sim-test

name	sim-test
description	Launch the Gravity Simulator with UDP server, send commands, and take screenshots for visual verification
argument-hint	["command sequence description"]

Sim Test Skill

Launch the Gravity Simulator with the UDP command server, execute commands, and capture screenshots for evaluation.

Workflow

1. Build (if needed)

cd D:/Projects/Gravity-Simulator && cmake --build build --config Debug --target Gravity-Simulator 2>&1 | tail -5

2. Launch the simulator in the background

cd D:/Projects/Gravity-Simulator/build/bin/Debug && ./Gravity-Simulator.exe --skip-launcher --windowed --udp-server 5555 2>&1

Run this as a background task. Wait ~3 seconds before sending commands.

3. Send UDP commands

Use Python to send commands to the simulator:

import socket

def cmd(c, host="127.0.0.1", port=5555, timeout=2.0):
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.settimeout(timeout)
    s.sendto(c.encode(), (host, port))
    try:
        r = s.recvfrom(4096)[0].decode()
    except socket.timeout:
        r = "TIMEOUT"
    s.close()
    return r

4. Take a screenshot

Use the existing screenshot script:

python D:/Projects/Gravity-Simulator/.claude/screenshot.py

Then read the output path with the Read tool to view the image.

5. Cleanup

Kill the simulator when done:

taskkill //F //IM Gravity-Simulator.exe

Available UDP Commands

Command	Syntax	Response
PING	PING	PONG
ADD	ADD <x> <y> <xv> <yv> <mass> [TYPE]	OK <id>
REMOVE	REMOVE <id>	OK / ERR not found
PAUSE	PAUSE	OK
UNPAUSE	UNPAUSE	OK
TOGGLE_PAUSE	TOGGLE_PAUSE	OK paused / OK running
TIMESTEP	TIMESTEP <value>	OK
RESET	RESET	OK
KEY	KEY <key_name>	OK
GET_OBJECT	GET_OBJECT <id>	<id> <x> <y> <xv> <yv> <mass> <radius> <type>
LIST	LIST	<id1> <id2> ...
COUNT	COUNT	<N>
STATE	STATE	<paused|running> <timestep> <count> <iteration>
SET	SET <key> <value>	OK
GET	GET <key>	<value>

ADD type override

Types: ROCKY, TERRESTRIAL, GASGIANT, BROWNDWARF, STAR, WHITEDWARF, NEUTRONSTAR, BLACKHOLE

Example: ADD 0 0 0 0 100 WHITEDWARF

SET/GET keys

gravity, heat, bloom, gui, autobound, fuel_burn, render_life, timestep, paused

Boolean settings use 0/1. Example: SET gravity 0, GET bloom

KEY names

P (pause), R (reset), N, O, A, D, C, G, S, Q, I, F, B, COMMA, PERIOD, F1 (toggle GUI)

Notes

• Always RESET before spawning test objects to start clean
• After RESET, IDs continue incrementing (they don't reset to 0)
• SET fuel_burn 0 prevents stars from consuming fuel during tests
• The simulator must be built and running before sending commands
• Screenshot script saves to .claude/screenshots/ with timestamps