1 files changed, 71 insertions, 0 deletions
diff --git a/intern/cycles/integrator/adaptive_sampling.cpp b/intern/cycles/integrator/adaptive_sampling.cpp
new file mode 100644
index 00000000000..23fbcfea5c2
--- /dev/null
+++ b/intern/cycles/integrator/adaptive_sampling.cpp
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2011-2021 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 "integrator/adaptive_sampling.h"
+
+#include "util/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