >>= 1;
+    y >>= 1;
+    // x--; y++;
+    tie(x, y) = make_pair(-x-y, x);
+    }
+  }
+
+bool sierpinski46(gp::loc g) {
+  int x = g.first;
+  int y = g.second;
+  set<pair<int, int>> visited;
+  if(S7 == 6)
+    x += 2785684, y += 289080;
+  else
+    x += 75239892, y += 7913772;
+  while(true) {
+    if(visited.count({x,y})) return false;
+    visited.insert({x,y});
+    if(x == 0 && y == 0) return true;
+    int dx = gmod(x, 3);
+    int dy = gmod(y, 3);
+    if(dx == 1 && dy == 1) return false;
+    if(S7 == 6 && dx == dy) return false;
+    x = (x-dx) / 3;
+    y = (y-dy) / 3;
+    }
+  }
+
+bool menger_sponge(euc::coord c) {
+  c[0] += 528120*9; c[1] += 438924*9; c[2] += 306712*9;
+  set<euc::coord> visited;
+  while(true) {
+    if(visited.count(c)) return false;
+    visited.insert(c);
+    if(c[0] == 0 && c[1] == 0 && c[2] == 0) return true;
+    int ones = 0;
+    for(int i=0; i<3; i++) {
+      int d = gmod(c[i], 3);
+      c[i] = (c[i] - d) / 3;
+      if(d == 1) ones++;
+      }
+    if(ones >= 2) return false;
+    }
+  }
+
+bool sierpinski_tet(euc::coord c) {
+  set<euc::coord> visited;
+  c[0] += 16 * (1+8+64+512);
+  c[1] += 16 * (1+8+64+512);
+  c[1] += 32 * (1+8+64+512);
+  c[2] += 32 * (1+8+64+512);
+  c[0] += 64 * (1+8+64+512);
+  c[1] += 64 * (1+8+64+512);
+  while(true) {
+    if(visited.count(c)) return false;
+    visited.insert(c);
+    if(c[0] == 0 && c[1] == 0 && c[2] == 0) return true;
+    int ones = 0;
+    for(int i=0; i<3; i++) {
+      int d = gmod(c[i], 2);
+      c[i] = (c[i] - d) / 2;
+      if(d == 1) ones++;
+      }
+    if(ones & 1) return false;
+    }
+  }
+
+EX bool is_in_fractal(cell *c) {
+  if(fake::in()) return FPIU(is_in_fractal(c));
+  if(mhybrid) { c = hybrid::get_where(c).first; return PIU(is_in_fractal(c)); }
+  switch(geometry) {
+    case gSierpinski3:
+      return sierpinski3(euc::full_coords2(c));
+    case gSierpinski4:
+    case gSixFlake:
+      return sierpinski46(euc::full_coords2(c));
+    case gMengerSponge:
+      return menger_sponge(euc::get_ispacemap()[c->master]);
+    case gSierpinskiTet: {
+      return sierpinski_tet(euc::get_ispacemap()[c->master]);
+      }
+    default:
+      return true;
+    }
+  }
+
+EX cell *fractal_rep(cell *c) {
+  switch(geometry) {
+    case gSierpinski3: {
+      auto co = euc::full_coords2(c);
+      co.first += 4;
+      co.first &= ~15;
+      co.first -= 4;
+      co.second += 2;
+      co.second &= ~15;
+      co.second -= 2;
+      if(co.first == -4 && co.second == -2) co.first = 0, co.second = 0;
+      return euc::get_at(euc::to_coord(co))->c7;
+      }
+    case gSierpinski4:
+    case gSixFlake: {
+      auto co = euc::full_coords2(c);
+      if(S7 == 6) co.first += 4;
+      co.first -= gmod(co.first, 9);
+      co.second -= gmod(co.second, 9);
+      return euc::get_at(euc::to_coord(co))->c7;
+      }
+    case gSierpinskiTet: {
+      auto co = euc::get_ispacemap()[c->master];
+      co[0] &=~7;
+      co[1] &=~7;
+      co[2] &=~7;
+      return euc::get_at(co)->c7;
+      }
+    case gMengerSponge: {
+      auto co = euc::get_ispacemap()[c->master];
+      for(int i=0; i<3; i++) co[i] = co[i] - gmod(co[i], 9);
+      return euc::get_at(co)->c7;
+      }
+    default:
+      throw hr_exception("unknown fractal");
+    }
+  }
+
 /** create a map in the current geometry */
 EX void initcells() {
   DEBB(DF_INIT, ("initcells"));

