I'd like to know how I check whether two UI Panels on my Unity Canvas are overlapping each other.
Currently I am doing this by comparing the canvas elements Rects
Canvas Settings
Canvas Scaler Settings
Code I am using to check
[Header("Check For Overlap")]
public RectTransform PlayerBar;
public RectTransform LeftBar;
public Rect RectOne;
public Rect RectTwo;
public bool overlapping;
//Check if the two canvas element Rects overlap each other
public void CheckForOverlap()
{
overlapping = false;
// Convert Canvas RectTransforms to World Rects
RectOne = GetWorldRect(LeftBar);
RectTwo = GetWorldRect(PlayerBar);
if (RectOne.Overlaps(RectTwo))
{
overlapping = true;
}
}
public Rect GetWorldRect(RectTransform rt)
{
// Get World corners, take top left
Vector3[] corners = new Vector3[4];
rt.GetWorldCorners(corners);
Vector3 topLeft = corners[0];
// Rect Size ... I'm not sure if this is working correctly?
Vector2 size = new Vector2(rt.rect.size.x, rt.rect.size.y);
return new Rect(topLeft, size);
}
What happens
'Overlapping' bool instantly changes to true.
The Rect One returns as (example)
X -7.5, Y 2.5 W 98.5, H 164.1667
Updated version considering scale of the rectTransform.
public static class RectTransformExtensions
{
public static bool Overlaps(this RectTransform a, RectTransform b) {
return a.WorldRect().Overlaps(b.WorldRect());
}
public static bool Overlaps(this RectTransform a, RectTransform b, bool allowInverse) {
return a.WorldRect().Overlaps(b.WorldRect(), allowInverse);
}
public static Rect WorldRect(this RectTransform rectTransform) {
Vector2 sizeDelta = rectTransform.sizeDelta;
float rectTransformWidth = sizeDelta.x * rectTransform.lossyScale.x;
float rectTransformHeight = sizeDelta.y * rectTransform.lossyScale.y;
Vector3 position = rectTransform.position;
return new Rect(position.x - rectTransformWidth / 2f, position.y - rectTransformHeight / 2f, rectTransformWidth, rectTransformHeight);
}
}