Unity C# Cheat Sheet

UnityCodingCheatSheet.txt

// Unity C# Cheat Sheet
// I made these examples for students with prior exerience working with C# and Unity. 
// Too much? Try Unity's very good tutorials to get up to speed: https://unity3d.com/learn/tutorials/topics/scripting

AudioExamples.cs

// Various audio examples for Unity
using UnityEngine;
using System.Collections;

public class AudioExamples : MonoBehaviour
{
    // Important: You need to have an AudioSource component attached to this gameObject
    private AudioSource audioSource;

    // Set an audioclip in the Inspector
    public AudioClip clip1;

    void Start()
    {
        // Get the AudioSource component
        audioSource = GetComponent<AudioSource>();

        // Plays the AudioClip set in the AudioSource component. Will be interrupted if the function is called again.
        audioSource.Play();
    }

    void Update()
    {
        // AudioSource.Play() can also be paused or stopped. 
        // Check if audioSource is playing a clip. Jump is space and Fire1 is left ctrl.
        if (audioSource.isPlaying)
        {
            if (Input.GetButtonDown("Jump"))
            {
                audioSource.Pause();
            }
            else if (Input.GetButtonDown("Fire1"))
            {
                audioSource.Stop();
            }
        }

        // PlayOneShot can be used to play a short clip. Will not be interrupted if the function is called again. 
        // Can't be used with Pause & Stop. Fire2 is left alt in the Input Manager.
        if (Input.GetButtonDown("Fire2"))
        {
            audioSource.PlayOneShot(clip1);

            // You can give this an optional volume setting as well (0-1 range)
            //audioSource.PlayOneShot(clip1, 0.5f);
        }

        // Fire3 is left shift
        if (Input.GetButtonDown("Fire3"))
        {
            // Set the pitch and volume of the clips played by Audio Source. Volume range is 0~1
            audioSource.pitch = Random.Range(0.25f, 2f);

            audioSource.volume = Random.Range(0.25f, 1f);
        }
    }
}

Collision2DExamples.cs

// Various 2D collision examples
using UnityEngine;
using System.Collections;

public class Collision2DExamples : MonoBehaviour
{
    // Collisions/Triggers require a collider component on both gameObjects and a rigidbody on at least one.
    // Collision = physics. Trigger = overlap.

    void OnCollisionEnter2D(Collision2D other)
    {
        // Do something when another collider touches this gameObject's collider
        Debug.Log("Collided with something");

        // Conditional statements can be used to filter collisions/triggers. Checking for a known tag is one option. Be sure to define tag in the Inspector or you will get an error.
        if (other.gameObject.CompareTag("tag1"))
        {
            Debug.Log("tag1 collision");
        }
        else if (other.gameObject.CompareTag("tag2"))
        {
            Debug.Log("tag2 collision");
        }
    }

    // Is Trigger needs to be selected on one of the colliders
    void OnTriggerEnter2D(Collider2D other)
    {
        // Do something if another collider overlaps this gameObject's collider
        Debug.Log("Triggered by something");
    }

    // Collision and Trigger also have exit and stay events
    void OnCollisionExit2D(Collision2D other)
    {
        // Do something after a collider is no longer touching this gameObject's collider
        Debug.Log("Collision ended");
    }

    void OnTriggerStay2D(Collider2D other)
    {
        // Do something while a collider is still overlapping with this gameObject's collider
        Debug.Log("Still triggering");
    }

}

EnableSetActiveExamples.cs

// Various ways of enabling/disabling a gameObject's components and activating/deactivating a gameObject.
using UnityEngine;
using System.Collections;

public class EnableSetActiveExamples : MonoBehaviour
{
    public GameObject targetGameObject;
    private Collider2D coll2D;

    void Start()
    {
        // SetActive can switch a gameObject on or off in the Hierarchy. Once deactivated, its components will no longer run until reactivated.
        targetGameObject.SetActive(false);

        // Get a collider2D component attached to this gameObject. Note: Collider2D will work with any kind of 2D collider component.
        coll2D = GetComponent<Collider2D>();

        // Disable or enable a component using a bool
        coll2D.enabled = false;
    }

    // Update is called once per frame
    void Update()
    {
        // Jump is space in Input Manager
        if (Input.GetButtonDown("Jump"))
        {
            // Check if a gameObject is active in the scene with activeInHierarchy. Reminder: The ! is shorthand for == false. If the gameObject is inactive, activate it
            if (!targetGameObject.activeInHierarchy)
            {
                targetGameObject.SetActive(true);
            }
        }

        // Fire1 is left ctrl in Input Manager
        if (Input.GetButtonDown("Fire1"))
        {
            // Check if a component is enabled. Reminder: The ! is shorthand for == false.
            if (!coll2D.enabled)
            {
                coll2D.enabled = true;
            }
        }
    }
}

