sdlsubsystem.h

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#pragma once
 
#include <promeki/namespace.h>
#include <promeki/application.h>
#include <promeki/eventloop.h>
#include <promeki/selfpipe.h>
#include <promeki/sdl/sdleventpump.h>
 
PROMEKI_NAMESPACE_BEGIN
 
class Widget;
 
class SdlSubsystem {
        public:
                SdlSubsystem();
 
                ~SdlSubsystem();
 
                SdlSubsystem(const SdlSubsystem &) = delete;
                SdlSubsystem &operator=(const SdlSubsystem &) = delete;
 
                static SdlSubsystem *instance() { return _instance; }
 
                SDLEventPump &eventPump() { return _eventPump; }
 
                EventLoop *eventLoop() { return _eventLoop; }
 
                Widget *focusedWidget() const { return _focusedWidget; }
 
                void setFocusedWidget(Widget *widget) { _focusedWidget = widget; }
 
        private:
                static SdlSubsystem *_instance;
 
                EventLoop   *_eventLoop = nullptr;
                SDLEventPump _eventPump;
                Widget      *_focusedWidget = nullptr;
 
                // Self-pipe used as the SDL → EventLoop bridge.
                // SDL_AddEventWatch writes one byte to the write end
                // from whatever thread pushed the event; the read
                // end is registered as an EventLoop IoSource whose
                // callback drains the pipe and pumps SDL's queue.
                SelfPipe _sdlPipe;
                int      _sdlSourceHandle = -1;
 
                // Periodic kick that calls @c SDL_PumpEvents so OS
                // input (keyboard, window close, mouse) gets pulled
                // into SDL's queue even when nothing on the promeki
                // side is pushing events.  Without this, a paused
                // playback pipeline (no frames, no wakeMainThread
                // user events) leaves OS events stranded: the
                // @c sdlEventWatch callback only fires when
                // @c SDL_PushEvent or a pump pulls a new event
                // in, so the watch → pipe → IoSource → pump chain
                // deadlocks without an external driver.
                int _pumpTimerId = -1;
 
                static bool sdlEventWatch(void *userdata, SDL_Event *event);
};
 
PROMEKI_NAMESPACE_END