using UnityEngine;

[ExecuteAlways]
public class FogNoiseGenerator : MonoBehaviour
{
    public Material targetMaterial;
    public string propertyName = "_FogNoise";
    public int size = 64;
    public float scale = 0.05f;
    public int seed = 1337;

    void Start() { if (Application.isPlaying) Generate(); }

    [ContextMenu("Generate Noise")]
    public void Generate()
    {
        if (targetMaterial == null) { Debug.LogWarning("No target material set"); return; }
        var tex = CreatePerlin3D(size, scale, seed);
        tex.wrapMode = TextureWrapMode.Repeat;
        tex.filterMode = FilterMode.Trilinear;
        tex.Apply();
        targetMaterial.SetTexture(propertyName, tex);
        Debug.Log("Generated Texture3D and assigned to material");
    }

    static Texture3D CreatePerlin3D(int size, float scale, int seed)
    {
        var tex = new Texture3D(size, size, size, TextureFormat.RGBA32, false);
        var cols = new Color[size * size * size];
        var rng = new System.Random(seed);
        float ox = (float)rng.NextDouble() * 10000f, oy = (float)rng.NextDouble() * 10000f, oz = (float)rng.NextDouble() * 10000f;
        int idx = 0;
        for (int z = 0; z < size; z++)
        {
            float wz = (z + oz) * scale;
            for (int y = 0; y < size; y++)
            {
                float wy = (y + oy) * scale;
                for (int x = 0; x < size; x++)
                {
                    float wx = (x + ox) * scale;
                    float n = FractalPerlin(wx, wy, wz, 3);
                    cols[idx++] = new Color(n, n, n, n);
                }
            }
        }
        tex.SetPixels(cols);
        return tex;
    }

    static float FractalPerlin(float x, float y, float z, int octaves)
    {
        float amp = 1f, freq = 1f, sum = 0f, max = 0f;
        for (int i = 0; i < octaves; i++)
        {
            sum += amp * Mathf.PerlinNoise(x * freq, y * freq);
            sum += amp * Mathf.PerlinNoise(y * freq, z * freq);
            sum += amp * Mathf.PerlinNoise(z * freq, x * freq);
            max += 3f * amp;
            amp *= 0.5f;
            freq *= 2f;
        }
        return Mathf.Clamp01(sum / max);
    }
}