C# style guide

Having well-defined and consistent coding conventions is important for every project, and Godot is no exception to this rule.

This page contains a coding style guide, which is followed by developers of and contributors to Godot itself. As such, it is mainly intended for those who want to contribute to the project, but since the conventions and guidelines mentioned in this article are those most widely adopted by the users of the language, we encourage you to do the same, especially if you do not have such a guide yet.

INFO

This article is by no means an exhaustive guide on how to follow the standard coding conventions or best practices. If you feel unsure of an aspect which is not covered here, please refer to more comprehensive documentation, such as C# Coding Conventions or Framework Design Guidelines.

Language specification

Godot currently uses C# version 10.0 in its engine and example source code, as this is the version supported by .NET 6.0 (the current baseline requirement). So, before we move to a newer version, care must be taken to avoid mixing language features only available in C# 11.0 or later.

For detailed information on C# features in different versions, please see What's New in C#.

Formatting

General guidelines

• Use line feed (LF) characters to break lines, not CRLF or CR.

• Use one line feed character at the end of each file, except for csproj files.

• Use UTF-8 encoding without a byte order mark.

• Use 4 spaces instead of tabs for indentation (which is referred to as "soft tabs").

• Consider breaking a line into several if it's longer than 100 characters.

Line breaks and blank lines

For a general indentation rule, follow the "Allman Style" which recommends placing the brace associated with a control statement on the next line, indented to the same level:

// Use this style:
if (x > 0)
{
    DoSomething();
}

// NOT this:
if (x > 0) {
    DoSomething();
}

However, you may choose to omit line breaks inside brackets:

• For simple property accessors.

• For simple object, array, or collection initializers.

• For abstract auto property, indexer, or event declarations.

// You may put the brackets in a single line in following cases:
public interface MyInterface
{
    int MyProperty { get; set; }
}

public class MyClass : ParentClass
{
    public int Value
    {
        get { return 0; }
        set
        {
            ArrayValue = new [] {value};
        }
    }
}

Insert a blank line:

• After a list of using statements.

• Between method, properties, and inner type declarations.

• At the end of each file.

Field and constant declarations can be grouped together according to relevance. In that case, consider inserting a blank line between the groups for easier reading.

Avoid inserting a blank line:

• After {, the opening brace.

• Before }, the closing brace.

• After a comment block or a single-line comment.

• Adjacent to another blank line.

using System;
using Godot;
                                          // Blank line after `using` list.
public class MyClass
{                                         // No blank line after `{`.
    public enum MyEnum
    {
        Value,
        AnotherValue                      // No blank line before `}`.
    }
                                          // Blank line around inner types.
    public const int SomeConstant = 1;
    public const int AnotherConstant = 2;

    private Vector3 _x;                  // Related constants or fields can be
    private Vector3 _y;                  // grouped together.

    private float _width;
    private float _height;

    public int MyProperty { get; set; }
                                          // Blank line around properties.
    public void MyMethod()
    {
        // Some comment.
        AnotherMethod();                  // No blank line after a comment.
    }
                                          // Blank line around methods.
    public void AnotherMethod()
    {
    }
}

Using spaces

Insert a space:

• Around a binary and ternary operator.

• Between an opening parenthesis and if, for, foreach, catch, while, lock or using keywords.

• Before and within a single line accessor block.

• Between accessors in a single line accessor block.

• After a comma which is not at the end of a line.

• After a semicolon in a for statement.

• After a colon in a single line case statement.

• Around a colon in a type declaration.

• Around a lambda arrow.

• After a single-line comment symbol (//), and before it if used at the end of a line.

• After the opening brace, and before the closing brace in a single line initializer.

Do not use a space:

• After type cast parentheses.

The following example shows a proper use of spaces, according to some of the above mentioned conventions:

public class MyClass<A, B> : Parent<A, B>
{
    public float MyProperty { get; set; }

    public float AnotherProperty
    {
        get { return MyProperty; }
    }

    public void MyMethod()
    {
        int[] values = { 1, 2, 3, 4 };
        int sum = 0;

        // Single line comment.
        for (int i = 0; i < values.Length; i++)
        {
            switch (i)
            {
                case 3: return;
                default:
                    sum += i > 2 ? 0 : 1;
                    break;
            }
        }

        i += (int)MyProperty; // No space after a type cast.
    }
}

Naming conventions

Use PascalCase for all namespaces, type names and member level identifiers (i.e. methods, properties, constants, events), except for private fields:

namespace ExampleProject
{
    public class PlayerCharacter
    {
        public const float DefaultSpeed = 10f;

        public float CurrentSpeed { get; set; }

        protected int HitPoints;

        private void CalculateWeaponDamage()
        {
        }
    }
}

Use camelCase for all other identifiers (i.e. local variables, method arguments), and use an underscore (_) as a prefix for private fields (but not for methods or properties, as explained above):

private Vector3 _aimingAt; // Use a `_` prefix for private fields.

private void Attack(float attackStrength)
{
    Enemy targetFound = FindTarget(_aimingAt);

    targetFound?.Hit(attackStrength);
}

There's an exception with acronyms which consist of two letters, like UI, which should be written in uppercase letters where PascalCase would be expected, and in lowercase letters otherwise.

Note that id is not an acronym, so it should be treated as a normal identifier:

public string Id { get; }

public UIManager UI
{
    get { return uiManager; }
}

It is generally discouraged to use a type name as a prefix of an identifier, like string strText or float fPower, for example. An exception is made, however, for interfaces, which should, in fact, have an uppercase letter I prefixed to their names, like IInventoryHolder or IDamageable.

Lastly, consider choosing descriptive names and do not try to shorten them too much if it affects readability.

For instance, if you want to write code to find a nearby enemy and hit it with a weapon, prefer:

FindNearbyEnemy()?.Damage(weaponDamage);

Rather than:

FindNode()?.Change(wpnDmg);

Member variables

Don't declare member variables if they are only used locally in a method, as it makes the code more difficult to follow. Instead, declare them as local variables in the method's body.

Local variables

Declare local variables as close as possible to their first use. This makes it easier to follow the code, without having to scroll too much to find where the variable was declared.

Implicitly typed local variables

Consider using implicitly typing (var) for declaration of a local variable, but do so only when the type is evident from the right side of the assignment:

// You can use `var` for these cases:

var direction = new Vector2(1, 0);

var value = (int)speed;

var text = "Some value";

for (var i = 0; i < 10; i++)
{
}

// But not for these:

var value = GetValue();

var velocity = direction * 1.5;

// It's generally a better idea to use explicit typing for numeric values, especially with
// the existence of the `real_t` alias in Godot, which can either be double or float
// depending on the build configuration.

var value = 1.5;

Other considerations

• Use explicit access modifiers.
• Use properties instead of non-private fields.
• Use modifiers in this order: public/protected/private/internal/virtual/override/abstract/new/static/readonly.
• Avoid using fully-qualified names or this. prefix for members when it's not necessary.
• Remove unused using statements and unnecessary parentheses.
• Consider omitting the default initial value for a type.
• Consider using null-conditional operators or type initializers to make the code more compact.
• Use safe cast when there is a possibility of the value being a different type, and use direct cast otherwise.