1 files changed, 51 insertions, 0 deletions
diff --git a/intern/cycles/kernel/sample/sample_lcg.h b/intern/cycles/kernel/sample/sample_lcg.h
new file mode 100644
index 00000000000..92cfff639b4
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+++ b/intern/cycles/kernel/sample/sample_lcg.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2011-2013 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.
+ */
+#pragma once
+
+CCL_NAMESPACE_BEGIN
+
+/* Linear Congruential Generator */
+
+ccl_device uint lcg_step_uint(uint *rng)
+{
+  /* implicit mod 2^32 */
+  *rng = (1103515245 * (*rng) + 12345);
+  return *rng;
+}
+
+ccl_device float lcg_step_float(uint *rng)
+{
+  /* implicit mod 2^32 */
+  *rng = (1103515245 * (*rng) + 12345);
+  return (float)*rng * (1.0f / (float)0xFFFFFFFF);
+}
+
+ccl_device uint lcg_init(uint seed)
+{
+  uint rng = seed;
+  lcg_step_uint(&rng);
+  return rng;
+}
+
+ccl_device_inline uint lcg_state_init(const uint rng_hash,
+                                      const uint rng_offset,
+                                      const uint sample,
+                                      const uint scramble)
+{
+  return lcg_init(rng_hash + rng_offset + sample * scramble);
+}
+
+CCL_NAMESPACE_END