add rose

examples/rose.scad

@@ -0,0 +1,57 @@
+include <polysections.scad>;
+include <util/reverse.scad>;
+
+thickness = 0.05;
+
+theta_from = PI * 1.75;
+theta_to = PI * 15;
+theta_step = 0.05;
+
+rf_to = 1;
+rf_step = 0.025;
+
+color("red") rose();
+
+module rose() {
+    function phi(theta) =
+        (PI / 2) * exp(-theta / (8 * PI));
+        
+    function wave(theta) = 
+         1 - 0.5 * pow(1.25 * pow(1- ((3.6 * theta) % (2 * PI)) / PI - (theta > 0 ? 0 : 2), 2) - 0.25, 2);
+
+    function g(rf, theta) =
+        let(angle = phi(theta) * 57.2958)
+        1.95653 * pow(rf, 2) * pow(1.27689 * rf - 1, 2) * sin(angle);
+
+    function r(rf,theta) = 
+        let(angle = phi(theta) * 180 / PI)
+        wave(theta) * (rf * sin(angle) + g(rf, theta) * cos(angle));
+
+    sections = [
+        for(theta = [theta_from:theta_step:theta_to])
+        let(
+            path = [ 
+                for(rf = [0:rf_step:rf_to])
+                let(
+                    r = r(rf,theta),
+                    angle = theta * 57.2958, 
+                    angle2 = phi(theta)* 57.2958,
+                    x = r*sin(angle), 
+                    y = r*cos(angle),
+                    z = wave(theta)*(rf*cos(angle2)-g(rf,theta)*sin(angle2))
+                )
+                [x, y, z]
+            ]
+        )
+        concat(
+            [
+                for(p = path)
+                p - [0, 0, thickness]
+            ],
+            reverse(path)
+        )
+    ];
+    
+    polysections(sections);
+}
+