forked from bartvdbraak/blender
46d8bcb617
Same as last commit, code is unused and this one actually would have required some fixes, as these variants output values outside the 0-1 value range, which doesn't fit Cycles shader design.
65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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CCL_NAMESPACE_BEGIN
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/* Turbulence */
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ccl_device_noinline float noise_turbulence(float3 p, float octaves, int hard)
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{
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float fscale = 1.0f;
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float amp = 1.0f;
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float sum = 0.0f;
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int i, n;
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octaves = clamp(octaves, 0.0f, 16.0f);
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n = float_to_int(octaves);
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for(i = 0; i <= n; i++) {
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float t = noise(fscale*p);
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if(hard)
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t = fabsf(2.0f*t - 1.0f);
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sum += t*amp;
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amp *= 0.5f;
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fscale *= 2.0f;
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}
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float rmd = octaves - floorf(octaves);
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if(rmd != 0.0f) {
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float t = noise(fscale*p);
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if(hard)
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t = fabsf(2.0f*t - 1.0f);
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float sum2 = sum + t*amp;
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sum *= ((float)(1 << n)/(float)((1 << (n+1)) - 1));
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sum2 *= ((float)(1 << (n+1))/(float)((1 << (n+2)) - 1));
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return (1.0f - rmd)*sum + rmd*sum2;
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}
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else {
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sum *= ((float)(1 << n)/(float)((1 << (n+1)) - 1));
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return sum;
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}
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}
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CCL_NAMESPACE_END
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