(Boolean/SFML) How do I create a boolean that checks collision? - c++

Question

So I recently got into SFML programming, and I need help creating a bool that checks if two rectangles are colliding or overlapping each other.
This is the code so far:
bool collision(sf::Rect rect, sf::Rect rect2){
return rect.getGlobalBounds().intersects(rect2.getGlobalBounds());
}
I'm receiving these errors:
missing template arguments before 'rect'
missing template arguments before 'rect2'
expected primary-expression before ')' token
I am making a platformer and cannot find an efficient way to test collision between the player and the world.
This is the kind of code I want to write for this simple program:
if(collision(rectangle1,rectangle2)){
std::cout << "collision" << std::endl;
}
Any help is appreciated! :)
Here is my code:
#include <SFML/Graphics.hpp>
#include <SFML/Window/Keyboard.hpp>
#include <SFML/Graphics/Rect.hpp>
int main(){
sf::RenderWindow window(sf::VideoMode(800,600),"INSERT_WINDOW_TITLE", sf::Style::Titlebar | sf::Style::Close);
sf::RectangleShape rect1(sf::Vector2f(20.f,20.f));
rect1.setFillColor(sf::Color::Blue);
sf::RectangleShape rect2(sf::Vector2f(20.f,20.f));
rect2.setFillColor(sf::Color::Green);
bool collision(sf::FloatRect r1, sf::FloatRect r2)
{
return r1.intersects(r2, sf::FloatRect());
}
while(window.isOpen()){
sf::Event event;
while(window.pollEvent(event)){
if (event.type == sf::Event::Closed)
window.close();
}
if(sf::Keyboard::isKeyPressed(sf::KeyBoard::W) && collision(rect1,rect2) == false) rect1.move(0.f,-1.f);
if(sf::Keyboard::isKeyPressed(sf::KeyBoard::S) && collision(rect1,rect2) == false) rect1.move(0.f,1.f);
if(sf::Keyboard::isKeyPressed(sf::KeyBoard::A) && collision(rect1,rect2) == false) rect1.move(-1.f,0.f);
if(sf::Keyboard::isKeyPressed(sf::KeyBoard::D) && collision(rect1,rect2) == false) rect1.move(1.f,0.f);
window.draw(rect1);
window.draw(rect2);
window.display();
}
}

Answer 1

Rect is a class template, not an actual class. There are predefined typedefs called IntRect and FloatRect for Rect<int> and Rect<float> respectively. You want to use one of those:
bool collision(sf::FloatRect r1, sf::FloatRect r2)
{
sf::FloatRect intersection;
return r1.intersects(r2, intersection);
}
UPDATE:
Here's a "fixed" version of your code. I added an overload that takes Shapes and forwards to the Rect collision-checking function. I also repositioned your rect2 rectangle; otherwise you cannot move as you already have a collision.
#include <SFML/Graphics.hpp>
#include <SFML/Window/Keyboard.hpp>
bool collision(sf::FloatRect r1, sf::FloatRect r2)
{
sf::FloatRect intersection;
return r1.intersects(r2, intersection);
}
bool collision(sf::Shape const & r1, sf::Shape const & r2)
{
return collision(r1.getGlobalBounds(), r2.getGlobalBounds());
}
int main(){
sf::RenderWindow window(sf::VideoMode(800,600),"INSERT_WINDOW_TITLE", sf::Style::Titlebar | sf::Style::Close);
sf::RectangleShape rect1(sf::Vector2f(20.f,20.f));
rect1.setFillColor(sf::Color::Blue);
sf::RectangleShape rect2(sf::Vector2f(20.f,20.f));
rect2.setFillColor(sf::Color::Green);
rect2.setPosition(100.f, 100.f);
while(window.isOpen()){
sf::Event event;
while(window.pollEvent(event)){
if (event.type == sf::Event::Closed)
window.close();
}
if(sf::Keyboard::isKeyPressed(sf::Keyboard::W) && collision(rect1,rect2) == false) rect1.move(0.f,-1.f);
if(sf::Keyboard::isKeyPressed(sf::Keyboard::S) && collision(rect1,rect2) == false) rect1.move(0.f,1.f);
if(sf::Keyboard::isKeyPressed(sf::Keyboard::A) && collision(rect1,rect2) == false) rect1.move(-1.f,0.f);
if(sf::Keyboard::isKeyPressed(sf::Keyboard::D) && collision(rect1,rect2) == false) rect1.move(1.f,0.f);
window.clear();
window.draw(rect1);
window.draw(rect2);
window.display();
}
}
Note that there are other issues here as well; e.g. your game loop runs as fast as possible right now, which is probably not what you want. This code does run, though.