adaptive_sampling.cpp

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/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
 *
 * SPDX-License-Identifier: Apache-2.0 */
 
#include "integrator/adaptive_sampling.h"
 
#include "util/math.h"
 
CCL_NAMESPACE_BEGIN
 
AdaptiveSampling::AdaptiveSampling() {}
 
int AdaptiveSampling::align_samples(int start_sample, int num_samples) const
{
  if (!use) {
    return num_samples;
  }
 
  /*
   * The naive implementation goes as following:
   *
   *   int count = 1;
   *   while (!need_filter(start_sample + count - 1) && count < num_samples) {
   *     ++count;
   *   }
   *   return count;
   */
 
  /* 0-based sample index at which first filtering will happen. */
  const int first_filter_sample = (min_samples + 1) | (adaptive_step - 1);
 
  /* Allow as many samples as possible until the first filter sample. */
  if (start_sample + num_samples <= first_filter_sample) {
    return num_samples;
  }
 
  const int next_filter_sample = max(first_filter_sample, start_sample | (adaptive_step - 1));
 
  const int num_samples_until_filter = next_filter_sample - start_sample + 1;
 
  return min(num_samples_until_filter, num_samples);
}
 
bool AdaptiveSampling::need_filter(int sample) const
{
  if (!use) {
    return false;
  }
 
  if (sample <= min_samples) {
    return false;
  }
 
  return (sample & (adaptive_step - 1)) == (adaptive_step - 1);
}
 
CCL_NAMESPACE_END