/// <summary>
/// Create bitmap array of noise values
/// </summary>
/// <param name="data"><c>NoiseData</c> struct with data about noise generation</param>
/// <param name="noiseObject"><c>INoise</c> interface that provides noise function</param>
/// <returns>Returns array of bytes with pixel values</returns>
public byte[] GenerateNoiseMap(NoiseData data, INoise noiseObject)
{
#if DEBUG
Stopwatch watch = Stopwatch.StartNew();
watch.Start();
#endif
int stride = data.stride;
byte[] noiseMap = new byte[stride * data.height];
float[] floatMap = new float[stride * data.height];
float scale = data.scale;
float halfWidth = scale / 2f;
float halfHeight = scale / 2f;
if (scale <= 0)
{
scale = 0.0001f;
}
float max = float.MinValue;
float min = float.MaxValue;
for (int y = 0; y < data.height; y++)
{
for (int x = 0; x < data.width; x++)
{
float amplitude = 1;
float frequency = 1;
float value = 0;
float range = 1;
float sampleX = MathHelper.Lerp(0, scale, (float)(x) / data.width) - halfWidth;
float sampleY = MathHelper.Lerp(0, scale, (float)(y) / data.height) - halfHeight;
for (int i = 0; i < data.octaves; i++)
{
//System.Diagnostics.Debug.WriteLine($"{sampleX} {sampleY}");
float noiseValue = noiseObject.GetValue((new Vector2(sampleX, sampleY)) * frequency + data.offset);
if (data.turbulence)
{
noiseValue = Math.Abs(noiseValue);
}
value += noiseValue * amplitude;
amplitude *= data.persistance;
frequency *= data.lacunarity;
range += amplitude;
}
value /= range;
if (value > max)
{
max = value;
}
if (value < min)
{
min = value;
}
floatMap[y * data.width + x] = value;
//noiseMap[y * data.width + x] = (byte)((value * 0.5f + 0.5f) * 255);
}
}
//System.Diagnostics.Debug.WriteLine($"Min: {min} Max: {max}");
for (int y = 0; y < data.height; y++)
{
for (int x = 0; x < data.width; x++)
{
int pos = y * data.width + x;
noiseMap[pos] = (byte)(MathHelper.InverseLerp(min, max, floatMap[pos]) * 255);
}
}
#if DEBUG
watch.Stop();
Debug.WriteLine(watch.ElapsedMilliseconds);
#endif
return(noiseMap);
}
