Add mathutils.geometry.delaunay_2d_cdt() function to Python API.

Provides Python API access to recently added Constrained Delaunay
Triangulation routine.
Reviewed in D5467.

3 files changed, 343 insertions, 0 deletions

diff --git a/source/blender/python/mathutils/mathutils.c b/source/blender/python/mathutils/mathutils.c
index befa6532e97..2b1ddbbb03a 100644
--- a/source/blender/python/mathutils/mathutils.c
+++ b/source/blender/python/mathutils/mathutils.c
@@ -25,6 +25,7 @@
 #include "BLI_math.h"
 #include "BLI_utildefines.h"
 
+#include "../generic/py_capi_utils.h"
 #include "../generic/python_utildefines.h"
 
 #ifndef MATH_STANDALONE
@@ -328,6 +329,153 @@ int mathutils_array_parse_alloc_v(float **array,
   return size;
 }
 
+/* Parse an sequence array_dim integers into array. */
+int mathutils_int_array_parse(int *array, int array_dim, PyObject *value, const char *error_prefix)
+{
+  int size, i;
+  PyObject *value_fast, **value_fast_items, *item;
+
+  if (!(value_fast = PySequence_Fast(value, error_prefix))) {
+    /* PySequence_Fast sets the error */
+    return -1;
+  }
+
+  if ((size = PySequence_Fast_GET_SIZE(value_fast)) != array_dim) {
+    PyErr_Format(PyExc_ValueError,
+                 "%.200s: sequence size is %d, expected %d",
+                 error_prefix,
+                 size,
+                 array_dim);
+    Py_DECREF(value_fast);
+    return -1;
+  }
+
+  value_fast_items = PySequence_Fast_ITEMS(value_fast);
+  i = size;
+  while (i > 0) {
+    i--;
+    if (((array[i] = PyC_Long_AsI32((item = value_fast_items[i]))) == -1) && PyErr_Occurred()) {
+      PyErr_Format(PyExc_TypeError, "%.200s: sequence index %d expected an int", error_prefix, i);
+      size = -1;
+      break;
+    }
+  }
+  Py_DECREF(value_fast);
+
+  return size;
+}
+
+/* Parse sequence of array_dim sequences of integers and return allocated result. */
+int mathutils_array_parse_alloc_vi(int **array,
+                                   int array_dim,
+                                   PyObject *value,
+                                   const char *error_prefix)
+{
+  PyObject *value_fast;
+  int i, size;
+
+  if (!(value_fast = PySequence_Fast(value, error_prefix))) {
+    /* PySequence_Fast sets the error */
+    return -1;
+  }
+
+  size = PySequence_Fast_GET_SIZE(value_fast);
+
+  if (size != 0) {
+    PyObject **value_fast_items = PySequence_Fast_ITEMS(value_fast);
+    int *ip;
+
+    ip = *array = PyMem_Malloc(size * array_dim * sizeof(int));
+
+    for (i = 0; i < size; i++, ip += array_dim) {
+      PyObject *item = value_fast_items[i];
+
+      if (mathutils_int_array_parse(ip, array_dim, item, error_prefix) == -1) {
+        PyMem_Free(*array);
+        *array = NULL;
+        size = -1;
+        break;
+      }
+    }
+  }
+
+  Py_DECREF(value_fast);
+  return size;
+}
+
+/* Parse sequence of variable-length sequences of int and return allocated
+ * triple of arrays to represent the result:
+ * The flattened sequences are put into *array.
+ * The start index of each sequence goes into start_table.
+ * The length of each index goes into len_table.
+ */
+int mathutils_array_parse_alloc_viseq(
