variable in main cpp bug in class - c++

Question

I have created a class takeDommage for apply a number or dmg and activate a countdown for create the invincibility frame.
And i us my "int pv; in my class so then i check the "int pv;" he didn't move
What's wrong ? pv is initialized before main and it's working then i do pv-=1; manually Oo
main :
//{ Include
#include <SFML/Graphics.hpp>
#include <string>
#include <iostream>
#include <cstdlib>
#include <cmath>
#include<vector>
#include <collision.h>
//}
//{ Constantes
//Constantes ecran
int tailleEcranX = 1280;
int tailleEcranY = 720;
//Constantes perso
int scalePerso = 3;
int tailleSpriteX = 32;
int tailleSpriteY = 48;
int speed(4);
int speedSprinte(10);
int milieuSpriteX = (tailleSpriteX/2)*scalePerso;
int milieuSpriteY = (tailleSpriteY/2)*scalePerso;
int pv = 100;
unsigned int pvMax = 100;
int eSpeed = 1;
//}
//{ Initialisation
//Initiation des dessins
sf::RenderWindow window;
sf::RectangleShape rect;
sf::Texture perso;
sf::Texture ennemis;
sf::Sprite sprite_perso;
sf::Sprite sprite_ennemis;
sf::View view;
sf::RectangleShape rectCol;
sf::RectangleShape pvBar;
sf::RectangleShape pvMaxBar;
enum Dir{Down,Left,Right,Up};
sf::Vector2i anim (1,Down);
#include "gestion_clavier.h"
#include <takeDommage.h>
//}
//{ Main
int main()
{
//{ Positionnement des objets
window.create(sf::VideoMode(tailleEcranX , tailleEcranY), "The Game I");
window.setPosition(sf::Vector2i(500,250));
window.setFramerateLimit(120);
//Fond d'ecran
rect.setFillColor(sf::Color(110,155,255));
rect.setSize(sf::Vector2f(tailleEcranX-10,tailleEcranY-10));
rect.setPosition(5,5);
rect.setOutlineColor(sf::Color(255,255,255));
rect.setOutlineThickness(3);
//rectangle de collision test
rectCol.setFillColor(sf::Color(0,0,200));
rectCol.setSize(sf::Vector2f(50,50));
rectCol.setPosition(400,500);
rectCol.setOutlineColor(sf::Color(255,255,255));
rectCol.setOutlineThickness(1);
//Bar pv
pvBar.setFillColor(sf::Color(20,255,30));
pvBar.setPosition(20,20);
pvMaxBar.setFillColor(sf::Color(0,0,0));
pvMaxBar.setPosition(20,20);
pvMaxBar.setOutlineColor(sf::Color(255,255,255));
pvMaxBar.setOutlineThickness(2);
//Perso
sprite_perso.setTexture(perso);
sprite_perso.setPosition(tailleEcranX/2-milieuSpriteX,tailleEcranY/2-milieuSpriteY);
sprite_perso.setScale(scalePerso,scalePerso);
//Ennemis
sprite_ennemis.setTexture(ennemis);
sprite_ennemis.setPosition(tailleEcranX/2-milieuSpriteX,tailleEcranY/2-milieuSpriteY);
sprite_ennemis.setTextureRect(sf::IntRect(anim.x*tailleSpriteX,anim.y*tailleSpriteY,tailleSpriteX,tailleSpriteY));
sprite_ennemis.setScale(scalePerso,scalePerso);
//Ennemis
sf::RectangleShape enemy;
enemy.setFillColor(sf::Color(200,0,0));
enemy.setSize(sf::Vector2f(50.f, 50.f));
takeDommage obj;
//Clock
sf::Clock time;
//sf::Clock takeDammageClock;
//}
//{Chargement des Sprites
if (!perso.loadFromFile("link/srpite.png",sf::IntRect(0,0,96,192)))
{
std::cout<<"erreur chargement player image"<<std::endl;
}
if (!ennemis.loadFromFile("link/srpite.png",sf::IntRect(288,0,96,192)))
{
std::cout<<"erreur chargement player image"<<std::endl;
}
//}
//{ Game Loop
while (window.isOpen())
{
sf::Event event;
while (window.pollEvent(event))
{
if (event.type == sf::Event::Closed)
window.close();
