Unexpected error in primitive al_draw_circle (aka Return Of The Bad Programmer)

no-reply@allegro.cc (mumu1000) — Sat, 07 Jul 2018 18:48:06 +0000

Hello everybody !
Once again i come back to you with a simple/weird (stupid?) question, and a new bug i cant figure out how to fix.

here's my code:

main.cpp

#SelectExpand
  1#include 
  2#include 
  3#include 
  4#include 
  5#include "allegro5/allegro.h"
  6#include "allegro5/allegro_color.h"
  7#include "allegro5/allegro_primitives.h"
  8
  9int main(int argc, char **argv)
 10{
 11    if (al_init() && al_init_primitives_addon())
 12    {
 13        std::cout<<"It Works";
 14    }else
 15    {
 16        std::cout << "Allegro Not Loaded";
 17        return 1;
 18    }
 19    al_set_new_display_flags(ALLEGRO_FRAMELESS+ALLEGRO_FULLSCREEN_WINDOW);
 20    ALLEGRO_DISPLAY * mainDisplay = al_create_display(1800,1000);
 21    
 22    al_clear_to_color(al_map_rgb(20,20,20));
 23    Planet* testPlanet = new Planet(100,100);
 24    testPlanet->draw();
 25    al_flip_display();
 26    std::this_thread::sleep_for(std::chrono::milliseconds(5000));
 27
 28    al_shutdown_primitives_addon();
 29    al_destroy_display(mainDisplay);
 30    return 0;
 31}

Planet.h

#SelectExpand
  1#include "allegro5/color.h"
  2#include "allegro5/allegro_primitives.h"
  3class Planet
  4{
  5    public:
  6        Planet();
  7        Planet(float xPos, float yPos);
  8        virtual ~Planet();
  9        virtual void const draw();
 10        float const getXPos(){return m_xPos;};
 11        float const getYPos(){return m_yPos;};
 12        void setXPos(float xPos){m_xPos = xPos;};
 13        void setYPos(float yPos){m_yPos = yPos;};
 14
 15    protected:
 16        float m_xPos;
 17        float m_yPos;
 18
 19    private:
 20        const static ALLEGRO_COLOR drawedColor;
 21};

Planet.cpp

#SelectExpand
  1#include "Planet.h"
  2
  3const ALLEGRO_COLOR Planet::drawedColor = al_map_rgb(20,200,20);
  4
  5Planet::Planet()
  6{
  7    m_xPos = 0;
  8    m_yPos = 0;
  9}
 10Planet::Planet(float xPos, float yPos)
 11{
 12    m_xPos = xPos;
 13    m_yPos = yPos;
 14}
 15
 16Planet::~Planet()
 17{
 18
 19}
 20void const Planet::draw()
 21{
 22    al_draw_circle(10+(m_xPos*30),10+(m_yPos*30),8,Planet::drawedColor,3);
 23}

What i figured out :
-The code compiles.
-The display opens, and i got the "It works" message in the console.
-The display stays black, and i get an error code after a few secs (0XC0000005)
-When i remove the al_draw_circle call, the code runs, and returns 0.
-When i call al_draw_circle from the main, it works.

Please help !

Have a great day !

Edit: The problem is not coming from here (i simplified the problem in this forum thread, but i think the problem comes from another part of the code)7

Edit 2: This is so confusing, i cant get it to work. Do you see any mistakes i've made in these sources ?

no-reply@allegro.cc (Edgar Reynaldo) — Sun, 08 Jul 2018 17:34:32 +0000

I see one thing. You're using a global const ALLEGRO_COLOR and caling al_map_rgb outside of al_init() because global constructors get called before main.

Calling allegro functions before al_init can give undefined behavior.

EDIT
Also, that code won't compile because you didn't #include "planet.h".

Post a minimal working example that compiles if the above didn't fix the problem.

no-reply@allegro.cc (mumu1000) — Sun, 08 Jul 2018 17:57:15 +0000

Edgar Reynaldo said:

I see one thing. You're using a global const ALLEGRO_COLOR and caling al_map_rgb outside of al_init() because global constructors get called before main.

Calling allegro functions before al_init can give undefined behavior.

Oh ! Very interesting ! Thx for the answer !

Edgar Reynaldo said:

Also, that code won't compile because you didn't #include "planet.h"

Oh yea my bad, this error comes from when i tried to synthetize the problem and refactored the code to describe my problem better. (As i told, my code compiles ^^)

Edgar Reynaldo said:

Post a minimal working example that compiles if the above didn't fix the problem.

This example is not relevant anymore, i've made a new post, with all the actual sources, and one new hell of an issue ;p

Great day !