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/*
* Copyright 2011-2013 Blender Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License
*/
#include "stdosl.h"
#include "node_texture.h"
/* Musgrave fBm
*
* H: fractal increment parameter
* lacunarity: gap between successive frequencies
* octaves: number of frequencies in the fBm
*
* from "Texturing and Modelling: A procedural approach"
*/
float noise_musgrave_fBm(point p, string basis, float H, float lacunarity, float octaves)
{
float rmd;
float value = 0.0;
float pwr = 1.0;
float pwHL = pow(lacunarity, -H);
int i;
for (i = 0; i < (int)octaves; i++) {
value += safe_noise(p, 0) * pwr;
pwr *= pwHL;
p *= lacunarity;
}
rmd = octaves - floor(octaves);
if (rmd != 0.0)
value += rmd * safe_noise(p, 0) * pwr;
return value;
}
/* Musgrave Multifractal
*
* H: highest fractal dimension
* lacunarity: gap between successive frequencies
* octaves: number of frequencies in the fBm
*/
float noise_musgrave_multi_fractal(point p, string basis, float H, float lacunarity, float octaves)
{
float rmd;
float value = 1.0;
float pwr = 1.0;
float pwHL = pow(lacunarity, -H);
int i;
for (i = 0; i < (int)octaves; i++) {
value *= (pwr * safe_noise(p, 0) + 1.0);
pwr *= pwHL;
p *= lacunarity;
}
rmd = octaves - floor(octaves);
if (rmd != 0.0)
value *= (rmd * pwr * safe_noise(p, 0) + 1.0); /* correct? */
return value;
}
/* Musgrave Heterogeneous Terrain
*
* H: fractal dimension of the roughest area
* lacunarity: gap between successive frequencies
* octaves: number of frequencies in the fBm
* offset: raises the terrain from `sea level'
*/
float noise_musgrave_hetero_terrain(point p, string basis, float H, float lacunarity, float octaves, float offset)
{
float value, increment, rmd;
float pwHL = pow(lacunarity, -H);
float pwr = pwHL;
int i;
/* first unscaled octave of function; later octaves are scaled */
value = offset + safe_noise(p, 0);
p *= lacunarity;
for (i = 1; i < (int)octaves; i++) {
increment = (safe_noise(p, 0) + offset) * pwr * value;
value += increment;
pwr *= pwHL;
p *= lacunarity;
}
rmd = octaves - floor(octaves);
if (rmd != 0.0) {
increment = (safe_noise(p, 0) + offset) * pwr * value;
value += rmd * increment;
}
return value;
}
/* Hybrid Additive/Multiplicative Multifractal Terrain
*
* H: fractal dimension of the roughest area
* lacunarity: gap between successive frequencies
* octaves: number of frequencies in the fBm
* offset: raises the terrain from `sea level'
*/
float noise_musgrave_hybrid_multi_fractal(point p, string basis, float H,
float lacunarity, float octaves, float offset, float gain)
{
float result, signal, weight, rmd;
float pwHL = pow(lacunarity, -H);
float pwr = pwHL;
int i;
result = safe_noise(p, 0) + offset;
weight = gain * result;
p *= lacunarity;
for (i = 1; (weight > 0.001) && (i < (int)octaves); i++) {
if (weight > 1.0)
weight = 1.0;
signal = (safe_noise(p, 0) + offset) * pwr;
pwr *= pwHL;
result += weight * signal;
weight *= gain * signal;
p *= lacunarity;
}
rmd = octaves - floor(octaves);
if (rmd != 0.0)
result += rmd * ((safe_noise(p, 0) + offset) * pwr);
return result;
}
/* Ridged Multifractal Terrain
*
* H: fractal dimension of the roughest area
* lacunarity: gap between successive frequencies
* octaves: number of frequencies in the fBm
* offset: raises the terrain from `sea level'
*/
float noise_musgrave_ridged_multi_fractal(point p, string basis, float H,
float lacunarity, float octaves, float offset, float gain)
{
float result, signal, weight;
float pwHL = pow(lacunarity, -H);
float pwr = pwHL;
int i;
signal = offset - fabs(safe_noise(p, 0));
signal *= signal;
result = signal;
weight = 1.0;
for (i = 1; i < (int)octaves; i++) {
p *= lacunarity;
weight = clamp(signal * gain, 0.0, 1.0);
signal = offset - fabs(safe_noise(p, 0));
signal *= signal;
signal *= weight;
result += signal * pwr;
pwr *= pwHL;
}
return result;
}
/* Shader */
shader node_musgrave_texture(
int use_mapping = 0,
matrix mapping = matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0),
string Type = "fBM",
float Dimension = 2.0,
float Lacunarity = 1.0,
float Detail = 2.0,
float Offset = 0.0,
float Gain = 1.0,
float Scale = 5.0,
point Vector = P,
output float Fac = 0.0,
output color Color = 0.0)
{
float dimension = max(Dimension, 1e-5);
float octaves = clamp(Detail, 0.0, 16.0);
float lacunarity = max(Lacunarity, 1e-5);
string Basis = "Perlin";
float intensity = 1.0;
point p = Vector;
if (use_mapping)
p = transform(mapping, p);
p = p * Scale;
if (Type == "Multifractal")
Fac = intensity * noise_musgrave_multi_fractal(p, Basis, dimension, lacunarity, octaves);
else if (Type == "fBM")
Fac = intensity * noise_musgrave_fBm(p, Basis, dimension, lacunarity, octaves);
else if (Type == "Hybrid Multifractal")
Fac = intensity * noise_musgrave_hybrid_multi_fractal(p, Basis, dimension, lacunarity, octaves, Offset, Gain);
else if (Type == "Ridged Multifractal")
Fac = intensity * noise_musgrave_ridged_multi_fractal(p, Basis, dimension, lacunarity, octaves, Offset, Gain);
else if (Type == "Hetero Terrain")
Fac = intensity * noise_musgrave_hetero_terrain(p, Basis, dimension, lacunarity, octaves, Offset);
Color = color(Fac, Fac, Fac);
}
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