8 constexpr float one_third = 1.0f/3.0f;
9 constexpr float one_sixth = 1.0f/6.0f;
15 GaloisLFSR::GaloisLFSR(std::uint64_t seed)
20 bool GaloisLFSR::operator ()() {
21 bool result = state & 1;
24 state |= 0x8000000000000000;
27 state &= 0x7FFFFFFFFFFFFFFF;
33 SimplexNoise::SimplexNoise(unsigned int seed)
36 { -1.0f, 1.0f, 0.0f },
37 { 1.0f, -1.0f, 0.0f },
38 { -1.0f, -1.0f, 0.0f },
40 { -1.0f, 0.0f, 1.0f },
41 { 1.0f, 0.0f, -1.0f },
42 { -1.0f, 0.0f, -1.0f },
44 { 0.0f, -1.0f, 1.0f },
45 { 0.0f, 1.0f, -1.0f },
46 { 0.0f, -1.0f, -1.0f },
48 unsigned int val = seed;
49 for (size_t i = 0; i < 256; ++i) {
50 val = 2346765 * val + 6446345;
52 perm[i + 256] = perm[i];
57 float SimplexNoise::operator ()(const glm::vec3 &in) const {
58 float skew = (in.x + in.y + in.z) * one_third;
60 glm::vec3 skewed(glm::floor(in + skew));
61 float tr = (skewed.x + skewed.y + skewed.z) * one_sixth;
63 glm::vec3 unskewed(skewed - tr);
65 offset[0] = in - unskewed;
67 glm::vec3 second, third;
69 if (offset[0].x >= offset[0].y) {
70 if (offset[0].y >= offset[0].z) {
71 second = { 1.0f, 0.0f, 0.0f };
72 third = { 1.0f, 1.0f, 0.0f };
73 } else if (offset[0].x >= offset[0].z) {
74 second = { 1.0f, 0.0f, 0.0f };
75 third = { 1.0f, 0.0f, 1.0f };
77 second = { 0.0f, 0.0f, 1.0f };
78 third = { 1.0f, 0.0f, 1.0f };
80 } else if (offset[0].y < offset[0].z) {
81 second = { 0.0f, 0.0f, 1.0f };
82 third = { 0.0f, 1.0f, 1.0f };
83 } else if (offset[0].x < offset[0].z) {
84 second = { 0.0f, 1.0f, 0.0f };
85 third = { 0.0f, 1.0f, 1.0f };
87 second = { 0.0f, 1.0f, 0.0f };
88 third = { 1.0f, 1.0f, 0.0f };
91 offset[1] = offset[0] - second + one_sixth;
92 offset[2] = offset[0] - third + one_third;
93 offset[3] = offset[0] - 0.5f;
95 unsigned char index[3] = {
96 (unsigned char)(skewed.x),
97 (unsigned char)(skewed.y),
98 (unsigned char)(skewed.z),
101 Perm(index[0] + Perm(index[1] + Perm(index[2]))),
102 Perm(index[0] + second.x + Perm(index[1] + second.y + Perm(index[2] + second.z))),
103 Perm(index[0] + third.x + Perm(index[1] + third.y + Perm(index[2] + third.z))),
104 Perm(index[0] + 1 + Perm(index[1] + 1 + Perm(index[2] + 1))),
108 for (size_t i = 0; i < 4; ++i) {
109 t[i] = 0.6f - dot(offset[i], offset[i]);
114 n[i] = t[i] * t[i] * dot(Grad(corner[i]), offset[i]);
118 return 32.0f * (n[0] + n[1] + n[2] + n[3]);
122 unsigned char SimplexNoise::Perm(size_t idx) const {
126 const glm::vec3 &SimplexNoise::Grad(size_t idx) const {
127 return grad[idx % 12];
131 WorleyNoise::WorleyNoise(unsigned int seed)
137 float WorleyNoise::operator ()(const glm::vec3 &in) const {
138 glm::vec3 center = floor(in);
140 float closest = 1.0f; // cannot be farther away than 1.0
142 for (int z = -1; z <= 1; ++z) {
143 for (int y = -1; y <= 1; ++y) {
144 for (int x = -1; x <= 1; ++x) {
145 glm::tvec3<int> cube(center.x + x, center.y + y, center.z + z);
146 unsigned int cube_rand =
152 for (int i = 0; i < num_points; ++i) {
153 glm::vec3 point(cube);
154 cube_rand = 190667 * cube_rand + 109807;
155 point.x += float(cube_rand % 200000) / 200000.0f;
156 cube_rand = 135899 * cube_rand + 189169;
157 point.y += float(cube_rand % 200000) / 200000.0f;
158 cube_rand = 159739 * cube_rand + 112139;
159 point.z += float(cube_rand % 200000) / 200000.0f;
161 glm::vec3 diff(in - point);
162 float distance = sqrt(dot(diff, diff));
163 if (distance < closest) {
171 // closest ranges (0, 1), so normalizing to (-1,1) is trivial
172 // though heavily biased towards lower numbers
173 return 2.0f * closest - 1.0f;