FindExamples.cs

// Various ways of finding things in Unity

using UnityEngine;
using System.Collections;

public class FindExamples : MonoBehaviour
{
    // Example needs a Rigidbody2D component to work
    private Rigidbody2D rb2D, otherRb2D, childRb2D;
    private GameObject hierarchyObject, childObject, taggedObject;

    void Start()
    {
        // Find a component attached to this GameObject
        rb2D = GetComponent<Rigidbody2D>();

        // Find a GameObject in the Hierarchy. NOTE: This will check all GameObjects in the Hierarchy! Proceed with caution...
        hierarchyObject = GameObject.Find("Name Of Object");
        
        // Find a GameObject in the hierarchy based on tag. NOTE: Fast than finding by name since it only needs to check GameObjects with the matching tag.
        taggedObject = GameObject.FindWithTag("Player");
        
        // Can be combined to find a component on a GameObject in the Hierarchy
        otherRb2D = GameObject.FindWithTag("Player").GetComponent<Rigidbody2D>();

        // Lowercase transform.Find can be used to search child GameObjects by name
        childObject = transform.Find("Name Of Object").gameObject;

        // Can also be combined
        childRb2D = transform.Find("Name Of Object").GetComponent<Rigidbody2D>();
    }
}

IEnumeratorExamples.cs

// Various IEnumerator timer examples for Unity
using UnityEngine;
using System.Collections;

public class IEnumeratorExamples : MonoBehaviour
{
    // Flag for checking if a coroutine is running
    private bool alreadyDelayed;

    // Necessary to stop a coroutine
    private IEnumerator coroutine;

    void Start()
    {
        // Coroutines run in Start are only called once. No if statement + bool needed.
        StartCoroutine(LoopingTimer(7f));

        // Set to an IEnumerator
        coroutine = LoopingTimer(1f);
        StartCoroutine(coroutine);
    }

    void Update()
    {
        // Left ctrl key is Fire1 in Input Manager
        if (Input.GetButtonDown("Fire1"))
        {
            StartCoroutine(DelayTimerOneShot(1f));
        }

        // Space bar is Jump in Input Manager
        if (Input.GetButtonDown("Jump"))
        {
            // This if statement ensures that a coroutine can't be run again if it is already running.
            if (!alreadyDelayed)
            {
                StartCoroutine(DelayTimerLatching(3f));
            }
        }

        // Left alt is Fire2 in Input Manager.
        if (Input.GetButtonDown("Fire2"))
        {
            // To stop a coroutine...
            StopCoroutine(coroutine);
            Debug.Log("Stopped at " + Time.time);
        }
    }

    // Wait for an amount of time before doing something (one shot behavior)
    private IEnumerator DelayTimerOneShot(float delayLength)
    {
        yield return new WaitForSeconds(delayLength);
        // Do something
        Debug.Log("Delayed One Shot");
    }

    // Wait for an amount of time before doing something (latching behavior)
    private IEnumerator DelayTimerLatching(float delayLength)
    {
        // Set the already delayed flag to signal that this coroutine is already running
        alreadyDelayed = true;
        // Do something 
        Debug.Log("Delayed Latch");
        yield return new WaitForSeconds(delayLength);
        // Do something
        Debug.Log("Delayed Latch Released");
        // Reset the already delayed flag so that this coroutine can be used once again.
        alreadyDelayed = false;
    }

    // Sequence of delays
    private IEnumerator DelayTimerSequence(float delayLength1, float delayLength2)
    {
        alreadyDelayed = true;
        yield return new WaitForSeconds(delayLength1);
        // Do first thing
        Debug.Log("First Delay");
        yield return new WaitForSeconds(delayLength2);
        // Do second thing
        Debug.Log("Second Delay");
        alreadyDelayed = false;
    }

    // This creates an endless loop
    private IEnumerator LoopingTimer(float loopInterval)
    {
        while (true)
        {
            // Do something
            Debug.Log("Repeat");
            yield return new WaitForSeconds(loopInterval);
        }
    }
}

InputExamples.cs

// Various examples of Input usage in Unity
using UnityEngine;
using System.Collections;

public class InputExamples : MonoBehaviour
{
    // These strings need to be set in the Inspector to match Input Manager entries
    public string horiAxis, vertAxis, jump, button1, button2;

    public KeyCode key1;

    public Vector2 speed = new Vector2(10f, 5f);

    void Update()
    {
        // Run only once when button is pressed
        if (Input.GetButtonDown(jump))
        {
            Debug.Log("Jump");
        }
        // Keep running while button is held down
        if (Input.GetButton(button1))
        {
            Debug.Log("Fire1");
        }
        // Run only once when the button is released
        if (Input.GetButtonUp(button2))
        {
            Debug.Log("Fire2");
        }

