add lemniscate_2circles

src/lemniscate_2circles.scad

@@ -0,0 +1,50 @@
+use <__comm__/__frags.scad>;
+use <path_extrude.scad>;
+use <shape_circle.scad>;
+
+function lemniscate_2circles(radius, c = 1) = 
+    let(
+	    fn = __frags(radius),
+	    t_step = 180 / fn,
+	    circle_path = shape_circle(radius = radius)
+	)
+    concat(
+		[
+			for(t = [0:fn - 1]) 
+			[circle_path[t][0] - radius, circle_path[t][1], cos(t * t_step) * c]
+		],
+		[
+			for(t = [0:fn - 1]) 
+			[-circle_path[t][0] + radius, circle_path[t][1], -cos(t * t_step) * c]
+		]
+	);
+
+/*
+use <path_extrude.scad>;
+use <lemniscate_2circles.scad>;
+	
+shape_pts = [
+    [3, -1.5],
+    [3, 1.5], 
+    [2, 1.5],
+    [2, 0.5],
+    [-2, 0.5],
+    [-2, 1.5],    
+    [-3, 1.5],    
+	[-3, -1.5],
+    [-2, -1.5],
+	[-2, -0.5],
+	[2, -0.5],
+	[2, -1.5]
+];
+
+$fn = 48;
+
+path = lemniscate_2circles(10, 2);
+
+path_extrude(
+    shape_pts, 
+	concat(path, [path[0]]), 
+	method = "EULER_ANGLE"
+);
+*/