SDL Application crash

[hnefatl]

Hi,

Edit: Sorry for the long code, I wasn't sure what was(n't) relevant.

Working on a basic game using SDL. Whenever I run the following code, my project crashes with status -1073741819 (application closed before it reach return 1 in int main() ).

#include "SDL/SDL.h"
#include "SDL/SDL_Image.h"
#include "SDL/SDL_TTF.h"
#include "SDL/SDL_Mixer.h"
#include <string>
#include <time.h>
#include <sstream>
#include <fstream>
#include <vector>

const int SCREEN_WIDTH=210;
const int SCREEN_HEIGHT=375;
const int SCREEN_BPP=32;
const int FRAMES_PER_SECOND=20;

int carCounter=0;
unsigned int x=0;
int currentScore=0;
int highScores[10];
std::string playerNames[10];
int timesPlayed=0;
std::string username;

SDL_Surface *screen=NULL;
SDL_Surface *road=NULL;
SDL_Surface *car1=NULL;
SDL_Surface *car2=NULL;
SDL_Surface *car3=NULL;
SDL_Surface *box1=NULL;
SDL_Surface *icon=NULL;
SDL_Surface *background=NULL;
Mix_Chunk *crash=NULL;
TTF_Font *font=NULL;
SDL_Color textColor={0, 0, 0};

SDL_Event event;

class playerCar;
class enemyCar;
class Timer;

std::vector <enemyCar> enemies;

void update();
bool init();
bool load_files();
void apply_surface(int x, int y, SDL_Surface *source, SDL_Surface *destination);
void clean_up();
void save();
void load();
void generate_wave();
void draw_score();

class Timer
{
    private:

    int startTicks;
    int pausedTicks;
    bool paused;
    bool started;
    public:

    Timer() {
        startTicks=0;
        pausedTicks=0;
        paused=false;
        started=false;
    }

    void start() {
        started=true;
        paused=false;

        startTicks=SDL_GetTicks();
    }

    void stop() {
        started=false;
        paused=false;
    }

    void pause() {
        if ((started==true) and (paused==false)) {
            paused=true;

            pausedTicks=SDL_GetTicks()-startTicks;
        }
    }

    void unpause() {
        if (paused==true) {
            paused=false;

            startTicks=SDL_GetTicks()-pausedTicks;

            pausedTicks=0;
        }
    }

    int get_ticks() {
        if (started==true) {
            if (paused==true) {
                return pausedTicks;
            }
            else {
                return SDL_GetTicks()-startTicks;
            }
        }
        return 0;
    }

    bool is_started() {
        return started;
    }

    bool is_paused() {
        return paused;
    }
};

Timer fps;

class playerCar
{
    private:
    int xPos, yPos;
    int xVel;
    int CAR_WIDTH;
    int additionalVelocity;
    SDL_Surface *sprite;

    public:
    playerCar() {
        additionalVelocity=2;
        yPos=300;
        xPos=105;
        CAR_WIDTH=5;
        sprite=IMG_Load("data/Resources/Sprites/car1.png");
    }
    ~playerCar() {
        SDL_FreeSurface(sprite);
    }
    void show() {
        apply_surface(xPos, yPos, sprite, screen);
    }

    void handle_input() {
        if (event.type==SDL_KEYDOWN) {
            switch (event.key.keysym.sym) {
                case SDLK_RIGHT: xVel+=CAR_WIDTH/2+additionalVelocity; break;
                case SDLK_LEFT: xVel-=CAR_WIDTH/2+additionalVelocity; break;
                default: ;
            }
        }

        if (event.type==SDL_KEYUP) {
            switch (event.key.keysym.sym) {
                case SDLK_RIGHT: xVel-=CAR_WIDTH/2+additionalVelocity; break;
                case SDLK_LEFT: xVel+=CAR_WIDTH/2+additionalVelocity; break;
                default: ;
            }
        }
    }

    void move() {
        xPos+=xVel;

        if ((xPos<0) or (xPos+42>SCREEN_WIDTH)) {
            xPos-=xVel;
        }
    }
};

class enemyCar
{
    private:
    int number;
    int xPos, yPos;
    int yVel;
    int CAR_WIDTH;
    SDL_Surface *sprite;

    public:
    enemyCar() {
        yVel=2;
        number=carCounter;
        carCounter++;
        yPos=0;
        CAR_WIDTH=5;
        generateSprite();
    }
    ~enemyCar() {
        enemies.erase(enemies.begin()+carCounter);
        SDL_FreeSurface(sprite);
    }
    int getNumber() {
        return number;
    }
    void generateSprite() {
        srand(fps.get_ticks());
        int random=(rand()/2);
        if (random==0) {
            sprite=IMG_Load("data/Resources/Sprites/car2.png");
        }
        else {
            sprite=IMG_Load("data/Resources/Sprites/car3.png");
        }
        if (sprite==NULL) {
            exit(0);
        }
    }

