viz: increase FPS to 30, drain UDP aggressively

- Poll timeout capped at 10ms for responsiveness
- Drain all pending UDP data before parsing
- Auto-reconnect router on error
- FPS 15 -> 30

scripts/led-matrix-viz.py

@@ -1,18 +1,19 @@
 #!/usr/bin/env python3
 """Listen for MIDI events via UDP and display note activity on LED matrix.
 
-Uses select() for polling both UDP and router RPC responses.
+Non-blocking I/O with immediate MIDI processing and fast frame rendering.
 """
-import socket, msgpack, time, os, select
+import socket, msgpack, time, os, select, collections
 
 VIZ_PORT = int(os.environ.get("VIZ_PORT", "8082"))
 ROUTER_SOCK = os.environ.get("ROUTER_SOCK", "/var/run/arduino-router.sock")
 DECAY_FRAMES = int(os.environ.get("DECAY_FRAMES", "8"))
-FPS = 15
+FPS = 30
 
 COLS = 13
 ROWS = 8
 
+
 def pack_frame(pixels):
     bits = 0
     for row in range(ROWS):
@@ -22,15 +23,24 @@ def pack_frame(pixels):
     return (bits & 0xFFFFFFFF, (bits >> 32) & 0xFFFFFFFF,
             (bits >> 64) & 0xFFFFFFFF, (bits >> 96) & 0xFFFFFFFF)
 
+
+def connect_router():
+    router = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    router.setblocking(False)
+    try:
+        router.connect(ROUTER_SOCK)
+    except OSError:
+        pass
+    return router
+
+
 def main():
     sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
     sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     sock.bind(("0.0.0.0", VIZ_PORT))
     sock.setblocking(False)
 
-    router = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
-    router.setblocking(False)
-    router.connect(ROUTER_SOCK)
+    router = connect_router()
     packer = msgpack.Packer()
 
     active_notes = {}
@@ -40,23 +50,33 @@ def main():
     frame_interval = 1.0 / FPS
     next_frame = time.monotonic()
     router_buf = b""
+    frames_sent = 0
+    frames_dropped = 0
 
     poller = select.poll()
     poller.register(sock, select.POLLIN)
-    poller.register(router, select.POLLIN)
 
     while True:
+        # Always poll UDP with short timeout
         timeout = max(0, int((next_frame - time.monotonic()) * 1000))
+        timeout = min(timeout, 10)  # cap at 10ms for responsiveness
+
         try:
             events = poller.poll(timeout)
         except OSError:
             events = []
 
+        # Process all pending UDP data immediately
         for fd, flags in events:
             if fd == sock.fileno() and flags & select.POLLIN:
                 try:
+                    while True:
                         data, _ = sock.recvfrom(1024)
                         buf += data
+                except BlockingIOError:
+                    pass
+
+                # Parse all complete messages
                 while b";" in buf:
                     msg, buf = buf.split(b";", 1)
                     msg = msg.decode().strip()
@@ -70,22 +90,25 @@ def main():
                             active_notes[note] = DECAY_FRAMES
                         elif msg_type == 0x80 or (msg_type == 0x90 and vel == 0):
                             active_notes.pop(note, None)
-                except BlockingIOError:
-                    pass
 
-            if fd == router.fileno() and flags & select.POLLIN:
+        # Also drain any pending router responses
+        if router.fileno() >= 0:
             try:
+                while True:
                     router_buf += router.recv(4096)
             except BlockingIOError:
                 pass
 
-        if time.monotonic() >= next_frame:
-            next_frame = time.monotonic() + frame_interval
+        # Render frame when it's time
+        now = time.monotonic()
+        if now >= next_frame:
+            next_frame = now + frame_interval
 
             pixels = [[0] * COLS for _ in range(ROWS)]
-            for note, decay in list(active_notes.items()):
+            expired = []
+            for note, decay in active_notes.items():
                 if decay <= 0:
-                    del active_notes[note]
+                    expired.append(note)
                     continue
                 active_notes[note] = decay - 1
                 note_min, note_max = 36, 96
@@ -94,6 +117,9 @@ def main():
                 col = note % 12
                 pixels[row][col] = 1
 
+            for note in expired:
+                del active_notes[note]
+
             frame = pack_frame(pixels)
             if frame != last_frame:
                 msg_id = (msg_id + 1) % 65535
@@ -101,9 +127,17 @@ def main():
                 req = packer.pack([0, msg_id, "draw_frame", params])
                 try:
                     router.sendall(req)
-                except BlockingIOError:
+                    frames_sent += 1
+                except (BlockingIOError, OSError):
+                    frames_dropped += 1
+                    # Reconnect on error
+                    try:
+                        router.close()
+                    except OSError:
                         pass
+                    router = connect_router()
                 last_frame = frame
 
+
 if __name__ == "__main__":
     main()