From 4da8319928ba5bc81de317043682df1c0f984d56 Mon Sep 17 00:00:00 2001
From: Thomas Kolb <cfr34k-git@tkolb.de>
Date: Wed, 23 Mar 2022 20:49:16 +0100
Subject: [PATCH] rgbw_racers: new version by Julian
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- racers now have a tail whose length depends on the racer’s speed
- speed is limited to ±2 LEDs/frame
---
 rgbw_racers.py | 47 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 8 deletions(-)
 mode change 100755 => 100644 rgbw_racers.py

diff --git a/rgbw_racers.py b/rgbw_racers.py
old mode 100755
new mode 100644
index 3923b6e..97b8a4f
--- a/rgbw_racers.py
+++ b/rgbw_racers.py
@@ -83,15 +83,16 @@ for loc in range(MAXLOC):
         s.commit()
 s.commit()
 
+
+print("{:>10} {:>8} {:>8}".format("frame", "AVG", "MAX"))
 # Hauptschleife
 f = 0  # frame counter
+clear_leds = []
 while True:
-    for r in racers:
+    for strip, led in clear_leds:
         # Clear leds
-        strip, led = loc2sl(int(r['loc']))
-        s.set_color(strip, led, 0,0,0,0)
-        strip, led = loc2sl(math.ceil(r['loc']))
         s.set_color(strip, led, 0,0,0,0)
+    clear_leds = []
         
     for r in racers:
         # Update location
@@ -107,17 +108,47 @@ while True:
         # Interpolate color linearly between two leds
         strip, led = loc2sl(int(r['loc']))
         s.add_color(strip, led, *tuple([int(c*(math.ceil(r['loc'])-r['loc'])) for c in r['color']]))
+        clear_leds.append((strip, led))
         strip, led = loc2sl(math.ceil(r['loc']))
         s.add_color(strip, led, *tuple([int(c*(r['loc']-int(r['loc']))) for c in r['color']]))
+        clear_leds.append((strip, led))
 
-        # Random speed variation
-        r['speed'] += (random.random()-0.5)*0.01
+        # Add tail of speed-depending length and logarithmicly decaying brightness
+        tail = r['speed'] * 10
+        if tail > 0:
+            tail_range = range(1, int(tail))
+        else:
+            tail_range = range(-1, int(tail), -1)
+        for i in tail_range:
+            if not 0 <= int(r['loc'])-i < MAXLOC:
+                continue
+            strip, led = loc2sl(int(r['loc'])-i)
+            color = tuple([int(c / (abs(i)*(abs(tail)/2)) ) for c in r['color'][:3]]+[0])  # blackout white
+            s.add_color(strip, led, *color)
+            clear_leds.append((strip, led))
+        # last tail segment is interpolated
+        if tail_range:
+            if not 0 <= int(r['loc'])-i < MAXLOC:
+                continue
+            last_loc = r['loc']-i
+            strip, led = loc2sl(math.ceil(last_loc))
+            s.add_color(strip, led, *tuple([int(c*(last_loc-int(last_loc))) for c in color]))
+            clear_leds.append((strip, led))
+
+        # Random speed variation, limited to [-2, 2] interval
+        r['speed'] = max(-2, min(2, r['speed'] + (random.random()-0.5)*0.01))
 
         # Use speed to define W-intensity ("whiteness")
-        r['color'][3] = min(int(abs(r['speed'])*200), 255)
+        r['color'][3] = min(int(abs(r['speed'])*128), 255)
+
+    if f % 600 == 0:
+        print("{:>10} {:>8.2f} {:>8.2f}".format(
+            f,
+            sum([abs(r['speed']) for r in racers])/len(racers),
+            max([abs(r['speed']) for r in racers])))
 
-    #print(max([abs(r['speed']) for r in racers]), min([abs(r['speed']) for r in racers]))
     s.commit()
+
     # Warte bis zum nächsten Frame
     time.sleep(interval)
     f += 1