noexcept all the things

[blank.git] / src / noise.cpp

diff --git a/src/noise.cpp b/src/noise.cpp
index c86f833ac3c126c894a53eeb5ad6df6c9c835d02..a5a9a2057957f361d449581eec3cbd29d94aeae6 100644 (file)
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -12,7 +12,25 @@ constexpr float one_sixth = 1.0f/6.0f;
 
 namespace blank {
 
-SimplexNoise::SimplexNoise(unsigned int seed)
+GaloisLFSR::GaloisLFSR(std::uint64_t seed) noexcept
+: state(seed) {
+
+}
+
+bool GaloisLFSR::operator ()() noexcept {
+       bool result = state & 1;
+       state >>= 1;
+       if (result) {
+               state |= 0x8000000000000000;
+               state ^= mask;
+       } else {
+               state &= 0x7FFFFFFFFFFFFFFF;
+       }
+       return result;
+}
+
+
+SimplexNoise::SimplexNoise(unsigned int seed) noexcept
 : grad({
        {  1.0f,  1.0f,  0.0f },
        { -1.0f,  1.0f,  0.0f },
@@ -27,16 +45,15 @@ 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];
        }
 }
 
 
-float SimplexNoise::operator ()(const glm::vec3 &in) const {
+float SimplexNoise::operator ()(const glm::vec3 &in) const noexcept {
        float skew = (in.x + in.y + in.z) * one_third;
 
        glm::vec3 skewed(glm::floor(in + skew));
@@ -101,22 +118,22 @@ float SimplexNoise::operator ()(const glm::vec3 &in) const {
 }
 
 
-unsigned char SimplexNoise::Perm(size_t idx) const {
+unsigned char SimplexNoise::Perm(size_t idx) const noexcept {
        return perm[idx];
 }
 
-const glm::vec3 &SimplexNoise::Grad(size_t idx) const {
+const glm::vec3 &SimplexNoise::Grad(size_t idx) const noexcept {
        return grad[idx % 12];
 }
 
 
-WorleyNoise::WorleyNoise(unsigned int seed)
+WorleyNoise::WorleyNoise(unsigned int seed) noexcept
 : seed(seed)
 , num_points(8) {
 
 }
 
-float WorleyNoise::operator ()(const glm::vec3 &in) const {
+float WorleyNoise::operator ()(const glm::vec3 &in) const noexcept {
        glm::vec3 center = floor(in);
 
        float closest = 1.0f;  // cannot be farther away than 1.0