How can you test for physics collisions?

Questions
1

The examples were unclear about this topic. I want to know how I can test if object 1 touches object 2 and how I can make change a Boolean if those two objects are touching.

2

This function works like the touch function:

function collide(c) 
--All collisions between physics bodies happen here. 
--Use c.state == BEGAN/c.state == MOVING/c.state == ENDED to collect the  
--relevant data from collisions as shown in the reference in Codea.
 if c.state == BEGAN then
  print("Collided!")
 end
end

It will print “Collided!” when two bodies hit.

3

What if I wanted to see if object 1 hit object 2 SPECIFICALLY rather than the floor?

4

@Paintcannon You can set an “info” field so that each object has a unique name. When a collision occurs, you check the “info” field and determine what you want to do based on that.

5

to amplify what dave said

--when you set up object A, also give it an id
A.info="A"

--then in the collide function
if bodyA.info=="A then  --bodyA is A
elseif bodyB.info=="A then --bodyB is A
6

@Paintcannon — Or, use this is draw():

if bodyA:testOverlap(bodyB) then
     --what is supposed to happen when they are touching
end
7

That is much simpler. Thank you.