Lag when checking for collision in a top down shooter

[URSvAir14]

Hello all!

I'm currently programming the backbones for a top-down shooting game using SFML 2.1 and C++. I'm getting around to implementing projectiles and collision detection between projectiles and enemy units, however when I added the bounding box collision detection to my game loop it made the game drop from an even 60 FPS to a low 30 FPS.

My game-loop looks similar to this:

while(playing)
{
    //input
    //other processing
    if(BBCollision(player.getProjectile().getSprite(), enemy.getSprite()) == true){
        enemy.setDraw(false);
    }
    // output
}

And my function looks like this:

bool BBCollision(sf::Sprite sprite1, sf::Sprite sprite2){
        if(     sprite1.getPosition().x > sprite2.getPosition().x + sprite2.getGlobalBounds().width &&
                sprite1.getPosition().y > sprite2.getPosition().y + sprite2.getGlobalBounds().height &&
                sprite2.getPosition().x > sprite1.getPosition().x + sprite1.getGlobalBounds().width &&
                sprite2.getPosition().y > sprite1.getPosition().y + sprite1.getGlobalBounds().height)
                return true;
        else
                return false;
}

So can anyone point me what I did wrong and what I could do to get rid of the lag? Thank you in advance

[AlejandroCoria]

You would have to pass Sprites by reference instead of copying.

[URSvAir14]

Ahh okay, thanks

[Nexus]

And you can simplify the code:

// instead of
if (xy == true)

// write
if (xy)

// instead of
if (xy)
    return true;
else
    return false;

// write
return xy;

Furthermore, keep in mind that sf::Sprite has a getGlobalBounds() method.