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 },
{ 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));
}
-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 = 4.0f;
+ float closest = 1.0f; // cannot be farther away than 1.0
for (int z = -1; z <= 1; ++z) {
for (int y = -1; y <= 1; ++y) {
point.z += float(cube_rand % 200000) / 200000.0f;
glm::vec3 diff(in - point);
- float distance = dot(diff, diff);
+ float distance = sqrt(dot(diff, diff));
if (distance < closest) {
closest = distance;
}
}
}
- return closest;
+ // closest ranges (0, 1), so normalizing to (-1,1) is trivial
+ // though heavily biased towards lower numbers
+ return 2.0f * closest - 1.0f;
}
}