using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class IKController : MonoBehaviour
{
    LineRenderer lineRenderer;
    GameObject P0Joint;
    GameObject P1Joint;
    GameObject P2Joint;
    GameObject EndEffector;
    GameObject Goal;
    Vector3 P0;
    Vector3 P1;
    Vector3 P2;
    Vector3 E;
    Vector3 G;
    Vector3 dE;
    Vector3 JT, JT1, JT2;
    Vector3 RotAxis;
    float dTheta, dTheta1, dTheta2;
    float angleTheta, angleTheta1, angleTheta2;
    Matrix4x4 transMat;
    Matrix4x4 rotMat;
    Matrix4x4 rotMat1;
    Matrix4x4 rotMat2;
    Vector3 newPosOfE;

    // Start is called before the first frame update
    void Start()
    {
        lineRenderer = GetComponent<LineRenderer>();
        P0Joint = GameObject.Find("P0Joint");
        P1Joint = GameObject.Find("P1Joint");
        P2Joint = GameObject.Find("P2Joint");
        EndEffector = GameObject.Find("EndEffector");
        Goal = GameObject.Find("Goal");
        E = EndEffector.transform.position;
        G = Goal.transform.position;
        dE = G - E;
        P0 = P0Joint.transform.position;
        P1 = P1Joint.transform.position;
        P2 = P2Joint.transform.position;
        RotAxis = new Vector3(0, 0, 1);
        angleTheta = 0.0f;
        transMat = Matrix4x4.Translate(new Vector3(4, 0, 0));
    }

    // Update is called once per frame
    void Update()
    {
        if (dE.magnitude > 0.01f)
        {
            Matrix4x4 JT = new Matrix4x4();
            JT.addColumn(Vector3.Cross(RotAxis, (E - P0)));
            JT.addColumn(Vector3.Cross(RotAxis, (E - P1)));
            JT.addColumn(Vector3.Cross(RotAxis, (E - P2)));

            dTheta = Vector3.Dot(JT,dE);
            angleTheta = angleTheta + 0.05f * dTheta;
            rotMat = Matrix4x4.Rotate(Quaternion.Euler(new Vector3(0, 0, angleTheta)));


            newPosOfE = (rotMat  * transMat).MultiplyPoint3x4(Vector3.zero);

            EndEffector.transform.position = newPosOfE;

            P0 = P0Joint.transform.position;
            P1 = P1Joint.transform.position;
            P2 = P2Joint.transform.position;
            E = EndEffector.transform.position;
            G = Goal.transform.position;
            dE = G - E;

            Vector3[] positions = new Vector3[4] { P0,P1,P2,E };
            lineRenderer.positionCount = 4;
            lineRenderer.SetPositions(positions);
        }
    }
}

C Sharp Online Compiler

Write, Run & Share C# code online using OneCompiler's C# online compiler for free. It's one of the robust, feature-rich online compilers for C# language, running on the latest version 8.0. Getting started with the OneCompiler's C# compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C# and start coding.

Read inputs from stdin

OneCompiler's C# online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

using System;
 
namespace Sample
{
  class Test
    {
      public static void Main(string[] args)
       {
         string name;
         name = Console.ReadLine();
         Console.WriteLine("Hello {0} ", name);
	}
     }
}

About C Sharp

C# is a general purpose object-oriented programming language by Microsoft. Though initially it was developed as part of .net but later it was approved by ECMA and ISO standards.

You can use C# to create variety of applications, like web, windows, mobile, console applications and much more using Visual studio.

Syntax help

Data types

Data TypeDescriptionRangesize
intTo store integers-2,147,483,648 to 2,147,483,6474 bytes
doubleto store large floating point numbers with decimalscan store 15 decimal digits8 bytes
floatto store floating point numbers with decimalscan store upto 7 decimal digits4 bytes
charto store single characters-2 bytes
stringto stores text-2 bytes per character
boolto stores either true or false-1 bit

Variables

Syntax

datatype variable-name = value;

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition or set of few conditions IF-ELSE is used.

if(conditional-expression) {
   // code
} 
else {
   // code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression) {    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
...    
    
default:     
 // code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement) {
  // code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {
 // code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

data-type[] array-name;

Methods

Method is a set of statements which gets executed only when they are called. Call the method name in the main function to execute the method.

Syntax

static void method-name() 
{
  // code to be executed
}