X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fnoise.cpp;h=d653d5d54ae0215228701dfffa600e61aef999b5;hb=1121e49e7cad94ce4efd0a02c72a44469c81494e;hp=1e1c6d86882703604475d2830812307b90db709a;hpb=e70967c971f77a4ac0f5c074e6eb94bdd0e2b7ab;p=blank.git

diff --git a/src/noise.cpp b/src/noise.cpp
index 1e1c6d8..d653d5d 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 },
@@ -27,86 +45,158 @@ 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);
+	unsigned char value;
 	for (size_t i = 0; i < 256; ++i) {
-		val = 2346765 * val + 6446345;
-		perm[i] = val % 256;
+		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 {
+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 offset[4];
-	offset[0] = in - unskewed;
+	glm::vec3 relative(in - unskewed);
 
 	glm::vec3 second, third;
 
-	if (offset[0].x >= offset[0].y) {
-		if (offset[0].y >= offset[0].z) {
-			second = { 1.0f, 0.0f, 0.0f };
-			third = { 1.0f, 1.0f, 0.0f };
-		} else if (offset[0].x >= offset[0].z) {
-			second = { 1.0f, 0.0f, 0.0f };
-			third = { 1.0f, 0.0f, 1.0f };
+	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 = { 0.0f, 0.0f, 1.0f };
-			third = { 1.0f, 0.0f, 1.0f };
+			second = { 0, 0, 1 };
+			third = { 1, 0, 1 };
 		}
-	} else if (offset[0].y < offset[0].z) {
-		second = { 0.0f, 0.0f, 1.0f };
-		third = { 0.0f, 1.0f, 1.0f };
-	} else if (offset[0].x < offset[0].z) {
-		second = { 0.0f, 1.0f, 0.0f };
-		third = { 0.0f, 1.0f, 1.0f };
+	} 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 = { 0.0f, 1.0f, 0.0f };
-		third = { 1.0f, 1.0f, 0.0f };
+		second = { 0, 1, 0 };
+		third = { 1, 1, 0 };
 	}
 
-	offset[1] = offset[0] - second + one_sixth;
-	offset[2] = offset[0] - third + one_third;
-	offset[3] = offset[0] - 0.5f;
-
-	unsigned char index[3] = {
-		(unsigned char)(skewed.x),
-		(unsigned char)(skewed.y),
-		(unsigned char)(skewed.z),
+	glm::vec3 offset[4] = {
+		in - unskewed,
+		relative - second + one_sixth,
+		relative - third + one_third,
+		relative - 0.5f,
 	};
-	size_t corner[4] = {
-		Perm(index[0] + Perm(index[1] + Perm(index[2]))),
-		Perm(index[0] + second.x + Perm(index[1] + second.y + Perm(index[2] + second.z))),
-		Perm(index[0] + third.x + Perm(index[1] + third.y + Perm(index[2] + third.z))),
-		Perm(index[0] + 1 + Perm(index[1] + 1 + Perm(index[2] + 1))),
+
+	int index[3] = {
+		(int)(skewed.x) & 0xFF,
+		(int)(skewed.y) & 0xFF,
+		(int)(skewed.z) & 0xFF,
 	};
-	float n[4];
-	float t[4];
-	for (size_t i = 0; i < 4; ++i) {
-		t[i] = 0.6f - dot(offset[i], offset[i]);
-		if (t[i] < 0.0f) {
-			n[i] = 0.0f;
-		} else {
-			t[i] *= t[i];
-			n[i] = t[i] * t[i] * dot(Grad(corner[i]), offset[i]);
-		}
+
+	float n = 0.0f;
+
+	// 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]);
+	}
+
+	// 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]);
 	}
 
-	return 32.0f * (n[0] + n[1] + n[2] + n[3]);
+	// 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]);
+	}
+
+	// 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]);
+	}
+
+	return 32.0f * n;
 }
 
 
-unsigned char SimplexNoise::Perm(size_t idx) const {
+int SimplexNoise::Perm(int idx) const noexcept {
 	return perm[idx];
 }
 
-const glm::vec3 &SimplexNoise::Grad(size_t idx) const {
-	return grad[idx % 12];
+int SimplexNoise::Perm12(int idx) const noexcept {
+	return perm12[idx];
+}
+
+const glm::vec3 &SimplexNoise::Grad(int idx) const noexcept {
+	return grad[idx];
+}
+
+
+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::vec3 cube(center.x + x, center.y + y, center.z + z);
+				unsigned int cube_rand =
+					(unsigned(cube.x) * 130223) ^
+					(unsigned(cube.y) * 159899) ^
+					(unsigned(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 % 262144) / 262144.0f;
+					cube_rand = 135899 * cube_rand + 189169;
+					point.y += float(cube_rand % 262144) / 262144.0f;
+					cube_rand = 159739 * cube_rand + 112139;
+					point.z += float(cube_rand % 262144) / 262144.0f;
+
+					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;
 }
 
 }