将SDL集成到GLib主循环中(Integrate SDL into GLib mainloop)

将SDL集成到GLib主循环中(Integrate SDL into GLib mainloop)

我正在计划一个使用SDL的小型Vala游戏项目，我想知道如何将SDL正确地集成到GLib主循环中。 我最后一次使用Vala和SDL做了一些事情，我使用了标准的SDL事件循环，但老实说，它是一堆废话，它打破了整个不错的Vala或GLib信号系统。

我找到了Cogl的集成 ，我正在寻找与SDL相同的东西。

I'm planning a small Vala game project with SDL and I wonder how to integrate SDL properly into the GLib mainloop. The last time I did something with Vala and SDL I used the standard SDL event loop, but honestly, it's a heap of crap and it breaks the whole nice Vala or rather GLib signal system.

I found an integration for Cogl and I'm looking for the same thing just with SDL.

最满意答案

GLib源由三个回调组成：

一个在轮询之前检查源是否就绪（并避免poll调用） 一个用于在轮询后检查源是否仍然准备就绪 一个派遣附加的回调

您可以非常简单地检查和调度事件。

public delegate bool SDLSourceFunc (SDL.Event event); public class SDLSource : Source { public SDL.Event event; public bool prepare (out uint timeout) { timeout = 0; return true; } public bool check () { return SDL.Event.poll (out event) > 0; } public bool dispatch (SourceFunc callback) { return ((SDLSourceFunc) callback) (event); } public void add_callback (SDLSourceFunc callback) { base.add_callback ((SourceFunc) callback); } }

然后，您将使用Source.CONTINUE循环：

var source = new SDLSource (); source.add_callback ((event) => { // handle event here return Source.CONTINUE; }); source.attach (MainContext.@default ());

这是非常基本的：您的源可以使用SDL.EventMask和SDL.peep过滤特定事件。 为单个源分派多个事件并附加相关文件描述符也更有效。

如果您使用某些异步代码，则可以直接从Source调度唤醒协程：

public async void next_event_async () { var source = new SDLSource (); source.attach (MainContext.@default ()); source.add_callback (handle_event_async.callback); yield; return source.event; }

GLib sources are composed of three callbacks:

one to check if the source is ready before polling (and avoid a poll call) one to check if the source is still ready after polling one to dispatch the attached callback

You could have a source checking and dispatching events fairly simply.

public delegate bool SDLSourceFunc (SDL.Event event); public class SDLSource : Source { public SDL.Event event; public bool prepare (out uint timeout) { timeout = 0; return true; } public bool check () { return SDL.Event.poll (out event) > 0; } public bool dispatch (SourceFunc callback) { return ((SDLSourceFunc) callback) (event); } public void add_callback (SDLSourceFunc callback) { base.add_callback ((SourceFunc) callback); } }

Then, you would loop with Source.CONTINUE:

var source = new SDLSource (); source.add_callback ((event) => { // handle event here return Source.CONTINUE; }); source.attach (MainContext.@default ());

This is very basic: your source could filter specific events with a SDL.EventMask and SDL.peep. It's also more efficient to dispatch multiple events for a single source and attach related file descriptors.

If you use some async code, you can wakeup the coroutine directly from a Source dispatch:

public async void next_event_async () { var source = new SDLSource (); source.attach (MainContext.@default ()); source.add_callback (handle_event_async.callback); yield; return source.event; }