From cd4dda3b39fc8261bffea308b38357e282cb3729 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Sun, 26 Dec 2021 18:50:16 +0800
Subject: [PATCH] add mz_wang_tiles

---
 src/maze/_impl/_mz_wang_tiles_impl.scad | 33 ++++++++++++++++++
 src/maze/mz_wang_tiles.scad             | 46 +++++++++++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 src/maze/_impl/_mz_wang_tiles_impl.scad
 create mode 100644 src/maze/mz_wang_tiles.scad

diff --git a/src/maze/_impl/_mz_wang_tiles_impl.scad b/src/maze/_impl/_mz_wang_tiles_impl.scad
new file mode 100644
index 00000000..0801efd3
--- /dev/null
+++ b/src/maze/_impl/_mz_wang_tiles_impl.scad
@@ -0,0 +1,33 @@
+use <../../util/has.scad>;
+
+function _mz_wang_tiles_top(x, y) =
+    let(
+        nx = x * 2,
+        ny = y * 2
+    )
+    [[nx + 1, ny + 2]];
+
+function _mz_wang_tiles_right(x, y) =
+    let(
+        nx = x * 2,
+        ny = y * 2
+    )
+    [[nx + 2, ny + 1]];
+    
+function _mz_wang_tiles_top_right(x, y) =
+    let(
+        nx = x * 2,
+        ny = y * 2
+    )
+    [[nx + 1, ny + 2], [nx + 2, ny + 1]];
+
+function _mz_wang_tile_type(dots, x, y) =
+    let(
+        px = x * 2 + 1,
+        py = y * 2 + 1,
+        c1 = !has(dots, [px, py + 1], sorted = true) ? 1 : 0,
+        c2 = !has(dots, [px + 1, py], sorted = true) ? 2 : 0,
+        c3 = !has(dots, [px, py - 1], sorted = true) ? 4 : 0,
+        c4 = !has(dots, [px - 1, py], sorted = true) ? 8 : 0
+    )
+    c1 + c2 + c3 + c4;
diff --git a/src/maze/mz_wang_tiles.scad b/src/maze/mz_wang_tiles.scad
new file mode 100644
index 00000000..4b4d4b54
--- /dev/null
+++ b/src/maze/mz_wang_tiles.scad
@@ -0,0 +1,46 @@
+/**
+* mz_wang_tiles.scad
+*
+* @copyright Justin Lin, 2020
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib3x-mz_wang_tiles.html
+*
+**/
+
+use <_impl/_mz_wang_tiles_impl.scad>;
+use <mz_square_cells.scad>;
+use <mz_square_get.scad>;
+use <../util/sort.scad>;
+use <../util/dedup.scad>;
+
+function mz_wang_tiles(rows, columns, start = [0, 0], init_cells, seed) =
+    let(
+        cells = mz_square_cells(  
+            rows, columns,
+            init_cells = init_cells,
+            seed = seed
+        ),
+        all = concat(
+            [
+                for(cell = cells)
+                let(
+                    x = mz_square_get(cell, "x"),
+                    y = mz_square_get(cell, "y"),
+                    type = mz_square_get(cell, "t"),
+                    pts = type == "TOP_WALL" ? _mz_wang_tiles_top(x, y) :
+                          type == "RIGHT_WALL" ? _mz_wang_tiles_right(x, y) :
+                          type == "TOP_RIGHT_WALL"  || type == "MASK" ? _mz_wang_tiles_top_right(x, y) : []
+                )
+                each pts
+            ],
+            [for(x = [0:columns - 1]) [x * 2 + 1, 0]],
+            [for(y = [0:rows - 1]) [0, y * 2 + 1]]
+        ),
+        dot_pts = dedup(sort(all, by = "vt"))
+    )
+    [
+        for(y = [0:rows - 1])
+            for(x = [0:columns - 1])
+            [x, y, _mz_wang_tile_type(dot_pts, x, y)]
+    ];
\ No newline at end of file