Converting Code from JavaScript to C#

I am rather new to scripting but I have been learning a lot. After watching a tutorial I have an awesome touch control script, but I am trying to convert it over from JavaScript to C#.

Here is what I have in JavaScript:

Code (JavaScript):

1. #pragma strict
2.  
3. public  var gravityDown : float;
4.  
5. private var ray : Ray;
6. private var hit : RaycastHit;
7.  
8. function Update ()
9. {
10.     if(Input.GetMouseButtonUp(0))
11.     {
12.         ray = Camera.main.ScreenPointToRay(Input.mousePosition);
13.         if(Physics.Raycast(ray,hit))
14.         {
15.             transform.position.x = hit.point.x;
16.             transform.position.y = hit.point.y;
17.             this.GetComponent.<Rigidbody2D>().gravityScale = gravityDown;
18.         }
19.     }      
20. }

Here is my attempt at re-writing it in C#:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class PlayerMovement : MonoBehaviour
5. {
6.     //gravity multiplier
7.     public float gravityDown;
8.  
9.     //used for raycasting
10.     public Ray ray;
11.     public RaycastHit hit;
12.  
13.      // Update is called once per frame
14.     void Update ()
15.     {
16.         if (Input.GetMouseButtonUp (0))
17.         {
18.             Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
19.             if(Physics.Raycast(ray,hit))
20.             {
21.                 transform.position.x = hit.point.x;
22.                 transform.position.y = hit.point.y;
23.                 this.rigidbody2D.gravityScale = gravityDown;
24.             }
25.         }
26.     }
27. }

I get the following errors:

Assets/Scripts/PlayerMovement.cs(21,36): error CS1502: The best overloaded method match for `UnityEngine.Physics.Raycast(UnityEngine.Ray, out UnityEngine.RaycastHit)' has some invalid arguments

Assets/Scripts/PlayerMovement.cs(23,43): error CS1612: Cannot modify a value type return value of `UnityEngine.Transform.position'. Consider storing the value in a temporary variable

Assets/Scripts/PlayerMovement.cs(21,36): error CS1620: Argument `#2' is missing `out' modifier

Assets/Scripts/PlayerMovement.cs(21,36): error CS1502: The best overloaded method match for `UnityEngine.Physics.Raycast(UnityEngine.Ray, out UnityEngine.RaycastHit)' has some invalid arguments

I have been pretty stuck on this, but I feel like it is very close. The JavaScript runs perfectly and all I am doing is trying to re-write it in C#. If someone could point me in the right direction that would be great!

 

Try this:

Code (csharp):

1.  
2.            if(Physics.Raycast(ray,out hit))  // Note the 'out' keyword here
3.            {
4.                 // Here you need to create a new Vector3 and assign that to transform.position. You can't modify the x and y directly.
5.                 transform.position = new Vector3(hit.point.x, hit.point.y);
6.                this.rigidbody2D.gravityScale = gravityDown;
7.            }
8.  

This is just off the top of my head, so it might not be 100 correct. Hope that helps.

 

A couple of things.
The lines numbers posted don't match the lines in your source ...
Assets/Scripts/PlayerMovement.cs(21,36) actually refers to line 19.

In line 18 : remove the Type designator Ray because the variable ray has already been declared.

In line 19 : Where is the variable hit assigned a value ??
check the docs http://docs.unity3d.com/ScriptReference/Physics.Raycast.html

 

OK here is what I got and it returns one error:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class PlayerMovement : MonoBehaviour
5. {
6.     //gravity multiplier
7.     public float gravityDown;
8.  
9.     //used for raycasting
10.     public Ray ray;
11.     public RaycastHit hit;
12.  
13.     void Update ()
14.     {
15.         if (Input.GetMouseButtonUp (0))
16.         {
17.             if(Physics.Raycast(transform.position,out hit))  // Note the 'out' keyword here
18.             {
19.                 // Here you need to create a new Vector3 and assign that to transform.position. You can't modify the x and y directly.
20.                [B][I] transform.position = new Vector3(hit.point.x, hit.point.y,);[/I][/B]
21.                 this.GetComponent<Rigidbody2D>().gravityScale = gravityDown;
22.             }
23.         }
24.     }
25. }

Error: Assets/Scripts/PlayerMovement.cs(20,89): error CS0839: An argument is missing

 

Sorry about the and , tried to bold and italicize the area but I guess you can't do that.

