update light levels from border on neighbor change

[blank.git] / src / noise.cpp

diff --git a/src/noise.cpp b/src/noise.cpp
index 1e1c6d86882703604475d2830812307b90db709a..8b716140e78c5b301fbd00a383778eb482e9166f 100644 (file)
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -12,6 +12,24 @@ constexpr float one_sixth = 1.0f/6.0f;
 
 namespace blank {
 
+GaloisLFSR::GaloisLFSR(std::uint64_t seed)
+: state(seed) {
+
+}
+
+bool GaloisLFSR::operator ()() {
+       bool result = state & 1;
+       state >>= 1;
+       if (result) {
+               state |= 0x8000000000000000;
+               state ^= mask;
+       } else {
+               state &= 0x7FFFFFFFFFFFFFFF;
+       }
+       return result;
+}
+
+
 SimplexNoise::SimplexNoise(unsigned int seed)
 : grad({
        {  1.0f,  1.0f,  0.0f },
@@ -27,10 +45,9 @@ SimplexNoise::SimplexNoise(unsigned int seed)
        {  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];
        }
 }
@@ -109,4 +126,50 @@ const glm::vec3 &SimplexNoise::Grad(size_t idx) const {
        return grad[idx % 12];
 }
 
+
+WorleyNoise::WorleyNoise(unsigned int seed)
+: seed(seed)
+, num_points(8) {
+
+}
+
+float WorleyNoise::operator ()(const glm::vec3 &in) const {
+       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::tvec3<int> cube(center.x + x, center.y + y, center.z + z);
+                               unsigned int cube_rand =
+                                       (cube.x * 130223) ^
+                                       (cube.y * 159899) ^
+                                       (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 % 200000) / 200000.0f;
+                                       cube_rand = 135899 * cube_rand + 189169;
+                                       point.y += float(cube_rand % 200000) / 200000.0f;
+                                       cube_rand = 159739 * cube_rand + 112139;
+                                       point.z += float(cube_rand % 200000) / 200000.0f;
+
+                                       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;
+}
+
 }