        // Input.GetAxis will return a number between -1 and 1, with smoothing applied (adjust Sensitivity in Input Manager)
        Debug.Log("Horizontal: " + Input.GetAxis(horiAxis));

        // Input.GetAxisRaw will return a number between -1 and 1, without Sensitivity smoothing applied
        Debug.Log("Vertical: " + Input.GetAxisRaw(vertAxis));

        // This is often multiplied by a number to create movement
        Debug.Log("Horizontal Modified: " + Input.GetAxis(horiAxis) * speed.x);

        // Key pressed down
        if (Input.GetKeyDown(KeyCode.T))
        {
            Debug.Log("Key T pressed");
        }

        // Key held down
        if (Input.GetKey(KeyCode.Y))
        {
            Debug.Log("Key A pressed");
        }

        // KeyCode can also be set in the Inspector as a variable
        if (Input.GetKeyUp(key1))
        {
            Debug.Log("Key released");
        }
    }
}

InstantiateExamples.cs

// Various Instantiate examples for Unity
using UnityEngine;
using System.Collections;

public class InstantiateExamples : MonoBehaviour
{
    // Set the object to be cloned in the Inspector. Be sure to use a Prefab from Project NOT Scene!
    public GameObject prefab;

    // Set a target transform in the Inspector to clone prefab from
    public Transform spawnPoint;

    // Update is called once per frame
    void Update()
    {
        // Basic cloning
        if (Input.GetButtonDown("Jump"))
        {
            // Pass the prefab as an argument and clone it at the transform of this gameObject. 
            Instantiate(prefab, transform);

            // Second argument could be set to different transform, if there is another place the prefab should be cloned.
            //Instantiate(prefab, spawnPoint);
        }

        // Advanced cloning
        if (Input.GetButtonDown("Fire1"))
        {
            // Overloaded method which can be positioned and rotated. 
            GameObject p = Instantiate(prefab, transform.position, Quaternion.identity) as GameObject;

            // Make this clone a child of the gameObject that spawned it
            p.transform.parent = transform;

            // This approach allows you to further manipulate the cloned prefab in this script. Such as...
            // Destroying the clone after a set amount of time
            Destroy(p, 3f);

            // Accessing the cloned prefab's components. Note: The prefab needs a Rigidbody2D component for the next 2 lines to work.
            Rigidbody2D pRB2D = p.GetComponent<Rigidbody2D>();
            pRB2D.AddForce(Vector2.up * 100f);
        }

        // Clone prefab at specified transform
        if (Input.GetButtonDown("Fire2"))
        {
            GameObject p = Instantiate(prefab, spawnPoint.position, Quaternion.identity) as GameObject;
            p.transform.parent = transform;
        }
    }
}

SceneManagementExamples.cs

// Various examples of scene management for Unity 5+
using UnityEngine;
using System.Collections;
// Needed in Unity 5+
using UnityEngine.SceneManagement;

public class SceneManagementExamples : MonoBehaviour
{
    // Name of new scene. Don't forget to add to build settings!
    public string scene;

    // Load the new scene
    public void LoadScene(string newScene)
    {
        SceneManager.LoadScene(newScene);
    }

    // Reload the current scene
    public void ReloadScene()
    {
        SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
    }
}

UIExamples.cs

// Various UI examples for Unity 5+
using UnityEngine;
using System.Collections;
// Needed fro UI in Unity 5+
using UnityEngine.UI;

public class UIExamples : MonoBehaviour
{
    // Set the target UI Text in the Inspector
    public Text uiText;

    // Set the target UI image in Inspector. UI Image must be "filled" type
    public Image uiImage;

    private int uiNumber = 7;

    void Update()
    {
        if (Input.GetButtonDown("Jump"))
        {
            // Basic usage
            uiText.text = "HELLO";

            // Fill amount is in a range from 0-1. Empty
            uiImage.fillAmount = 0;
        }
        else if (Input.GetButtonDown("Fire1"))
        {
            // Numbers must be converted to strings
            uiText.text = uiNumber.ToString();
            
            // Larger ranges of number can be converted by dividing with the max value. Halfway
            uiImage.fillAmount = 3.5f/uiNumber;
        }
        else if (Input.GetButtonDown("Fire2"))
        {
            // Numbers can be formatted to display a certain number of places
            uiText.text = uiNumber.ToString("000");

            // Full
            uiImage.fillAmount = 1;
        }
    }
}

this is great!

Very nice basics list

[RequireComponent (typeof (AudioSource))]
instead of the comment is much more robust and cleaner.

thx a lot, this is great

nice, thx

Awesome thank you!

Thanks for this.

Thank you wow.

thank you man. good share.

Thank you maga!

GODLIKE !!!

very helpful. thank you

Awesome

Thankyou

Thanks this was very helpful!

This great thank you mate.