Clean stale tuft density comment

blender/generate_scene.py

@@ -352,9 +352,9 @@ def load_tuft_variants():
 
 
 def tuft_density_wave(x, y):
-    # A lawn wants gentle clumping, not the hard banding a shrub bed needs:
-    # low amplitude keeps most of the polygon planted so the bare stretches
-    # read as mown patches rather than as dead ground.
+    # Low-amplitude deterministic waves leave occasional open patches while
+    # keeping most of the lawn planted, so the tufts read as uneven grass
+    # rather than a regular grid.
     return (math.sin(x * 0.21 + y * 0.17)
             + 0.55 * math.sin(x * 0.44 - y * 0.29 + 1.3))