Messages

1

General discussions / Re: RenderWindow object breaks srand

« on: April 09, 2017, 04:10:40 pm »

Which version of SFML are you running? There's no call to "srand()" in SFML's source.

Edit:
Also, what happens if you create a second sf::RenderWindow and run the loop again (without calling srand() a second time)?

(click to show/hide)

#include "SFML-2.4.2/include/SFML/Graphics.hpp"
#include <iostream>
#include <time.h>
using namespace sf;

int main()
{
        VideoMode vdm = VideoMode(400, 533);

        unsigned int init_time = time(NULL);
        std::cout << init_time << "\n";
        srand(init_time);
       
        RenderWindow app(vdm, "Game!");

        for (int i=0;i<5;i++)
        {
                std::cout << rand()%100 << " " << rand()%100 << "\n";
        }

        RenderWindow app2(vdm, "Game!");

        std::cout << "\n";
        for (int i=0;i<5;i++)
        {
                std::cout << rand()%100 << " " << rand()%100 << "\n";
        }
        return 0;
}
 

out:

(click to show/hide)

$ ./a.out
1491747014
87 83
25 80
71 54
75 87
54 20

73 57
8 64
90 79
61 86
93 34
$ ./a.out
1491747015
87 83
25 80
71 54
75 87
54 20

73 57
8 64
90 79
61 86
93 34
$ ./a.out
1491747016
87 83
25 80
71 54
75 87
54 20

73 57
8 64
90 79
61 86
93 34

 

2

General discussions / Re: RenderWindow object breaks srand

« on: April 09, 2017, 04:06:19 pm »

It really strange
see :

code:

(click to show/hide)

#include "SFML-2.4.2/include/SFML/Graphics.hpp"
#include <iostream>
#include <time.h>
using namespace sf;

int main()
{
        VideoMode vdm = VideoMode(400, 533);

        unsigned int init_time = time(NULL);
        std::cout << init_time << "\n";
        srand(init_time);
       
        for (int i=0;i<5;i++)
        {
                std::cout << rand()%100 << " " << rand()%100 << "\n";
        }
        std::cout << "\n";
       
        RenderWindow app(vdm, "Game!");

        for (int i=0;i<5;i++)
        {
                std::cout << rand()%100 << " " << rand()%100 << "\n";
        }
        return 0;
}

// g++ main2.cpp -lsfml-graphics -lsfml-window -lsfml-system -std=c++11
 

out:

(click to show/hide)

./a.out
1491746597
64 56
79 33
16 81
8 17
53 6

87 83
25 80
71 54
75 87
54 20
$ ./a.out
1491746599
62 63
94 82
31 56
12 90
35 64

87 83
25 80
71 54
75 87
54 20
$ ./a.out
1491746647
73 15
67 39
69 95
3 75
63 76

87 83
25 80
71 54
75 87
54 20
$
 

like

RenderWindow app(vdm, "Game!");

reinitializes srand()

3

General discussions / Re: RenderWindow object breaks srand

« on: April 09, 2017, 04:01:25 pm »

I tried the latest stable version
code:

(click to show/hide)

#include "SFML-2.4.2/include/SFML/Graphics.hpp"
#include <iostream>
#include <time.h>
using namespace sf;

int main()
{
        VideoMode vdm = VideoMode(400, 533);

        unsigned int init_time = time(NULL);
        srand(init_time);
        std::cout << init_time << "\n";

        RenderWindow app(vdm, "Game!");

        for (int i=0;i<5;i++)
        {
                std::cout << rand()%100 << " " << rand()%100 << "\n";
        }
        return 0;
}

// g++ main2.cpp -lsfml-graphics -lsfml-window -lsfml-system -std=c++11

out:

(click to show/hide)

1491746044
87 83
25 80
71 54
75 87
54 20
$ ./a.out
1491746045
87 83
25 80
71 54
75 87
54 20
$ ./a.out
1491746048
87 83
25 80
71 54
75 87
54 20

the same problem
putting srand() after RenderWindow app(vdm, "Game!"); repairs for me.

It can be bag?

$ uname -a
Linux dunaev-desktop 4.4.0-71-generic #92-Ubuntu SMP Fri Mar 24 12:59:01 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
 

What else about the system to provide?

4

General discussions / Re: RenderWindow object breaks srand

« on: April 09, 2017, 03:46:47 pm »

As for me, it looks like RenderWindow object initializes srand with one const number

5

General discussions / Re: RenderWindow object breaks srand

« on: April 09, 2017, 02:41:13 pm »

see screenshot
srand out of loop before RenderWindow initialise
it only once, at the start of main()
If i will put srand after RenderWindow creation, everything OK.

6

General discussions / RenderWindow object breaks srand

« on: April 08, 2017, 08:01:54 pm »

When

srand((unsigned)time(NULL));

called before RenderWindow class object creation, rand() return same value, like srand() initialize by const var.
If i will put srand after RenderWindow creation, everything OK.
see attached screenshot

I'm confused that the example "examples/pong/Pong.cpp" uses a similar code:
https://github.com/SFML/SFML/blob/fae3b65f0567f87fa9925cd42d28df15eb69e79c/examples/pong/Pong.cpp
srand before RenderWindow

P.S. sorry for my English, it's my second language.

code and compile parameters:

(click to show/hide)

#include <SFML/Graphics.hpp>
#include <iostream>
#include <time.h>
using namespace sf;

int main()
{
        VideoMode vdm = VideoMode(400, 533);

        srand((unsigned)time(NULL));

        RenderWindow app(vdm, "Game!");

        for (int i=0;i<10;i++)
        {
                std::cout << rand()%100 << " " << rand()%100 << "\n";
        }
        return 0;
}

// g++ main2.cpp -lsfml-graphics -lsfml-window -lsfml-system -std=c++11