using Noise;
using System.IO;

long width  = 1024;
long height = 1024;
double scaleX = 128.0;
double scaleY = 128.0;

byte[] resBytes = new byte[width*height*3];

// Console.WriteLine(PerlinNoise.perlin(3.25    , 0, 0));
// Console.WriteLine(PerlinNoise.perlin(3.25+256, 0, 0));
// Console.WriteLine(PerlinNoise.perlin(3.25+512, 0, 0));

for(int i = 0; i<width; i++) {
  for(int j = 0; j<height; j++) {
    double res = PerlinNoise.perlin(((double)i)/scaleX, ((double)j)/scaleY, 1.0);
    byte bRes = (byte)(res * 256);
    resBytes[(i*width+j)*3+0] = bRes;
    resBytes[(i*width+j)*3+1] = bRes;
    resBytes[(i*width+j)*3+2] = bRes;
  }
}

using (var fs = new FileStream("out.rif", FileMode.Create, FileAccess.Write)) {
  // Convert width to a byte array in big-endian order
  byte[] widthBytes = BitConverter.GetBytes(width);
  if (BitConverter.IsLittleEndian)
      Array.Reverse(widthBytes); // Convert to big-endian if the system is little-endian

  byte[] header = new byte[] {
    // Magic
    0x72, 0x69, 0x66, 0x56, 0x30, 0x30, 0x30, 0x31,
    // Width
    widthBytes[0], widthBytes[1], widthBytes[2], widthBytes[3],
    widthBytes[4], widthBytes[5], widthBytes[6], widthBytes[7],
    // Format (R8G8B8)
    0x00
  };
  fs.Write(header,   0,   header.Length);
  fs.Write(resBytes, 0, resBytes.Length);
}