Godot 4 源码分析 - 初探

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已于 2023-06-03 13:23:56 修改 · 3.3k 阅读

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文章标签：

#godot #游戏引擎

于 2023-06-03 11:22:20 首次发布

文章指导如何从GitHub获取Godot引擎源码，使用git和SCons进行编译，特别介绍了在Windows平台下生成VS解决方案及编译细节。作者实践了修改启动界面Logo的过程，展示了对二进制图像数据的操作与处理。

准备研究GoDot 4源码。

源码下载

获取源代码

在进入 SCons 构建系统并编译 Godot 之前，你需要将 Godot 的源代码下载到本地。

源代码位于 GitHub 上, 虽然你可以通过网站手动下载它, 但是通常你希望通过 git 版本控制系统来下载.

如果你是为了做贡献或拉动请求而进行编译，你应该遵循拉取请求工作流中的说明。

如果你还不太了解 git，在各种网站上都有大量的 Git 教程。

通常，你需要安装 git 和/或其他带有 git 的 GUI 客户端。

之后，要获得最新版本的 Godot 源代码（不稳定的 master 分支），可以使用 git clone。

如果你使用 git 命令行，可以通过在终端输入下列命令来完成：

git clone https://github.com/godotengine/godot.git
# You can add the --depth 1 argument to omit the commit history.
# Faster, but not all Git operations (like blame) will work.

要获取稳定版本的源代码，请访问源代码发布页面然后单击所需发行版的链接。然后，你可以从页面上的下载链接下载并解压源代码。

使用 git 时你还可以通过在 --branch （或者 -b ）参数后指定分支或者标签，来克隆稳定版本：

# Clone the continuously maintained stable branch (`3.x` as of writing).
git clone https://github.com/godotengine/godot.git -b 3.x

# Clone the `3.2.3-stable` tag. This is a fixed revision that will never change.
git clone https://github.com/godotengine/godot.git -b 3.2.3-stable

此外，你可以通过 git 在各个主要版本的分支间进行切换。

获取到 Godot 的源代码之后，你就可以继续编译 Godot 了。

编译运行

采用scons进行编译，可以直接使用cd到godot源码目录：

scons platform=windows

或者使用cpu多线程进行编译：

scons -j6 platform=windows

编译完成后，会在godot\bin目录下生成基于当前平台的一个exe程序，这个程序一般是godot.windows.tools.64，带有tools的，如果你是32或者64想打包32，可以直接加修饰词：

scons platform=windows bits=32

默认打包是debug+tools，如果想要打包其他的配置，可以使用：

target=release_debug
target=release
target=debug

三种作为scons构建的修饰词。

至此这里是使用scons构建基于windows平台的exe程序。

我的一个小目标是研究godot源码，妄想对引擎进行拓展和改进，这就需要使用VS进行构建，

需要使用命令生成vs解决方案：

scons p=windows vsproj=yes

生成结果：

用VS打开

以前没怎么用过VS，不过看这个工程是控制台程序，倒也不用考虑太多，先直接运行起来。按F5

改动小试

单步调试可知：godot还是一个正常的windows程序，它定位到main函数进入，初始化，循环，结束。

至于初始化、循环都处理了啥，以后再研究。今天看到既然可以单步调试，那就先改动一点点，看看具体效果。先从Flash界面来处理：

要不要把这个换一下？

先确定是在哪里出来的，单步调试可知

Error err = Main::setup(argv_utf8[0], argc - 1, &argv_utf8[1]);

进一步，发现获取之处

Ref<Image> splash = memnew(Image(boot_splash_png));
...
RenderingServer::get_singleton()->set_boot_image(splash, boot_bg_color, false);

其中，boot_splash_png定义在splash.gen.h中

稍一研究，这就是PGN图像的二进制格式数据。为了检验，可以直接保存成图像来看一下。Godot中实现了各种格式素材IO，就象这个Image，有个Image.cpp/h专门处理。难怪代码这么多。

Ref<Image> splash = memnew(Image(boot_splash_png));
splash->save_png("D:/1.png");

保存后的打开D:/1.png，是这效果。

再在底色(static const Color boot_splash_bg_color = Color(0.14, 0.14, 0.14))基础上就看到LOGO效果。

根据原LOGO图大小，做一个自己的LOGO图片

生成数据字符串

	DWORD dwFileSize = 0;
	BYTE * bytes = THelper::File::GetBinaryFileContent(L"D:\\BaiduNetdiskDownload\\Godot_DrGraph.png", dwFileSize);
	THelper::Log::SaveDataInfo(bytes, dwFileSize, L"LOGO文件内容", true, 0, L",");
	delete bytes;

生成结果：

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