From 0ab4a30406f316673f13b3d0eeb1c9c36f1cc6bb Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Wed, 21 Aug 2019 07:33:24 +0200
Subject: [PATCH] product:: backwall optimization

---
 geometry.cpp     |  1 +
 graph.cpp        |  5 ++++-
 nonisotropic.cpp | 38 ++++++++++++++++++++++++++++++++++----
 polygons.cpp     |  1 +
 4 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/geometry.cpp b/geometry.cpp
index 609d23ff..d44de350 100644
--- a/geometry.cpp
+++ b/geometry.cpp
@@ -245,6 +245,7 @@ hpcshape
     shAnimatedGargoyle, shAnimatedGargoyle2, shAnimatedBat, shAnimatedBat2;  
 
   vector<hpcshape> shPlainWall3D, shWireframe3D, shWall3D, shMiniWall3D;
+  vector<hyperpoint> walltester;
 
   vector<struct plain_floorshape*> all_plain_floorshapes;
   vector<struct escher_floorshape*> all_escher_floorshapes;
diff --git a/graph.cpp b/graph.cpp
index 4b1e1f20..1eb5031c 100644
--- a/graph.cpp
+++ b/graph.cpp
@@ -4559,7 +4559,7 @@ void radar_grid(cell *c, const transmatrix& V) {
   }
 
 int wall_offset(cell *c) {
-  if(prod) return product::wall_offset(c);
+  if(prod) return product::cwall_offset;
   if(penrose && kite::getshape(c->master) == kite::pKite) return 10;
   return 0;
   }
@@ -6048,6 +6048,9 @@ EX void drawcell(cell *c, transmatrix V, int spinv, bool mirrored) {
                   case 6: case 7: if (pmodel == mdPerspective && V[2][LDIM] <= -l) continue; break;
                   }
                 }
+              else if(prod) {
+                if(!((product::cwall_mask >> a) & 1)) continue;
+                }
               if(qfi.fshape && wmescher) {
                 auto& poly = queuepoly(V, cgi.shWall3D[ofs + a], darkena(wcol2 - d * get_darkval(c, a), 0, 0xFF));
                 #if CAP_TEXTURE
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 36710982..95455537 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -625,12 +625,30 @@ EX namespace product {
   
   EX pair<cell*, int> get_where(cell *c) { return ((hrmap_product*)currentmap)->where[c]; }
   
+  EX int cwall_offset, cwall_mask;
+  
   void drawcell_stack(cell *c, transmatrix V, int spinv, bool mirrored) {
     if(sphere) gmatrix[c] = V; /* some computations need gmatrix0 for underlying geometry */
+    bool s = sphere;
     in_actual([&] { 
+      cell *c0 = get_at(c, current_view_level);
+      cwall_offset = wall_offset(c0);
+      if(s) cwall_mask = (1<<c->type) - 1;
+      else {
+        cwall_mask = 0;
+        ld d = V[2][2];
+        for(int i=0; i<c->type; i++) {
+          ld d1 = (V * cgi.walltester[cwall_offset + i])[2];
+          if(c0->item == itGold) println(hlog, i, ": ", d, " vs ", d1);
+          if(d1 < d - 1e-6) cwall_mask |= (1<<i);
+          }
+        }
+      cwall_mask |= (2<<c->type);
       int flat_distance = hdist0(product_decompose(tC0(V)).second);
       int max_z = flat_distance > sightranges[gProduct] ? 0 : sqrt(sightranges[gProduct] * sightranges[gProduct] - flat_distance * flat_distance) + 1;
       for(int z=-max_z; z<=max_z; z++) {
+        if(z == 0) cwall_mask ^= (2<<c->type);
+        if(z == 1) cwall_mask ^= (1<<c->type);
         cell *c1 = get_at(c, current_view_level+z);
         setdist(c1, 7, NULL);
         drawcell(c1, V * mscale(Id, cgi.plevel * z), spinv, mirrored); 
@@ -667,10 +685,22 @@ EX namespace product {
       cell *c1 = get_where(c).first;
       wo = isize(cgi.shWall3D);
       int won = wo + c->type;
-      cgi.shWall3D.resize(won);
-      cgi.shPlainWall3D.resize(won);
-      cgi.shWireframe3D.resize(won);
-      cgi.shMiniWall3D.resize(won);
+      cgi.reserve_wall3d(won);
+      
+      for(int i=0; i<c1->type; i++) {
+        hyperpoint w;
+        in_underlying_geometry([&] { 
+          /* mirror image of C0 in the axis h1-h2 */
+          hyperpoint h1 = get_corner_position(c1, i);
+          hyperpoint h2 = get_corner_position(c1, i+1);
+          transmatrix T = gpushxto0(h1);
+          T = spintox(T * h2) * T;
+          w = T * C0;
+          w[1] = -w[1];
+          w = inverse(T) * w;
+          });
+        cgi.walltester[wo + i] = w;
+        } 
 
       for(int i=0; i<c1->type; i++)
        cgi.make_wall(wo + i, {product::get_corner(c1, i, -1), product::get_corner(c1, i, +1), product::get_corner(c1, i+1, +1), product::get_corner(c1, i+1, -1)});
diff --git a/polygons.cpp b/polygons.cpp
index cd70b8a0..9db2429d 100644
--- a/polygons.cpp
+++ b/polygons.cpp
@@ -794,6 +794,7 @@ void geometry_information::reserve_wall3d(int i) {
   shPlainWall3D.resize(i);
   shWireframe3D.resize(i);
   shMiniWall3D.resize(i);
+  walltester.resize(i);
   }
 
 void geometry_information::create_wall3d() {