Accumulating and fading color on a render texture | Official Unity Discord | Page 1

I'm trying to accumulate white color on a texture that is also faded over time. It paints white on the texture based on player's location.

How do I begin to do this? All I really know is that it involves a camera and render textures but I don't really know how to accumulate the color and fade it to create a trail that follows the player.

I've tried to follow somewhat-related tutorials such as snow deformation (though my use-case is NOT for snow) but they're all either:

Using a different render pipeline (I'm using URP)
Use shadergraph (I refuse to use it due to the many limitations it has and find it almost impossible to translate the shadergraphs in the video to HLSL)
Use out of date APIs

so I haven't really been able to gain much from them.

All I really have right now is a basic skeleton class that creates a render texture. I don't know what to do to it beyond that.

    [SerializeField] RenderTexture accumulationTexture;
    
    Camera cam;
    private void OnEnable()
    {
        cam = GetComponent<Camera>();
    }

    private void OnDisable()
    {
        ReleaseResources();
    }

    private void CreateResources()
    {
        //Create a B/W texture to store player position
        if (accumulationTexture == null)
        {
            accumulationTexture = new RenderTexture(Screen.width / 4, Screen.height / 4, 0, RenderTextureFormat.ARGB32)
            {
                enableRandomWrite = true,
                filterMode = FilterMode.Point,
                wrapMode = TextureWrapMode.Clamp
            };
            accumulationTexture.Create();
        }
        
    }

    private void ReleaseResources()
    {
        if (accumulationTexture != null)
        {
            accumulationTexture.Release();
            accumulationTexture = null;
        }
    }

    private void Update()
    {
        //Ensure resources are created
        if (accumulationTexture == null)
        {
            CreateResources();
        }
        
        //Do something to accumulate player position into the texture
    }

Would really like to be pointed in the right direction.

#Accumulating and fading color on a render texture