Allegro, outputting mouse click

Question

I want to print out the coordinates of my mouse in the graphical window, and when the user clicks it, there should appear a message "clicked". But the problem is when the user does click it, instead of 1 message, I get around 5-10 messages. I understand it's probably because of how fast I release the button. Is there a way to print just one time?

#include <allegro.h>
#include <iostream>

int main(){

    allegro_init();
    install_keyboard();
    install_mouse();
    set_color_depth(32);
    set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);

    BITMAP *pic = load_bitmap("mouse.bmp",NULL);
    BITMAP *buffer = create_bitmap(640,480);

    int x = 0, y = 0;

    while(!key[KEY_ESC]){
        blit(buffer, screen, 0,0,0,0, buffer->w,buffer->h);

        draw_sprite(buffer, pic, mouse_x, mouse_y);
        blit(buffer, screen, 0,0,0,0, buffer->w, buffer->h);
        clear_bitmap(buffer);

        if(mouse_x!=x && mouse_y!=y){
            std::cout<<mouse_x<<":"<<mouse_y<<std::endl;
        }
        if(mouse_b&1){
            std::cout<<std::endl<<">>CLICKED<<"<<std::endl;
        }

        x=mouse_x, y=mouse_y;
    }

    destroy_bitmap(pic);
    destroy_bitmap(buffer);
    return 0;
}
END_OF_MAIN()

score 1 · Answer 1 · answered Jan 05 '13 at 15:52

Does mouse_b hold the state of the mouse? If so it could be outputing the messages once every frame for however long your mouse is down.

Similar to how you handle x,y store the previous state of the button and only send a message if the state changes, this should give you just 1 message.

score 0 · Answer 2 · answered Feb 26 '14 at 01:53

It is much easier to use allegro events. Here is how allegro wiki explains events.

The following code would accomplish your task.

  if(ev.type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN) {
      std::cout<<std::endl<<">>CLICKED<<"<<std::endl;    
  }
  else if(ev.type == ALLEGRO_EVENT_MOUSE_AXES ||
          ev.type == ALLEGRO_EVENT_MOUSE_ENTER_DISPLAY) { 
        std::cout<<mouse_x<<":"<<mouse_y<<std::endl;
  }

Allegro, outputting mouse click

2 Answers2