# DistanceBasedCollision

Another way of detecting collisions. This type works perfectly with circles. It checks if the distance of one object to the other is less than the sum of their radii (plural of radius.)

Variable Definitions : ax, ay = circleA's center coordinates; bx, by = circleB's center coordinates; ar, br = circleA's and circleB's radii, respectively.

```function checkCircularCollision(ax, ay, bx, by, ar, br)
local dx = bx - ax
local dy = by - ay
local dist = math.sqrt(dx * dx + dy * dy)
return dist < ar + br
end```

Don't want an extra square root function? Try this other function

```function checkCircularCollision(ax, ay, bx, by, ar, br)
local dx = bx - ax
local dy = by - ay
return dx^2 + dy^2 < (ar + br)^2
end```

Although I do keep the sqrt function to know that I am dealing with distances.

Do note that while the second may seem faster since it avoids a costly square root, that's still one function, instead of the second version's three squarings. That said, Löve uses LuaJIT, so if one really needs to optimize, check which is faster.