Initial commit.

Framework/include/random_sampler.hpp

@@ -0,0 +1,114 @@
+// Copyright 2009-2021 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <math/vec.h>
+
+namespace embree {
+
+struct RandomSampler
+{
+  unsigned int s;
+};
+
+__forceinline unsigned int MurmurHash3_mix(unsigned int hash, unsigned int k)
+{
+  const unsigned int c1 = 0xcc9e2d51;
+  const unsigned int c2 = 0x1b873593;
+  const unsigned int r1 = 15;
+  const unsigned int r2 = 13;
+  const unsigned int m = 5;
+  const unsigned int n = 0xe6546b64;
+
+  k *= c1;
+  k = (k << r1) | (k >> (32 - r1));
+  k *= c2;
+
+  hash ^= k;
+  hash = ((hash << r2) | (hash >> (32 - r2))) * m + n;
+
+  return hash;
+}
+
+__forceinline unsigned int MurmurHash3_finalize(unsigned int hash)
+{
+  hash ^= hash >> 16;
+  hash *= 0x85ebca6b;
+  hash ^= hash >> 13;
+  hash *= 0xc2b2ae35;
+  hash ^= hash >> 16;
+
+  return hash;
+}
+
+__forceinline unsigned int LCG_next(unsigned int value)
+{
+  const unsigned int m = 1664525;
+  const unsigned int n = 1013904223;
+
+  return value * m + n;
+}
+
+__forceinline void RandomSampler_init(RandomSampler& self, int id)
+{
+  unsigned int hash = 0;
+  hash = MurmurHash3_mix(hash, id);
+  hash = MurmurHash3_finalize(hash);
+
+  self.s = hash;
+}
+
+__forceinline void RandomSampler_init(RandomSampler& self, int pixelId, int sampleId)
+{
+  unsigned int hash = 0;
+  hash = MurmurHash3_mix(hash, pixelId);
+  hash = MurmurHash3_mix(hash, sampleId);
+  hash = MurmurHash3_finalize(hash);
+
+  self.s = hash;
+}
+
+__forceinline void RandomSampler_init(RandomSampler& self, int x, int y, int sampleId)
+{
+  RandomSampler_init(self, x | (y << 16), sampleId);
+}
+
+__forceinline int RandomSampler_getInt(RandomSampler& self) {
+  self.s = LCG_next(self.s); return self.s >> 1;
+}
+
+__forceinline unsigned int RandomSampler_getUInt(RandomSampler& self) {
+  self.s = LCG_next(self.s); return self.s;
+}
+
+__forceinline float RandomSampler_getFloat(RandomSampler& self) {
+  return (float)RandomSampler_getInt(self) * 4.656612873077392578125e-10f;
+}
+
+__forceinline float RandomSampler_get1D(RandomSampler& self) {
+  return RandomSampler_getFloat(self);
+}
+
+__forceinline Vec2f RandomSampler_get2D(RandomSampler& self)
+{
+  const float u = RandomSampler_get1D(self);
+  const float v = RandomSampler_get1D(self);
+  return Vec2f(u,v);
+}
+
+__forceinline Vec3fa RandomSampler_get3D(RandomSampler& self)
+{
+  /*
+  const float u = RandomSampler_get1D(self);
+  const float v = RandomSampler_get1D(self);
+  const float w = RandomSampler_get1D(self);
+  return Vec3fa(u,v,w);
+  */
+  const int u = RandomSampler_getUInt(self);
+  const int v = RandomSampler_getUInt(self);
+  const int w = RandomSampler_getUInt(self);
+  return Vec3fa(srl(Vec3ia(u,v,w), 1)) * 4.656612873077392578125e-10f;
+}
+
+} // namespace embree