--- /dev/null
+#include "GaloisLFSR.hpp"
+#include "SimplexNoise.hpp"
+
+#include <cmath>
+
+
+namespace {
+
+constexpr float one_third = 1.0f/3.0f;
+constexpr float one_sixth = 1.0f/6.0f;
+
+}
+
+namespace tacos {
+
+SimplexNoise::SimplexNoise(std::uint64_t seed) noexcept
+: grad({
+ { 1.0f, 1.0f, 0.0f },
+ { -1.0f, 1.0f, 0.0f },
+ { 1.0f, -1.0f, 0.0f },
+ { -1.0f, -1.0f, 0.0f },
+ { 1.0f, 0.0f, 1.0f },
+ { -1.0f, 0.0f, 1.0f },
+ { 1.0f, 0.0f, -1.0f },
+ { -1.0f, 0.0f, -1.0f },
+ { 0.0f, 1.0f, 1.0f },
+ { 0.0f, -1.0f, 1.0f },
+ { 0.0f, 1.0f, -1.0f },
+ { 0.0f, -1.0f, -1.0f },
+})
+, second_ints({
+ // x>y x>z y>z
+ { 0, 0, 1 }, // 0 0 0 ZYX
+ { 0, 1, 0 }, // 0 0 1 YZX
+ { 0, 0, 1 }, // 0 1 0 illogical, but ZYX
+ { 0, 1, 0 }, // 0 1 1 YXZ
+ { 0, 0, 1 }, // 1 0 0 ZXY
+ { 1, 0, 0 }, // 1 0 1 illogical, but XYZ
+ { 1, 0, 0 }, // 1 1 0 XZY
+ { 1, 0, 0 }, // 1 1 1 XYZ
+})
+, third_ints({
+ // x>y x>z y>z
+ { 0, 1, 1 }, // 0 0 0 ZYX
+ { 0, 1, 1 }, // 0 0 1 YZX
+ { 0, 1, 1 }, // 0 1 0 illogical, but ZYX
+ { 1, 1, 0 }, // 0 1 1 YXZ
+ { 1, 0, 1 }, // 1 0 0 ZXY
+ { 1, 1, 0 }, // 1 0 1 illogical, but XYZ
+ { 1, 0, 1 }, // 1 1 0 XZY
+ { 1, 1, 0 }, // 1 1 1 XYZ
+})
+, second_floats({
+ // x>y x>z y>z
+ { 0.0f, 0.0f, 1.0f }, // 0 0 0 ZYX
+ { 0.0f, 1.0f, 0.0f }, // 0 0 1 YZX
+ { 0.0f, 0.0f, 1.0f }, // 0 1 0 illogical, but ZYX
+ { 0.0f, 1.0f, 0.0f }, // 0 1 1 YXZ
+ { 0.0f, 0.0f, 1.0f }, // 1 0 0 ZXY
+ { 1.0f, 0.0f, 0.0f }, // 1 0 1 illogical, but XYZ
+ { 1.0f, 0.0f, 0.0f }, // 1 1 0 XZY
+ { 1.0f, 0.0f, 0.0f }, // 1 1 1 XYZ
+})
+, third_floats({
+ // x>y x>z y>z
+ { 0.0f, 1.0f, 1.0f }, // 0 0 0 ZYX
+ { 0.0f, 1.0f, 1.0f }, // 0 0 1 YZX
+ { 0.0f, 1.0f, 1.0f }, // 0 1 0 illogical, but ZYX
+ { 1.0f, 1.0f, 0.0f }, // 0 1 1 YXZ
+ { 1.0f, 0.0f, 1.0f }, // 1 0 0 ZXY
+ { 1.0f, 1.0f, 0.0f }, // 1 0 1 illogical, but XYZ
+ { 1.0f, 0.0f, 1.0f }, // 1 1 0 XZY
+ { 1.0f, 1.0f, 0.0f }, // 1 1 1 XYZ
+}) {
+ GaloisLFSR random(seed ^ 0x0123456789ACBDEF);
+ unsigned char value;
+ for (size_t i = 0; i < 256; ++i) {
+ 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 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 relative(in - unskewed);
+
+ bool x_ge_y = relative.x >= relative.y;
+ bool x_ge_z = relative.x >= relative.z;
+ bool y_ge_z = relative.y >= relative.z;
+ unsigned int st = (x_ge_y << 2) | (x_ge_z << 1) | y_ge_z;
+
+ glm::ivec3 second_int(second_ints[st]);
+ glm::ivec3 third_int(third_ints[st]);
+ glm::vec3 second_float(second_floats[st]);
+ glm::vec3 third_float(third_floats[st]);
+
+ glm::vec3 offset[4] = {
+ in - unskewed,
+ relative - second_float + one_sixth,
+ relative - third_float + one_third,
+ relative - 0.5f,
+ };
+
+ int index[3] = {
+ (int)(skewed.x) & 0xFF,
+ (int)(skewed.y) & 0xFF,
+ (int)(skewed.z) & 0xFF,
+ };
+
+ float n = 0.0f;
+
+ // 0
+ float t = glm::clamp(0.5f - dot(offset[0], offset[0]), 0.0f, 1.0f);
+ t *= t;
+ int corner = Perm12(index[0] + Perm(index[1] + Perm(index[2])));
+ n += t * t * dot(Grad(corner), offset[0]);
+
+ // 1
+ t = glm::clamp(0.5f - dot(offset[1], offset[1]), 0.0f, 1.0f);
+ t *= t;
+ corner = Perm12(index[0] + second_int.x + Perm(index[1] + second_int.y + Perm(index[2] + second_int.z)));
+ n += t * t * dot(Grad(corner), offset[1]);
+
+ // 2
+ t = glm::clamp(0.5f - dot(offset[2], offset[2]), 0.0f, 1.0f);
+ t *= t;
+ corner = Perm12(index[0] + third_int.x + Perm(index[1] + third_int.y + Perm(index[2] + third_int.z)));
+ n += t * t * dot(Grad(corner), offset[2]);
+
+ // 3
+ t = glm::clamp(0.5f - dot(offset[3], offset[3]), 0.0f, 1.0f);
+ t *= t;
+ 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;
+}
+
+
+int SimplexNoise::Perm(int idx) const noexcept {
+ return perm[idx];
+}
+
+int SimplexNoise::Perm12(int idx) const noexcept {
+ return perm12[idx];
+}
+
+const glm::vec3 &SimplexNoise::Grad(int idx) const noexcept {
+ return grad[idx];
+}
+
+}
projects / tacos.git / blobdiff