| public Write ( int u, int v, Color4 value, bool wrap = true ) : void | ||
| u | int | |
| v | int | |
| value | Color4 | |
| wrap | bool | |
| return | void | |
/// <summary>
/// Generate perline noise
/// </summary>
/// <param name="kernelSize"></param>
/// <param name="numHarmonics"></param>
/// <param name="persistence"></param>
/// <returns></returns>
static public Image GeneratePerlinNoise ( int kernelSize, int numHarmonics, float persistence = 0.5f )
{
var kernel = new Image[numHarmonics];
for ( int i=0; i<numHarmonics; i++) {
kernel[i] = new Image( kernelSize << i, kernelSize << i );
kernel[i].FillUniformNoise( true );
kernel[i].Normalize();
}
int size = kernelSize << numHarmonics;
Image noise = new Image( size, size );
for ( int x = 0; x<size; x++ ) {
for ( int y = 0; y<size; y++ ) {
Color4 value = Color4.Zero;
float freq = 1.0f;
float amp = 0.5f;
float fx = x / (float)size;
float fy = y / (float)size;
for (int i=0; i<numHarmonics; i++) {
value += kernel[i].Sample( fx * freq, fy * freq, true, true ) * amp;
amp *= persistence;
freq *= 2;
}
noise.Write( x, y, value, true );
}
}
noise.Normalize();
return noise;
}
/// <summary>
/// ComputeGradient
/// </summary>
public Image ComputeGradient ()
{
Image image = new Image( Width, Height );
for ( int i=0; i<Width; i++ ) {
for ( int j=0; j<Height; j++) {
float center = Luminance( Sample( i, j ) );
float nx = 0.5f * ( center - Luminance( Sample( i+1, j ) ) )
+ 0.5f * ( Luminance( Sample( i-1, j ) ) - center );
float ny = 0.5f * ( center - Luminance( Sample( i, j+1 ) ) )
+ 0.5f * ( Luminance( Sample( i, j-1 ) ) - center );
float nz = (float)Math.Sqrt( MathUtil.Clamp( 1 - nx*nx + ny*ny, 0, 1 ) );
image.Write( i, j, new Color4( nx, ny, nz, center ) );
}
}
return image;
}
/// <summary>
/// http://www.lighthouse3d.com/opengl/terrain/index.php3?particle
/// </summary>
/// <param name="iterations"></param>
/// <param name="displace"></param>
/// <returns></returns>
public static Image ParticleDeposition ( int sizeX, int sizeY, int iterations, float displace )
{
var rand = new Random();
var image = new Image( sizeX, sizeY );
int x = rand.Next() % sizeX;
int y = rand.Next() % sizeY;
var disp = new Color4( displace, displace, displace, displace );
for (int i=0; i<iterations; i++) {
int dir = rand.Next(4);
if (dir==0) x++;
if (dir==1) x--;
if (dir==2) y++;
if (dir==3) y--;
var value = image.Sample(x,y);
image.Write( x,y, value + disp );
}
return image;
}
/// <summary>
///
/// </summary>
/// <param name="amount"></param>
/// <returns></returns>
public Image GradientDistortion ( float amount )
{
Image image = new Image( Width, Height );
Image dudvImage = this.ComputeGradient();
for ( int i=0; i<Width; i++ ) {
for ( int j=0; j<Height; j++) {
float x = i/(float)Width;
float y = j/(float)Height;
Color4 dudv = dudvImage.Sample( x, y );
Color4 v = Sample( x + dudv.Red * amount, y + dudv.Green * amount );
image.Write( i, j, v );
}
}
return image;
}