celldrawer.cpp

@@ -1751,6 +1751,22 @@ void celldrawer::draw_features_and_walls_3d() {
 #if MAXMDIM >= 4
   color_t dummy;
   int ofs = currentmap->wall_offset(c);
+
+  if((cgflags & qFRACTAL) && c->wall == waChasm && c->land == laMemory) {
+    for(int a=0; a<c->type; a++) if(c->move(a) && c->move(a)->land != laMemory) {
+      if(anyshiftclick) {
+        auto& poly = queuepoly(V, cgi.shPlainWall3D[ofs+a], 0xFFFFFFFF - 0xF0F0F00 * get_darkval(c, a));
+        poly.tinf = &floor_texture_vertices[cgi.shFullFloor.id];
+        ensure_vertex_number(*poly.tinf, poly.cnt);
+        }
+      else {
+        auto& poly = queuepoly(V, cgi.shWireframe3D[ofs + a], 0);
+        poly.outline = 0xFFFFFFFF;
+        }
+      }
+    if(anyshiftclick) return;
+    }
+
   if(isWall3(c, wcol)) {
     if(!no_wall_rendering) {
     if(c->wall == waChasm && c->land == laMemory && !in_perspective()) {

classes.cpp

@@ -751,6 +751,7 @@ enum eGeometry {
   gSpace345, gSpace353, gSpace354, gSpace355,
   gHalfBring,
   gAperiodicHat,
+  gSierpinski3, gSierpinski4, gSixFlake, gMengerSponge, gSierpinskiTet,
   gGUARD};
 
 enum eGeometryClass { gcHyperbolic, gcEuclid, gcSphere, gcSol, gcNIH, gcSolN, gcNil, gcProduct, gcSL2 };
@@ -830,6 +831,8 @@ static const flagtype qCAT             = Flag(28);
 static const flagtype qAPERIODIC       = Flag(29);
 static const flagtype qHAT             = Flag(30);
 
+static const flagtype qFRACTAL         = Flag(31);
+
 // note: dnext assumes that x&7 equals 7
 static const int SEE_ALL = 50;
 // note: check_football_colorability in arbitrile.cpp assumes OINF is divisible by 3
@@ -958,7 +961,12 @@ EX vector<geometryinfo> ginf = {
   {"{3,5,4}","none",    "{3,5,4} hyperbolic honeycomb",               "354",     20, 5, qIDEAL | qULTRA,    giHyperb3, {{7, 2}}, eVariation::pure},
   {"{3,5,5}","none",    "{3,5,5} hyperbolic honeycomb",               "355",     20, 5, qIDEAL | qULTRA,    giHyperb3, {{7, 2}}, eVariation::pure},
   {"{5,4}", "pBring",   "projective Bring's Surface",                 "pBring",   5, 4, qsSMALLN,   giHyperb2, {{6, 4}}, eVariation::bitruncated},
-  {"hat",    "none",    "aperiodic hat",                              "hat",     14, 3, qAPERIODIC | qHAT,     giEuclid2, {{7, 7}}, eVariation::pure},
+  {"hat",    "none",    "aperiodic hat",                              "hat",     14, 3, qAPERIODIC | qHAT,  giEuclid2, {{7, 7}}, eVariation::pure},
+  {"triangle","none",   "Sierpiński triangle",                        "S3",       6, 3, qFRACTAL,  giEuclid2, {{10, 10}}, eVariation::pure},
+  {"carpet", "none",    "Sierpiński carpet",                          "S4",       4, 4, qFRACTAL,  giEuclid2, {{10, 10}}, eVariation::pure},
+  {"6-flake","none",    "6-flake fractal",                            "S6",       6, 3, qFRACTAL,  giEuclid2, {{10, 10}}, eVariation::pure},
+  {"{4,3,4}","none",    "Menger sponge",                              "S8",       6, 4, qFRACTAL,  giEuclid3, {{10, 10}}, eVariation::pure},
+  {"rh{4,3,4}","none",  "Sierpiński tetrahedron",                     "S4b",     12, 3, qFRACTAL,  giEuclid3, {{10, 10}}, eVariation::pure},
   };
   // bits: 9, 10, 15, 16, (reserved for later) 17, 18
 

euclid.cpp

@@ -46,10 +46,12 @@ EX namespace euc {
 
     switch(g) {
       case gCubeTiling:
+      case gMengerSponge:
         shifttable = { +D0, +D1, +D2 };
         break;
       
       case gRhombic3:
+      case gSierpinskiTet:
         shifttable = { D0+D1, D0+D2, D1+D2, D1-D2, D0-D2, D0-D1 };
         break;
       
