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);
+ unsigned char value;
for (size_t i = 0; i < 256; ++i) {
- val = 2346765 * val + 6446345;
- perm[i] = val % 256;
+ perm[i] = random(value);
+ perm[i] &= 0xFF;
perm[i + 256] = perm[i];
+ perm12[i] = perm[i] % 12;
+ perm12[i + 256] = perm12[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));
float tr = (skewed.x + skewed.y + skewed.z) * one_sixth;
glm::vec3 unskewed(skewed - tr);
- glm::vec3 offset[4];
- offset[0] = in - unskewed;
+ glm::vec3 relative(in - unskewed);
glm::vec3 second, third;
- if (offset[0].x >= offset[0].y) {
- if (offset[0].y >= offset[0].z) {
- second = { 1.0f, 0.0f, 0.0f };
- third = { 1.0f, 1.0f, 0.0f };
- } else if (offset[0].x >= offset[0].z) {
- second = { 1.0f, 0.0f, 0.0f };
- third = { 1.0f, 0.0f, 1.0f };
+ if (relative.x >= relative.y) {
+ if (relative.y >= relative.z) {
+ second = { 1, 0, 0 };
+ third = { 1, 1, 0 };
+ } else if (relative.x >= relative.z) {
+ second = { 1, 0, 0 };
+ third = { 1, 0, 1 };
} else {
- second = { 0.0f, 0.0f, 1.0f };
- third = { 1.0f, 0.0f, 1.0f };
+ second = { 0, 0, 1 };
+ third = { 1, 0, 1 };
}
- } else if (offset[0].y < offset[0].z) {
- second = { 0.0f, 0.0f, 1.0f };
- third = { 0.0f, 1.0f, 1.0f };
- } else if (offset[0].x < offset[0].z) {
- second = { 0.0f, 1.0f, 0.0f };
- third = { 0.0f, 1.0f, 1.0f };
+ } else if (relative.y < relative.z) {
+ second = { 0, 0, 1 };
+ third = { 0, 1, 1 };
+ } else if (relative.x < relative.z) {
+ second = { 0, 1, 0 };
+ third = { 0, 1, 1 };
} else {
- second = { 0.0f, 1.0f, 0.0f };
- third = { 1.0f, 1.0f, 0.0f };
+ second = { 0, 1, 0 };
+ third = { 1, 1, 0 };
}
- offset[1] = offset[0] - second + one_sixth;
- offset[2] = offset[0] - third + one_third;
- offset[3] = offset[0] - 0.5f;
-
- unsigned char index[3] = {
- (unsigned char)(skewed.x),
- (unsigned char)(skewed.y),
- (unsigned char)(skewed.z),
+ glm::vec3 offset[4] = {
+ in - unskewed,
+ relative - second + one_sixth,
+ relative - third + one_third,
+ relative - 0.5f,
};
- size_t corner[4] = {
- Perm(index[0] + Perm(index[1] + Perm(index[2]))),
- Perm(index[0] + second.x + Perm(index[1] + second.y + Perm(index[2] + second.z))),
- Perm(index[0] + third.x + Perm(index[1] + third.y + Perm(index[2] + third.z))),
- Perm(index[0] + 1 + Perm(index[1] + 1 + Perm(index[2] + 1))),
+
+ int index[3] = {
+ (int)(skewed.x) & 0xFF,
+ (int)(skewed.y) & 0xFF,
+ (int)(skewed.z) & 0xFF,
};
- float n[4];
- float t[4];
- for (size_t i = 0; i < 4; ++i) {
- t[i] = 0.6f - dot(offset[i], offset[i]);
- if (t[i] < 0.0f) {
- n[i] = 0.0f;
- } else {
- t[i] *= t[i];
- n[i] = t[i] * t[i] * dot(Grad(corner[i]), offset[i]);
- }
+
+ float n = 0.0f;
+
+ // 0
+ float t = 0.6f - dot(offset[0], offset[0]);
+ if (t > 0.0f) {
+ t *= t;
+ int corner = Perm12(index[0] + Perm(index[1] + Perm(index[2])));
+ n += t * t * dot(Grad(corner), offset[0]);
+ }
+
+ // 1
+ t = 0.6f - dot(offset[1], offset[1]);
+ if (t > 0.0f) {
+ t *= t;
+ int corner = Perm12(index[0] + int(second.x) + Perm(index[1] + int(second.y) + Perm(index[2] + int(second.z))));
+ n += t * t * dot(Grad(corner), offset[1]);
}
- return 32.0f * (n[0] + n[1] + n[2] + n[3]);
+ // 2
+ t = 0.6f - dot(offset[2], offset[2]);
+ if (t > 0.0f) {
+ t *= t;
+ int corner = Perm12(index[0] + int(third.x) + Perm(index[1] + int(third.y) + Perm(index[2] + int(third.z))));
+ n += t * t * dot(Grad(corner), offset[2]);
+ }
+
+ // 3
+ t = 0.6f - dot(offset[3], offset[3]);
+ if (t > 0.0f) {
+ t *= t;
+ int corner = Perm12(index[0] + 1 + Perm(index[1] + 1 + Perm(index[2] + 1)));
+ n += t * t * dot(Grad(corner), offset[3]);
+ }
+
+ return 32.0f * n;
}
-unsigned char SimplexNoise::Perm(size_t idx) const {
+int SimplexNoise::Perm(int idx) const noexcept {
return perm[idx];
}
-const glm::vec3 &SimplexNoise::Grad(size_t idx) const {
- return grad[idx % 12];
+int SimplexNoise::Perm12(int idx) const noexcept {
+ return perm12[idx];
+}
+
+const glm::vec3 &SimplexNoise::Grad(int idx) const noexcept {
+ return grad[idx];
+}
+
+
+WorleyNoise::WorleyNoise(unsigned int seed) noexcept
+: seed(seed)
+, num_points(8) {
+
+}
+
+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
+
+ for (int z = -1; z <= 1; ++z) {
+ for (int y = -1; y <= 1; ++y) {
+ for (int x = -1; x <= 1; ++x) {
+ glm::vec3 cube(center.x + x, center.y + y, center.z + z);
+ unsigned int cube_rand =
+ (unsigned(cube.x) * 130223) ^
+ (unsigned(cube.y) * 159899) ^
+ (unsigned(cube.z) * 190717) ^
+ seed;
+
+ for (int i = 0; i < num_points; ++i) {
+ glm::vec3 point(cube);
+ cube_rand = 190667 * cube_rand + 109807;
+ point.x += float(cube_rand % 262144) / 262144.0f;
+ cube_rand = 135899 * cube_rand + 189169;
+ point.y += float(cube_rand % 262144) / 262144.0f;
+ cube_rand = 159739 * cube_rand + 112139;
+ point.z += float(cube_rand % 262144) / 262144.0f;
+
+ glm::vec3 diff(in - point);
+ float distance = sqrt(dot(diff, diff));
+ if (distance < closest) {
+ closest = distance;
+ }
+ }
+ }
+ }
+ }
+
+ // closest ranges (0, 1), so normalizing to (-1,1) is trivial
+ // though heavily biased towards lower numbers
+ return 2.0f * closest - 1.0f;
}
}
projects / blank.git / blobdiff