    void show() {
        apply_surface(xPos, yPos, sprite, screen);
    }

    void move() {
        yPos-=yVel;
    }

    void setXpos(int column) {
        xPos=column;
    }
};

playerCar player;

int main(int argc, char* args[]) {
    timesPlayed++;
    bool quit=false;
    if (!init()) {
        return 0;
    }
    generate_wave();
    while (quit==false) {
        fps.start();
        while (SDL_PollEvent(&event)) {

            player.handle_input();

            if (event.type==SDL_QUIT) {
                return 0;
            }
        }

        player.move();
        for (x=0; x<enemies.size(); x++) {
            enemies[x].move();
        }

        apply_surface(0, 0, background, screen);
        apply_surface(0, 0, road, screen);

        player.show();
        for (x=0; x<enemies.size(); x++) {
            enemies[x].show();
        }
        draw_score();

        update();
    }

    clean_up();

    return 0;
}

void generate_wave() {
    enemies.clear();
    int random=0;
    int temp=SDL_GetTicks()%10;
    srand(temp);
    random=rand()%5;
    if (random==0) {
        enemyCar a;
        enemies.push_back(a);
        enemies[a.getNumber()].setXpos(42);
    }
    else if (random==1) {
        enemyCar b;
        enemies.push_back(b);
        enemies[b.getNumber()].setXpos(0);
    }
    else if (random==2) {
        enemyCar c;
        enemies.push_back(c);
        enemies[c.getNumber()].setXpos(84);
    }
    else if (random==3) {
        enemyCar d;
        enemies.push_back(d);
        enemies[d.getNumber()].setXpos(126);
    }
    else {
        enemyCar e;
        enemies.push_back(e);
        enemies[e.getNumber()].setXpos(168);
    }
}

void apply_surface(int x, int y, SDL_Surface* source, SDL_Surface* destination) {
    SDL_Rect offset;
    offset.x=x;
    offset.y=y;

    SDL_BlitSurface(source, NULL, destination, &offset);
}

bool init() {
    if (SDL_Init(SDL_INIT_EVERYTHING)==-1) {
        return false;
    }

    if (TTF_Init()==-1) {
        return false;
    }

    if (Mix_OpenAudio(22050, MIX_DEFAULT_FORMAT, 2, 4096)==-1) {
        return false;
    }
    screen=SDL_SetVideoMode(SCREEN_WIDTH+200, SCREEN_HEIGHT, SCREEN_BPP, SDL_SWSURFACE);

    if (screen==NULL) {
        return false;
    }

    if (load_files()==false) {
        return false;
    }

    SDL_WM_SetCaption("Road Rage", NULL);

    return true;
}

bool load_files() {
    road=IMG_Load("data/Resources/Sprites/road.png");
    car1=IMG_Load("data/Resources/Sprites/car1.png");
    car2=IMG_Load("data/Resources/Sprites/car2.png");
    car3=IMG_Load("data/Resources/Sprites/car3.png");
    box1=IMG_Load("data/Resources/Sprites/box1.png");
    icon=IMG_Load("data/Resources/Sprites/icon.ico");
    background=IMG_Load("data/Resources/Sprites/background.png");
    font=TTF_OpenFont("data/Resources/Fonts/Font1.ttf", 56);
    crash=Mix_LoadWAV("data/Resources/SFX/crash1.wav");

    if (road==NULL or car1==NULL or car2==NULL or car3==NULL or font==NULL or box1==NULL or icon==NULL or crash==NULL) {
        return false;
    }
    return true;
}

I've omitted some irrelevant functions to stay within the message length limit.

I've managed to track the error down to generate_wave(), in the penultimate "if" statement, but am unable to figure out my mistake. Any help is appreciated.

Edit: Due to the random element I use during the program, it appears the error is inside those if statements, though it is present in each one.

Thanks,
hnefatl

[Hippogriff]

You are usually only meant to call the srand() function once in your code, however you are calling it 2-3 times.

Try putting srand(time(NULL)); at the start of your main function, then delete the rest of the srand() lines around your program and try running it again.

Hard to tell if that will solve everything though.

[hnefatl]

I've changed my code; Thanks for that info. However, it still crashes whenever I run it.

Anyone have any ideas?

hnefatl

[Peter87]

In the enemyCar destructor you do enemies.erase(enemies.begin()+carCounter);. The iterator is one after the last element so it is undefined behaviour and might crash the program. If you did remove a valid element there would be problems with carCounter > enemies.size() because the destructor runs more often than the default constructor.

I think one of the problem is that your class tries to handle things outside the class that it shouldn't really care about. Does enemyCar really have to know there is a vector called enemies?

Take a look at the rule of three. http://en.wikipedia.org/wiki/Rule_of_three_%28C%2B%2B_programming%29