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Archive for March, 2015

Adding Transform.LookAt2D like it belongs to the Unity API

March 31 | 15

Unfortunately there is no Transform.LookAt2D in Unity as for now in Unity5. BUT with an extension method this can be added into the API quick and easy!.

Its pretty simple. We just need to have a namespace included wherever we want to use Transform.LookAt2D and thats pretty much!, here’s how:

Lets create the extension method for LookAt2D:

using UnityEngine;

namespace UnityTransformExtensions {
    public static class TransformExtension {
        //first arg is the class we want to add the extension method to.
        public static void LookAt2D(this Transform tr, Transform target) {
            Vector3 relative = tr.InverseTransformPoint(target.position);
            float angle = Mathf.Atan2(relative.x, relative.y) * Mathf.Rad2Deg;
            tr.Rotate(0,0, -angle, Space.Self);
        }
        public static void LookAt2D(this Transform tr, Vector3 pos) {
            Vector3 relative = tr.InverseTransformPoint(pos);
            float angle = Mathf.Atan2(relative.x, relative.y) * Mathf.Rad2Deg;
            tr.Rotate(0,0, -angle, Space.Self);
        }
    }
}

using UnityEngine;

namespace UnityTransformExtensions {

public static class TransformExtension {

//first arg is the class we want to add the extension method to.

public static void LookAt2D(this Transform tr, Transform target) {

Vector3 relative = tr.InverseTransformPoint(target.position);

float angle = Mathf.Atan2(relative.x, relative.y) * Mathf.Rad2Deg;

tr.Rotate(0,0, -angle, Space.Self);

}

public static void LookAt2D(this Transform tr, Vector3 pos) {

Vector3 relative = tr.InverseTransformPoint(pos);

float angle = Mathf.Atan2(relative.x, relative.y) * Mathf.Rad2Deg;

tr.Rotate(0,0, -angle, Space.Self);

}

And then we just need to call it from any of our scripts as part of the Transform methods! here’s a quick example:

using UnityEngine;
using System.Collections;
using UnityTransformExtensions;//Remember to include the extension namespace

public class LookAt2DTest : MonoBehaviour {
    void Update () {
        Vector3 lookPoint = Input.mousePosition - Camera.main.WorldToScreenPoint(transform.position);
        transform.LookAt2D(lookPoint);//called like its part of the API!
    }
}

using UnityEngine;

using System.Collections;

using UnityTransformExtensions;//Remember to include the extension namespace

public class LookAt2DTest : MonoBehaviour {

void Update () {

Vector3 lookPoint = Input.mousePosition - Camera.main.WorldToScreenPoint(transform.position);

transform.LookAt2D(lookPoint);//called like its part of the API!

}

Quick, easy and clean!

Getting a random enum value and also be able to exclude some values

March 5 | 15

As the post says, in the game I am working on I needed to get a random value of an enumeration but on some cases I needed to exclude some values of the enumeration, so I came up with this small snippet of code that given an enum type and an array of enum excluded values it will return you a random value of the enumeration.

It works with any type of enum you create 😀

//this is done in case someone introduces all the enum as excluded values in the parameters
private static int numberOfTries = 1000;

//Given an enum type returns a random value of the enum type.
public static T GetRandomEnumValue<T>(T[] excludedValues = null) {
    T[] values = (T[]) Enum.GetValues(typeof(T));
    T generatedVal = values[UnityEngine.Random.Range(0,values.Length)];
    if(excludedValues != null) {
        int generatedTries = 0;
        for(int i = 0; i < excludedValues.Length; i++) {
            if(EqualityComparer<T>.Default.Equals(excludedValues[i],generatedVal)) {
                generatedVal = values[UnityEngine.Random.Range(0,values.Length)];
                generatedTries++;
                i = -1;//so when the loop finishes it gets set to 0
            }
            if(generatedTries > numberOfTries) {
                Debug.LogError("Exceded the max number of tries.");
                return generatedVal;
            }
        }
    }
    return generatedVal;
}

//this is done in case someone introduces all the enum as excluded values in the parameters

private static int numberOfTries = 1000;

//Given an enum type returns a random value of the enum type.

public static T GetRandomEnumValue<T>(T[] excludedValues = null) {

T[] values = (T[]) Enum.GetValues(typeof(T));

T generatedVal = values[UnityEngine.Random.Range(0,values.Length)];

if(excludedValues != null) {

int generatedTries = 0;

for(int i = 0; i < excludedValues.Length; i++) {

if(EqualityComparer<T>.Default.Equals(excludedValues[i],generatedVal)) {

generatedVal = values[UnityEngine.Random.Range(0,values.Length)];

generatedTries++;

i = -1;//so when the loop finishes it gets set to 0

}

if(generatedTries > numberOfTries) {

Debug.LogError("Exceded the max number of tries.");

return generatedVal;

}

return generatedVal;

}

If you have a better way to do it _please_ let me know :).

Quick example on how to use it:

enum DIRECTION {
    NONE = 0,
    UP = 1,
    DOWN = 2,
    LEFT = 3,
    RIGHT = 4
}

void Start() {
    /******* Exclude DIRECTION.NONE *********/
    DIRECTION generated = GetRandomEnumValue<DIRECTION>(new DIRECTION[] { DIRECTION.NONE });
    Debug.Log("Generated direction Exclude DIRECTION.NONE: " + generated);

    /****** Dont exclude any direction ******/
    DIRECTION generatedNoExclude = GetRandomEnumValue<DIRECTION>();
    Debug.Log("Generated direction: " + generatedNoExclude);
}

enum DIRECTION {

NONE = 0,

UP = 1,

DOWN = 2,

LEFT = 3,

RIGHT = 4

}

void Start() {

/******* Exclude DIRECTION.NONE *********/

DIRECTION generated = GetRandomEnumValue<DIRECTION>(new DIRECTION[] { DIRECTION.NONE });

Debug.Log("Generated direction Exclude DIRECTION.NONE: " + generated);

/****** Dont exclude any direction ******/

DIRECTION generatedNoExclude = GetRandomEnumValue<DIRECTION>();

Debug.Log("Generated direction: " + generatedNoExclude);

}

RT @munificentbob: Finally! The next chapter of Crafting Interpreters, "Resolving and Binding" is done. It's semantic analysis time! https:…

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Archive for March, 2015

Adding Transform.LookAt2D like it belongs to the Unity API

Getting a random enum value and also be able to exclude some values

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