@@ -58,10 +60,13 @@ EX namespace euc {
         break;
       
       case gEuclid:
+      case gSierpinski3:
+      case gSixFlake:
         shifttable = { D0, D1, D1-D0, -D0, -D1, D0-D1 };
         break;
 
       case gEuclidSquare:
+      case gSierpinski4:
         shifttable = { D0, D1, -D0, -D1 };
         break;
       

geom-exp.cpp

@@ -346,6 +346,8 @@ void set_or_configure_geometry(eGeometry g) {
 
 /** is g2 the same tiling as the current geometry (geometry)? */
 bool same_tiling(eGeometry g2) {
+  /* no quotients for fractals */
+  if(cgflags & qFRACTAL) return g2 == geometry;
   if(g2 == gCrystal)
     return S3 == 4;
   if(g2 == gFieldQuotient && (hyperbolic || (geometry == gCubeTiling && reg3::cubes_reg3)) && standard_tiling())
@@ -602,7 +604,7 @@ EX void select_quotient_screen() {
   }
 
 EX void select_quotient() {
-  if(meuclid && !aperiodic && !arcm::in() && !reg3::cubes_reg3) {
+  if(meuclid && !aperiodic && !arcm::in() && !reg3::cubes_reg3 && !(cgflags & qFRACTAL)) {
     euc::prepare_torus3();
     pushScreen(euc::show_torus3);
     }
@@ -1029,6 +1031,8 @@ EX void showEuclideanMenu() {
     menuitem_nilwidth('v');
     }
   else if((WDIM == 3 || aperiodic || arb::in()) && !reg3::in() && geometry != gCubeTiling) dialog::addBreak(100);
+  else if(cgclass && qFRACTAL)
+    dialog::addBreak(100);
   else 
     menuitem_change_variation('v');
 

graph.cpp

@@ -3970,7 +3970,7 @@ EX int colorhash(color_t i) {
 
 EX bool isWall3(cell *c, color_t& wcol) {
   if(isWall(c)) return true;
-  if(c->wall == waChasm && c->land == laMemory) { wcol = 0x606000; return true; }
+  if(c->wall == waChasm && c->land == laMemory && (anyshiftclick || !(cgflags & qFRACTAL))) { wcol = 0x606000; return true; }
   if(c->wall == waInvisibleFloor) return false;
   // if(chasmgraph(c)) return true;
   if(among(c->wall, waMirror, waCloud, waMineUnknown, waMineMine)) return true;

help.cpp

@@ -240,7 +240,7 @@ EX void buildCredits() {
     "Kojiguchi Kazuki, baconcow, Alan, SurelyYouJest, hotdogPi, DivisionByZero, xXxWeedGokuxXx, jpystynen, Dmitry Marakasov, Alexandre Moine, Arthur O'Dwyer, "
     "Triple_Agent_AAA, bluetailedgnat, Allalinor, Shitford, KittyTac, Christopher King, KosGD, TravelDemon, Bubbles, rdococ, frozenlake, MagmaMcFry, "
     "Snakebird Priestess, roaringdragon2, Stopping Dog, bengineer8, Sir Light IJIJ, ShadeBlade, Saplou, shnourok, Ralith, madasa, 6% remaining, Chimera245, Remik Pi, alien foxcat thing, "
-    "Piotr Grochowski, Ann, still-flow, tyzone, Paradoxica, LottieRatWorld, aismallard, albatross, EncodedSpirit, Jacob Mandelson, CrashTuvai, cvoight, jennlbw, Kali Ranya"
+    "Piotr Grochowski, Ann, still-flow, tyzone, Paradoxica, LottieRatWorld, aismallard, albatross, EncodedSpirit, Jacob Mandelson, CrashTuvai, cvoight, jennlbw, Kali Ranya, spiritbackup"
     );
 #ifdef EXTRALICENSE
   help += EXTRALICENSE;

