C++ SFML Segfault between renderer and object - c++

Question

Before I start, I'm going to apologize ahead of time for any seemingly obvious mistakes I may have made. I'm pretty in over my head at this point and there's probably quite a few errors in here.
Any suggestions on fixing what I have, or better ways of setting up what I want are appreciated.
I have two classes, the Renderer and the FParticle.
What I want is for the FParticle constructor to pass a pointer of itself to the Renderer. The Renderer will store the various FParticle pointers in a vector and then when DrawObjects() is called, it will draw all of the objects using the list of pointers.
This way I don't have to worry about passing each particle into the renderer each step of the game loop, and can instead just draw them from the list of pointers.
The problem is that the program is segfaulting and I can't figure out how to deal with it.
The segfault occurs in renderer.cpp
The files are here:
renderer.h
#pragma once
#ifndef RENDERER_H
#define RENDERER_H
#include <SFML/Graphics.hpp>
#include <vector>
class FParticle;
class Renderer {
private:
std::vector<const FParticle*> object_buffer_;
sf::RectangleShape rectangle_;
public:
Renderer();
void addObject(const FParticle &object);
void drawObjects(sf::RenderWindow &window);
};
#endif // RENDERER_H
renderer.cpp
#include "renderer.h"
#include "fparticle.h"
#include <iostream>
Renderer::Renderer() {}
void Renderer::addObject(const FParticle &object)
{
object_buffer_.push_back(&object);
}
void Renderer::drawObjects(sf::RenderWindow &window)
{
for (int i = object_buffer_.size(); i > 0; i--)
{
rectangle_.setSize(object_buffer_[i]->get_size()); // <------- SEGFAULT HERE
rectangle_.setPosition(object_buffer_[i]->get_position());
rectangle_.setFillColor(sf::Color::White);
std::cout << object_buffer_[i]->get_size().x << std::endl;
window.draw(rectangle_);
}
}
fparticle.h
#pragma once
#ifndef FPARTICLE_H
#define FPARTICLE_H
#include <SFML/Graphics.hpp>
class Renderer;
class FParticle
{
protected:
sf::Vector2f size_;
sf::Vector2f position_;
sf::Vector2f velocity_;
sf::Vector2f acceleration_;
float inverse_mass_;
float damping_;
public:
FParticle(Renderer &picasso);
sf::Vector2f get_size() const;
sf::Vector2f get_position() const;
void set_mass();
void set_inverse_mass();
};
#endif // FPARTICLE_H
fparticle.cpp
#include "fparticle.h"
#include "renderer.h"
#include <iostream>
FParticle::FParticle(Renderer &picasso)
{
size_.x = 5.f;
size_.y = 5.f;
position_.x = 10.f;
position_.y = 10.f;
picasso.addObject(*this);
}
sf::Vector2f FParticle::get_size() const
{
return size_;
}
sf::Vector2f FParticle::get_position() const
{
return position_;
}
pseudo main.cpp
int main()
{
Renderer picasso;
FParticle p1(picasso);
while(gamestate != Exiting)
{
window.clear(Black);
picasso.drawObjects(window_);
window.display();
}
return 0
}
Like I said, I'm relatively in over my head and am still in the early stages of learning. Any suggestions or advice on anything are appreciated.

Answer 1

Your vector is only indexible from 0... size-1. You're starting at size, thus out of range, thus invoking undefined behavior, thus (because you were actually fortunate) your crash.
Use an iterator for your collection. If you want this in reverse, use a reverse-iterator.
for (auto it = object_buffer.rbegin(); it != object_buffer.rend(); ++it)
{
rectangle_.setSize((*it)->get_size());
rectangle_.setPosition((*it)->get_position());
rectangle_.setFillColor(sf::Color::White);
std::cout << (*it)->get_size().x << std::endl;
window.draw(rectangle_);
}
or something to that effect.
Note: When in doubt, replace vector/deque operator[i] usage with obj.at(i) accessors instead. The latter is range-checked and will bark at you via assertion the moment you pass an invalid-ranged index.
Best of luck.