6a529e14f4
Previously shutter was instantly opening, staying opened for the shutter time period of time and then instantly closing. This isn't quite how real cameras are working, where shutter is opening with some curve. Now it is possible to define user curve for how much shutter is opened across the sampling period of time. This could be used for example to make motion blur trails softer.
68 lines
2.0 KiB
C++
68 lines
2.0 KiB
C++
/*
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* Copyright 2011-2015 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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#include "util_math_cdf.h"
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#include "util_algorithm.h"
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#include "util_math.h"
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CCL_NAMESPACE_BEGIN
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/* Invert pre-calculated CDF function. */
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void util_cdf_invert(const int resolution,
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const float from,
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const float to,
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const vector<float> &cdf,
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const bool make_symmetric,
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vector<float> &inv_cdf) {
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const float inv_resolution = 1.0f / (float)resolution;
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const float range = to - from;
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inv_cdf.resize(resolution);
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if(make_symmetric) {
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const int half_size = (resolution - 1) / 2;
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for(int i = 0; i <= half_size; i++) {
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float x = i / (float)half_size;
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int index = upper_bound(cdf.begin(), cdf.end(), x) - cdf.begin();
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float t;
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if(index < cdf.size() - 1) {
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t = (x - cdf[index])/(cdf[index+1] - cdf[index]);
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} else {
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t = 0.0f;
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index = cdf.size() - 1;
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}
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float y = ((index + t) / (resolution - 1)) * (2.0f * range);
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inv_cdf[half_size+i] = 0.5f*(1.0f + y);
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inv_cdf[half_size-i] = 0.5f*(1.0f - y);
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}
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}
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else {
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for(int i = 0; i < resolution; i++) {
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float x = from + range * (float)i * inv_resolution;
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int index = upper_bound(cdf.begin(), cdf.end(), x) - cdf.begin();
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float t;
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if(index < cdf.size() - 1) {
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t = (x - cdf[index])/(cdf[index+1] - cdf[index]);
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} else {
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t = 0.0f;
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index = resolution;
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}
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inv_cdf[i] = (index + t) * inv_resolution;
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}
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}
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}
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CCL_NAMESPACE_END
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