 

The errors usually give a good indication of what's wrong.
"Error: Assets/Scripts/PlayerMovement.cs(20,89): error CS0839: An argument is missing"

If you look on line 20, you'll notice this:
new Vector3(hit.point.x, hit.point.y, );

You can clearly see it's missing the 3rd argument.

Edit: The 3rd argument is Z. Since you're dealing with 2D and likely do not care to modify the z, you can simply pass in it's own z:
new Vector3(hit.point.x, hit.point.y, transform.position.z);

 

Further to the comments by @Juice-Tin

http://docs.unity3d.com/ScriptReference/Vector3-ctor.html

your statement : new Vector3(hit.point.x, hit.point.y, );
If you remove the trailing comma the constructor will create the Vector3 with a default value of 0 for the z axis

Kerry,

 

I thought I had it as a 0, sorry. Even after adding a 0 into the "z" spot (or if I leave it blank and removing comma) I get the following errors:

Assets/Scripts/PlayerMovement.cs(17,36): error CS10502: The best overloaded method match for Unity Engine. Physics.Raycast(UnityEngine.Vector3)' has some invalid arguments.

Assets/Scripts/PlayerMovement.cs(17,36): error CS1615: Argument ' #2" does not require ' out' modifier. Consider removing ' out' modifier

So does that mean I don't need that "out" modifier? When I remove the "out" modifier i get another error that states:

Assets/Scripts/PlayerMovement.cs(17,36): error CS1503: Argument ' #2' cannot convert ' UnityEngine.RaycastHit' expression type ' UnityEngine.Vector3

This line appears to be giving me the most issue. Should I use another type other than "out"?

 

May we see the code after changes, please? Specific when you removed "out" (although i think is needed there).

 

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class PlayerMovement : MonoBehaviour
5. {
6.     //gravity multiplier
7.     public float gravityDown;
8.  
9.     //used for raycasting
10.     public Ray ray;
11.     public RaycastHit hit;
12.  
13.     void Update ()
14.     {
15.         if (Input.GetMouseButtonUp (0))
16.         {
17.             if(Physics.Raycast(transform.position, hit))  // Note the 'out' keyword here
18.             {
19.                 // Here you need to create a new Vector3 and assign that to transform.position. You can't modify the x and y directly.
20.                 transform.position = new Vector3(hit.point.x, hit.point.y,0);
21.                 this.GetComponent<Rigidbody2D>().gravityScale = gravityDown;
22.             }
23.         }
24.     }
25. }

Errors are as follows:

Assets/Scripts/PlayerMovement.cs(17,36): error CS1502: The best overloaded method match for `UnityEngine.Physics.Raycast(UnityEngine.Vector3, UnityEngine.Vector3)' has some invalid arguments

Assets/Scripts/PlayerMovement.cs(17,36): error CS1615: Argument `#2' does not require `out' modifier. Consider removing `out' modifier

I get the same errors if I remove the 0 from the "z" field.

 

@DarrikM7
The issue as I see it is as a result of your revisions --- the Physics.Raycast arguments are now incorrect.

Essentially the Raycast should be told where to 'fire' from and in which direction ( the function has some default arguments that aren't essential)

The original code used a Ray type variable which contains the to and from data.
The current code only uses the 'from' data ie the Vector3 transform.position.

These are the function signatures

Code (CSharp):

