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Zonsa

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Use value from another Class
« on: December 10, 2021, 03:16:04 pm »
Hey,
i cant use a value from another class ... in this example videoMode.height, and videoMode.width are 0 even tho i give the value of the window size in void starship::windowValues(int width, int height)
Im quite a beginner in c++ ... so im lost here :(

My plan was to give the size of the window in a function defined in starship.h, and use it in game.cpp to give the value of width and height, and then give these values to sf::VideoMode  videoMode; in starship.cpp.

starship.cpp
#include "game.h"
#include "starship.h"
#include <math.h>

//Constructor/Destructor

starship::starship()
{
    //Init
    initVariables();
    initShip();
    initBullet();
    void windowValues(int , int );
}

starship::~starship()
{
   
}

void starship::initVariables()
{
    // Dont change
    spawnBulletBool = false;
    speedCur = 0.f;

    //Parameters
    acceleration = 0.00001f; //Speed the Ship Accelerates -- Normal 0.000025f - Fast 0.00005f - Slow 0.00001f
    speedMax = 0.1f; //Max Speed the Ship travels -- Normal 0.1f

   
}


//Init Stuff

void starship::initShip()
{
    //Load Texture
    texture.loadFromFile("assets/graphics/starship.png");
    ship.setTexture(texture);

    //Change Origin
    ship.setOrigin(ship.getGlobalBounds().width / 2, ship.getGlobalBounds().height / 2);
    ship.setPosition(500 , 500);

    std::cout << videoMode.height; // <------------------
    std::cout << videoMode.width;  // <------------------
}

void starship::initBullet()
{
    //Load Texture
    bulletTexture.loadFromFile("assets/graphics/bullet.png");
    bullet.setTexture(bulletTexture);

    //Change Origin
    bullet.setOrigin(bullet.getGlobalBounds().width / 2, bullet.getGlobalBounds().height / 2);
}

//Functions

void starship::controlShip()
{
    if(sf::Keyboard::isKeyPressed(sf::Keyboard::Left))
    {
        ship.rotate(-1 * 0.06);
    }

    if(sf::Keyboard::isKeyPressed(sf::Keyboard::Right))
    {
        ship.rotate(1 * 0.06);
    }

    if(sf::Keyboard::isKeyPressed(sf::Keyboard::Up))
    {
        if(speedCur < speedMax)
            speedCur += acceleration;

        ship.move(sin((ship.getRotation() / 180) * 3.14) * speedCur, -1 * cos((ship.getRotation() / 180) * 3.14) * speedCur);
    }    

    if(sf::Keyboard::isKeyPressed(sf::Keyboard::Down))
    {
        if(speedCur > speedMax * -1)
            speedCur -= acceleration;

        ship.move(sin((ship.getRotation() / 180) * 3.14) * speedCur, -1 * cos((ship.getRotation() / 180) * 3.14) * speedCur);
    }

    if(sf::Keyboard::isKeyPressed(sf::Keyboard::Space) && spawnBulletBool == false)
    {
       
        prevTimeBullet = time.asSeconds();

        spawnBulletBool = true;

        spawnBullet();
    } else if(!sf::Keyboard::isKeyPressed(sf::Keyboard::Space)) spawnBulletBool = false;
   
    //Breaking
    if(!sf::Keyboard::isKeyPressed(sf::Keyboard::Up) && !sf::Keyboard::isKeyPressed(sf::Keyboard::Down))
    {
        if(speedCur > 0)
            speedCur -= acceleration;
        if(speedCur < 0)
            speedCur += acceleration;

        ship.move(sin((ship.getRotation() / 180) * 3.14) * speedCur, -1 * cos((ship.getRotation() / 180) * 3.14) * speedCur);
    }
}

void starship::windowValues(int width, int height)
{
    starship::videoMode.width = width;
    starship::videoMode.height = height;
}

void starship::spawnBullet()
{
    bullet.setRotation(ship.getRotation());
    bullet.setPosition(ship.getPosition().x, ship.getPosition().y);

    bullets.push_back(bullet);
}


//Update Stuff

void starship::updateShip()
{
    controlShip();
    updateBullet();
}

void starship::updateBullet()
{
    for(int i = 0; i < bullets.size(); i++)
        bullets[i].move(sin((bullets[i].getRotation() / 180) * 3.14) / 5, -1 * cos((bullets[i].getRotation() / 180) * 3.14) / 5);
}


