Measure moving average of update rate

Okay, the threshoding is _kind_ of effective, and the version Glen
liked was actually doing it. In light of that, I've quantified the
update frequency a bit better.

interactions.py

@@ -75,6 +75,7 @@ fullsat = 254
 # --- control methods and diagnostics
 
 updates = 0
+new_updates = 0
 
 def set_light_hsv(e, color, hit_bridge):
   command = {
@@ -85,14 +86,15 @@ def set_light_hsv(e, color, hit_bridge):
   if hit_bridge:
     if b != None:
       b.set_light(edges[e].light_id, command)
-    global updates
-    updates += 1
+    global new_updates
+    new_updates += 1
   rgb_color = tuple(255*c for c in colorsys.hsv_to_rgb(*color))
   pygame.draw.aaline(screen, rgb_color, vertices[vertex_adj[e][0]], vertices[vertex_adj[e][1]])
 
 # === interaction parameters ===
 
 frame_rate = 24
+ema_weight = 2/(frame_rate+1)
 
 inductance = 0.001
 
@@ -144,9 +146,12 @@ def set_wave_light(e, i):
 
 def show_data(screen):
   # light updates
+  global updates, new_updates
+  updates = ema_weight*new_updates + (1 - ema_weight)*updates
+  new_updates = 0
   text = font.render('updates', True, (255, 255, 255))
   screen.blit(text, (20, viewsize))
-  text = font.render(str(updates), True, (255, 255, 255))
+  text = font.render(str(updates / (1 - 0.9)), True, (255, 255, 255))
   screen.blit(text, (120, viewsize))
   
   # energy