How to check which objects collide - collision

Question

i have an example : player object, obstacle_1 object and obstacle_2 object. How do I check which one player collides with? I mean I want to do script_1 for colliding player with obstacle_1 and do script_2 when player collides with obstacle_2. Example:
private void OnTriggerEnter2D(Collider2D collision)
{
//script 1 when this object(player) collides with obstacle_1;
//script 2 when this object(player) collides with obstacle_2;
}

Answer 1

It seems like you're asking how to differentiate between objects. There are many ways of doing so, and it's hard to say which will work best for you since you didn't give a lot of context. Here are some ideas:
One of the simplest ways would be comparing the object's names:
private void OnTriggerEnter2D(Collider2D collision)
{
if(collision.gameObject.name == "Obstacle_1"){
//React to obstacle 1
}
else if (collision.gameObject.name == "Obstacle_2"){
//React to obstacle 2
}
}
I really wouldn't encourage this though, since the name of the objects can be changed quite easily.
You could add Tags to obstacle_1 and obstacle_2, and compare tags, like:
private void OnTriggerEnter2D(Collider2D collision)
{
if(collision.gameObject.CompareTag("Obstacle 1")){
//React to obstacle 1
}
else if (collision.gameObject.CompareTag("Obstacle 2")){
//React to obstacle 2
}
}
This is a bit better, since changing tags is not as easy as changing names, but there's still room for spelling errors. Comparing strings is not very efficient either, especially if done frequently.
You could create different components for obstacle_1 (BouncyObstacle) and obstacle_2 (SpikeObstacle), and then have your player try to get these components, like:
private void OnTriggerEnter2D(Collider2D collision) {
if(collision.gameObject.TryGetComponent(out BouncyObstacle bouncyObs){
// React to bouncy obstacle
}
else if(collision.gameObject.TryGetComponent(out SpikeObstacle spikeObs)
{
//React to spike obstacle
}
}
This is a little bit better, but every time you want to add a new obstacle, you need to add an if to your player code.
Again, it's hard to say which solution would be best. From your snippet, it seems like the player class is responsible for reacting to the obstacles, and this means that every time you want to add a new obstacle, you need to open the player class and change the OnTriggerEnter method. Perhaps it would be better to move this responsibility to separate components. That way you'll be able to add as many obstacles you want without changing any of the previous classes you made. Something like:
public class BouncyObstacle : MonoBehaviour
{
void OnTriggerEnter2D(Collider2D other)
{
if(other.TryGetComponent(out Player player))
{
player.Bounce();
}
}
}
public class SpikeObstacle : MonoBehaviour
{
void OnTriggerEnter2D(Collider2D other)
{
if(other.TryGetComponent(out Player player))
{
player.Kill();
}
}
}
// etc..