Wrong element is removed after leaving method which used std::erase succesfully - c++

Question

I am working on a graphics engine. The engine has a std::vector of drawables. A Drawable is an object which contains a Model and a DrawableObject, which in turn holds a shader program and a bunch vertices from a 2D or 3D model. Adding new Drawables goes well, the problem occurs when I try to remove a Drawable. The last Drawable will always be removed and the second to last will have its values changed.
Code
Drawable.h
class Drawable
{
public:
Drawable& operator=(const Drawable& other)
{
Drawable tmp(other);
std::swap(model, other.model);
std::swap(drawableObject, other.drawableObject);
return *this;
}
Drawable(domain::Model& model, DrawableObject& drawableObject) :
model(model),
drawableObject(drawableObject)
{}
domain::Model& model;
DrawableObject& drawableObject;
};
game.cpp
void Game::init_game()
{
human = domain::Model(glm::vec3(0, 0, -3));
moveables.push_back(&human);
room = domain::Model(glm::vec3(0, 0, -10));
props.push_back(&room);
cube = domain::Model(glm::vec3(0, 0, 0));
props.push_back(&cube);
}
void Game::init_graphics_engine()
{
// ... load graphics models
// add drawables
graphicsEngine->add(cube, Drawable::CUBE);
graphicsEngine->add(human, Drawable::HUMAN);
graphicsEngine->add(room, Drawable::ROOM);
graphicsEngine->add(topDownScene->cursor, Drawable::MARKER);
}
graphics_engine/engine.cpp
void Engine::add(domain::Model& model, unsigned int object)
{
auto drawableObject = drawableObjects[object];
// make sure not to add a model that already is represented
auto it = std::find_if(drawables.begin(), drawables.end(), [&model](Drawable& drawable) {return &drawable.model == &model;});
if(drawableObject && it == drawables.end())
drawables.push_back(Drawable(model, *drawableObject));
}
void Engine::remove(domain::Model& model)
{
auto predicate = [&model](Drawable& drawable)
{
return &drawable.model == &model;
};
drawables.erase(std::remove_if(drawables.begin(), drawables.end(), predicate), drawables.end());
}
Scenes
This is what the scene looks like when I start the application:
This is what the scene looks like after attempting to erase the small 'human' cube in the middle:
The code removes the last Drawable, which is the white marker, instead of the 'human' cube, and changed the z position of the room. This almost always happens, it removes the last element and changed the z of the second to last. It only works if I add the 'human' cube last in the init method.
Breakpoints
Before removing the object:
After removing the object:
This is correct.
Leaving the remove method and taking a look in the render loop:
Somehow changed.

Answer 1

I changed the class members to pointers. Now it works. The comments were right, I didn't do anything with the tmp variable.
class Drawable
{
public:
Drawable& operator=(const Drawable& other)
{
this->model = other.model;
this->drawableObject = other.drawableObject;
return *this;
}
Drawable(domain::Model* model, std::shared_ptr<DrawableObject> drawableObject) :
model(model),
drawableObject(drawableObject)
{}
domain::Model* model;
std::shared_ptr<DrawableObject> drawableObject;
};