+    int **array, int **start_table, int **len_table, PyObject *value, const char *error_prefix)
+{
+  PyObject *value_fast, *subseq;
+  int i, size, start, subseq_len;
+  int *ip;
+
+  *array = NULL;
+  *start_table = NULL;
+  *len_table = NULL;
+  if (!(value_fast = PySequence_Fast(value, error_prefix))) {
+    /* PySequence_Fast sets the error */
+    return -1;
+  }
+
+  size = PySequence_Fast_GET_SIZE(value_fast);
+
+  if (size != 0) {
+    PyObject **value_fast_items = PySequence_Fast_ITEMS(value_fast);
+
+    *start_table = PyMem_Malloc(size * sizeof(int));
+    *len_table = PyMem_Malloc(size * sizeof(int));
+
+    /* First pass to set starts and len, and calculate size of array needed */
+    start = 0;
+    for (i = 0; i < size; i++) {
+      subseq = value_fast_items[i];
+      if ((subseq_len = (int)PySequence_Size(subseq)) == -1) {
+        PyErr_Format(
+            PyExc_ValueError, "%.200s: sequence expected to have subsequences", error_prefix);
+        PyMem_Free(*start_table);
+        PyMem_Free(*len_table);
+        Py_DECREF(value_fast);
+        *start_table = NULL;
+        *len_table = NULL;
+        return -1;
+      }
+      (*start_table)[i] = start;
+      (*len_table)[i] = subseq_len;
+      start += subseq_len;
+    }
+
+    ip = *array = PyMem_Malloc(start * sizeof(int));
+
+    /* Second pass to parse the subsequences into array */
+    for (i = 0; i < size; i++) {
+      subseq = value_fast_items[i];
+      subseq_len = (*len_table)[i];
+
+      if (mathutils_int_array_parse(ip, subseq_len, subseq, error_prefix) == -1) {
+        PyMem_Free(*array);
+        PyMem_Free(*start_table);
+        PyMem_Free(*len_table);
+        *array = NULL;
+        *len_table = NULL;
+        *start_table = NULL;
+        size = -1;
+        break;
+      }
+      ip += subseq_len;
+    }
+  }
+
+  Py_DECREF(value_fast);
+  return size;
+}
+
 int mathutils_any_to_rotmat(float rmat[3][3], PyObject *value, const char *error_prefix)
 {
   if (EulerObject_Check(value)) {
diff --git a/source/blender/python/mathutils/mathutils.h b/source/blender/python/mathutils/mathutils.h
index 8afd60a7324..c9d0dee044f 100644
--- a/source/blender/python/mathutils/mathutils.h
+++ b/source/blender/python/mathutils/mathutils.h
@@ -167,6 +167,16 @@ int mathutils_array_parse_alloc_v(float **array,
                                   int array_dim,
                                   PyObject *value,
                                   const char *error_prefix);
+int mathutils_int_array_parse(int *array,
+                              int array_dim,
+                              PyObject *value,
+                              const char *error_prefix);
+int mathutils_array_parse_alloc_vi(int **array,
+                                   int array_dim,
+                                   PyObject *value,
+                                   const char *error_prefix);
+int mathutils_array_parse_alloc_viseq(
+    int **array, int **start_table, int **len_table, PyObject *value, const char *error_prefix);
 int mathutils_any_to_rotmat(float rmat[3][3], PyObject *value, const char *error_prefix);
 