}
//Stat avec rafrechisement
//Bar pv
pvMaxBar.setSize(sf::Vector2f(4*pvMax,10));
pvBar.setSize(sf::Vector2f(4*pv,10));
//Perso
sprite_perso.setTextureRect(sf::IntRect(anim.x*tailleSpriteX,anim.y*tailleSpriteY,tailleSpriteX,tailleSpriteY));
//Ennemy
std::vector<sf::RectangleShape> enemies;
enemies.push_back(sf::RectangleShape(enemy));
int enemySpawnTimer = 0;
ProcessInput();
//gestion_clavier();
if(sf::Keyboard::isKeyPressed(sf::Keyboard::Z)||sf::Keyboard::isKeyPressed(sf::Keyboard::S)||sf::Keyboard::isKeyPressed(sf::Keyboard::D)||sf::Keyboard::isKeyPressed(sf::Keyboard::Q))
{
if (time.getElapsedTime().asMilliseconds()>= 50)
{
anim.x++;
if(anim.x*tailleSpriteX >= perso.getSize().x)
anim.x=0;
time.restart();
}
}
//Boucle Pv
if(pv>=pvMax)
{
pv=pvMax;
}
if(pv<=0)
{
pv=0;
}
//ENEMIES
if(enemySpawnTimer < 50)
enemySpawnTimer++;
if (enemySpawnTimer >= 50)
{
enemy.setPosition((rand() % int(window.getSize().x - enemy.getSize().x)), 0.f);
enemies.push_back(sf::RectangleShape(enemy));
enemySpawnTimer = 0;
}
for (size_t i = 0; i < enemies.size(); i++)
{
enemies[i].move(0, eSpeed);
if (enemies[i].getPosition().y > window.getSize().y)
enemies.erase(enemies.begin() + i);
}
//Collision
if(Collision::PixelPerfectTest(sprite_perso,sprite_ennemis))
{
//std::cout<<"collision pp"<<std::endl;
obj.prendreDegat(50 ,pv);
//std::cout<<pv<<std::endl;
}
//Dessinage
window.draw(rect);
window.draw(rectCol);
window.draw(sprite_perso);
window.draw(sprite_ennemis);
window.draw(pvMaxBar);
window.draw(pvBar);
//Boucle dessinage
for (size_t i = 0; i < enemies.size(); i++)
{
window.draw(enemies[i]);
}
window.display();
window.clear();
}
//}
return 0;
}
takeDommage.h :
#ifndef TAKEDOMMAGE_H
#define TAKEDOMMAGE_H
#include <SFML/Graphics.hpp>
#include <string>
#include <iostream>
#include <cstdlib>
#include <cmath>
class takeDommage
{
public:
takeDommage();
void prendreDegat(int Dommage, int pv);
//virtual ~takeDommage();
protected:
sf::Clock takeDammageClock;
int Dommage;
private:
};
#endif // TAKEDOMMAGE_H
takeDommage.cpp :
#include "takeDommage.h"
takeDommage::takeDommage()
{
}
void takeDommage::prendreDegat(int Dommage, int pv)
{
if(takeDammageClock.getElapsedTime().asSeconds()>3)
{
std::cout << "bite" << std::endl;
pv -= Dommage;
takeDammageClock.restart();
}
}

Answer 1

if(Collision::PixelPerfectTest(sprite_perso,sprite_ennemis))
{
//std::cout<<"collision pp"<<std::endl;
obj.prendreDegat(50 ,pv);
//std::cout<<pv<<std::endl;
}
you are passing the pv by value.
this causes the void takeDommage::prendreDegat(int Dommage, int pv) to make a local copy of of the pv and decrements the value by Dommage.
what you have to do is pass it by reference. in c++ you do that by Type&
so in your case you change your takeDommage to void takeDommage::prendreDegat(int Dommage, int& pv)
since the pv is now passed by reference, any operation you make in takeDommage::prendreDegat will affect the global pv.
Edit: passing the global variables is not considered a good code practice. But im not going to go into details into that since you just starting c++. Try moving your std::cout<<pv<<std::endl from your main and place it into void takeDommage::prendreDegat(int Dommage, int pv) without making changes and see what happens.