From c3d5484fde396a7ec8f34b4a1285b09a724e7876 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Thu, 9 Apr 2020 14:53:05 +0800
Subject: [PATCH] symmetric

---
 examples/voronoi/voronoi_torus.scad           | 15 ++++++++++++++
 .../_impl/_voronoi_square_cells_impl.scad     | 20 +++++++++++--------
 src/experimental/voronoi_square_cells.scad    | 10 +++++++---
 3 files changed, 34 insertions(+), 11 deletions(-)
 create mode 100644 examples/voronoi/voronoi_torus.scad

diff --git a/examples/voronoi/voronoi_torus.scad b/examples/voronoi/voronoi_torus.scad
new file mode 100644
index 00000000..7da18956
--- /dev/null
+++ b/examples/voronoi/voronoi_torus.scad
@@ -0,0 +1,15 @@
+use <experimental/voronoi_square_cells.scad>;
+use <hull_polyline3d.scad>;
+use <ptf/ptf_torus.scad>;
+
+size = [40, 80];
+grid_w = 5;
+cells = voronoi_square_cells(size, grid_w);
+
+$fn = 4;
+
+for(cell = cells) {
+    cell_poly = [for(p = cell[1]) ptf_torus(size, p, [10, 5], [360, 360])];
+
+    hull_polyline3d(cell_poly, thickness = 1);
+}
\ No newline at end of file
diff --git a/src/experimental/_impl/_voronoi_square_cells_impl.scad b/src/experimental/_impl/_voronoi_square_cells_impl.scad
index 65861ec7..f9ef0317 100644
--- a/src/experimental/_impl/_voronoi_square_cells_impl.scad
+++ b/src/experimental/_impl/_voronoi_square_cells_impl.scad
@@ -4,28 +4,32 @@ _noise_table = [0.592157, 0.627451, 0.537255, 0.356863, 0.352941, 0.0588235, 0.5
 
 function _lookup_noise_table(i) = _noise_table[i % 256];
 
-function cell_pt(fcord, grid_w, seed, x, y) = 
+function cell_pt(fcord, grid_w, seed, x, y, gw, gh) = 
     let(
         nx = fcord[0] + x,
         ny = fcord[1] + y,
-        sd_base = abs(nx + ny * grid_w),
+        sd_x = nx < 0 ? nx + gw : 
+                nx >= gw ? nx % gw : nx,
+        sd_y = ny < 0 ? ny + gh : 
+                ny >= gh ? ny % gh : ny,                 
+        sd_base = abs(sd_x + sd_y * grid_w),
         sd1 = _lookup_noise_table(seed + sd_base),
         sd2 = _lookup_noise_table(sd1 * 255 + sd_base)
     )
     [(nx + sd1) * grid_w, (ny + sd2) * grid_w];
 
 // 21-nearest-neighbor 
-function _neighbors(fcord, seed, grid_w) = 
+function _neighbors(fcord, seed, grid_w, gw, gh) = 
     concat(
         [
             for(y = [-1:1])
                 for(x = [-1:1])
-                    cell_pt(fcord, grid_w, seed, x, y)
+                    cell_pt(fcord, grid_w, seed, x, y, gw, gh)
         ],
-        [for(x = [-1:1]) cell_pt(fcord, grid_w, seed, x, -2)],
-        [for(x = [-1:1]) cell_pt(fcord, grid_w, seed, x, 2)],
-        [for(y = [-1:1]) cell_pt(fcord, grid_w, seed, -2, y)],
-        [for(y = [-1:1]) cell_pt(fcord, grid_w, seed, 2, y)]
+        [for(x = [-1:1]) cell_pt(fcord, grid_w, seed, x, -2, gw, gh)],
+        [for(x = [-1:1]) cell_pt(fcord, grid_w, seed, x, 2, gw, gh)],
+        [for(y = [-1:1]) cell_pt(fcord, grid_w, seed, -2, y, gw, gh)],
+        [for(y = [-1:1]) cell_pt(fcord, grid_w, seed, 2, y, gw, gh)]
     );
 
 function _cells_lt_before_intersection(shape, size, points, pt, half_region_size) =
diff --git a/src/experimental/voronoi_square_cells.scad b/src/experimental/voronoi_square_cells.scad
index c57a18c3..6e1cd5a5 100644
--- a/src/experimental/voronoi_square_cells.scad
+++ b/src/experimental/voronoi_square_cells.scad
@@ -8,13 +8,17 @@ function voronoi_square_cells(size, grid_w, seed) =
         region_size = grid_w * 3,
         half_region_size = region_size * 0.5,
         shape = shape_square(grid_w * 3),
-        cell_nbrs_lt = [for(cy = [0:grid_w:size[1]]) 
-            for(cx = [0:grid_w:size[0]])
+        gw = size[0] / grid_w,
+        gh = size[1] / grid_w,
+        cell_nbrs_lt = [for(cy = [-grid_w:grid_w:size[1]]) 
+            for(cx = [-grid_w:grid_w:size[0]])
             let(
                 nbrs = _neighbors(
                     [floor(cx / grid_w), floor(cy / grid_w)],
                     sd, 
-                    grid_w
+                    grid_w,
+                    gw, 
+                    gh
                 ),
                 p = nbrs[4],
                 points = concat(