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Capturing a keypress in an event loop
nshade
Member #4,372
February 2004

I'm trying to capture if any key was pressed, however my event queue is kind of all over the place. (It's spanned across several c files) It's not detecting if I have a key pressed...

Because my C files are getting on the heavy side, I'll cut/paste the relevant info.

From main.c

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1ALLEGRO_TIMER *timer = NULL; 2ALLEGRO_EVENT_QUEUE *event_queue = NULL; 3ALLEGRO_EVENT event; 4 5al_install_keyboard(); 6 7int main(int argc, char **argv) 8{ 9 init_gfx(); 10 11 while (1) 12 { 13 14 al_wait_for_event(event_queue, &event); 15 16 if if ((event.type == ALLEGRO_EVENT_TIMER) || (event.type == ALLEGRO_EVENT_KEY_DOWN)) 17 { 18 logics(); 19 need_redraw = true; 20 } 21 22 if (need_redraw && al_event_queue_is_empty(event_queue)) 23 { 24 al_clear_to_color(al_map_rgb_f(0, 0, 0)); 25 drawing(); 26 al_flip_display(); 27 28 } 29 30 } 31 32}

gfx.c

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1 2extern ALLEGRO_TIMER *timer 3extern ALLEGRO_EVENT_QUEUE *event_queue 4extern ALLEGRO_EVENT event; 5 6void logics(void) 7 8{ 9 if (event.type == ALLEGRO_EVENT_TIMER) { printf("timer\n"); } 10 if (event.type == ALLEGRO_EVENT_KEY_DOWN) { printf("Keyboard!\n"); } 11 switch (title_state) 12 { 13 case scrolling: 14 { ......} 15 } 16}

The keyboard events don't seem to be be coming though. I just see it printing "timer" on my screen. Did I for forget to get something?

beoran
Member #12,636
March 2011

It is hard to say from your code but did you initialize your event queue with al_create_event_qyeue and register the keyboard event source with al_register_event_source?

nshade
Member #4,372
February 2004

Whoops found my event initialization function.. Guess what was missing.. Thanks.

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1void init_events(void) 2{ 3 // Start a timer to regulate speed. 60bps 4 timer = al_create_timer(ALLEGRO_BPS_TO_SECS(60)); 5 al_start_timer(timer); 6 7 // Start the event queue to handle keyboard input and the timer 8 event_queue = al_create_event_queue(); 9 al_register_event_source(event_queue, al_get_timer_event_source(timer)); 10 11 // I forgot this 12 al_register_event_source(event_queue, al_get_keyboard_event_source()); 13}

beoran
Member #12,636
March 2011

Well, it happens to everyone at times. Glad I could be of help.

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