public float Value(Vector3 position)
{
int ix = Perlin.FlooredRemainder(Mathf.FloorToInt(position.x), Perlin.SIZE);
int iy = Perlin.FlooredRemainder(Mathf.FloorToInt(position.y), Perlin.SIZE);
int iz = Perlin.FlooredRemainder(Mathf.FloorToInt(position.z), Perlin.SIZE);
float fx = position.x - Mathf.FloorToInt(position.x);
float fy = position.y - Mathf.FloorToInt(position.y);
float fz = position.z - Mathf.FloorToInt(position.z);
float u = Perlin.Fade(fx);
float v = Perlin.Fade(fy);
float w = Perlin.Fade(fz);
int aa = this.hashes[ix + iy * Perlin.SIZE].x + iz;
int ab = this.hashes[ix + iy * Perlin.SIZE].y + iz;
int ba = this.hashes[ix + iy * Perlin.SIZE].z + iz;
int bb = this.hashes[ix + iy * Perlin.SIZE].w + iz;
Vector3 g000 = this.gradients[aa];
Vector3 g100 = this.gradients[ba];
Vector3 g010 = this.gradients[ab];
Vector3 g110 = this.gradients[bb];
Vector3 g001 = this.gradients[aa + 1];
Vector3 g101 = this.gradients[ba + 1];
Vector3 g011 = this.gradients[ab + 1];
Vector3 g111 = this.gradients[bb + 1];
Vector3 p = new Vector3(fx, fy, fz);
float v000 = Vector3.Dot(g000, p + directionLookup[0]);
float v100 = Vector3.Dot(g100, p + directionLookup[1]);
float v010 = Vector3.Dot(g010, p + directionLookup[2]);
float v110 = Vector3.Dot(g110, p + directionLookup[3]);
float v001 = Vector3.Dot(g001, p + directionLookup[4]);
float v101 = Vector3.Dot(g101, p + directionLookup[5]);
float v011 = Vector3.Dot(g011, p + directionLookup[6]);
float v111 = Vector3.Dot(g111, p + directionLookup[7]);
float a = v000;
float b = v100 - v000;
float c = v010 - v000;
float d = v001 - v000;
float e = v110 - v010 - v100 + v000;
float f = v101 - v001 - v100 + v000;
float g = v011 - v001 - v010 + v000;
float h = v111 - v011 - v101 + v001 - v110 + v010 + v100 - v000;
return(a + b * u + (c + e * u) * v + (d + f * u + (g + h * u) * v) * w);
}
public PerlinSample Sample(Vector3 position)
{
int ix = Perlin.FlooredRemainder(Mathf.FloorToInt(position.x), Perlin.SIZE);
int iy = Perlin.FlooredRemainder(Mathf.FloorToInt(position.y), Perlin.SIZE);
int iz = Perlin.FlooredRemainder(Mathf.FloorToInt(position.z), Perlin.SIZE);
float fx = position.x - Mathf.FloorToInt(position.x);
float fy = position.y - Mathf.FloorToInt(position.y);
float fz = position.z - Mathf.FloorToInt(position.z);
float u = Perlin.Fade(fx);
float v = Perlin.Fade(fy);
float w = Perlin.Fade(fz);
float du = Perlin.FadeDerivative(fx);
float dv = Perlin.FadeDerivative(fy);
float dw = Perlin.FadeDerivative(fz);
int aa = this.hashes[ix + iy * Perlin.SIZE].x + iz;
int ab = this.hashes[ix + iy * Perlin.SIZE].y + iz;
int ba = this.hashes[ix + iy * Perlin.SIZE].z + iz;
int bb = this.hashes[ix + iy * Perlin.SIZE].w + iz;
Vector3 g000 = this.gradients[aa];
Vector3 g100 = this.gradients[ba];
Vector3 g010 = this.gradients[ab];
Vector3 g110 = this.gradients[bb];
Vector3 g001 = this.gradients[aa + 1];
Vector3 g101 = this.gradients[ba + 1];
Vector3 g011 = this.gradients[ab + 1];
Vector3 g111 = this.gradients[bb + 1];
Vector3 p = new Vector3(fx, fy, fz);
float v000 = Vector3.Dot(g000, p + directionLookup[0]);
float v100 = Vector3.Dot(g100, p + directionLookup[1]);
float v010 = Vector3.Dot(g010, p + directionLookup[2]);
float v110 = Vector3.Dot(g110, p + directionLookup[3]);
float v001 = Vector3.Dot(g001, p + directionLookup[4]);
float v101 = Vector3.Dot(g101, p + directionLookup[5]);
float v011 = Vector3.Dot(g011, p + directionLookup[6]);
float v111 = Vector3.Dot(g111, p + directionLookup[7]);
float a = v000;
float b = v100 - v000;
float c = v010 - v000;
float d = v001 - v000;
float e = v110 - v010 - v100 + v000;
float f = v101 - v001 - v100 + v000;
float g = v011 - v001 - v010 + v000;
float h = v111 - v011 - v101 + v001 - v110 + v010 + v100 - v000;
Vector3 da = g000;
Vector3 db = g100 - g000;
Vector3 dc = g010 - g000;
Vector3 dd = g001 - g000;
Vector3 de = g110 - g010 - g100 + g000;
Vector3 df = g101 - g001 - g100 + g000;
Vector3 dg = g011 - g001 - g010 + g000;
Vector3 dh = g111 - g011 - g101 + g001 - g110 + g010 + g100 - g000;
PerlinSample sample = new PerlinSample();
sample.value = a + b * u + (c + e * u) * v + (d + f * u + (g + h * u) * v) * w;
sample.derivative = da + db * u + (dc + de * u) * v + (dd + df * u + (dg + dh * u) * v) * w;
sample.derivative.x += du * (b + e * v + (f + h * v) * w);
sample.derivative.y += dv * (c + e * u + (g + h * u) * w);
sample.derivative.z += dw * (d + f * u + (g + h * u) * v);
return(sample);
}
