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up vote 2 down vote favorite

Hi im making a platformer in javascript and this is the collision function that I have

if(obj2.y > obj1.y + obj1.height ||
   obj2.y + obj2.height < obj1.y||
   obj2.x > obj1.x + obj1.width ||
   obj2.x + obj2.width < obj1.x){
    return false;
} else {
    return true;
}

so my question is how do I tell which side obj1 is colliding with obj2?.

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1 Answer 1

up vote 1 down vote accepted

In your collision function, instead of returning a boolean, return a string so that you can detect each face:

function colCheck(args) {
    if(obj2.y > obj1.y + obj1.height) {
        return "u"
    }
    if(obj2.y + obj2.height < obj1.y) {
        return "d"
    }
    if(obj2.x > obj1.x + obj1.width) {
        return "r"
    }
    if(obj2.x + obj2.width < obj1.x) {
        return "l"
    } else {
        return false;
    }
}

Depending on the collision, the function will return u,d,l, or r, which you can use however you like

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