add pnoise3_demo

src/experimental/demo/pnoise3_demo.scad

@@ -0,0 +1,68 @@
+use <util/rand.scad>;
+use <function_grapher.scad>;
+use <experimental/pnoise2.scad>;
+use <experimental/pnoise3.scad>;
+
+module demo1() {
+    points = [
+        for(z = [0:.2:3])
+            for(y = [0:.2:5])
+                for(x = [0:.2:5])
+                    [x, y, z]
+    ];
+    noise = pnoise3(points);
+
+    for(i = [0:len(points) - 1]) {
+        if(noise[i] > 0) {
+            translate(points[i])
+                cube(.2);
+        }
+    }
+}
+
+
+module demo2() {
+    points = [
+        for(y = [0:.2:10])
+            [
+                for(x = [0:.2:10])
+                [x, y]
+            ]
+    ];
+    
+    seed = rand(0, 256);
+    
+    points_with_h = [
+            for(ri = [0:len(points) - 1])
+                let(ns = pnoise2(points[ri], seed))
+                    [
+                        for(ci = [0:len(ns) - 1])
+                            [points[ri][ci][0], points[ri][ci][1], ns[ci] + 1]
+                    ]
+        ];
+    
+    h_scale = 1.5;
+    for(row = points_with_h) {        
+        for(i = [0:len(row) - 1]) {
+            p = row[i];
+            pts = [
+                for(z = [0:.2:p[2] * h_scale]) [p[0], p[1], z]
+            ];
+            noise = pnoise3(pts, seed);
+            for(j = [0:len(pts) - 1]) {
+                if(noise[j] > 0) {
+                    translate(pts[j])
+                        cube(.2);
+                }           
+            }
+        }
+    }
+    
+    linear_extrude(.2)
+        square(10);
+}
+
+demo1();
+
+translate([8, 0]) 
+    demo2();