New pywasm3 example: Hondarribia by Peter Salomonsen

platforms/python/examples/pygame-audio.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+
+import os, struct, time
+import multiprocessing as mp
+import wasm3
+import numpy
+
+os.environ['PYGAME_HIDE_SUPPORT_PROMPT'] = "true"
+
+def consumer(conn):
+    import pygame
+    pygame.mixer.pre_init(frequency=44100, size=-16, channels=2)
+    pygame.init()
+
+    channel = pygame.mixer.Channel(0)
+    while True:
+        chunk = pygame.mixer.Sound(buffer=conn.recv())
+
+        indicator = '|' if channel.get_queue() else '.'
+        print(indicator, end='', flush=True)
+        while channel.get_queue() != None:
+            time.sleep(0.01)
+
+        channel.queue(chunk)
+
+    pygame.quit()
+
+
+if __name__ == '__main__':
+    print("Hondarribia - Intro song WebAssembly Summit 2020 by Peter Salomonsen")
+    print("Source:      https://petersalomonsen.com/webassemblymusic/livecodev2/?gist=5b795090ead4f192e7f5ee5dcdd17392")
+    print("Synthesized: https://soundcloud.com/psalomo/hondarribia")
+
+    conn, child_conn = mp.Pipe()
+    p = mp.Process(target=consumer, args=(child_conn,))
+    p.start()
+
+    scriptpath = os.path.dirname(os.path.realpath(__file__))
+    wasm_fn = os.path.join(scriptpath, "./wasm/hondarribia.wasm")
+
+    # Prepare Wasm3 engine
+
+    env = wasm3.Environment()
+    rt = env.new_runtime(1024)
+    with open(wasm_fn, "rb") as f:
+        mod = env.parse_module(f.read())
+        rt.load(mod)
+
+    buff = b''
+    buff_sz = 256
+    print("Pre-buffering...")
+
+    def fd_write(fd, wasi_iovs, iows_len, nwritten):
+        global buff, buff_sz
+        mem = rt.get_memory(0)
+
+        # decode
+        (off, size) = struct.unpack("<II", mem[wasi_iovs:wasi_iovs+8])
+        arr = numpy.frombuffer(mem[off:off+size], dtype=numpy.float32) * 32768
+        buff += arr.astype(numpy.int16).tobytes()
+
+        # buffer
+        if len(buff) > buff_sz*1024:
+            conn.send(buff)
+            buff = b''
+            buff_sz = 64
+
+        return size
+
+    mod.link_function("wasi_unstable", "fd_write", "i(i*i*)", fd_write)
+
+    wasm_start = rt.find_function("_start")
+    wasm_start()
+
+    p.join()