Apply an Addforce type of effect to a Kinematic Rigidbody2D

Hey guys,

So I have a doodle jump style game, I originally had the player bouncing off of the platforms, whilst the platforms themselves merely moved down the screen and got moved to the top of the screen. I've been told by folk that this would eat up a mobile device's memory a fair chunk so why not make it so the platforms have the addforce effect going down? Essentially making the play space not move.

Here's my problem, I am moving the bounce platforms with a Kinematic Rigidbody 2D, and I can't do an addforce type of effect on them as they are already moving downwards...

Code (CSharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class BouncePlatform : MonoBehaviour
6. {  
7.     public int jumpAmount;
8.     public int moveSpeed;
9.        
10.     private Transform myTransform;
11.     private BoxCollider2D platformBoxCollider;
12.     private Player player;
13.     private Rigidbody2D rb;
14.      
15.     void Start()  
16.     {  
17.         platformBoxCollider = GetComponent<BoxCollider2D>();
18.         myTransform = this.transform;
19.         rb = GetComponent<Rigidbody2D>();
20.         player = FindObjectOfType<Player>();  
21.     }  
22.    
23.     void Update()  
24.     {
25.         rb.velocity = Vector2.down;
26.         if(player == null)
27.         {
28.             return;
29.         }
30.         else
31.         {
32.             if(player.transform.position.y > myTransform.transform.position.y)  
33.             {      
34.                 platformBoxCollider.enabled = true;  
35.             }    
36.             else  
37.             {  
38.                 platformBoxCollider.enabled = false;          
39.             }
40.         }  
41.     }
42.    
43.     public void Jump()
44.     {
45.         //Addforce downward to the platforms
46.     }
47. }
48.  

And also here is my player script which is adding jumpforce as the rigidbody2D isn't kinematic...

Code (CSharp):

1.  
2. using UnityEngine;
3. using UnityEngine.UI;
4. using System.Collections;
5.  
6. public class Player : MonoBehaviour
7. {      
8.     public float moveFactor;
9.     public int health;
10.     public GameObject playerHealthText;
11.     public bool isInvulnerable;
12.  
13.     private Animator animationController;
14.     private Rigidbody2D rb;
15.     private float invulnerableTimer;
16.     private BouncePlatform bouncePlatform;
17.    
18.     public void Start()
19.     {
20.         invulnerableTimer = 5.0f;
21.         animationController = GetComponent<Animator> ();
22.         rb = GetComponent<Rigidbody2D>();
23.         bouncePlatform = FindObjectOfType<BouncePlatform>();
24.     }
25.    
26.     void Update()
27.     {  
28.         playerHealthText.GetComponent<Text> ().text = "Health: " + health.ToString();
29.         health = Mathf.Clamp (health, 0, 3);
30.  
31.         if (health <= 0)
32.         {
33.             //TODO Some sort of level end thing, this also probably belongs in a GameManager object?
34.             Destroy(gameObject);
35.         }
36.  
37.         //invulnerability timer
38.         if(isInvulnerable)
39.         {
40.             invulnerableTimer -= Time.deltaTime;
41.             if(invulnerableTimer <= 0.0)
42.             {
43.                 isInvulnerable = false;
44.             }
45.         }
46.  
47.         //Camera things
48.         OnBecameInvisible();
49.     }
50.  
51.     void FixedUpdate()
52.     {
53.         //Horizontal Movement
54.         float playerXInput = Input.GetAxis("Horizontal");
55.         float movePlayer = playerXInput * moveFactor;
56.         rb.AddForce(new Vector2(movePlayer, 0f));
57.     }
58.  
59.     void OnBecameInvisible()
60.     {
61.         var cam = Camera.main;
62.         var viewportPosition = cam.WorldToViewportPoint(transform.position);
63.         var newPosition = transform.position;
64.  
65.         if (viewportPosition.x > 1 || viewportPosition.x < 0)
66.         {
67.             newPosition.x = -newPosition.x;
68.         }
69.         transform.position = newPosition;
70.     }
71.    
72.     void OnTriggerEnter2D(Collider2D collider)
73.     {
74.         if(collider.gameObject.tag == "BouncePlatform")
75.         {
76.             Debug.Log("Hit: " + collider.gameObject.tag);
77.             bouncePlatform.Jump();
78.             rb.AddForce(Vector2.up * 500);
79.         }
80.     }
81.  
82.     public void Damage(int damage)
83.     {
84.         if(!isInvulnerable)
85.         {
86.             animationController.SetTrigger ("damageTrigger");
87.             health -= damage;
88.         }
89.         else
90.         {
91.             //TODO some sort of animation S***
92.             return;
93.         }
94.     }
95.    
96.     public void Heal(int heal)
97.     {
98.         health += heal;
99.     }
100.    
101.     public void IsInvulnerable(bool active)
102.     {
103.         isInvulnerable = active;
104.     }
105. }
106.  

Looking forward to getting schooled!

 

I have not had any luck directly manipulating a kinematic Rigidbody's velocity through script. The kinematic Rigidbody still doesn't move.

 

In my case this satisfied me just like AddForce()

Just play with the values;

!!Didn't tested for syntax errors but i hope you get the idea

Code (CSharp):

1.  
2. float forceAmount = 5f;
3.  
4. IEnumerator FakeAddForceMotion()
5. {
6.     float i = 0.01f;
7.     while (forceAmount > i)
8.     {
9.      _rigidBody2D.velocity = new Vector2(forceAmount / i, _rigidBody2D.velocity.y); // !! For X axis positive force
10.      i = i + Time.deltaTime;
11.      yield return new WaitForEndOfFrame();      
12.     }
13.     _rigidBody2D.velocity = Vector2.zero;
14.     yield return null;
15. }
16.  
17. // Call this when you want to apply force
18. void AddForce()
19. {
20.     StartCoroutine(FakeAddForceMotion);
21. }

 

I personally set a certain object to kinematic in the hope that addforce would indeed not affect it, but now it still gets flung away...