// Render Stuff

void starship::renderShip(sf::RenderTarget& target)
{
    //Render Bullets
    for(auto &e : this->bullets)
    {
        target.draw(e);
    }

    //Render Ship
    target.draw(ship);
}
 

starship.h
#ifndef __STARSHIP_H
#define __STARSHIP_H

#include <SFML/Graphics.hpp>
#include <SFML/Window.hpp>
#include <SFML/Network.hpp>
#include <SFML/System.hpp>
#include <SFML/Audio.hpp>

#include <iostream>


class starship
{
public:
    sf::VideoMode videoMode;

    //Functions
    void windowValues(int, int);
    void spawnBullet();

    //Render
    void renderShip(sf::RenderTarget& target);
    void renderBullet(sf::RenderTarget& target);

    //Update
    void updateShip();
    void updateBullet();
    void controlShip();

    //Constructor/Destructor
    starship();
    ~starship();

private:
    //Ship
    sf::Sprite ship;
    sf::Texture texture;

    //Bullets
    sf::Sprite bullet;
    sf::Texture bulletTexture;
    std::vector<sf::Sprite> bullets;
    sf::Time time;

    //Variables
    int prevTimeBullet;
    int attackSpeed;
    bool spawnBulletBool;
    float speedMax;
    float acceleration;
    float speedCur;

    //Init
    void initVariables();
    void initShip();
    void initBullet();
};
#endif

game.cpp
#include "game.h"
#include "starship.h"


//Private functions
void Game::initVariables()
{
    this->window = nullptr;
}
void Game::initWindow()
{

    this->videoMode.width = 1280;
    this->videoMode.height = 720;
   
    starship::windowValues(videoMode.width, videoMode.height);

    this->window = new sf::RenderWindow(this->videoMode, "Window", sf::Style::Titlebar | sf::Style::Close);

    //this->window->setFramerateLimit(140);
}


//Constructors / Destructors
Game::Game()
{
    this->initVariables();
    this->initWindow();

}

Game::~Game()
{
delete this->window;

}

//Accessors
const bool Game::getWindowIsOpen() const
{
    return this->window->isOpen();
}


//Functions
void Game::pollEvent()
{
while(this->window->pollEvent(this->ev))
    {
    switch(this->ev.type)
    {
        case sf::Event::Closed:
        this->window->close();
        break;
        case sf::Event::KeyPressed:
        if (this->ev.key.code == sf::Keyboard::Escape)
            this->window->close();
        break;
        }
    }
}

void Game::update()
{
    //Event polling
    this->pollEvent();
    starship::updateShip();
    enemy::updateAsteroids();

}

void Game::render()
{
    /*
        @return void

        * clear old frame
        * render objects
        * display frame in window
       
        Renders the game objects.
    */


    this->window->clear(sf::Color(190, 63, 63, 255));

    //Draw game objects
    starship::renderShip(*window);
    enemy::renderAsteroids(*window);
    this->window->display();
   
}
 

game.h
#ifndef __GAME_H
#define __GAME_H

#include <SFML/Graphics.hpp>
#include <SFML/Window.hpp>
#include <SFML/Network.hpp>
#include <SFML/System.hpp>
#include <SFML/Audio.hpp>

#include <iostream>
#include "starship.h"
#include "enemy.h"

/*
    Class that acts as the game engine.
    Wrapper class.
*/


class Game : public starship, public enemy
{
private:


    //Private function
    void initVariables();
    void initWindow();

public:
    //Window
    sf::RenderWindow* window;
    sf::VideoMode videoMode;
    sf::Event ev;


    //Constructors / Destructors
    Game();
    virtual ~Game();

    //Accessors
    const bool getWindowIsOpen() const;

    //Functions
    void pollEvent();
    void update();
    void render();
};

#endif

kojack

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Re: Use value from another Class
« Reply #1 on: December 10, 2021, 05:29:50 pm »
The width and height are printed in initShip().
initShip() is called by the starship constructor.
Since Game inherits from starship (it's saying the game is actually a starship and an enemy at the same time), so when Game is created it automatically calls the starship constructor.
https://www.studytonight.com/cpp/order-of-constructor-call.php
This means the values of videoMode are printed before you have called windowValues to set the values.

Also, there's two videoMode variables. One in the starship base class, one in Game which is shadowing the one in starship.
Shadowing in C++ is when there's two variables with the same name and one is hiding the other from being used. It can cause bugs because depending on where you try to access it, you might get either of the variables.