Bezier curve script from js to C#

Unity Engine
1

Hello everybody, I have got the script of how to draw a bezier curve but this script is js. I have tried to make the C# version but i got many difficulties because the use of function are not the same. Someone can help me please ?

@script ExecuteInEditMode()
#pragma strict
public var start : GameObject;
public var middle : GameObject;
public var end : GameObject;
public var color : Color = Color.white;
public var width : float = 0.2;
public var numberOfPoints : int = 20;
function Start()
{
   // initialize line renderer component
   var lineRenderer : LineRenderer =
      GetComponent(LineRenderer);
   if (null == lineRenderer)
   {
      gameObject.AddComponent(LineRenderer);
   }
   lineRenderer = GetComponent(LineRenderer);
   lineRenderer.useWorldSpace = true;
   lineRenderer.material = new Material(
      Shader.Find("Particles/Additive"));
}
function Update()
{
   // check parameters and components
   var lineRenderer : LineRenderer =
      GetComponent(LineRenderer);
   if (null == lineRenderer || null == start
      || null == middle || null == end)
   {
      return; // no points specified
   }
   // update line renderer
   lineRenderer.SetColors(color, color);
   lineRenderer.SetWidth(width, width);
   if (numberOfPoints > 0)
   {
      lineRenderer.SetVertexCount(numberOfPoints);
   }
   // set points of quadratic Bezier curve
   var p0 : Vector3 = start.transform.position;
   var p1 : Vector3 = middle.transform.position;
   var p2 : Vector3 = end.transform.position;
   var t : float;
   var position : Vector3;
   for(var i : int = 0; i < numberOfPoints; i++)
   {
      t = i / (numberOfPoints - 1.0);
      position = (1.0 - t) * (1.0 - t) * p0
         + 2.0 * (1.0 - t) * t * p1
         + t * t * p2;
      lineRenderer.SetPosition(i, position);
   }
}
2

  1. Change “function” to “void”. Unless it says “function x() : int”, in which case change it to int (or whatever type is there)

  2. Change “var x : int = …” to “int x = …”

  3. Surround the whole thing with:

using UnityEngine;
using System.Collections;
public class ThisScriptFileName : MonoBehaviour {
.... existing code ....
}

  1. For AddComponent and GetComponent, use syntax like this: gameObject.AddComponent();

  2. Any floating point numbers (e.g. 1.0, 3.14) should have “f” after them (1f, 3.14f)

These steps will get you 90% of the way to converting most JS to C#. Start with those, and if there are still things you need help converting, come back with any questions.

3 Likes
3

This ought to do it, but it’s off the top of my head & isn’t tested… That said, StarManta’s breakdown is solid, as you’ll see when comparing the two :slight_smile: Normally I wouldn’t do the work for you, but I’m in a good mood and enjoy the practice these conversions gives me, haha. Also, please note that this is a direct conversion & I didn’t go out of my way to correct or alter anything beyond that.

[ExecuteInEditMode]
public GameObject start;
public GameObject middle;
public GameObject end;
public Color color = Color.white;
public float width = 0.2f;
public int numberOfPoints = 20;

void Start()
{
  
    // initialize line renderer component
    LineRenderer lineRenderer = GetComponent<LineRenderer>();
    if (lineRenderer == null)
    {
        gameObject.AddComponent<LineRenderer>();
    }
    lineRenderer = GetComponent<LineRenderer>();
    lineRenderer.useWorldSpace = true;
    lineRenderer.material = new Material(Shader.Find("Particles/Additive"));
}

void Update()
{
    // check parameters and components
    lineRenderer = GetComponent<LineRenderer>();
    if (lineRenderer == null || start == null || middle == null || end == null)
    {
        return; // no points specified
    }
    // update line renderer
    lineRenderer.SetColors(color, color);
    lineRenderer.SetWidth(width, width);
    if (numberOfPoints > 0)
    {
        lineRenderer.SetVertexCount(numberOfPoints);
    }
    // set points of quadratic Bezier curve
    Vector3 p0 = start.transform.position;
    Vector3 p1 = middle.transform.position;
    Vector3 p2 = end.transform.position;
    float t ;
    Vector3 position;
    for(int i = 0; i < numberOfPoints; i++)
    {
        t = i / (numberOfPoints - 1.0);
        position = (1.0 - t) * (1.0 - t) * p0 + 2.0 * (1.0 - t) * t * p1 + t * t * p2;
        lineRenderer.SetPosition(i, position);
    }
}