From 8829123ade16ea37d6510b30bb913c191140d245 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Fri, 30 Jul 2021 10:55:36 +0800
Subject: [PATCH] add tile_truchet

---
 examples/tiled_lines.scad          | 37 +++++++++++-------------------
 src/experimental/tile_truchet.scad | 29 +++++++++++++++++++++++
 2 files changed, 43 insertions(+), 23 deletions(-)
 create mode 100644 src/experimental/tile_truchet.scad

diff --git a/examples/tiled_lines.scad b/examples/tiled_lines.scad
index d3b58079..0021d077 100644
--- a/examples/tiled_lines.scad
+++ b/examples/tiled_lines.scad
@@ -1,28 +1,19 @@
+use <experimental/tile_truchet.scad>;
 use <line2d.scad>;
-use <util/rand.scad>;
-
-module tiled_lines(size, step, line_width = 1) {
-    sizexy = is_num(size) ? [size, size] : size;
-    s = is_undef(step) ? line_width * 2 : step;
- 
-    module rand_diagonal_line(x, y, size) {
-        if(rand(0, 1) >= 0.5) {
-            line2d([x, y], [x + size, y + size], width = line_width);
-        } 
-        else {
-            line2d([x + size, y], [x, y + size], width = line_width);
-        }
-    } 
-    
-    for(x = [0:s:sizexy[0] - s]) {
-        for(y = [0:s:sizexy[1] - s]) {
-            rand_diagonal_line(x, y, s);    
-        }
-    }
-}
 
 size = [50, 25];
-step = 2; 
+tile_width = 5;
 line_width = 1;
 
-tiled_lines(size, step, line_width);
+for(tile = tile_truchet(size)) {
+    x = tile[0];
+	y = tile[1];
+	i = tile[2];
+	
+	if(i <= 1) {
+	    line2d([x, y] * tile_width , [x + 1, y + 1] * tile_width, width = line_width);
+	}
+	else {
+	    line2d([x + 1, y] * tile_width, [x, y + 1] * tile_width, width = line_width);
+	}
+}
\ No newline at end of file
diff --git a/src/experimental/tile_truchet.scad b/src/experimental/tile_truchet.scad
new file mode 100644
index 00000000..859c55f1
--- /dev/null
+++ b/src/experimental/tile_truchet.scad
@@ -0,0 +1,29 @@
+use <util/choose.scad>;
+
+function tile_truchet(size, mask, seed) =
+    let(
+        rows = size[1], 
+        columns = size[0],
+		y_range = [0:rows - 1],
+		x_range = [0:columns - 1],
+        nums = [0, 1, 2, 3],
+		m = is_undef(mask) ? [
+			for(y = y_range)
+				[for(x = x_range) 1]
+		] : [
+			for(y = rows - 1; y > -1; y = y - 1)
+				[for(x = x_range) mask[y][x]]
+		]
+	)
+	is_undef(seed) ? [
+        for(y = y_range)
+            for(x = x_range) 
+            if(m[y][x] == 1)
+                [x, y, choose(nums)]
+        
+    ] : [
+        for(y = y_range)        
+            for(x = x_range) 
+            if(m[y][x] == 1)
+                [x, y, choose(nums, x + y * rows + seed)]
+    ];
\ No newline at end of file