From b19a0fda78fc528dff4f0e254dfa4b64dbb8bfb9 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Sat, 17 Oct 2020 09:15:05 +0800
Subject: [PATCH] add spiral_city

---
 examples/spiral_city.scad | 129 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 examples/spiral_city.scad

diff --git a/examples/spiral_city.scad b/examples/spiral_city.scad
new file mode 100644
index 00000000..9fb28396
--- /dev/null
+++ b/examples/spiral_city.scad
@@ -0,0 +1,129 @@
+use <archimedean_spiral.scad>;
+use <arc.scad>;
+use <rounded_cube.scad>;
+use <util/reverse.scad>;
+
+num_of_buildings = 10;
+seed_value = 15; 
+
+spiral_city(num_of_buildings, seed_value);  
+
+module spiral_city(num_of_buildings, seed_value) {
+    $fn = 48;
+    arm_distance = 30;
+
+    points_angles = archimedean_spiral(
+        arm_distance = arm_distance,
+        init_angle = 270,
+        point_distance = 30,
+        num_of_points = num_of_buildings + 1
+    ); 
+
+    pts = reverse([for(pa = points_angles) pa[0]]);
+    leng_pts = len(pts);
+
+    floor_h = 30;
+    roof_h = 7;
+    w_size = floor_h / 6;
+
+    for(i = [0:leng_pts - 2]) {
+        mid_pt = (pts[i] + pts[i + 1]) / 2;
+        arc_r = norm(mid_pt);
+        d_pts = norm(pts[i] - pts[i + 1]);
+        arc_a = angle(arc_r, d_pts) * (i > leng_pts - 4 ? 0.85 : 0.95); 
+        
+        is_even = i % 2 == 0;
+        half_a = arc_a / 2;
+        
+        building_h = floor_h * (floor(i / 5 + 1) + (is_even ? floor_h / 65: 0));
+        ra_arc = atan2(mid_pt[1], mid_pt[0]) - (i > leng_pts - 4 ? arc_a / 4.5 : arc_a / 5);
+        
+        translate(mid_pt)
+        rotate(ra_arc)
+        union() {
+            difference() {
+                union() {
+                    linear_extrude(building_h)
+                    translate([-arc_r, 0])
+                    minkowski() {
+                        arc(radius = arc_r, angle = [-half_a, half_a], width = arm_distance / (is_even ? 2.5 : 1.7));
+                        circle(1, $fn = 12);
+                    }
+                }  
+                
+                // windows
+                cubes(i, arm_distance, building_h, w_size, arc_a, arc_r, seed_value);
+            }        
+            
+
+            roof(i, arm_distance, building_h, roof_h, arc_a, arc_r);
+        }
+    }
+    
+    function angle(arc_r, d_pts) = 180 * d_pts / (arc_r * PI);
+    
+    module cubes(i, arm_distance, building_h, w_size, arc_a, arc_r, seed_value) {
+        half_a = arc_a / 2;
+        is_even = i % 2 == 0;
+        arc_w = arm_distance / (is_even ? 2.5 : 1.7);
+        union() {  
+            rs = is_undef(seed_value) ?
+                rands(-1, 1, 4) : 
+                rands(-1, 1, 4, seed_value = seed_value + i);
+            
+            outer_cube_size = [w_size / 2, w_size  + rs[0] , w_size + rs[1]];
+            inter_cube_size = [w_size / 2, (w_size + rs[0]) * 0.85, w_size + rs[1]];
+            
+            h_step = w_size * 1.5;
+            h_to = building_h - w_size * 1.5; 
+            
+            a_from = -half_a  + (rs[3] > 0 ? arc_a / 8 : arc_a / 6);
+            a_step = rs[3] > 0 ? arc_a / 4 : arc_a / 3;
+            
+            outer_cube_p = [arc_r + arc_w / 2, 0, w_size * 0.75];
+            inner_cube_p = [arc_r - arc_w / 2, 0, w_size * 0.75]; 
+            
+            for(h = [0:h_step: h_to]) {                
+                translate([-arc_r, 0, h + rs[2] + 1])
+                for(a = [a_from:a_step:half_a]) {
+                    r = is_undef(seed_value) ?
+                           rands(0, 1, 1)[0] :
+                           rands(0, 1, 1, seed_value = seed_value)[0];
+                    s = [r > 0.5 ? 2.75 : 1, 1, 1];
+                    rotate(a) {
+                        translate(outer_cube_p)
+                        scale(s)
+                            rounded_cube(outer_cube_size, 1, center = true, $fn = 7);
+                            
+                        translate(inner_cube_p)
+                        scale(s)
+                            rounded_cube(inter_cube_size, 1, center = true, $fn = 7);      
+                    }                        
+                }
+            } 
+        }    
+    }
+    
+    module roof(i, arm_distance, building_h, roof_h, arc_a, arc_r) {
+        is_even = i % 2 == 0;
+        half_a = arc_a / 2;
+        if(is_even) {
+            translate([0, 0, building_h])
+            linear_extrude(roof_h, scale = [0.1, 0.65], slices = 10)
+            translate([-arc_r, 0])    
+            minkowski() {
+                arc(radius = arc_r, angle = [-half_a * 1.075, half_a * 1.075], width = arm_distance * 0.5);   
+                circle(1, $fn = 12);
+            }
+        }  
+        else {
+            translate([0, 0, building_h])        
+            linear_extrude(roof_h * 0.8, scale = [0.1, 0.65], slices = 10)
+            translate([-arc_r, 0])    
+            minkowski() {
+                arc(radius = arc_r, angle = [-half_a, half_a], width = arm_distance * 0.65);   
+                circle(1, $fn = 12);
+            }  
+        }      
+    }    
+}
\ No newline at end of file