C++ SFML collision detection between different classes

Question

I am making a C++ SFML version of Frogger and currently trying to implement collision detection between the frog and other objects (cars, trucks, logs etc). I have separate classes for the frog and the game objects and want to use bounding boxes to detect intersections as shown below.

// get the bounding box of the entity
sf::FloatRect boundingBox = entity.getGlobalBounds();
// check collision with another box (like the bounding box of another 
entity)
sf::FloatRect otherBox = ...;
if (boundingBox.intersects(otherBox))
{
    // collision!
} 

The problem I am having is that I have no idea how to make this work with two sprites from separate classes and after days of searching I can't find an explanation of how to do it.

Answer 1

Suppose there are two objects 'a' and 'b' that contain the sprites that you want to test for. Then you can call the following in your code to test for a collision between them:

#include "MyEntityA.hpp"
#include "MyEntityB.hpp"

MyEntityA entity_a;
MyEntityB entity_b;   

if(entity_a.getSprite().getGlobalBounds().intersects(entity_b.getSprite().getGlobalBounds()))
{
    // A collision happened.
}

Look here for further information: https://www.sfml-dev.org/tutorials/2.1/graphics-transform.php#bounding-boxes

Answer 2

You have to forward declare your classes in order to make each other see each other.

carsprite.h

class FrogSprite; //declare your FrogSprite here

class CarSprite
{

};

frogsprite.h

class CarSprite;

class FrogSprite
{

};

after that, you can include the header files in its cpp files to see the classes's full definition.

carsprite.cpp

#include "frogsprite.h"

frogsprite.cpp

#include "carsprite.ccp"