landgen.cpp

@@ -2226,7 +2226,7 @@ EX void giantLandSwitch(cell *c, int d, cell *from) {
           int hardchance = items[itRuby] + yendor::hardness();
           if(hardchance > 25) hardchance = 25;
           bool hardivy = hrand(100) < hardchance;
-          if(hat::in() ?  buildIvy(c, 0, 4) : (hardivy ? buildIvy(c, 1, 9) : buildIvy(c, 0, c->type)) && !peace::on)
+          if((cgflags & qFRACTAL) ? buildIvy(c, 0, 2) : hat::in() ?  buildIvy(c, 0, 4) : (hardivy ? buildIvy(c, 1, 9) : buildIvy(c, 0, c->type)) && !peace::on)
             c->item = itRuby;
           }
         }
@@ -2826,7 +2826,9 @@ EX void setland_randomwalk(cell *c) {
   if(c->land) return;
   if(hrand(10) == 0) setland(c, currentlands[hrand(isize(currentlands))]);
   else {
-    cell *c2 = c->cmove(hrand(c->type));
+    cell *c2 = nullptr;
+    for(int i=0; i<10 && !(c2 && (!disksize || is_in_disk(c2)) && is_in_fractal(c2)); i++)
+      c2 = c->cmove(hrand(c->type));
     setland_randomwalk(c2);
     c->land = c2->land;
     }
@@ -2836,6 +2838,11 @@ EX eLand random_land() {
   return hrand_elt(isize(cheatdest_list) ? cheatdest_list : currentlands);
   }
 
+EX void share_land(cell *c, cell *c2) {
+  if(!c2->land) setland(c2, random_land());
+  c->land = c2->land;
+  }
+
 EX void set_land_for_geometry(cell *c) {
 
   if(!c->land && isize(currentlands)) {
@@ -2844,15 +2851,17 @@ EX void set_land_for_geometry(cell *c) {
       return;
       }
      /* note: Nil patched chaos done in setLandNil */
-    if(ls::patched_chaos() && stdeuc) {
+    if(ls::patched_chaos() && (cgflags & qFRACTAL)) {
+      share_land(c, fractal_rep(c));
+      }
+    else if(ls::patched_chaos() && stdeuc) {
       cell *c2 = c;
       while(true) {
         forCellCM(c3, c2) if(cdist50(c3) < cdist50(c2)) { c2 = c3; goto again; }
         break;
         again: ;
         }
-      if(!c2->land) setland(c2, random_land());
+      share_land(c, c2);
-      c->land = c2->land;
       return;
       }
     if(ls::patched_chaos() && aperiodic) {
@@ -2861,8 +2870,7 @@ EX void set_land_for_geometry(cell *c) {
         c2 = c->master->cmove(0)->cmove(0)->cmove(1)->cmove(1)->c7;
       else
         c2 = c->master->cmove(0)->cmove(0)->cmove(0)->cmove(0)->cmove(0)->cmove(1)->cmove(1)->cmove(1)->cmove(1)->cmove(1)->c7;
-      if(!c2->land) setland(c2, random_land());
+      share_land(c, c2);
-      c->land = c2->land;
       return;
       }
     if(land_structure == lsChaosRW) {
@@ -3058,7 +3066,7 @@ EX void setdist(cell *c, int d, cell *from) {
       }
     }
 
-  if(disksize && !is_in_disk(c)) {
+  if((disksize && !is_in_disk(c)) || ((cgflags & qFRACTAL) && !is_in_fractal(c))) {
     setland(c, laMemory);
     if(!isMultitile(c)) c->monst = moNone;
     c->item = itNone;

landlock.cpp

@@ -159,6 +159,8 @@ EX void fix_land_structure_choice() {
     land_structure = lsSingle;
   if(aperiodic && !among(land_structure, lsChaosRW, lsTotalChaos, lsPatchedChaos, lsSingle))
     land_structure = lsPatchedChaos;
+  if((cgflags & qFRACTAL) && !among(land_structure, lsChaosRW, lsTotalChaos, lsPatchedChaos, lsSingle))
+    land_structure = lsPatchedChaos;
   }
 
 EX bool landUnlockedRPM(eLand n) {