__device__ __inline__ int
circleInBoxConservative(
    float circleX, float circleY, float circleRadius,
    float boxL, float boxR, float boxT, float boxB)
{

    // expand box by circle radius.  Test if circle center is in the
    // expanded box.

    if ( circleX >= (boxL - circleRadius) &&
         circleX <= (boxR + circleRadius) &&
         circleY >= (boxB - circleRadius) &&
         circleY <= (boxT + circleRadius) ) {
        return 1;
    } else {
        return 0;
    }
}

__device__ __inline__ int
circleInBox(
    float circleX, float circleY, float circleRadius,
    float boxL, float boxR, float boxT, float boxB)
{

    // clamp circle center to box (finds the closest point on the box)
    float closestX = (circleX > boxL) ? ((circleX < boxR) ? circleX : boxR) : boxL;
    float closestY = (circleY > boxB) ? ((circleY < boxT) ? circleY : boxT) : boxB;

    // is circle radius less than the distance to the closest point on
    // the box?
    float distX = closestX - circleX;
    float distY = closestY - circleY;

    if ( ((distX*distX) + (distY*distY)) <= (circleRadius*circleRadius) ) {
        return 1;
    } else {
        return 0;
    }
}