1.  
2. public static bool Raycast(
3. Ray ray);
4.  
5. public static bool Raycast(
6. Ray ray,
7. float distance);
8.  
9. public static bool Raycast(
10. Ray ray,
11. out RaycastHit hitInfo);
12.  
13. public static bool Raycast(
14. Vector3 origin,
15. Vector3 direction);
16.  
17. public static bool Raycast(
18. Ray ray,
19. [DefaultValue("Mathf.Infinity")]  float distance,
20. [DefaultValue("DefaultRaycastLayers")]  int layerMask);
21.  
22. public static bool Raycast(
23. Ray ray,
24. out RaycastHit hitInfo,
25. float distance);
26.  
27. public static bool
28. Raycast(Vector3 origin,
29. Vector3 direction,
30. float distance);
31.  
32. public static bool Raycast(
33. Vector3 origin,
34. Vector3 direction,
35. out RaycastHit hitInfo);
36.  
37. public static bool Raycast(
38. Ray ray,
39. out RaycastHit hitInfo,
40. [DefaultValue("Mathf.Infinity")]  float distance,
41. [DefaultValue("DefaultRaycastLayers")] int layerMask);
42.  
43. public static bool Raycast(
44. Vector3 origin,
45. Vector3 direction,
46. [DefaultValue("Mathf.Infinity")]  float distance,
47. [DefaultValue("DefaultRaycastLayers")]  int layerMask);
48.  
49. public static bool Raycast(
50. Vector3 origin,
51. Vector3 direction,
52. out RaycastHit hitInfo,
53. float distance);
54.  
55. public static bool Raycast(
56. Vector3 origin,
57. Vector3 direction,
58. out RaycastHit hitInfo,
59. [DefaultValue("Mathf.Infinity")]  float distance,
60. [DefaultValue("DefaultRaycastLayers")]  int layerMask);
61.  

Regards, Kerry

 

afterthought:
IF the scene is 2D I'm wondering if the Physics.Raycast( ... ) could/should be Physics.Raycast2D( ... )

 

It is a 2D scene. When I make the the code:

transform.position=newVector2(hit.point.x, hit.point.y);

I get the following errors:

Assets/Scripts/PlayerMovement.cs(17,36): error CS1502: The best overloaded method match for `UnityEngine.Physics.Raycast(UnityEngine.Vector3, UnityEngine.Vector3)' has some invalid arguments

Assets/Scripts/PlayerMovement.cs(17,36): error CS1615: Argument `#2' does not require `out' modifier. Consider removing `out' modifier

It is still showing the error with a Vector3 which seems strange to me, and that 'out' modifier message is back again saying that I do not need it. It seems strange that the syntax for this part seems to be a lot different than the Javascript code (the Javascript is assuming a lot it seems). Here is what I have for the code at this point (just changed to a Vector2):

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class PlayerMovement : MonoBehaviour
5. {
6.     //gravity multiplier
7.     public float gravityDown;
8.  
9.     //used for raycasting
10.     public Ray ray;
11.     public RaycastHit hit;
12.  
13.     void Update ()
14.     {
15.         if (Input.GetMouseButtonUp (0))
16.         {
17.             if(Physics.Raycast(transform.position,out hit))  // Note the 'out' keyword here
18.             {
19.                 // Here you need to create a new Vector3 and assign that to transform.position. You can't modify the x and y directly.
20.                 transform.position = new Vector2(hit.point.x, hit.point.y);
21.                 this.GetComponent<Rigidbody2D>().gravityScale = gravityDown;
22.             }
23.         }
24.     }
25. }

 

Which direction is your Raycast firing ?

 

What is supposed to happen is I have that code attached to my player object, and when you click/tap the screen the object will jump to wherever you touched the screen (I am developing for Android). It works fine in the JavaScript version, just not in the C# version.

 

According to the documentation, the best call for your use is this one:

Code (CSharp):

1. public static bool Raycast(Ray ray, out RaycastHit hitInfo, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers);

Here:

Code (CSharp):

1.  
2. using UnityEngine;
3. using System.Collections;
4.  
5. public class PlayerMovement : MonoBehaviour
6. {
7.   //gravity multiplier
8.   public float gravityDown;
9.  
10.   //used for raycasting
11.   public Ray ray;
12.   public RaycastHit hit;
13.  
14.   void Update ()
15.   {
16.     if (Input.GetMouseButtonUp (0))
17.     {
18.       Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
19.       if(Physics.Raycast(ray, out hit, 100)) // there is one more parameters (optional) that you specify the layer you firing the raycast
20.       {
21.         // Here you need to create a new Vector3 and assign that to transform.position. You can't modify the x and y directly.
22.         transform.position = new Vector2(hit.point.x, hit.point.y);
23.         this.GetComponent<Rigidbody2D>().gravityScale = gravityDown;
24.       }
25.     }
26.   }
27. }

just wondering: since it is a touch-screen, why not use Input.GetTouch? I haven't use it yet, but in the documentation seems to have what you need. Have you tried?

 

Hmm I may try the Input.GetTouch and see what happens, I will also try the code you provided and see if I can get it working, thanks!