[Bf-blender-cvs] [548ef2d] master: Cycles: Add utility functions to evaluate CDF of a given functor
Sergey Sharybin
noreply at git.blender.org
Tue Oct 27 23:17:10 CET 2015
Commit: 548ef2d88b941d5b20692a6eea997e37366fbe2b
Author: Sergey Sharybin
Date: Mon Oct 26 19:20:40 2015 +0500
Branches: master
https://developer.blender.org/rB548ef2d88b941d5b20692a6eea997e37366fbe2b
Cycles: Add utility functions to evaluate CDF of a given functor
===================================================================
M intern/cycles/util/CMakeLists.txt
A intern/cycles/util/util_math_cdf.cpp
A intern/cycles/util/util_math_cdf.h
===================================================================
diff --git a/intern/cycles/util/CMakeLists.txt b/intern/cycles/util/CMakeLists.txt
index 0acb9e9..e103cfa 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 0000000..cafe4c5
--- /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<float> &cdf,
+ const bool make_symmetric,
+ vector<float> &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 0000000..6a8af77
--- /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 <typename Functor>
+void util_cdf_evaluate(const int resolution,
+ const float from,
+ const float to,
+ const Functor functor,
+ vector<float> &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<float> &cdf,
+ const bool make_symmetric,
+ vector<float> &inv_cdf);
+
+/* Evaluate inverted CDF of a given functor with given range and resolution. */
+template <typename Functor>
+void util_cdf_inverted(const int resolution,
+ const float from,
+ const float to,
+ const Functor functor,
+ const bool make_symmetric,
+ vector<float> &inv_cdf)
+{
+ vector<float> 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__ */
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