#!/usr/bin/env python3
"""Demo: Automatic bounce detection and counting.
This demonstrates the new Phase 1.1 feature: automatic bounce event detection.
"""
import asyncio
import os
os.environ["RAPIER_SERVICE_URL"] = "https://rapier.chukai.io"
os.environ["PHYSICS_PROVIDER"] = "rapier"
from chuk_mcp_physics.server import (
create_simulation,
add_rigid_body,
record_trajectory_with_events,
destroy_simulation,
)
from chuk_mcp_physics.analysis import count_bounces, get_last_bounce_above_threshold
async def demo_bounce_detection():
"""Demonstrate automatic bounce detection."""
print("=" * 70)
print("DEMO: Automatic Bounce Detection (Phase 1.1)")
print("=" * 70)
# Create simulation
print("\n1. Creating simulation...")
sim = await create_simulation(gravity_y=-9.81, dt=0.008)
print(f" ✓ Simulation ID: {sim.sim_id}")
try:
# Add ground plane
print("\n2. Adding ground plane...")
await add_rigid_body(
sim_id=sim.sim_id,
body_id="ground",
body_type="static",
shape="plane",
normal=[0.0, 1.0, 0.0],
restitution=0.3,
friction=0.8,
)
print(" ✓ Ground plane added")
# Add bouncing ball
print("\n3. Adding ball (10cm diameter, 1kg, dropped from 10m)...")
await add_rigid_body(
sim_id=sim.sim_id,
body_id="ball",
body_type="dynamic",
shape="sphere",
size=[0.05], # 5cm radius = 10cm diameter
mass=1.0,
position=[0.0, 10.0, 0.0],
restitution=0.3, # Soft rubber
friction=0.8,
)
print(" ✓ Ball added")
# Record trajectory WITH EVENTS (new feature!)
print("\n4. Recording 5-second trajectory WITH event detection...")
steps = int(5.0 / 0.008)
# Note: Ball radius is 0.05m, so center is at 0.05m when touching ground
# Use threshold of 0.1m to catch bounces reliably
trajectory = await record_trajectory_with_events(
sim_id=sim.sim_id,
body_id="ball",
steps=steps,
detect_bounces=True,
bounce_height_threshold=0.1, # 10cm threshold (2x ball radius)
)
print(f" ✓ Recorded {trajectory.meta.num_frames} frames")
print(f" ✓ Detected {len(trajectory.bounces)} bounces!")
# Display bounce details
print("\n5. Bounce Analysis:")
print(" " + "-" * 66)
print(
f" {'Bounce':<8} {'Time (s)':<10} {'Height (m)':<12} "
f"{'Speed Before':<14} {'Speed After':<14} {'Energy Loss':<12}"
)
print(" " + "-" * 66)
for bounce in trajectory.bounces:
print(
f" #{bounce.bounce_number:<7} {bounce.time:<10.3f} "
f"{bounce.height_at_bounce:<12.4f} "
f"{bounce.speed_before:<14.3f} {bounce.speed_after:<14.3f} "
f"{bounce.energy_loss_percent:<12.1f}%"
)
# Answer the original question!
print("\n6. Answering: 'When did the ball stop bouncing above 5mm?'")
last_bounce_above_5mm = get_last_bounce_above_threshold(trajectory, height_threshold=0.005)
if last_bounce_above_5mm:
print(
f" ✓ Last bounce above 5mm: Bounce #{last_bounce_above_5mm.bounce_number} "
f"at t={last_bounce_above_5mm.time:.2f}s"
)
print(
f" Height at this bounce: {last_bounce_above_5mm.height_at_bounce * 1000:.1f}mm"
)
else:
print(" ✓ No bounces detected above 5mm threshold")
# Count bounces above different thresholds
print("\n7. Bounce Statistics:")
total_bounces = count_bounces(trajectory)
bounces_above_1cm = count_bounces(trajectory, min_height=0.01)
bounces_above_5mm = count_bounces(trajectory, min_height=0.005)
print(f" Total bounces detected: {total_bounces}")
print(f" Bounces above 1cm: {bounces_above_1cm}")
print(f" Bounces above 5mm: {bounces_above_5mm}")
# Physical insights
if len(trajectory.bounces) >= 2:
first = trajectory.bounces[0]
last = trajectory.bounces[-1]
print("\n8. Physical Analysis:")
print(
f" First bounce: {first.speed_before:.2f} m/s → {first.speed_after:.2f} m/s "
f"({first.energy_loss_percent:.1f}% energy loss)"
)
print(
f" Last bounce: {last.speed_before:.2f} m/s → {last.speed_after:.2f} m/s "
f"({last.energy_loss_percent:.1f}% energy loss)"
)
print(f" Time between bounces: {last.time - first.time:.2f}s")
print("\n" + "=" * 70)
print("✅ SUCCESS! Phase 1.1 bounce detection works perfectly!")
print("=" * 70)
# Show how this answers the user's question
print("\n💡 Original Question:")
print(' "How many bounces would a 10cm ball that weighs 1 kilo')
print(' before it would stop bouncing over 5mm?"')
print(f"\n🎯 Answer: {bounces_above_5mm} bounces above 5mm threshold")
if last_bounce_above_5mm:
print(f" Last bounce above 5mm occurred at t={last_bounce_above_5mm.time:.2f}s")
finally:
await destroy_simulation(sim.sim_id)
print("\n✓ Simulation destroyed\n")
if __name__ == "__main__":
asyncio.run(demo_bounce_detection())
