UnsafeUtility.ArrayElementAsRef

Parameters

Returns

T A reference to the value of type T at the specified index within the array. This reference allows direct manipulation of the value at its memory location.

Description

Obtains a reference to a value of type T in an array at a specified index in memory.

The ArrayElementAsRef method allows direct access to an array element by its index in memory. This method provides a reference to the element, enabling efficient data manipulation without copying. Use this method with care, as incorrect pointer usage can cause memory corruption or application crashes.

using UnityEngine;
using Unity.Collections.LowLevel.Unsafe;
using System.Runtime.InteropServices;

public class ArrayElementAsRefExample : MonoBehaviour
{
    [StructLayout(LayoutKind.Sequential)]
    struct CustomStruct
    {
        public int Id;
        public float Value;
    }

    void Start()
    {
        int arrayLength = 5;

        // Allocate a buffer for CustomStruct using stackalloc
        unsafe
        {
            CustomStruct* structArray = stackalloc CustomStruct[arrayLength];

            // Initialize the array with values
            for (int i = 0; i < arrayLength; i++)
            {
                structArray[i].Id = i;
                structArray[i].Value = i * 1.5f;
            }

            // Get a reference to an element using ArrayElementAsRef
            ref CustomStruct element = ref UnsafeUtility.ArrayElementAsRef<CustomStruct>(structArray, 2);
            element.Value = 99.9f;  // Modify the value in place

            // Output the modified value
            Debug.Log($"Modified element at index 2: Id = {structArray[2].Id}, Value = {structArray[2].Value}");
        }
    }
}

Additional resources: UnsafeUtility.ReadArrayElement, UnsafeUtility.WriteArrayElement.