Add libcircle

circle.scad

@@ -0,0 +1,86 @@
+/*
+ * circle
+ *
+ *
+ * Functions:
+ *  libcircle_quarter and its alias libcircle_14
+ *  libcircle_half and its alias libcircle_24 and libcircle_12
+ *  libcircle_threequarter and its alias libcircle_34
+ *
+ * All functions take either r (radius) or d (diameter) as argument.
+ * If both are given (for whatever reason you'd do this), radius is chosen over diameter.
+ * Same applies for libcircle_degrees, however you also need to pass this module
+ * the "degrees" argument which is pretty self-explanatory.
+ */
+ 
+$fn = 36;
+
+module libcircle_14(r=0, d=0) {
+    libcircle_quarter(r, d);
+}
+
+module libcircle_quarter(r=0, d=0) {
+    diameter = __diameter_radius_conversion(r, d);
+    intersection() {
+        circle(d=diameter);
+        square([radius, radius]);
+    }
+}
+
+module libcircle_24(r=0, d=0) {
+    libcircle_half(r, d);
+}
+
+module libcircle_12(r=0, d=0) {
+    libcircle_half(r, d);
+}
+
+module libcircle_half(r=0, d=0) {
+    diameter = __diameter_radius_conversion(r, d);
+    intersection() {
+        circle(d=diameter);
+        translate([0, -diameter, 0])
+        square([diameter, diameter*2]);
+    }
+}
+
+module libcircle_34(r=0, d=0) {
+    libcircle_threequarter(r, d);
+}
+
+module libcircle_threequarter(r=0, d=0) {
+    diameter = __diameter_radius_conversion(r, d);
+    difference() {
+        circle(d=diameter);
+        translate([-diameter, 0, 0])
+        square([diameter, diameter]);
+    }
+}
+
+module libcircle_degrees(r=0, d=0, degrees) {
+    diameter = __diameter_radius_conversion(r, d);
+    degrees = degrees % 360;
+
+    if(degrees > 180) {
+        __half_circle_degrees(diameter, 180);
+        rotate([0, 0, 180])
+        __half_circle_degrees(diameter, degrees-180);
+    } else {
+        __half_circle_degrees(diameter, degrees);
+    }
+}
+
+module __half_circle_degrees(diameter, degrees) {
+    // This is the most dirty hack I've pulled in a while.
+    // But... Who cares? #sorrynotsorry ;)
+    difference() {
+        libcircle_half(d=diameter);
+        rotate([0, 0, degrees])
+        translate([0, -diameter/2])
+        square([diameter/2, diameter]);
+    }
+}
+
+// https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/General#Scope_of_variables
+// let's work our way around this... ;(
+function __diameter_radius_conversion(r=0, d=0) = (r > 0) ? r*2 : d;