Getting parameter problems.

no-reply@allegro.cc (Doctor Cop) — Thu, 25 Apr 2019 19:15:34 +0000

This code is working fine if I copy paste its contents into main but why is it not working when it's called as a function?

#SelectExpand
  1void list_box(ALLEGRO_EVENT event, int *y)
  2{
  3    int i;
  4    // Main Background rectangle
  5    al_draw_filled_rectangle(75, 75, 775, 575, al_map_rgb(12, 83, 95));// rgb(51, 102, 153)
  6
  7    // Drawing separation lines
  8    for(i=0; i < 475; i+=25)
  9    {
 10        al_draw_line(100, 100+i, 740, 100+i, al_map_rgb(255, 255, 255), 1);
 11    }
 12    //al_draw_filled_rectangle(750, 75, 775, 575, al_map_rgb(51, 102, 153));
 13
 14    //scroll bar
 15    al_draw_line(757, 100, 757, 550, al_map_rgb(255, 255, 255), 1);
 16
 17    if(event.type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN && event.mouse.x >= 754 && event.mouse.x <= 760 && event.mouse.y >= 100+*y && event.mouse.y <= 200+*y)
 18        {
 19            if(event.mouse.button == 1)
 20            {
 21                *y += 5;
 22            }
 23
 24        }
 25
 26    al_draw_filled_rounded_rectangle(754, 100+*y, 760, 200+*y, 2, 2, al_map_rgb(255, 255, 70));
 27
 28}

no-reply@allegro.cc (Audric) — Thu, 25 Apr 2019 19:56:04 +0000

What is not working ? The function appears to do three things :
- draw a fixed shape
- optionally, modify the caller's y
- draw a single element at a position that depends on (the new) y
What does it do different ?

The usual convention for typedef structs (UPPERCASE types) is to pass them by reference, so it's suspicious to see ALLEGRO_EVENT event rather than ALLEGRO_EVENT *event
I don't know the internals enough to say if there's an issue in passing a "flat copy" of the allegro event like that.

Be sure that you're not passing wrong type (ie. the second parameter should be the address of an int, not the address of a short, or unsigned int, or anything else)

no-reply@allegro.cc (Doctor Cop) — Thu, 25 Apr 2019 20:59:54 +0000

Audric, everything I did was working fine, it's just that the event passed to the function is not working.

Yes, I tried to change it to pointer but it didn't work and my other functions are taking the event as a 'flat copy', they are working fine.

when I commented out the if statements containing event.mouse.* something, it worked.
If I don't comment it out then it does nothing.

Here's the function calling: list_box(event, &y);

no-reply@allegro.cc (Edgar Reynaldo) — Thu, 25 Apr 2019 21:16:20 +0000

Check the order of operations being performed in your event check. you may find that operator precedence is making things go haywire.

no-reply@allegro.cc (Doctor Cop) — Thu, 25 Apr 2019 21:25:13 +0000

Here's my code and I don't find any operator precedence problem and if it is working fine when the event part is copied to main then why should be operator precedence problem.

Thinking of it, I remember that when I previously created menu_icon() function then at that time the event passed by parameters didn't work. What might be causing it?

