Passing Setup class to get screen height

For Beginners

Started by Qweasdzxcaa Qweasdzxcaal October 15, 2015 05:33 PM

3 comments, last by Bregma 9 years, 2 months ago

Qweasdzxcaa Qweasdzxcaal

Author

102

October 15, 2015 05:33 PM

There seems to be something wrong with the way i pass the variable SCREEN_HEIGHT:

from this class:


class First {
    public:
        First();
        ~First();
         SDL_Renderer* renderer = NULL;
         SDL_Window* gWindow = NULL;

        int SCREEN_WIDTH;
        int SCREEN_HEIGHT;
};

to this:


class Second {
    public:
        Second(First f);
        int y;
};

and this is the implementation for the classes :


#include "First.h"
First :: First()
: SCREEN_WIDTH(640), SCREEN_HEIGHT(SCREEN_WIDTH/16*9)
{
    SDL_Init( SDL_INIT_VIDEO );

    SDL_SetHint( SDL_HINT_RENDER_SCALE_QUALITY, "1" );

    gWindow = SDL_CreateWindow( "Testing", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );

    renderer = SDL_CreateRenderer( gWindow, -1, SDL_RENDERER_ACCELERATED );

    SDL_SetRenderDrawColor( renderer, 0xFF, 0xFF, 0xFF, 0xFF );

    IMG_Init( IMG_INIT_PNG );
}

First :: ~First()
{
SDL_DestroyRenderer( renderer );
SDL_DestroyWindow( gWindow );
gWindow = NULL;
renderer = NULL;

IMG_Quit();
SDL_Quit();
}



#include "Second.h"

Second :: Second(First f) {
    y = f.SCREEN_HEIGHT / 2;
}

what i dont understand is why do i get from SDL_GetError() invalid texture ?

this is the main function:


#include "First.h"
#include "Second.h"
#include <iostream>
int main( int argc, char* args[] )
{
    First first;
    Second second(first);
    bool quit = false;
    SDL_Event e;

    while( !quit )
    {
        while( SDL_PollEvent( &e ) != 0 )
            {
                if( e.type == SDL_QUIT )
                {
                    quit = true;
                }
            }
            SDL_SetRenderDrawColor( first.renderer, 0x00, 0x00, 0x00, 0xFF );
            SDL_RenderClear( first.renderer );
            std::cout << SDL_GetError() << std::endl;
            SDL_RenderPresent( first.renderer );
    }
return 0;
}

Lactose

11,696

October 15, 2015 06:48 PM

Why do you think there's a problem with second.y? You create an instance of Second, but that instance is never used anywhere.

To find out where your error about invalid textures comes from (you should really copy error messages verbatim, not paraphrase them), you should check every SDL call you make. Currently, you seem to almost 10 SDL calls before your first SDL_GetError() call.

Basically, check the return values and see the first point it tells you something's wrong.

Also, this is a small enough program that I would definitely recommend you learning how to use a debugger (setting breakpoints, looking at variables and seeing the flow through your code, etc), if you don't already know how.

Hello to all my stalkers.

Qweasdzxcaa Qweasdzxcaal

Author

102

October 15, 2015 06:54 PM

I did check every variable and function.
the problem comes from


y = f.SCREEN_HEIGHT / 2;

everything else works as intended.
if i put the code in main it will work with no problem, but when i put it in a different file there is the error invalid texture from SDL_GetError();
maybe im passing the first class variable wrong ?