To highlight this, I quickly refactored the Circle test.
#include <Collision.hpp>
struct BoundingCircle
{
sf::Vector2f centre;
float radius;
};
sf::Vector2f GetSpriteCenter(const sf::Sprite& object)
{
auto dimensions = object.getGlobalBounds();
return sf::Vector2f (dimensions.left + dimensions.width / 2.0f,
dimensions.top + dimensions.height / 2.0f);
}
sf::Vector2f GetSpriteSize(const sf::Sprite& object)
{
auto originalSize = object.getTextureRect();
auto scale = object.getScale();
return sf::Vector2f (originalSize.width * scale.x, originalSize.height * scale.y);
}
float GetRadiusOfRectangleWithSize(sf::Vector2f size)
{
return (size.x + size.y) / 4;
}
BoundingCircle GetBoundingCircle(const sf::Sprite& object)
{
auto objSize = GetSpriteSize(object);
auto radius = GetRadiusOfRectangleWithSize(objSize);
return BoundingCircle({ GetSpriteCenter(object), radius });
}
bool AreBoundingCirclesIntersecting(BoundingCircle boundingCircleOne, BoundingCircle boundingCircleTwo)
{
auto distance = boundingCircleOne.centre - boundingCircleTwo.centre;
auto magnitudeOfDistanceSquared = distance.x * distance.x + distance.y * distance.y;
auto maximumCollidingDistanceBetweenBoundings = (boundingCircleOne.radius + boundingCircleTwo.radius) * (boundingCircleOne.radius + boundingCircleTwo.radius);
return (magnitudeOfDistanceSquared <= maximumCollidingDistanceBetweenBoundings);
}
bool CircleTest(const sf::Sprite& object1, const sf::Sprite& object2)
{
auto boundingCircleOne = GetBoundingCircle(object1);
auto boundingCircleTwo = GetBoundingCircle(object2);
return AreBoundingCirclesIntersecting(boundingCircleOne, boundingCircleTwo);
}
Note the code is longer, but functionality should be unchanged. I cannot, admittedly, guarantee this as I neglected to take the time to properly surround the code in tests before refactoring. The really interesting part is it reveals the nature of this function: It's actually two,
1. Get the bounding circle of the sprites
2. Check if the bounding circles intersect
