From c89c440bdaf08e07cc7854e5057737518d884357 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Tue, 18 Feb 2020 17:18:11 +0800
Subject: [PATCH] add sf_square

---
 src/experimental/sf_square.scad | 52 +++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 src/experimental/sf_square.scad

diff --git a/src/experimental/sf_square.scad b/src/experimental/sf_square.scad
new file mode 100644
index 00000000..6a332d7c
--- /dev/null
+++ b/src/experimental/sf_square.scad
@@ -0,0 +1,52 @@
+use <experimental/sf_solidify.scad>;
+use <experimental/tf_sphere.scad>;
+
+/*
+    levels : A list of numbers (0 ~ 255).
+    thickness: square thickness
+    invert: inverts how the gray levels are translated into height values.
+*/
+module sf_square(levels, thickness, invert = false) {
+    columns = len(levels);
+    rows = len(levels[0]);
+    
+    size = [columns - 1, rows - 1];
+
+    surface1 = [
+        for(r = [0:rows - 1]) 
+        [
+            for(c = [0:columns - 1]) 
+            let(lv = invert ? 255 - levels[c][r] : levels[c][r])
+            [c, r, lv / 255 * thickness]
+        ]
+    ];
+
+    surface2 = [
+        for(r = [0:rows - 1]) 
+        [
+            for(c = [0:columns - 1]) 
+            [c, r, 0]
+        ]
+    ];
+
+    sf_solidify(
+        [
+            for(r = [0:rows - 1]) 
+            [
+                for(c = [0:columns - 1]) 
+                let(
+                    lv = invert ? 255 - levels[c][r] : levels[c][r],
+                    offset_z = invert ? thickness : 0
+                )
+                [c, r, lv / 255 * thickness + offset_z]
+            ]
+        ],
+        [
+            for(r = [0:rows - 1]) 
+            [
+                for(c = [0:columns - 1]) 
+                [c, r, 0]
+            ]
+        ]      
+    );
+}
\ No newline at end of file