From cf5d70c1ef52cc1d7f0b44e22925c8f8fc7a75be Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Fri, 3 Jun 2022 12:46:54 +0800
Subject: [PATCH] add forest

---
 examples/circle_packing/forest.scad | 106 ++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 examples/circle_packing/forest.scad

diff --git a/examples/circle_packing/forest.scad b/examples/circle_packing/forest.scad
new file mode 100644
index 00000000..d6d6c0c8
--- /dev/null
+++ b/examples/circle_packing/forest.scad
@@ -0,0 +1,106 @@
+use <polyline_join.scad>;
+use <turtle/t3d.scad>;
+use <util/rand.scad>;
+use <shape_circle.scad>;
+use <util/rands_disk.scad>;
+
+use <experimental/tri_circle_packing.scad>;
+use <experimental/tri_subdivide.scad>;
+use <experimental/circle_packing.scad>;
+
+trunk_leng = 1.5;
+branch_scale = 0.7;
+branch_angle = 30;
+width = 1;
+
+$fn = 12;
+min_r = .5;
+r = 35;
+count = 20;
+
+fractal_tree = true;
+
+points = concat(rands_disk(r, count), shape_circle(r));
+circles = circle_packing(points, min_r);
+
+if(fractal_tree) {
+    for(c = circles) {
+        translate([each c[0], c[1] / 12.5])
+        rotate([0, -90, rands(0, 360, 1)[0]])
+            tree(t3d(), c[1], branch_scale, branch_angle, width, $fn = 5);    
+    }
+} 
+else {
+    for(c = circles) {
+        translate([each c[0], c[1] * 3])
+            sphere(c[1]);    
+            
+        translate(c[0])
+        linear_extrude(c[1] * 3)
+            circle(c[1] / 3);
+    }
+}
+
+translate([0, 0, -width / 10])
+linear_extrude(width / 1.5, center = true)
+    circle(r, $fn = $fn * 3);
+    
+module line(t1, t2, start_width, end_width) {
+    polyline_join([t3d(t1, "point"), t3d(t2, "point")]) {
+        sphere(start_width / 2);
+        sphere(end_width / 2);
+    }
+}
+
+module shoot(t, trunk_leng, branch_scale, branch_angle, width) {
+    t2 = t3d(t, "forward", leng = trunk_leng);
+    branch_leng = trunk_leng * branch_scale;
+        
+    color("NavajoWhite")
+    line(t, t2, branch_leng * branch_scale, branch_leng);
+
+    color("green") {
+        t3 = t3d(t2, "turn", angle = branch_angle);
+        line(
+            t2, 
+            t3d(t3, "forward", leng = branch_leng * rand(1, 2)), 
+            branch_leng,
+            width * branch_scale * rand(2, 4),
+            $fn = rand(4, 6)
+        );
+
+        t4 = t3d(t2, "turn", angle = -branch_angle);  
+        line(
+            t2, 
+            t3d(t4, "forward", leng = branch_leng * rand(1, 2)), 
+            branch_leng,
+            width * branch_scale * rand(2, 4),
+            $fn = rand(4, 6)
+        );
+    }
+}
+
+module tree(t, trunk_leng, branch_scale, branch_angle, width) {
+    if(trunk_leng > width * 2) {
+        t2 = t3d(t, "forward", leng = trunk_leng * rand(0.6, 1));
+        
+        color("NavajoWhite")
+        line(t, t2, trunk_leng / 3, trunk_leng / 3 * branch_scale);
+
+        rolled = t3d(t2, "roll", angle = 120 * rand(0.6, 1));
+        branch_leng = trunk_leng * branch_scale;
+        
+        t3 = t3d(rolled, "turn", angle = branch_angle * rand(0.6, 1));
+        tree(t3, branch_leng, branch_scale, branch_angle, width);
+
+        t4 = t3d(rolled, "turn", angle = -branch_angle * rand(0.6, 1));        
+        tree(t4, branch_leng, branch_scale, branch_angle, width);
+    }
+    else {
+        branch_leng = trunk_leng * branch_scale;
+        shoot(t, branch_leng, branch_scale, branch_angle, width);
+    }
+}
+
+
+