How to test for intersection of two 2D sprites without using a collision detector?

Questions & Answers
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1

I have a Canvas with a large Image component. Now I place two child objects under that Image component (2D sprites).

How can I check whether or not the two objects intersect?

(without using any physics, mesh colliders, etc ideally)

My main problem is that I don’t understand how to get the coordinates of the bounding boxes of both objects in the coordinate system of the parent Image component.
Easiest for me would be to work with relative coordinates, i.e. the parent game object should provide a coordinate system from 0..1 for both x and y direction.
Any idea how to make each of the sprites “live” in that “0…1” coordinate system of it’s common parent?

3

Easy:

  1. Construct pair of Bounds (AABB is the same thing) from your two sprites.
  2. Run a intersection test for this pair of Bounds.
bool intersetion = a.Intersects(b);

References:

→ Unity - Scripting API: Bounds
→ Unity - Scripting API: Bounds.Intersects
→ Unity - Scripting API: Sprite.bounds
→ Unity - Scripting API: RectTransform.GetWorldCorners
→ Unity - Scripting API: Bounds.SetMinMax
→ Struct AABB | Entities | 1.0.16

2

I must say, the unity forum experience is annoying. Am I asking at the wrong place? Is there a discord / slack channel I’m missing? Should I simply return to stackoverflow. at least my non-unity-questions get almost instantaneous attention there and “easy” questions get commented or answered within a day.

This here feels like writing a question into my own diary…