Add optimized 2D cellular noise module

__init__.py

@@ -9,11 +9,11 @@
 
 __version__ = "1.2.3"
 
-from . import _perlin, _simplex
-
+from . import _perlin, _simplex, _cellular
 snoise2 = _simplex.noise2
 snoise3 = _simplex.noise3
 snoise4 = _simplex.noise4
 pnoise1 = _perlin.noise1
 pnoise2 = _perlin.noise2
 pnoise3 = _perlin.noise3
+cnoise2 = _cellular.noise2

_cellular.c

@@ -0,0 +1,100 @@
+// Copyright (c) 2008, Casey Duncan (casey dot duncan at gmail dot com)
+// see LICENSE.txt for details
+// $Id$
+
+#include "Python.h"
+#include "_noise.h"
+#include <math.h>
+
+#define PERM_SIZE 256
+#define PERM_MASK (PERM_SIZE - 1)
+#define OFFSET_INV 0.0625f  /* 1.0 / 16.0 */
+
+static inline float sqr_dist(float x1, float y1, float x2, float y2) {
+  return ((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2));
+}
+
+// cellular noise implementation
+// https://en.wikipedia.org/wiki/Worley_noise
+// https://sangillee.com/2025-04-18-cellular-noises/
+float noise2_cellular(float x, float y) {
+    int ix = fastfloor(x);
+    int iy = fastfloor(y);
+
+    float xf = x - (float)ix;
+    float yf = y - (float)iy;
+    float min_dist_sq = 8.0f;
+
+    int i_wrapped[3], j_wrapped[3];
+    for (int n = 0; n < 3; n++) {
+        i_wrapped[n] = (ix + (n - 1) + 1024) & PERM_MASK;
+        j_wrapped[n] = (iy + (n - 1) + 1024) & PERM_MASK;
+    }
+
+    for (int i = 0; i < 3; i++) {
+        float dx_base = (float)(i - 1) - xf;
+        int o = PERM[i_wrapped[i]];
+        for (int j = 0; j < 3; j++) {
+            int hash = PERM[o + j_wrapped[j]];
+            float dx = dx_base + (float)(hash & 15) * OFFSET_INV;
+            float dy = ((float)(j - 1) - yf) + (float)(hash >> 4) * OFFSET_INV;
+
+            float d_sq = (dx * dx) + (dy * dy);
+
+            if (d_sq < min_dist_sq) {
+                min_dist_sq = d_sq;
+            }
+        }
+    }
+    return sqrtf(min_dist_sq);
+}
+
+static PyObject *py_noise2_cellular(PyObject *self, PyObject *args) {
+  float x, y;
+  if (!PyArg_ParseTuple(args, "ff", &x, &y))
+    return NULL;
+  return PyFloat_FromDouble((double)noise2_cellular(x, y));
+}
+
+PyDoc_STRVAR(noise2_doc,
+    "noise2(x, y)\n\n"
+    "2 dimensional cellular (Worley) noise function.\n"
+    "Returns the distance to the nearest feature point.");
+
+static PyMethodDef cellular_functions[] = {
+    {"noise2", (PyCFunction) py_noise2_cellular, METH_VARARGS | METH_KEYWORDS, noise2_doc},
+    {NULL}
+};
+
+PyDoc_STRVAR(module_doc, "Native-code implementation of cellular (Worley) noise functions");
+
+
+#if PY_MAJOR_VERSION >= 3
+
+static struct PyModuleDef moduledef = {
+    PyModuleDef_HEAD_INIT,
+    "_cellular",              
+    module_doc,               
+    -1,                       /* m_size            */
+    cellular_functions,       /* m_methods         */
+    NULL,                     /* m_reload (unused) */
+    NULL,                     /* m_traverse        */
+    NULL,                     /* m_clear           */
+    NULL                      /* m_free            */
+};
+
+PyObject *
+PyInit__cellular(void)
+{
+    return PyModule_Create(&moduledef);
+}
+
+#else
+
+void
+init_cellular(void)
+{
+    Py_InitModule3("_cellular", cellular_functions, module_doc);
+}
+
+#endif

examples/cellnoise.py

@@ -0,0 +1,33 @@
+"""Writes a 256x256 grayscale cell noise texture to a file in pgm format
+(see http://netpbm.sourceforge.net/doc/pgm.html)
+"""
+# $Id: cellnoise.py $
+
+import sys
+from noise import _cellular 
+
+if len(sys.argv) not in (2, 3) or '--help' in sys.argv or '-h' in sys.argv:
+	print()
+	print(__doc__)
+	raise SystemExit
+
+if len(sys.argv) < 2:
+    print('Usage: python cellular_texture.py OUTPUT_FILE.pgm')
+    sys.exit(1)
+
+filename = sys.argv[1]
+size = 256
+scale = 16.0 
+
+with open(filename, 'wt') as f:
+    f.write('P2\n')             
+    f.write(f'{size} {size}\n')
+    f.write('255\n')            
+
+    for y in range(size):
+        for x in range(size):
+            val = _cellular.noise2(x / scale, y / scale)
+            brightness = int((1.0 - min(val, 1.0)) * 255)
+            f.write(f"{brightness}\n")
+
+print(f"Texture saved to {filename}")

setup.py

@@ -64,6 +64,9 @@
         ),
         Extension('noise._perlin', ['_perlin.c'],
             extra_compile_args=compile_args,
+        ),
+        Extension('noise._cellular', ['_cellular.c'],
+            extra_compile_args=compile_args,
         )
     ],
 )