add dora-joy node publishing gamepad axes and buttons

dora_joy/probe.py

@@ -0,0 +1,85 @@
+"""Show what the pad is doing, with no dataflow and nothing attached to it.
+
+`dora-joy-probe` opens the gamepad and prints, live: every axis SDL reports and
+every button it sees pressed, by index.
+
+It exists because a consumer's axis and button indices are almost always SDL's
+documented layout rather than an observed one, and a pad that numbers its
+controls differently is otherwise discovered by watching a real machine move the
+wrong way. Push one control at a time and read off the index it moves.
+
+This shows the reading and nothing else — it has no idea what any index is *for*,
+which is the same thing that makes this node reusable.
+
+Nothing here can move anything. There is no dora node and no connection to
+anything; this only reads.
+"""
+
+import argparse
+import time
+
+from dora_joy.config import Config
+from dora_joy.gamepad import Gamepad
+
+CLEAR = "\033[H\033[J"
+
+
+def bar(value: float, width: int = 21) -> str:
+    """Draw a centred bar for a value between -1 and 1.
+
+    Seeing the bar sit off-centre with the stick released is how a worn pad
+    announces itself, which is most of the point of looking at raw numbers.
+    """
+    middle = width // 2
+    position = middle + round(max(-1.0, min(1.0, value)) * middle)
+    cells = ["-"] * width
+    cells[middle] = "|"
+    cells[position] = "#"
+    return "".join(cells)
+
+
+def render(sample, config: Config) -> str:
+    """Build the whole display for one reading."""
+    lines = ["dora-joy probe — Ctrl-C to stop", ""]
+
+    if not sample.present:
+        lines += [
+            "  no gamepad found.",
+            "",
+            f"  looking for joystick index {config.joystick_index};",
+            "  plug one in and this will pick it up.",
+        ]
+        return "\n".join(lines)
+
+    lines.append(f"  axes ({len(sample.axes)} reported)")
+    for index, value in enumerate(sample.axes):
+        lines.append(f"    {index}  {value:+.3f}  {bar(value)}")
+
+    held = [str(index) for index, down in enumerate(sample.buttons) if down]
+    lines += ["", f"  buttons ({len(sample.buttons)} reported)", f"    {', '.join(held) or 'none pressed'}"]
+    lines += ["", "  push one control at a time and note the index it moves."]
+    return "\n".join(lines)
+
+
+def main() -> None:
+    """Open the pad and print what it is doing until interrupted."""
+    parser = argparse.ArgumentParser(description="Show what the gamepad is doing. Moves nothing.")
+    parser.add_argument("--hz", type=float, default=10.0, help="Redraw rate. Defaults to 10.")
+    args = parser.parse_args()
+
+    config = Config.from_env()
+    gamepad = Gamepad(config.joystick_index)
+    gamepad.start()
+
+    try:
+        while True:
+            print(CLEAR + render(gamepad.read(), config), flush=True)
+            time.sleep(1.0 / args.hz)
+    except KeyboardInterrupt:
+        print()
+    finally:
+        gamepad.shutdown()
+
+
+if __name__ == "__main__":
+    main()