public static Texture2D PerlinCloudsTiling(int size, int seed)
{
Texture2D tex = GetTexture2D(size, "PerlinCloudsTiling" + TextureIndex++);
float step = 1.0f / size;
for (int y = 0; y < size; y++)
{
for (int x = 0; x < size; x++)
{
Vector2 uv = new Vector2((x + 0.5f) * step, (y + 0.5f) * step);
Vector3 samplepos = new Vector3(uv.x - 0.5f, seed * uv.x + uv.y - 0.5f, 0.0f);
tex.SetPixel(x, y, Color.white * (Noise.Eval2DFrac(samplepos.x, samplepos.y, 8, 6, 1) * 0.5f + 0.5f));
}
}
tex.Apply();
return(tex);
}
public static Texture2D Perlin(int size, float offsetX = 0, float offsetY = 0, int frequency = 1)
{
Texture2D tex = GetTexture2D(size, "PerlinClouds" + TextureIndex++);
float step = 1.0f / size;
for (int y = 0; y < size; y++)
{
for (int x = 0; x < size; x++)
{
Vector2 uv = new Vector2((x + offsetX + 0.5f) * step, (y + offsetY + 0.5f) * step);
Vector3 samplepos = new Vector3(uv.x - 0.5f, uv.y - 0.5f, 0.0f);
tex.SetPixel(x, y, Color.white * (Noise.Eval2DFrac(samplepos.x, samplepos.y, frequency, 1) * 0.5f + 0.5f));
}
}
tex.Apply();
return(tex);
}
public static Texture2D PerlinCurl(int size, int seed)
{
Texture2D tex = GetTexture2D(size, "PerlinCurl" + TextureIndex++);
float step = 1.0f / size;
float[] values = new float[size * size];
for (int y = 0; y < size; y++)
{
for (int x = 0; x < size; x++)
{
Vector2 uv = new Vector2((x + 0.5f) * step, (y + 0.5f) * step);
Vector3 samplepos = new Vector3(uv.x - 0.5f, seed * uv.x + uv.y - 0.5f, 0.0f);
values[x + y * size] = Noise.Eval2DFrac(samplepos.x, samplepos.y, 8, 2, 1) * 0.5f + 0.5f;
}
}
float getValue(int x, int y)
{
int xwrap = (x + size) % size;
int ywrap = (y + size) % size;
return(values[xwrap + ywrap * size]);
};
for (int y = 0; y < size; y++)
{
for (int x = 0; x < size; x++)
{
// centered-difference
float dFdx = (getValue(x + 1, y) - getValue(x - 1, y)) / (2 * step);
float dFdy = (getValue(x, y + 1) - getValue(x, y - 1)) / (2 * step);
Vector2 curl = new Vector2(dFdy, -dFdx);
float speed = curl.magnitude;
curl.Normalize();
tex.SetPixel(x, y, new Color(curl.x, curl.y, speed));
}
}
tex.Apply();
return(tex);
}
