From 548ef2d88b941d5b20692a6eea997e37366fbe2b Mon Sep 17 00:00:00 2001 From: Sergey Sharybin Date: Mon, 26 Oct 2015 19:20:40 +0500 Subject: [PATCH] Cycles: Add utility functions to evaluate CDF of a given functor --- intern/cycles/util/CMakeLists.txt | 2 + intern/cycles/util/util_math_cdf.cpp | 67 ++++++++++++++++++++++++ intern/cycles/util/util_math_cdf.h | 78 ++++++++++++++++++++++++++++ 3 files changed, 147 insertions(+) create mode 100644 intern/cycles/util/util_math_cdf.cpp create mode 100644 intern/cycles/util/util_math_cdf.h diff --git a/intern/cycles/util/CMakeLists.txt b/intern/cycles/util/CMakeLists.txt index 0acb9e9304c..e103cfa4eee 100644 --- a/intern/cycles/util/CMakeLists.txt +++ b/intern/cycles/util/CMakeLists.txt @@ -12,6 +12,7 @@ set(SRC util_aligned_malloc.cpp util_cache.cpp util_logging.cpp + util_math_cdf.cpp util_md5.cpp util_path.cpp util_string.cpp @@ -49,6 +50,7 @@ set(SRC_HEADERS util_logging.h util_map.h util_math.h + util_math_cdf.h util_math_fast.h util_md5.h util_opengl.h diff --git a/intern/cycles/util/util_math_cdf.cpp b/intern/cycles/util/util_math_cdf.cpp new file mode 100644 index 00000000000..cafe4c5abeb --- /dev/null +++ b/intern/cycles/util/util_math_cdf.cpp @@ -0,0 +1,67 @@ +/* + * Copyright 2011-2015 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 "util_math_cdf.h" + +#include "util_algorithm.h" +#include "util_math.h" + +CCL_NAMESPACE_BEGIN + +/* Invert pre-calculated CDF function. */ +void util_cdf_invert(const int resolution, + const float from, + const float to, + const vector &cdf, + const bool make_symmetric, + vector &inv_cdf) { + const float inv_resolution = 1.0f / (float)resolution; + const float range = to - from; + inv_cdf.resize(resolution); + if(make_symmetric) { + const int half_size = (resolution - 1) / 2; + for(int i = 0; i <= half_size; i++) { + float x = i / (float)half_size; + int index = upper_bound(cdf.begin(), cdf.end(), x) - cdf.begin(); + float t; + if(index < cdf.size()) { + t = (x - cdf[index])/(cdf[index+1] - cdf[index]); + } else { + t = 0.0f; + index = cdf.size() - 1; + } + float y = ((index + t) / (resolution - 1)) * (2.0f * range); + inv_cdf[half_size+i] = 0.5f*(1.0f + y); + inv_cdf[half_size-i] = 0.5f*(1.0f - y); + } + } + else { + for(int i = 0; i <= resolution; i++) { + float x = from + range * (float)i * inv_resolution; + int index = upper_bound(cdf.begin(), cdf.end(), x) - cdf.begin(); + float t; + if(index < cdf.size()) { + t = (x - cdf[index])/(cdf[index+1] - cdf[index]); + } else { + t = 0.0f; + index = resolution; + } + inv_cdf[i] = (index + t) * inv_resolution; + } + } +} + +CCL_NAMESPACE_END diff --git a/intern/cycles/util/util_math_cdf.h b/intern/cycles/util/util_math_cdf.h new file mode 100644 index 00000000000..6a8af7741f9 --- /dev/null +++ b/intern/cycles/util/util_math_cdf.h @@ -0,0 +1,78 @@ +/* + * Copyright 2011-2015 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. + */ + +#ifndef __UTIL_MATH_CDF_H__ +#define __UTIL_MATH_CDF_H__ + +#include "util_algorithm.h" +#include "util_math.h" +#include "util_vector.h" + +CCL_NAMESPACE_BEGIN + +/* Evaluate CDF of a given functor with given range and resolution. */ +template +void util_cdf_evaluate(const int resolution, + const float from, + const float to, + const Functor functor, + vector &cdf) +{ + const int cdf_count = resolution + 1; + const float range = to - from; + cdf.resize(cdf_count); + cdf[0] = 0.0f; + /* Actual CDF evaluation. */ + for(int i = 0; i < resolution; ++i) { + float x = from + range * (float)i / (resolution - 1); + float y = functor(x); + cdf[i + 1] = cdf[i] + fabsf(y); + } + /* Normalize the CDF. */ + for(int i = 0; i <= resolution; i++) { + cdf[i] /= cdf[resolution]; + } +} + +/* Invert pre-calculated CDF function. */ +void util_cdf_invert(const int resolution, + const float from, + const float to, + const vector &cdf, + const bool make_symmetric, + vector &inv_cdf); + +/* Evaluate inverted CDF of a given functor with given range and resolution. */ +template +void util_cdf_inverted(const int resolution, + const float from, + const float to, + const Functor functor, + const bool make_symmetric, + vector &inv_cdf) +{ + vector cdf; + /* There is no much smartness going around lower resolution for the CDF table, + * this just to match the old code from pixel filter so it all stays exactly + * the same and no regression tests are failed. + */ + util_cdf_evaluate(resolution - 1, from, to, functor, cdf); + util_cdf_invert(resolution, from, to, cdf, make_symmetric, inv_cdf); +} + +CCL_NAMESPACE_END + +#endif /* __UTIL_MATH_H_CDF__ */