How to pass an array of unfixed size to a shader?

Questions & Answers
1

Just started learning shader programming and I can’t figure out how to do this. I know how to pass an array of fixed size to a shader.

This script passes the array to the shader:

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

// Whenever "sizeOfShaderArray" is changed, this script will update the _Array property of the shader
public class ArrayShaderScript : MonoBehaviour {
    
    public int sizeOfShaderArray = 20;

    [ExecuteInEditMode]
    void Awake()
    {
        InitializeArray();
    }

    void OnValidate()
    {
        InitializeArray();
    }

    private void InitializeArray()
    {
        // Initialize the array with data
        float[] data = new float[sizeOfShaderArray];
        for (int i = 0; i < sizeOfShaderArray; i++)
            data *= 0.5f;*

// Add the array to the material.
MaterialPropertyBlock arrayPropertyBlock = new MaterialPropertyBlock();
arrayPropertyBlock.SetFloatArray(“_Array”, data);
GetComponent().SetPropertyBlock(arrayPropertyBlock);
}
}
And this is how I define and use the array in my shader script:
sampler2D _MainTex;
float _Array[20]; // Instead of having a fixed size, I want this to be my “sizeOfShaderArray” variable in the ArrayShaderScript.

fixed4 frag (v2f i) : SV_Target
{

  • fixed4 col = tex2D(_MainTex, i.uv);*

col *= _Array[5]; // Do stuff with array here

  • return col;*
    }
2

The array initialization needs a length. You must look for other way.

Shader array initialization