add nz_worley3

src/experimental/_impl/_nz_worley3_comm.scad

@@ -0,0 +1,45 @@
+use <experimental/sum.scad>;
+
+_noise_table = [0.592157, 0.627451, 0.537255, 0.356863, 0.352941, 0.0588235, 0.513725, 0.0509804, 0.788235, 0.372549, 0.376471, 0.207843, 0.760784, 0.913725, 0.027451, 0.882353, 0.54902, 0.141176, 0.403922, 0.117647, 0.270588, 0.556863, 0.0313725, 0.388235, 0.145098, 0.941176, 0.0823529, 0.0392157, 0.0901961, 0.745098, 0.0235294, 0.580392, 0.968627, 0.470588, 0.917647, 0.294118, 0, 0.101961, 0.772549, 0.243137, 0.368627, 0.988235, 0.858824, 0.796078, 0.458824, 0.137255, 0.0431373, 0.12549, 0.223529, 0.694118, 0.129412, 0.345098, 0.929412, 0.584314, 0.219608, 0.341176, 0.682353, 0.0784314, 0.490196, 0.533333, 0.670588, 0.658824, 0.266667, 0.686275, 0.290196, 0.647059, 0.278431, 0.52549, 0.545098, 0.188235, 0.105882, 0.65098, 0.301961, 0.572549, 0.619608, 0.905882, 0.32549, 0.435294, 0.898039, 0.478431, 0.235294, 0.827451, 0.521569, 0.901961, 0.862745, 0.411765, 0.360784, 0.160784, 0.215686, 0.180392, 0.960784, 0.156863, 0.956863, 0.4, 0.560784, 0.211765, 0.254902, 0.0980392, 0.247059, 0.631373, 0.00392157, 0.847059, 0.313725, 0.286275, 0.819608, 0.298039, 0.517647, 0.733333, 0.815686, 0.34902, 0.0705882, 0.662745, 0.784314, 0.768627, 0.529412, 0.509804, 0.454902, 0.737255, 0.623529, 0.337255, 0.643137, 0.392157, 0.427451, 0.776471, 0.678431, 0.729412, 0.0117647, 0.25098, 0.203922, 0.85098, 0.886275, 0.980392, 0.486275, 0.482353, 0.0196078, 0.792157, 0.14902, 0.576471, 0.462745, 0.494118, 1, 0.321569, 0.333333, 0.831373, 0.811765, 0.807843, 0.231373, 0.890196, 0.184314, 0.0627451, 0.227451, 0.0666667, 0.713725, 0.741176, 0.109804, 0.164706, 0.87451, 0.717647, 0.666667, 0.835294, 0.466667, 0.972549, 0.596078, 0.00784314, 0.172549, 0.603922, 0.639216, 0.27451, 0.866667, 0.6, 0.396078, 0.607843, 0.654902, 0.168627, 0.67451, 0.0352941, 0.505882, 0.0862745, 0.152941, 0.992157, 0.0745098, 0.384314, 0.423529, 0.431373, 0.309804, 0.443137, 0.878431, 0.909804, 0.698039, 0.72549, 0.439216, 0.407843, 0.854902, 0.964706, 0.380392, 0.894118, 0.984314, 0.133333, 0.94902, 0.756863, 0.933333, 0.823529, 0.564706, 0.0470588, 0.74902, 0.701961, 0.635294, 0.945098, 0.317647, 0.2, 0.568627, 0.921569, 0.976471, 0.054902, 0.937255, 0.419608, 0.192157, 0.752941, 0.839216, 0.121569, 0.709804, 0.780392, 0.415686, 0.615686, 0.721569, 0.329412, 0.8, 0.690196, 0.45098, 0.47451, 0.196078, 0.176471, 0.498039, 0.0156863, 0.588235, 0.996078, 0.541176, 0.92549, 0.803922, 0.364706, 0.870588, 0.447059, 0.262745, 0.113725, 0.0941176, 0.282353, 0.952941, 0.552941, 0.501961, 0.764706, 0.305882, 0.258824, 0.843137, 0.239216, 0.611765, 0.705882];
+
+function _lookup_noise_table(i) = _noise_table[i % 256];
+
+function _neighbors(fcord, seed, dim, m, n, o) = [
+    for(z = [-1:1])    
+        for(y = [-1:1])
+            for(x = [-1:1])
+            let(
+                nx = fcord[0] + x,
+                ny = fcord[1] + y,
+                nz = fcord[2] + z,
+                sd_base = nx + ny * dim + nz * dim * dim,
+                sd1 = _lookup_noise_table(seed + sd_base),
+                sd2 = _lookup_noise_table(sd1 * 255 + sd_base),
+                sd3 = _lookup_noise_table(sd2 * 255 + sd_base),
+                nbr = [(nx + sd1) * m, (ny + sd2) * n, (nz + sd3) * o]
+            )
+            nbr
+];
+    
+function _manhattan(v) = sum([for(d = v) abs(d)]);
+
+function _chebyshev(p1, p2) =
+    max([for(i = [0:len(p1) - 1]) abs(p1[i] - p2[i])]);
+    
+function _distance(nbr, p, dist) = 
+    dist == "euclidean" ? norm(nbr - p) :
+    dist == "manhattan" ? _manhattan(nbr - p) :
+    dist == "chebyshev" ? _chebyshev(nbr, p) : 
+                          assert("Unknown distance option");
+    
+function _nz_worley3(p, seed, dim, m, n, o, dist) = 
+    let(
+        fcord = [floor(p[0] / m), floor(p[1] / n), floor(p[2] / o)],
+        nbrs = _neighbors(fcord, seed, dim, m, n, o),
+        dists = [
+            for(nbr = nbrs) 
+                if(!is_undef(nbr[1])) // Here's a workaround for a weired undef problem. bug of 2019.05? 
+                    _distance(nbr, p, dist)
+        ]
+    )
+    min(dists);

src/experimental/demo/nz_worley3_demo.scad

@@ -0,0 +1,21 @@
+use <experimental/nz_worley3.scad>;
+
+size = [30, 30, 30];
+dim = 5;
+dist = "euclidean"; // [euclidean, manhattan, chebyshev] 
+seed = 5;
+
+points = [
+    for(z = [0:size[2] - 1]) 
+        for(y = [0:size[1] - 1]) 
+            for(x = [0:size[0] - 1]) 
+                [x, y, z, nz_worley3(size, x, y, z, seed, dim, dist)]
+];
+
+max_dist = max([for(p = points) p[3]]);
+for(p = points) {
+    c = p[3] / max_dist;
+    color([c, c, c, c])
+    translate([p[0], p[1], p[2]])
+        cube(1);
+}

src/experimental/nz_worley3.scad

@@ -0,0 +1,12 @@
+use <util/rand.scad>;
+use <experimental/_impl/_nz_worley3_comm.scad>;
+
+function nz_worley3(size, x, y, z, seed, dim = 3, dist = "euclidean") =
+    let(
+        sd = 6 + (is_undef(seed) ? floor(rand(0, 256)) : seed % 256),
+        // m*n pixels per grid
+        m = size[0] / dim,
+        n = size[1] / dim,
+        o = size[2] / dim
+    )
+    _nz_worley3([x, y, z], sd, dim, m, n, o, dist);