print(f"Creating Spout sender 'PythonSender' at {WIDTH}x{HEIGHT} @ {FPS} fps")

print("Press Ctrl+C to stop.\n")

# Vectorised gradient bases — computed once, reused every frame.

xs = np.arange(WIDTH, dtype=np.uint16)

ys = np.arange(HEIGHT, dtype=np.uint16)[:, None]

rgba = np.empty((HEIGHT, WIDTH, 4), dtype=np.uint8)

rgba[..., 3] = 255 # alpha opaque

with SpoutSender("PythonSender") as sender:

frame = 0

interval = 1.0 / FPS

t_start = time.perf_counter()

while True:

t0 = time.perf_counter()

t = frame / FPS

r_off = int((np.sin(t) * 0.5 + 0.5) * 255)

g_off = int((np.sin(t * 1.3) * 0.5 + 0.5) * 255)

b_off = int((np.cos(t * 0.7) * 0.5 + 0.5) * 255)

rgba[..., 0] = (xs + r_off) & 0xFF # R

rgba[..., 1] = (ys + g_off) & 0xFF # G

rgba[..., 2] = ((xs ^ ys) + b_off) & 0xFF # B

ok = sender.send_image(rgba.tobytes(), WIDTH, HEIGHT, GL_RGBA)

if frame % FPS == 0:

status = "OK" if ok else "FAILED"

print(

f"Frame {frame:6d} send={status} "

f"fps={sender.fps:5.1f} "

f"wall={(time.perf_counter() - t_start):6.2f}s "

f"initialized={sender.is_initialized}"

)

frame += 1

elapsed = time.perf_counter() - t0

sleep = max(0.0, interval - elapsed)