namespace blank {
-SimplexNoise::SimplexNoise(unsigned int seed) noexcept
+SimplexNoise::SimplexNoise(std::uint64_t 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 },
{ 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;
glm::vec3 unskewed(skewed - tr);
glm::vec3 relative(in - unskewed);
- glm::vec3 second, third;
-
- 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, 0, 1 };
- third = { 1, 0, 1 };
- }
- } 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, 1, 0 };
- third = { 1, 1, 0 };
- }
+ 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 + one_sixth,
- relative - third + one_third,
+ relative - second_float + one_sixth,
+ relative - third_float + one_third,
relative - 0.5f,
};
float n = 0.0f;
+ // I know 0.6 is wrong, but for some reason it looks better than 0.5
+
// 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]);
- }
+ float t = glm::clamp(0.6f - 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 = 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]);
- }
+ t = glm::clamp(0.6f - 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 = 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]);
- }
+ t = glm::clamp(0.6f - 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 = 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]);
- }
+ t = glm::clamp(0.6f - 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;
}