Support generators and add City Builder example

examples/City Builder.py

@@ -0,0 +1,32 @@
+# Create a curve object as the base.
+# In Edit Mode, use the Draw tool to create new roads in the city.
+
+from geometry_script import *
+
+@tree("City Builder")
+def city_builder(geometry: Geometry, building_size_min: Vector = (0.1, 0.1, 0.2), building_size_max: Vector = (0.3, 0.3, 1), size_x: Float = 5.0, size_y: Float = 5.0, road_width: Float = 0.25, seed: Int = 0, resolution: Int = 60):
+    # Road geometry from input curves
+    road_points = geometry.curve_to_points().points
+    yield geometry.curve_to_mesh(
+        profile_curve=curve_line(
+            start=combine_xyz(x=road_width * -0.5),
+            end=combine_xyz(x=road_width / 2)
+        )
+    )
+
+    # Randomly distribute buildings on a grid
+    building_points = grid(
+        size_x=size_x, size_y=size_y,
+        vertices_x=resolution, vertices_y=resolution
+    ).distribute_points_on_faces(
+        seed=seed
+    # Delete invalid building points based on proximity to a road
+    ).points.delete_geometry(
+        domain='POINT',
+        selection=road_points.geometry_proximity(target_element='POINTS', source_position=position()).distance < road_width * 2
+    )
+    random_scale = random_value(data_type='FLOAT_VECTOR', min=building_size_min, max=building_size_max, seed=seed + id())
+    yield building_points.instance_on_points(
+        instance=cube(size=(1, 1, 1)).transform(translation=(0, 0, 0.5)),
+        scale=random_scale
+    )