Get merged area between 2 surfaces ?

stalex

Hello everyone ! I searched in the documentation but I haven't found anything regarding this simple point: I'm using Area2D and built a drag and drop system. My moved area2D is effectively launching an area_entered event when I move it onto another Area2D:

Appropriate example is a Scrabble letter that goes onto a Scrabble grid. Is there a way in Godot to simply know what is the surface (in pixels ? in ???) that overlaps the two Area2D.

It corresponds to the green surface on my draw, when the letter is moved on a grid cell, I want to know if the letter is only partially included in the overlapped grid cell or almost totally included. So I think the overlapped zone in pixel would be great.

Do you have any clue on how to proceed ? Thanks a lot !!

pkowal1982

If areas are rectangular you can calculate overlapping area by simple math like in test project.

Calinou

The Rect2 type (which represents a 2D axis-aligned box) has an intersect() method you can use for this purpose.

stalex

@pkowal1982 said: If areas are rectangular you can calculate overlapping area by simple math like in test project.

Hello ! Thanks for for answer ! In your code, can you tell me what const EXTENT := 20 corresponds to ?

It sounds the moved zone size, in this case why not taking simply $Moving/ColorRect.size instead of a const ?

pkowal1982

Probably I should call it SIZE, as it's equal to width and height of areas.

I assumed that you needed square areas as shown in your example. If you need areas to be any size (but rectangular) you can use the modified test project. It uses Rect2.clip() and Rect2.get_area().

Rect2.intersects() will only tell you if rectangles overlap, you'll still need to somehow calculate the size of overlapping zone.

cybereality

You need to use the intersection() function of the AABB class. https://docs.godotengine.org/en/stable/classes/class_aabb.html

stalex

Thanks for your help, this solved my problem. @cybereality , AABB is used for 3D. The counterpart for 2D is Rect2 as pokawl pointed me out.

Again thanks.

cybereality

Okay cool. Yes, I mostly work in 3D so I am not as strong in 2D knowledge.