Programming Weapon Sway

Weapon sway in games can easily be taken for granted by players. However, when it's not implemented the game looks plain and undone with a stationary weapon in the first person view. So that begs the question, how do first person shooters implement that cool weapon sway?! The truth is it's quite simple and this post will provide a brief code snippet on how to do it. Keep in mind that there are 1000 ways to skin a cat and the technique I'm presenting is one of those ways..but it is fairly popular.

Let's talk about Lissajous curves. There are plenty of websites that go into great detail about all the history, equations, and cool stuff you can do with Lissajous curves. I'll explain it simply and in terms of weapon sway. Think in your mind of your favorite FPS. As you walk the weapon typically sways horizontally and vertically in nice harmonic pattern. This complex motion in the x and y dimension is a Lissajous pattern.

Now, to program sway via Lissajous curves you can simply combine sin and/or cosine waves. There are different forms of the equations that use sin and/or cosine waves but for our example we will use 2 sin waves. Basically the goal is to oscillate vertically and horizontally harmoniously. From there you can customize your waves to get the effect you want.

This code will get you that traditional figure eight sway (this is a Unity C# snippet). Enjoy!

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

public class SimpleWeaponSway : MonoBehaviour 

{

    [SerializeField]

    Transform weapon;

    [Range(0, 1f)]

    [SerializeField]

    float verticalSwayAmount = 0.5f;

    [Range(0, 1f)]

    [SerializeField]

    float horiztonalSwayAmount = 1f;

    [Range(0, 15f)]

    [SerializeField]

    float swaySpeed = 4f;

    // Update is called once per frame

    void Update () 

    {

        float x = 0, y = 0;

        y += verticalSwayAmount * Mathf.Sin((swaySpeed * 2) * Time.time);

        x += horiztonalSwayAmount * Mathf.Sin(swaySpeed * Time.time);        

        weapon.position = new Vector3(x, y, weapon.position.z);

    }

}

WebAPI Using Entity Framework Core and Postgres in Visual Studio Code

It seems like Visual Studio Code is really starting to get some traction so I finally decided to bite the bullet and see what all the buzz is about. I set out a goal of putting together a webapi that would incorperate Entity Framework Core and Postgres. This seemed like this was a good route because there was some confusing/lacking information I came across when trying to put this project together. So hopefully in this blog post I can give you folks a nice, clean, and easy to understand guide to putting this stuff together.

I do recommend that the audience for this has some knowledge Entity Framework, database drivers, etc. I'm not going into great detail in this post about that stuff - it's more for just project setup. Regardless this will get you generating a code first databases! Enjoy.

Here goes...


My Environment
I've ran through this process on a Windows 7 desktop and a Mac bootcamping Windows 10

Software requirements

.Net Core SDK 1.1.1

Download the .exe download and use the default install options

https://www.microsoft.com/net/download/core

Visual Studio Code 1.10.2 

Downloaded the installer for windows and used all the default install options.

https://code.visualstudio.com/Download

Visual Studio Code Extensions

Navigate to the extension tab in VSCode, or use the shortcut  Ctrl+Shift+X, and install:  C#, C# Extensions, C# XML Documentation Comments, and Code Runner

PostgreSql 9.6.2

Download and run the installer, default settings are fine, you will be prompted to enter your superuser password.

Creating the Project

First create a folder in a spot on your machine where you want your project to live. I'm going to put mine on my desktop.

Example Path: C:\Users\Adam\Desktop\MyProject

Open Windows PowerShell and navigate to the folder you created

Execute the command: dotnet new

Then execute the command: dotnet new webapi

Finally execute:  code .

This will open your project in VSCode

Adding NuGet Packages

Open your terminal (Ctrl+`)

Execute the following commands

dotnet add package Microsoft.EntityFrameworkCore

dotnet add package Microsoft.EntityFrameworkCore.Design

dotnet add package NpgSql.EntityFrameworkCore.PostgreSQL

dotnet add package NpgSql.EntityFrameworkCore.PostgreSQL.Design

dotnet add package Microsoft.EntityFrameworkCore.Tools.DotNet

You will need to add the <ItemGroup> for tools and add the reference to the Entity Framework Tools to your csproj file. The file should reflect the image above

Create Your Database

Open PgAdmin 4

In the Create-Server Dialog enter a server name in the General tab, I chose "MyProject". In the Connection tab you can enter localhost for the hostname and type a password of your choice. For this example my password will be password. You can leave the other fields as their default values.

Create DbContext and Model

In VSCode create a file  called dbContext.cs. File contents:

using Microsoft.EntityFrameworkCore;

using MyProject.Models;

namespace MyProject

{

    public class MyProjectDbContext : DbContext

    {

        public DbSet<Person> People { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

        {

            optionsBuilder.UseNpgsql("Host=localhost;Port=5432;Username=postgres;Password=password;Database=MyProject;");

        }

    }

}

In VSCode create a Models Folder in the root of your project. Inside of the Models folder create a Person.cs. File contents:

namespace MyProject.Models

{

    public class Person

    {

        public int PersonId { get; set; }

        public string Name { get; set; }

    }

}

Adding Migration and Updating Database

It's finally time to add your migration and update your database. We are going to call our migration "initial" but you can call it whatever you like.

In the VSCode terminal execute the command: dotnet ef migrations add initial

This should have generated some files under a new folder in your project called Migrations

Lastly to update the database execute the command: dotnet ef database update

Your database should now be updated in PgAdmin. You may have to refresh the database to see the changes.

That's it, thank you very much for reading. Please comment if you run into any issues I might be able to help with!