#SelectExpand
   1#include 
   2#include 
   3//#include 
   4#include 
   5#include 
   6#include 
   7#include 
   8
   9void menu_icon(int, int, int, int, ALLEGRO_COLOR, int);
  10void list_box(ALLEGRO_EVENT, int*);
  11
  12#define MAXWIDTH 800
  13#define MAXHEIGHT 600
  14
  15    int width=50, height=50, place_x=25, place_y=25, animate = 0;
  16
  17int main()
  18{
  19    al_init();
  20    al_init_primitives_addon();
  21    //al_init_image_addon();
  22    al_init_font_addon();
  23    al_init_ttf_addon();
  24    al_install_keyboard();
  25    al_install_mouse();
  26
  27    //al_set_new_bitmap_flags(ALLEGRO_MIN_LINEAR);
  28
  29    ALLEGRO_DISPLAY *display = al_create_display(MAXWIDTH, MAXHEIGHT);
  30    ALLEGRO_EVENT_QUEUE *queue = al_create_event_queue();
  31    ALLEGRO_TIMER *timer = al_create_timer(2.0/60.0);
  32    ALLEGRO_COLOR m_color = al_map_rgb(255, 214, 51);
  33    ALLEGRO_FONT *font = al_load_ttf_font("res/L.ttf", 14, 1);
  34    //ALLEGRO_BITMAP *background = al_load_bitmap("res/background.jpg");
  35
  36    int x=0, y=0, main_loop = true, menu = 0;
  37    int width=50, height=50, place_x=25, place_y=25, animate = 0;
  38    //enum {};
  39
  40    al_register_event_source(queue, al_get_display_event_source(display));
  41    al_register_event_source(queue, al_get_mouse_event_source());
  42    al_register_event_source(queue, al_get_keyboard_event_source());
  43    al_register_event_source(queue, al_get_timer_event_source(timer));
  44
  45    al_start_timer(timer);
  46
  47    while(main_loop)
  48    {
  49        ALLEGRO_EVENT event;
  50        //if(al_is_event_queue_empty(queue))
  51        al_wait_for_event(queue, &event);
  52
  53        if(event.type == ALLEGRO_EVENT_DISPLAY_CLOSE)
  54            main_loop = false;
  55
  56        else if(event.type == ALLEGRO_EVENT_TIMER)
  57        {
  58            al_clear_to_color(al_map_rgb(0, 77, 77)); //rgb(153,50,204)
  59
  60        //al_draw_scaled_bitmap(background, 0, 0, 4896, 3264, 0, 0, 800, 600, 0);
  61        al_draw_rounded_rectangle(400-100, 300-20, 400+100, 300+20, 20, 20, al_map_rgb(70, 60, 100), 2);
  62        al_draw_filled_rectangle(0, 0, 50, 50, m_color);
  63        al_draw_filled_rectangle(0, 50, 50, MAXHEIGHT, al_map_rgb(255, 214, 51)); //rgb(218, 112, 214) rgb(255, 214, 51) al_map_rgb(230, 46, 0)
  64        al_draw_line(50, 0, 50, MAXHEIGHT, al_map_rgb(0, 0, 0), 1);
  65        menu_icon(50, 50, 25, 25, al_map_rgb(0, 0, 0), animate);
  66        list_box(event, &y);
  67
  68        if(menu)
  69        {
  70            al_draw_filled_rectangle(50, 0, MAXWIDTH, 50, al_map_rgb(22, 88, 110));
  71        }
  72
  73        al_flip_display();
  74        al_rest(0.02);
  75        }
  76
  77        else if(event.type == ALLEGRO_EVENT_MOUSE_AXES)
  78        {
  79                if(event.mouse.x < 50 && event.mouse.y < 50)
  80                    m_color = al_map_rgb(140, 152, 63);
  81                else
  82                    m_color = al_map_rgb(255, 214, 51);
  83        }
  84
  85        else if(event.type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN && event.mouse.x >= (place_x-(width/2)) && event.mouse.x <= (place_x+(width/2)) && event.mouse.y >= (place_y-(height/2)) && event.mouse.y <= (place_y+(height/2)))
  86        {
  87            if(event.mouse.button == 1)
  88            {
  89                (5 == animate) ? (animate = 0) : (animate = 5);
  90                menu = !menu;
  91            }
  92
  93        }
  94
  95        if(event.type == ALLEGRO_EVENT_KEY_DOWN)
  96        {
  97            switch(event.keyboard.keycode)
  98            {
  99                case ALLEGRO_KEY_ESCAPE :
 100                    exit(1);
 101                    break;
 102            }
 103        }
 104
 105    }
 106
 107    al_destroy_display(display);
 108    al_destroy_event_queue(queue);
 109    return 0;
 110}
 111
 112void menu_icon(int width, int height, int place_x, int place_y, ALLEGRO_COLOR colorU, int animate)
 113{
 114    al_draw_line(place_x-(width/2)+width/4 + animate, place_y-(height/2)+height/3, place_x-(width/2)+width-(width/4) + animate, place_y-(height/2)+height/3, colorU, 5);
 115    al_draw_line(place_x-(width/2)+width/4 - animate, place_y-(height/2)+(height/2), place_x-(width/2)+width-(width/4) - animate, place_y-(height/2)+(height/2), colorU, 5);
 116    al_draw_line(place_x-(width/2)+width/4 + animate, place_y-(height/2)+height-(height/3), place_x-(width/2)+width-(width/4) + animate, place_y-(height/2)+height-(height/3), colorU, 5);
 117}
 118
 119void list_box(ALLEGRO_EVENT event, int *y)
 120{
 121    int i;
 122    // Main Background rectangle
 123    al_draw_filled_rectangle(75, 75, 775, 575, al_map_rgb(12, 83, 95));// rgb(51, 102, 153)
 124
 125    // Drawing separation lines
 126    for(i=0; i < 475; i+=25)
 127    {
 128        al_draw_line(100, 100+i, 740, 100+i, al_map_rgb(255, 255, 255), 1);
 129    }
 130    //al_draw_filled_rectangle(750, 75, 775, 575, al_map_rgb(51, 102, 153));
 131
 132    //scroll bar
 133    al_draw_line(757, 100, 757, 550, al_map_rgb(255, 255, 255), 1);
 134
 135    if(event.type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN && event.mouse.x >= 754 && event.mouse.x <= 760 && event.mouse.y >= 100+*y && event.mouse.y <= 200+*y)
 136        {
 137            if(event.mouse.button == 1)
 138            {
 139                *y += 5;
 140            }
 141
 142        }
 143
 144    al_draw_filled_rounded_rectangle(754, 100+*y, 760, 200+*y, 2, 2, al_map_rgb(255, 255, 70));
 145
 146}

no-reply@allegro.cc (Audric) — Fri, 26 Apr 2019 02:37:01 +0000

In your last post, the function is only called from inside the block if(event.type == ALLEGRO_EVENT_TIMER) { }. (The indentation of lines 60-74 is misguiding)
So you're calling list_box() with an event that can never be a ALLEGRO_EVENT_MOUSE_BUTTON_DOWN. I bet that the version of your code 'that works' actually has the 3 pieces of code at different places.

You're using a system where you systematically redraw everything 30 times per second, it's fine, it means you don't need to bother keep track of "what has changed, what graphic part is obsolete and should be redrawn) So, keep the input code separate from the display one : When the user clicks on "next" arrow, you only modify the "current item" value.
Note that on line 95 you're missing an else. It's misguiding, because the entire series of if (event.type == type1) {} else if (event.type == type2) is meant to process ONE event, and handle different situations.

no-reply@allegro.cc (Doctor Cop) — Fri, 26 Apr 2019 08:37:14 +0000

Thanks Audric and yes, when I tried to 'work' my code out I just copied that portion into another (previously saved version before Edgar suggested me) copy to not to mess with my code.

It now works, thanks.