X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fnoise.cpp;h=a5a9a2057957f361d449581eec3cbd29d94aeae6;hb=76b3ec0f6aa0dacf6d4944a2787991f3585299e8;hp=1e1c6d86882703604475d2830812307b90db709a;hpb=e70967c971f77a4ac0f5c074e6eb94bdd0e2b7ab;p=blank.git

diff --git a/src/noise.cpp b/src/noise.cpp
index 1e1c6d8..a5a9a20 100644
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -12,7 +12,25 @@ constexpr float one_sixth = 1.0f/6.0f;
 
 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 },
@@ -27,16 +45,15 @@ 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];
 	}
 }
 
 
-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));
@@ -101,12 +118,58 @@ float SimplexNoise::operator ()(const glm::vec3 &in) const {
 }
 
 
-unsigned char SimplexNoise::Perm(size_t idx) const {
+unsigned char SimplexNoise::Perm(size_t idx) const noexcept {
 	return perm[idx];
 }
 
-const glm::vec3 &SimplexNoise::Grad(size_t idx) const {
+const glm::vec3 &SimplexNoise::Grad(size_t idx) const noexcept {
 	return grad[idx % 12];
 }
 
+
+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::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;
+}
+
 }