update light levels from border on neighbor change

[blank.git] / src / noise.cpp

diff --git a/src/noise.cpp b/src/noise.cpp
index c86f833ac3c126c894a53eeb5ad6df6c9c835d02..8b716140e78c5b301fbd00a383778eb482e9166f 100644 (file)
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -12,6 +12,24 @@ constexpr float one_sixth = 1.0f/6.0f;
 
 namespace blank {
 
+GaloisLFSR::GaloisLFSR(std::uint64_t seed)
+: state(seed) {
+
+}
+
+bool GaloisLFSR::operator ()() {
+       bool result = state & 1;
+       state >>= 1;
+       if (result) {
+               state |= 0x8000000000000000;
+               state ^= mask;
+       } else {
+               state &= 0x7FFFFFFFFFFFFFFF;
+       }
+       return result;
+}
+
+
 SimplexNoise::SimplexNoise(unsigned int seed)
 : grad({
        {  1.0f,  1.0f,  0.0f },
@@ -27,10 +45,9 @@ SimplexNoise::SimplexNoise(unsigned int seed)
        {  0.0f,  1.0f, -1.0f },
        {  0.0f, -1.0f, -1.0f },
 }) {
-       unsigned int val = seed;
+       GaloisLFSR random(seed ^ 0x0123456789ACBDEF);
        for (size_t i = 0; i < 256; ++i) {
-               val = 2346765 * val + 6446345;
-               perm[i] = val % 256;
+               random(perm[i]);
                perm[i + 256] = perm[i];
        }
 }