Get closest point on 2D perimeter using Bounds

Questions & Answers
1

I’m using the Bounds.ClosestPoint to get the closest point on bounds but when inside the bounds you just get the current spot but I want to keep getting a point on the perimeter.

Can anyone throw me the calculations for that?

2

heh. interesting.

I can't think of a way to shortcut it,
so you'd need to find the shortest distance to each edge yourself.  

Note that Bounds is an Axis-Aligned Bounding Box,
which means the edges are parallel to the X and Y axes,
which simplifies finding the distance from a point to an edge.
3

okay, this actually works. there was another error in my example as well, but I’ve tested this.

Vector3 finder(Vector3 p, Bounds b)
{
    // I'll assume the 2D aspect of this is X and Y, and ignore Z.

    Vector3[] edgePoints = new Vector3[4];

    // point on left edge
    edgePoints[0].x = b.min.x;
    edgePoints[0].y = Mathf.Clamp(p.y, b.min.y, b.max.y);
    edgePoints[0].z = b.center.z;

    // point on right edge
    edgePoints[1].x = b.max.x;
    edgePoints[1].y = Mathf.Clamp(p.y, b.min.y, b.max.y);
    edgePoints[1].z = b.center.z;

    // point on bottom edge
    edgePoints[2].x = Mathf.Clamp(p.x, b.min.x, b.max.x);
    edgePoints[2].y = b.min.y;
    edgePoints[2].z = b.center.z;

    // point on top edge
    edgePoints[3].x = Mathf.Clamp(p.x, b.min.x, b.max.x);
    edgePoints[3].y = b.max.y;
    edgePoints[3].z = b.center.z;

    // now find the closest.

    float closestSqrDist = -1; // value doesn't matter.
    int closestIndex = -1; // value doesn't matter.
    for (int n = 0; n < 4; ++n)
    {
        float sqrDist = (edgePoints[n] - p).sqrMagnitude;
        if ((n == 0) || (sqrDist < closestSqrDist))
        {
            closestSqrDist = sqrDist;
            closestIndex = n;
        }
    }

    Vector3 closestPointOnEdgeOfBoundingBox = edgePoints[closestIndex];

    return closestPointOnEdgeOfBoundingBox;
}