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本文皆在教您如何对 DDNet 开发 ，因为这是一款开源游戏（源代码公开），它依赖于一些善良的人们在空余时间的贡献。

开发环境

截至目前，基于以下原因，我们强烈推荐使用Linux系统进行DDNet开发：

• 大多数DDNet贡献者使用Linux，使用Linux与之前的开发者交流起来更加方便。
• 软件包管理更简单，您可以轻松地安装所有需要的库。
• 本文专注于Linux，还没有涉及Windows。

首先，DDNet由 C++ 语言编写，开发者需要对它相当熟悉，但您也可以在只有基础知识的情况下慢慢学习深入。

学习C++的一些有用资源：

• learncpp.com
• cppreference.com
• 百度。

DDNet的源代码使用Git托管，这是一个版本控制系统，也是与多个开发人员协作的重要工具。

如果您的Linux发行版中还没有git，请安装它，例如在大多数基于debian/ubuntu的发行版中，你可以打开终端，输入：sudo-apt-install git。

获取源代码

源代码位于Github，您可以在不需要帐户的情况下通过Clone获得源代码，但如果您想将更改放入官方源代码，则需要一个账号。

如果您不熟悉git/github，可以在这里学习基本知识： Hello World - Github

下载依赖项

如果您在Linux上，您可以通过阅读DDNet github页面上的自述文件来安装所有需要的依赖项：https://github.com/ddnet/ddnet#dependencies-在linux上--macos

对于Arch Linux：

控制台输入 sudo pacman -S --needed base-devel cmake curl freetype2 git glew gmock libnotify opusfile python sdl2 sqlite wavpack

For Debian:

sudo apt install build-essential cargo cmake git glslang-tools google-mock libavcodec-extra libavdevice-dev libavfilter-dev libavformat-dev libavutil-dev libcurl4-openssl-dev libfreetype6-dev libglew-dev libnotify-dev libogg-dev libopus-dev libopusfile-dev libpng-dev libsdl2-dev libsqlite3-dev libssl-dev libvulkan-dev libwavpack-dev libx264-dev python rustc spirv-tools4

编译DDNet

我们使用CMake来控制编译进程，如果你所有的依赖项都下载了，那么它会很简单，只要输入这些命令（确保你在DDNet文件夹下）：

mkdir build
cd build
cmake ..
make -j$(nproc)

通用信息

以下是一些通用信息：

• 目前，源代码是使用C++17标准编译的，但您会看到代码的许多部分更像C，因为只有大多数新代码使用C++17。
• std::string很少使用，字符数组加system.h方法才是常态。
• 大多数输入输出代码、格式化和Print都是使用system.h提供的方法完成的。

源代码布局

现在你可以构建DDNet了，可以开始编辑它了。

src/base 目录

由于DDNet是一个跨平台游戏，需要一个抽象层来简化开发，因此该目录包含许多有用的函数来处理这一问题。

src/engine 目录

游戏引擎就在这里，它处理大多数与游戏无关的东西，比如图形、声音、网络等。

src/game 目录

所有玩游戏的代码都在这里，分为客户端和服务器。

服务器端

这个游戏使用自己的实体组件系统，所有其他实体派生到的主类是CEntity，位于src/game/server/Entity.h中。

这些实体由位于此处的游戏世界管理src/game/server/gameworld.h

一些重要实体有：

CCharacter: 代表着一个tee 是活着的, 当一个tee产生时它被实例化，当它死亡时它被删除。有关玩家在死亡之间的信息，请参阅CPlayer.

客户端

The client side is made up of components, these are classes that inherit CComponent: These components can implement the virtual methods such as OnInit, OnMessage, etc. to provide their functionality.

Networking

The network protocol is mostly generated by python scripts that output C++ code, for example, datasrc/network.py defines all network packets.

Code conventions

The ongoing discussion on code conventions is located here: ddnet#2945

Currently, the following applies:

Indentation style

Allman style is used.

This style puts the brace associated with a control statement on the next line, indented to the same level as the control statement. Statements within the braces are indented to the next level.

while(x == y)
{
    Something();
    SomethingElse();
}
</div>

<div lang="en" dir="ltr" class="mw-content-ltr">
FinalThing();

Classes and Structs

Must be prefixed by C (for legacy reasons this is ignored for structs in some places, such as in graphics code) or I for interfaces. New structs should be prefixed by S.

Example:

class CCharacter : public CEntity
{
    // ...
}

Enums and constants

Should be screaming snake case, for example: MAX_PLAYERS

enum
{
	FAKETUNE_FREEZE = 1,
	FAKETUNE_SOLO = 2,
	FAKETUNE_NOJUMP = 4,
	FAKETUNE_NOCOLL = 8,
	FAKETUNE_NOHOOK = 16,
	FAKETUNE_JETPACK = 32,
	FAKETUNE_NOHAMMER = 64,
};

Variable naming

• The names of variables contain 3 parts: qualifier, prefix and name.
• Variable names should start with uppercase unless they are 1 char long without any prefix or qualifier, for example: i, x, y.
• Variables can have more than 1 qualifier (or zero) and more than 1 prefix (or zero).

These are laid out like this: [qualifiers]_[prefixes][Name]

Qualifiers

• m for member variables: m_MyVariable.
• s for static variables: s_MyStaticVariable, ms_MyStaticMemberVariable.
• g for global variables with external linkage: gs_MyGlobalStaticVar.

Prefixes

• p for pointers: pMyPointer, m_pCharacter, ppMyPointerToPointer.
• a for arrays: aMyArray, aBuf.
• v for std::vectors: vMyVector, vpvMyVectorOfPointersToVectors.
• fn for functions: pfnMyCallback, m_papfnMyPointerToArrayOfCallbacks.

Common snippets

Here is a list of code that you may frequently see across the codebase:

Formatting text

char aBuf[128];
str_format(aBuf, sizeof(aBuf), "number: %d", 2);

See printf documentation for a list of all format specifiers.

Iterating over all players

for(int i = 0; i < MAX_CLIENTS; i++)
{
    // Server-side
    CPlayer *pPlayer = GameServer()->m_apPlayers[i];
}

Printing to the game console

Console()->Print(IConsole::OUTPUT_LEVEL_STANDARD, "wikiprint", "Hello from the ddnet wiki!");

Debug printing

int i = 2;
dbg_msg("wikiprint", "Hello from the ddnet wiki: %d", i);

Translating text in the client

Localize can be used in the game client to get the translation for a specific string from the language file selected by the user.

DoButton(..., Localize("Connect"), ...);

The string can also contain format specifiers. The translated string must contain the same format specifiers.

char aBuf[128];
str_format(aBuf, sizeof(aBuf), Localize("%d of %d servers"), NumServers, TotalServers);

A script is used to scan the code for calls to Localize and collect the strings to update the translation files. For this reason, the call to Localize must not contain any other code, or the script cannot determine the text correctly.

// Do NOT do this:
const char *pStr = Localize(Team == TEAM_RED ? "Red team" : "Blue team");
</div>

<div lang="en" dir="ltr" class="mw-content-ltr">
// Do this instead:
const char *pStr = Team == TEAM_RED ? Localize("Red team") : Localize("Blue team");

External resources

• UI Code in DDraceNetwork by Ryozuki
• An intro to the DDraceNetwork game source code by Ryozuki
• Code conventions in DDraceNetwork by Ryozuki
• Implementing a chat command in DDraceNetwork by Ryozuki
• Auto generated docs
• Technical documentation of Teeworlds file formats and network protocol
• The Anatomy of a One Tick Unfreeze
• Teeworlds programming YouTube tutorial by ChillerDragon