Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/kernel/sample/lcg.h

@@ -0,0 +1,53 @@
+/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+#pragma once
+
+#include "util/hash.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* Linear Congruential Generator */
+
+/* This is templated to handle multiple address spaces on Metal. */
+template<class T> ccl_device uint lcg_step_uint(T rng)
+{
+  /* implicit mod 2^32 */
+  *rng = (1103515245 * (*rng) + 12345);
+  return *rng;
+}
+
+/* This is templated to handle multiple address spaces on Metal. */
+template<class T> ccl_device float lcg_step_float(T rng)
+{
+  /* implicit mod 2^32 */
+  *rng = (1103515245 * (*rng) + 12345);
+  return (float)*rng * (1.0f / (float)0xFFFFFFFF);
+}
+
+template<class T> ccl_device float3 lcg_step_float3(T rng)
+{
+  /* Make sure the random numbers are evaluated in order. */
+  const float rand_x = lcg_step_float(rng);
+  const float rand_y = lcg_step_float(rng);
+  const float rand_z = lcg_step_float(rng);
+  return make_float3(rand_x, rand_y, rand_z);
+}
+
+ccl_device uint lcg_init(const 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 hash_uint3(rng_hash ^ scramble, rng_offset, sample);
+}
+
+CCL_NAMESPACE_END