Wednesday, January 03, 2018

Allocations in the Unity Editor when using GetComponent.

If you call gameObject.GetComponent, and there is no Collider on that gameObject, null is returned, but you will also see a memory allocation in the Unity profiler.

Why?

The call is actually returning a "fake null" object, so that when you try and use it a custom error message is displayed. This custom error message causes the allocation.

This behaviour is disabled in a build, so you will only ever see it in the editor.

Friday, September 15, 2017

Avoid FindObjectsOfType with this Pattern

public class SomeComponent : MonoBehaviour
{
    public static List<SomeComponent> Instances = new List<SomeComponent>();
    private int instanceIndex = -1;

    void OnDisable() {
        var lastIndex = Instances.Count - 1;
        Instances[instanceIndex] = Instances[lastIndex];
        Instances[instanceIndex].instanceIndex = instanceIndex;
        Instances.RemoveAt(lastIndex);
    }

    void OnEnable()
    {
        Instances.Add(this);
        instanceIndex = Instances.Count - 1;
    }
}

Tuesday, August 22, 2017

Vector3.sqrMagnitude vs Vector3.magntiude


sqrMagnitude is 20% faster than magnitude.

magnitude: 0.862013
srqMagnitude: 0.689175


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

public class MagVsSqrMag : MonoBehaviour
{

    void Start()
    {
        var C = 10000000f;
        var sw = new Stopwatch();
        var vec = new Vector3(Random.value, Random.value, Random.value);
        var r = 0f;
        for (var i = 0; i < C; i++)
        {
            sw.Start();
            r += vec.magnitude;
            sw.Stop();
        }
        UnityEngine.Debug.Log("magnitude:" + (sw.ElapsedTicks / C));
        sw.Reset();
        vec = new Vector3(Random.value, Random.value, Random.value);
        for (var i = 0; i < C; i++)
        {
            sw.Start();
            r += vec.sqrMagnitude;
            sw.Stop();
        }
        UnityEngine.Debug.Log("srqMagnitude:" + (sw.ElapsedTicks / C));

        UnityEngine.Debug.Log(r);
    }

}

Monday, February 13, 2017

Take a Unity Screenshot with Alpha

This script takes a screenshot and saves it to the user desktop. It has options to use an alpha background, and also upscale the image. Useful for taking pictures of a scene or model for composition by artists.


using UnityEngine;
using System.IO;
using System;

[RequireComponent (typeof(Camera))]
public class CaptureWithAlpha : MonoBehaviour
{
    public int UpScale = 4;
    public bool AlphaBackground = true;

    Texture2D Screenshot ()
    {
        var camera = GetComponent<Camera> ();
        int w = camera.pixelWidth * UpScale;
        int h = camera.pixelHeight * UpScale;
        var rt = new RenderTexture (w, h, 32);
        camera.targetTexture = rt;
        var screenShot = new Texture2D (w, h, TextureFormat.ARGB32, false);
        var clearFlags = camera.clearFlags;
        if (AlphaBackground) {
            camera.clearFlags = CameraClearFlags.SolidColor;
            camera.backgroundColor = new Color (0, 0, 0, 0);
        }
        camera.Render ();
        RenderTexture.active = rt;
        screenShot.ReadPixels (new Rect (0, 0, w, h), 0, 0);
        screenShot.Apply ();
        camera.targetTexture = null;
        RenderTexture.active = null;
        DestroyImmediate (rt);
        camera.clearFlags = clearFlags;
        return screenShot;
    }

    [ContextMenu ("Capture Screenshot")]
    public void SaveScreenshot ()
    {
        var path = Environment.GetFolderPath (Environment.SpecialFolder.Desktop);
        var filename = "SS-" + DateTime.Now.ToString ("yyyy.MM.dd.HH.mm.ss") + ".png";
        File.WriteAllBytes (Path.Combine (path, filename), Screenshot ().EncodeToPNG ());
    }
}

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