Mathf.PerlinNoise only outputs a single number in editor window

I have created a button that opens a editor window that displays a texture as a way to preview my heightmap/noisemap, but when i try to use Mathf.PerlinNoise i only get the nummer 0.4652731 regardless of what values i input. Any ideas why it only outputs 0.4652731?

On the third code sample you can see the specific problem, but i included the whole call sequence.

 if(GUILayout.Button("Preview Noise"))
         {
             texture = TerrainNoiseGeneration.NoiseMap(10,10);
             TerrainGeneratorEditorWindow.OpenNoisePreviewWindow(texture);
         }

 public static void OpenNoisePreviewWindow(Texture2D previewTexture)
 {

     EditorWindow.GetWindow<TerrainGeneratorEditorWindow>("Preview Noise");
     EditorWindow.GetWindow<TerrainGeneratorEditorWindow>("Preview Noise").texture = previewTexture;

 }
 
 void OnGUI()
 {
     GUILayout.Label("Test", EditorStyles.boldLabel);
     //texture = new Texture2D(200, 200);
     if (texture == null)
     {
         texture = Texture2D.blackTexture;
     }
     
     EditorGUI.DrawPreviewTexture(new Rect(20, 20, 300, 300), texture);
 }

     public static Texture2D NoiseMap(int mapWidth, int mapHeight)
     {
 
 
 
         float[,] noiseMap = new float[mapWidth, mapHeight];
         float maxNoiseHeight = float.MinValue;
         float minNoiseHeight = float.MaxValue;
 
         float noiseHeight = 0;
         //Mathf.PerlinNoise
         //        float centerWidth = mapWidth / 2f;
         //        float centerHeight = mapHeight / 2f;
 
         for (int y = 0; y < mapHeight; y++)
         {
             for (int x = 0; x < mapWidth; x++)
             {
                 //values
                 float sampleX = x;
                 float sampleY = y;
 
                 float perlinNoise = Mathf.PerlinNoise(sampleX, sampleY); //0.4652731 ???
                 noiseHeight = perlinNoise;
                 if (noiseHeight > maxNoiseHeight)
                 {
                     maxNoiseHeight = noiseHeight;
                 }
                 else if (noiseHeight < minNoiseHeight)
                 {
                     minNoiseHeight = noiseHeight;
                 }
 
                 noiseMap[x, y] = perlinNoise;

             }
 
         }
 
         for (int y = 0; y < mapHeight; y++)
         {
             for (int x = 0; x < mapWidth; x++)
             {
                 noiseMap[x, y] = Mathf.InverseLerp(minNoiseHeight, maxNoiseHeight, noiseMap[x, y]);
                 
             }
         }
 
         int width = noiseMap.GetLength(0);
         int height = noiseMap.GetLength(1);
 
         Texture2D texture = new Texture2D(width, height);
         texture.GetPixels();
 
         Color[] colourMap = new Color[width * height];
 
         for (int y = 0; y < height; y++)
         {
             for (int x = 0; x < width; x++)
             {
                 colourMap[y * width + x] = Color.Lerp(Color.black, Color.white, noiseMap[x, y]);
             }
         }
         texture.SetPixels(colourMap);
         texture.Apply();
 
 
 
         return texture;
     }