blender/intern/cycles/kernel/svm/svm_musgrave.h

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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
*/
CCL_NAMESPACE_BEGIN
/* 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"
*/
ccl_device_noinline float noise_musgrave_fBm(float3 p, NodeNoiseBasis basis, float H, float lacunarity, float octaves)
{
float rmd;
float value = 0.0f;
float pwr = 1.0f;
float pwHL = powf(lacunarity, -H);
int i;
for(i = 0; i < float_to_int(octaves); i++) {
value += snoise(p) * pwr;
pwr *= pwHL;
p *= lacunarity;
}
rmd = octaves - floorf(octaves);
if(rmd != 0.0f)
value += rmd * snoise(p) * pwr;
return value;
}
/* Musgrave Multifractal
*
* H: highest fractal dimension
* lacunarity: gap between successive frequencies
* octaves: number of frequencies in the fBm
*/
ccl_device_noinline float noise_musgrave_multi_fractal(float3 p, NodeNoiseBasis basis, float H, float lacunarity, float octaves)
{
float rmd;
float value = 1.0f;
float pwr = 1.0f;
float pwHL = powf(lacunarity, -H);
int i;
for(i = 0; i < float_to_int(octaves); i++) {
value *= (pwr * snoise(p) + 1.0f);
pwr *= pwHL;
p *= lacunarity;
}
rmd = octaves - floorf(octaves);
if(rmd != 0.0f)
value *= (rmd * pwr * snoise(p) + 1.0f); /* 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'
*/
ccl_device_noinline float noise_musgrave_hetero_terrain(float3 p, NodeNoiseBasis basis, float H, float lacunarity, float octaves, float offset)
{
float value, increment, rmd;
float pwHL = powf(lacunarity, -H);
float pwr = pwHL;
int i;
/* first unscaled octave of function; later octaves are scaled */
value = offset + snoise(p);
p *= lacunarity;
for(i = 1; i < float_to_int(octaves); i++) {
increment = (snoise(p) + offset) * pwr * value;
value += increment;
pwr *= pwHL;
p *= lacunarity;
}
rmd = octaves - floorf(octaves);
if(rmd != 0.0f) {
increment = (snoise(p) + 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'
*/
ccl_device_noinline float noise_musgrave_hybrid_multi_fractal(float3 p, NodeNoiseBasis basis, float H, float lacunarity, float octaves, float offset, float gain)
{
float result, signal, weight, rmd;
float pwHL = powf(lacunarity, -H);
float pwr = pwHL;
int i;
result = snoise(p) + offset;
weight = gain * result;
p *= lacunarity;
for(i = 1; (weight > 0.001f) && (i < float_to_int(octaves)); i++) {
if(weight > 1.0f)
weight = 1.0f;
signal = (snoise(p) + offset) * pwr;
pwr *= pwHL;
result += weight * signal;
weight *= gain * signal;
p *= lacunarity;
}
rmd = octaves - floorf(octaves);
if(rmd != 0.0f)
result += rmd * ((snoise(p) + 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'
*/
ccl_device_noinline float noise_musgrave_ridged_multi_fractal(float3 p, NodeNoiseBasis basis, float H, float lacunarity, float octaves, float offset, float gain)
{
float result, signal, weight;
float pwHL = powf(lacunarity, -H);
float pwr = pwHL;
int i;
signal = offset - fabsf(snoise(p));
signal *= signal;
result = signal;
weight = 1.0f;
for(i = 1; i < float_to_int(octaves); i++) {
p *= lacunarity;
weight = clamp(signal * gain, 0.0f, 1.0f);
signal = offset - fabsf(snoise(p));
signal *= signal;
signal *= weight;
result += signal * pwr;
pwr *= pwHL;
}
return result;
}
/* Shader */
ccl_device float svm_musgrave(NodeMusgraveType type, float dimension, float lacunarity, float octaves, float offset, float intensity, float gain, float3 p)
{
NodeNoiseBasis basis = NODE_NOISE_PERLIN;
if(type == NODE_MUSGRAVE_MULTIFRACTAL)
return intensity*noise_musgrave_multi_fractal(p, basis, dimension, lacunarity, octaves);
else if(type == NODE_MUSGRAVE_FBM)
return intensity*noise_musgrave_fBm(p, basis, dimension, lacunarity, octaves);
else if(type == NODE_MUSGRAVE_HYBRID_MULTIFRACTAL)
return intensity*noise_musgrave_hybrid_multi_fractal(p, basis, dimension, lacunarity, octaves, offset, gain);
else if(type == NODE_MUSGRAVE_RIDGED_MULTIFRACTAL)
return intensity*noise_musgrave_ridged_multi_fractal(p, basis, dimension, lacunarity, octaves, offset, gain);
else if(type == NODE_MUSGRAVE_HETERO_TERRAIN)
return intensity*noise_musgrave_hetero_terrain(p, basis, dimension, lacunarity, octaves, offset);
return 0.0f;
}
ccl_device void svm_node_tex_musgrave(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node, int *offset)
{
uint4 node2 = read_node(kg, offset);
uint4 node3 = read_node(kg, offset);
uint type, co_offset, color_offset, fac_offset;
uint dimension_offset, lacunarity_offset, detail_offset, offset_offset;
uint gain_offset, scale_offset;
decode_node_uchar4(node.y, &type, &co_offset, &color_offset, &fac_offset);
decode_node_uchar4(node.z, &dimension_offset, &lacunarity_offset, &detail_offset, &offset_offset);
decode_node_uchar4(node.w, &gain_offset, &scale_offset, NULL, NULL);
float3 co = stack_load_float3(stack, co_offset);
float dimension = stack_load_float_default(stack, dimension_offset, node2.x);
float lacunarity = stack_load_float_default(stack, lacunarity_offset, node2.y);
float detail = stack_load_float_default(stack, detail_offset, node2.z);
float foffset = stack_load_float_default(stack, offset_offset, node2.w);
float gain = stack_load_float_default(stack, gain_offset, node3.x);
float scale = stack_load_float_default(stack, scale_offset, node3.y);
dimension = fmaxf(dimension, 1e-5f);
detail = clamp(detail, 0.0f, 16.0f);
lacunarity = fmaxf(lacunarity, 1e-5f);
float f = svm_musgrave((NodeMusgraveType)type,
dimension, lacunarity, detail, foffset, 1.0f, gain, co*scale);
if(stack_valid(fac_offset))
stack_store_float(stack, fac_offset, f);
if(stack_valid(color_offset))
stack_store_float3(stack, color_offset, make_float3(f, f, f));
}
CCL_NAMESPACE_END