Intoduction

Program by Michael Fragano

This is a 3D N-Body simulator based off of the 2D N-body simulator I made with Seth Norman, and the 3D renderer I made.

Installation instructions for 3DGravity Simulator

Here are instructions for installing and running the 3D Gravity simulator on Windows using WSL.

These instructions assume that WSL and OCaml were installed using the instructions provided in the CS3110 textbook. These can be found at

https://cs3110.github.io/textbook/chapters/preface/install.html

Along with the above installation, we will need to install some extra libraries and applications to run graphics through WSL.

Install X-server (VcXsrv)

In Windows, you will need to install an X-server for WSL to communicate with and show graphics through, as there is not a native way to show graphics through WSL alone.

We will use VcXsrv as our X-server. Visit

https://sourceforge.net/projects/vcxsrv/

and click the green "Download" button. After a couple seconds, the installer for VcXsrv should begin to download.

Open the installer. Windows should ask if the installer can make changes to your device. Say yes, and then proceed through the default installation of VcXsrv. (It should just be selecting "Next" and then "Install").

After VcXsrv has been installed, you should see a new desktop icon called XLaunch.

Run X-server (XLaunch)

When you want to run the X-server (you have to have the server running before you open WSL), open XLaunch.

The first screen should have "Multiple windows" selected, and "Display number" set to -1. Select "Next".

The next screen should have "Start no client" selected. Select "Next".

On the third screen, make sure all checkboxes are checked, and select "Next".

From the final screen, you can save the configuration we just made, and run it instead of repeating this process, but from this screen, press "Finish" to start the X-server.

You should see an X-server icon appear in the System Tray (lower left on the default Windows taskbar). To stop the X-server, right click the icon, and select "Exit...". After exiting, you would need to repeat these steps or run the saved configuration to re-run the X-server.

Connecting WSL to X-server

Whenever you open a new WSL terminal (the X-server must be running), you will need to set the DISPLAY variable in WSL to use the X-server.

Run the following command to set the DISPLAY variable in WSL

export DISPLAY=$(echo $(grep nameserver /etc/resolv.conf | sed 's/nameserver //'):0.0)

Package Installation in WSL

The main package needed to be installed is the OCaml graphics library.

Step 1: install pkg-config

sudo apt-get update -y

sudo apt-get install -y pkg-config

Run the above commands in WSL to install pkg-config.

Step 2: install graphics library

You can install the library in an opam switch of your choice, as long as the switch is setup as instructed in the CS3110 Ocaml installation instructions mentioned previously.

opam update

opam upgrade

opam install graphics

Run the above commands in WSL to install the graphics library.

SETTING UP OUR CODE

Our submission will be a zip file you can bring into WSL and unzip into a folder of your choice. There are a number of subfolders, notably a data folder, which has a number of preset systems to show off the functionality of our project.

In the root folder there is a makefile, which lists a number of make commands you can use to build, test, and run our program. The individual commands are documented in the make file, but some important ones are:

make build: builds and compiles the program

make run: executes the main program (run make build first)

RUNNING OUR CODE

After running make run, the program will prompt you to enter a preset name. the json files found in the data subfolder (except system_schema.json) are the choices for presets, so the full list can be found there, as well as here

binary

triple

comet

moon

When you run a preset system, a window will pop up with the system running. To close the system, simply use the X at the top of the window. The prompt will again ask you to run a preset, so you can run another if you choose to, or you can exit the program by typing Q.

Once the simulation is running the following buttons have these effects:

Click: play/pause the simulation <: Slow down the simulation >: Speed up the simulation w: Move in the +y direction s: Move in the -y direction d: Move in the +x direction a: Move in the -x direction Space Bar: Move in the +z direction z: Move in the -z direction

i : rotate in the +x direction k : rotate in the -x direction j : rotate in the +z direction l : rotate in the -z direction o : rotate in the +y direction u : rotate in the -y direction

1 : zoom in 2 : zoom out

q: Quit the simulation