X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fnoise.cpp;h=6d59224c2f41f4de89ae982627387fcacd7235a2;hb=e74f1ad236429f05db90c0ace825277e2a3fbc05;hp=d192b27fcce8646109d310754b2d7e70c8536f75;hpb=f62562b0f87d571bd7b32ae2f8ca659c24e9911b;p=blank.git

diff --git a/src/noise.cpp b/src/noise.cpp
index d192b27..6d59224 100644
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -3,8 +3,32 @@
 #include <cmath>
 
 
+namespace {
+
+constexpr float one_third = 1.0f/3.0f;
+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({
@@ -25,17 +49,18 @@ SimplexNoise::SimplexNoise(unsigned int seed)
 	for (size_t i = 0; i < 256; ++i) {
 		val = 2346765 * val + 6446345;
 		perm[i] = val % 256;
+		perm[i + 256] = perm[i];
 	}
 }
 
 
 float SimplexNoise::operator ()(const glm::vec3 &in) const {
-	float skew = (in.x + in.y + in.z) / 3.0f;
+	float skew = (in.x + in.y + in.z) * one_third;
 
-	glm::vec3 skewed(std::floor(in.x + skew), std::floor(in.y + skew), std::floor(in.z + skew));
-	float tr = (skewed.x + skewed.y + skewed.z) / 6.0f;
+	glm::vec3 skewed(glm::floor(in + skew));
+	float tr = (skewed.x + skewed.y + skewed.z) * one_sixth;
 
-	glm::vec3 unskewed(skewed.x - tr, skewed.y - tr, skewed.z - tr);
+	glm::vec3 unskewed(skewed - tr);
 	glm::vec3 offset[4];
 	offset[0] = in - unskewed;
 
@@ -63,14 +88,14 @@ float SimplexNoise::operator ()(const glm::vec3 &in) const {
 		third = { 1.0f, 1.0f, 0.0f };
 	}
 
-	offset[1] = offset[0] - second + glm::vec3(1.0f/6.0f);
-	offset[2] = offset[0] - third + glm::vec3(1.0f/3.0f);
-	offset[3] = offset[0] - glm::vec3(0.5f);
+	offset[1] = offset[0] - second + one_sixth;
+	offset[2] = offset[0] - third + one_third;
+	offset[3] = offset[0] - 0.5f;
 
-	size_t index[3] = {
-		unsigned(skewed.x) % 256,
-		unsigned(skewed.y) % 256,
-		unsigned(skewed.z) % 256,
+	unsigned char index[3] = {
+		(unsigned char)(skewed.x),
+		(unsigned char)(skewed.y),
+		(unsigned char)(skewed.z),
 	};
 	size_t corner[4] = {
 		Perm(index[0] + Perm(index[1] + Perm(index[2]))),
@@ -95,11 +120,57 @@ float SimplexNoise::operator ()(const glm::vec3 &in) const {
 
 
 unsigned char SimplexNoise::Perm(size_t idx) const {
-	return perm[idx % 256];
+	return perm[idx];
 }
 
 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;
+}
+
 }