#!/usr/bin/env python3
"""Demo script for Phase 1.2: Contact Events from Rapier.
This demonstrates that contact events from the Rapier physics engine
are being correctly tracked and reported alongside bounce detection.
"""
# IMPORTANT: Set environment variable BEFORE any imports
import os
if "RAPIER_SERVICE_URL" not in os.environ:
os.environ["RAPIER_SERVICE_URL"] = "https://rapier.chukai.io"
import asyncio
from chuk_mcp_physics.providers.rapier import RapierProvider
from chuk_mcp_physics.models import (
SimulationConfig,
RigidBodyDefinition,
BodyType,
ShapeType,
)
async def main():
print("🦀 Phase 1.2 Demo: Contact Events from Rapier\n")
print("=" * 60)
# Get the configured service URL
service_url = os.environ.get("RAPIER_SERVICE_URL", "https://rapier.chukai.io")
print(f"Using Rapier service: {service_url}\n")
provider = RapierProvider()
# Create simulation
print("1️⃣ Creating simulation...")
sim = await provider.create_simulation(
SimulationConfig(
gravity=[0.0, -9.81, 0.0],
dimensions=3,
dt=0.016,
)
)
print(f" ✓ Simulation created: {sim.sim_id}\n")
# Add ground plane
print("2️⃣ Adding ground plane...")
await provider.add_body(
sim.sim_id,
RigidBodyDefinition(
id="ground",
kind=BodyType.STATIC,
shape=ShapeType.PLANE,
normal=[0.0, 1.0, 0.0],
offset=0.0,
friction=0.5,
restitution=0.3, # 30% energy retention per bounce
),
)
print(" ✓ Ground plane added\n")
# Add bouncing ball
print("3️⃣ Adding bouncing ball...")
ball_radius = 0.05 # 5cm radius (10cm diameter)
await provider.add_body(
sim.sim_id,
RigidBodyDefinition(
id="ball",
kind=BodyType.DYNAMIC,
shape=ShapeType.SPHERE,
size=[ball_radius],
mass=1.0, # 1kg
position=[0.0, 10.0, 0.0], # Drop from 10m
velocity=[0.0, 0.0, 0.0],
friction=0.5,
restitution=0.3, # Match ground restitution
),
)
print(" ✓ Ball added (1kg, 10cm diameter)\n")
# Record trajectory with contact events
print("4️⃣ Recording trajectory (10 seconds, 625 frames)...")
steps = 625 # 10 seconds at 0.016s per step
trajectory = await provider.record_trajectory(
sim_id=sim.sim_id,
body_id="ball",
steps=steps,
)
print(f" ✓ Recorded {len(trajectory.frames)} frames\n")
# Analyze contact events
print("5️⃣ Analyzing contact events from Rapier...\n")
print("=" * 60)
if not trajectory.contact_events:
print("⚠️ No contact events detected!")
print(" This might mean:")
print(" - Rapier service doesn't have Phase 1.2 code")
print(" - Contact detection isn't working")
print(" - Ball hasn't hit ground yet")
else:
print(f"✅ Detected {len(trajectory.contact_events)} contact events!\n")
# Group events by type
started_events = [e for e in trajectory.contact_events if e.event_type == "started"]
ended_events = [e for e in trajectory.contact_events if e.event_type == "ended"]
ongoing_events = [e for e in trajectory.contact_events if e.event_type == "ongoing"]
print(f" Contact starts: {len(started_events)}")
print(f" Contact ends: {len(ended_events)}")
print(f" Ongoing: {len(ongoing_events)}\n")
# Show first 10 contact events
print("First contact events:")
print("-" * 60)
for i, event in enumerate(trajectory.contact_events[:10]):
print(f"{i + 1}. t={event.time:.3f}s - {event.event_type.upper()}")
print(f" Bodies: {event.body_a} ↔ {event.body_b}")
print(
f" Contact point: [{event.contact_point[0]:.3f}, {event.contact_point[1]:.3f}, {event.contact_point[2]:.3f}]"
)
print(
f" Normal: [{event.normal[0]:.3f}, {event.normal[1]:.3f}, {event.normal[2]:.3f}]"
)
print(f" Impulse magnitude: {event.impulse_magnitude:.3f}")
print(
f" Relative velocity: [{event.relative_velocity[0]:.3f}, {event.relative_velocity[1]:.3f}, {event.relative_velocity[2]:.3f}]"
)
print()
if len(trajectory.contact_events) > 10:
print(f"... and {len(trajectory.contact_events) - 10} more events\n")
# Analyze bounces from contact starts
print("=" * 60)
print("6️⃣ Bounce analysis from contact events:\n")
bounce_count = 0
for event in started_events:
if abs(event.impulse_magnitude) > 0.1: # Filter noise
bounce_count += 1
height = event.contact_point[1]
print(f"Bounce #{bounce_count} at t={event.time:.3f}s")
print(f" Height: {height:.4f}m")
print(f" Impulse: {event.impulse_magnitude:.3f}")
print(f" Rel. velocity: {event.relative_velocity[1]:.3f} m/s")
print()
# Cleanup
print("=" * 60)
print("7️⃣ Cleaning up...")
await provider.destroy_simulation(sim.sim_id)
print(" ✓ Simulation destroyed\n")
print("=" * 60)
print("✨ Phase 1.2 Demo Complete!\n")
print("Contact events are being tracked from Rapier physics engine.")
print("This provides ground-truth collision data for validation.")
if __name__ == "__main__":
asyncio.run(main())
