CODEWITHSUNDEEP
javaandroidcollision-detectiongame-physicsphysics-engine
MehDi
MehDi

Reputation: 514

Android 2d game collision detection

I developed a 2d game in android studio using SurfaceView, it's not complex in context of collision, just need to check collision between a moving-point and some static circles, for detect collision for one circle, I simply check if X of the point is between circle minX and maxX && point Y is between minY and maxY of circle.

So for checking collision in whole of the game, I repeat to check above code for all circles in each frame.

Game work so good when I have for example 10 circles, but if I add 30 circles, its FPS decrease so much and I face so much lag!

What should I do for this problem? should I use Box 2d physics ? what does it do for collision detection that games doesn't face lag problem even if there is so much objects which collide together?

Please help me with more detail, because I was wonder how a game engine work and decided to make a simple one, not only wanted to make and release a game(otherwise I could use a ready game engine).

Thanks in advance

Upvotes: 3

Views: 1784

Answers (2)

Tamoghna Chowdhury
Tamoghna Chowdhury

Reputation: 208

As for how game engines do it, it is probably easiest to look at their source code directly, as at least one version of Unity can do it - you can find the source code of Unity here.

In your case, you could potentially trade off increased memory consumption by your app to make collision detections essentially constant-time regardless of the number of circles, as suggested by @SagarGautam in his comment.

What you can do to achieve this is store a 2D array of booleans indicating all map pixels, setting each element to true if it is inside a circle (as per your previous code) or false otherwise. Doing this during the loading phase of the level/map should be fine, because now during rendering you can just look up the pixel coordinates in the array and see if it is inside a circle or not.

Upvotes: 3

Prathamesh Sahasrabhojane
Prathamesh Sahasrabhojane

Reputation: 89

In 3d game i use Colliders so check if there is any collider(mesh,box,etc.) give tag to that objects.and identify them by tag Example:

using UnityEngine;

using System.Collections;

public class ExampleClass : MonoBehaviour {

    void OnCollisionEnter2D(Collision2D coll) {
        if (coll.gameObject.tag == "Enemy")
            coll.gameObject.SendMessage("collided", 10);

    }
}

Upvotes: 1

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