 Py_hash_t mathutils_array_hash(const float *float_array, size_t array_len);
diff --git a/source/blender/python/mathutils/mathutils_geometry.c b/source/blender/python/mathutils/mathutils_geometry.c
index 32ce78f702d..a6dded4ee8b 100644
--- a/source/blender/python/mathutils/mathutils_geometry.c
+++ b/source/blender/python/mathutils/mathutils_geometry.c
@@ -29,6 +29,7 @@
 #  include "BLI_blenlib.h"
 #  include "BLI_boxpack_2d.h"
 #  include "BLI_convexhull_2d.h"
+#  include "BLI_delaunay_2d.h"
 #  include "BKE_displist.h"
 #  include "BKE_curve.h"
 #endif
@@ -1507,6 +1508,186 @@ static PyObject *M_Geometry_convex_hull_2d(PyObject *UNUSED(self), PyObject *poi
   return ret;
 }
 
+/* Return a PyObject that is a list of lists, using the flattened list array
+ * to fill values, with start_table and len_table giving the start index
+ * and length of the toplevel_len sublists
+ */
+static PyObject *list_of_lists_from_arrays(int *array,
+                                           int *start_table,
+                                           int *len_table,
+                                           int toplevel_len)
+{
+  PyObject *ret, *sublist;
+  int i, j, sublist_len, sublist_start, val;
+
+  ret = PyList_New(toplevel_len);
+  for (i = 0; i < toplevel_len; i++) {
+    sublist_len = len_table[i];
+    sublist = PyList_New(sublist_len);
+    sublist_start = start_table[i];
+    for (j = 0; j < sublist_len; j++) {
+      val = array[sublist_start + j];
+      PyList_SET_ITEM(sublist, j, PyLong_FromLong(val));
+    }
+    PyList_SET_ITEM(ret, i, sublist);
+  }
+  return ret;
+}
+
+PyDoc_STRVAR(
+    M_Geometry_delaunay_2d_cdt_doc,
+    ".. function:: delaunay_2d_cdt(vert_coords, edges, faces, output_type, epsilon)\n"
+    "\n"
+    "Computes the Constrained Delaunay Triangulation of a set of vertices, "
+    "with edges and faces that must appear in the triangulation. "
+    "Some triangles may be eaten away, or combined with other triangles, "
+    "according to output type. "
+    "The returned verts may be in a different order from input verts, may be moved "
+    "slightly, and may be merged with other nearby verts. "
+    "The three returned orig lists give, for each of verts, edges, and faces, the list of "
+    "input element indices corresponding to the positionally same output element. "
+    "For edges, the orig indices start with the input edges and then continue "
+    "with the edges implied by each of the faces (n of them for an n-gon).\n"
+    "\n"
+    "   :arg vert_coords: Vertex coordinates (2d)\n"
+    "   :type vert_coords: list of :class:`mathutils.Vector`\n"
+    "   :arg edges: Edges, as pairs of indices in `vert_coords`\n"
+    "   :type edges: list of (int, int)\n"
+    "   :arg faces: Faces, each sublist is a face, as indices in `vert_coords` (CCW oriented)\n"
+    "   :type faces: list of list of int\n"
+    "   :arg output_type: What output looks like. 0 => triangles with convex hull. "
+    "1 => triangles inside constraints. "
+    "2 => the input constraints, intersected. "
+    "3 => like 2 but with extra edges to make valid BMesh faces.\n"
+    "   :type output_type: int\\n"
+    "   :arg epsilon: For nearness tests; should not be zero\n"
+    "   :type epsilon: float\n"
+    "   :return: Output tuple, (vert_coords, edges, faces, orig_verts, orig_edges, orig_faces)\n"
+    "   :rtype: (list of `mathutils.Vector`, "
+    "list of (int, int), "
+    "list of list of int, "
+    "list of list of int, "
+    "list of list of int, "
+    "list of list of int)\n"
+    "\n");
+static PyObject *M_Geometry_delaunay_2d_cdt(PyObject *UNUSED(self), PyObject *args)
+{
+  const char *error_prefix = "delaunay_2d_cdt";
+  PyObject *vert_coords, *edges, *faces, *item;
+  int output_type;
+  float epsilon;
+  float(*in_coords)[2] = NULL;
+  int(*in_edges)[2] = NULL;
+  int *in_faces = NULL;
+  int *in_faces_start_table = NULL;
+  int *in_faces_len_table = NULL;
+  Py_ssize_t vert_coords_len, edges_len, faces_len;
+  CDT_input in;
+  CDT_result *res = NULL;
+  PyObject *out_vert_coords = NULL;
+  PyObject *out_edges = NULL;
+  PyObject *out_faces = NULL;
+  PyObject *out_orig_verts = NULL;
+  PyObject *out_orig_edges = NULL;
+  PyObject *out_orig_faces = NULL;
+  PyObject *ret_value = NULL;
+  int i;
+
+  if (!PyArg_ParseTuple(
+          args, "OOOif:delaunay_2d_cdt", &vert_coords, &edges, &faces, &output_type, &epsilon)) {
+    return NULL;
+  }
+
+  vert_coords_len = mathutils_array_parse_alloc_v(
+      (float **)&in_coords, 2, vert_coords, error_prefix);
+  if (vert_coords_len == -1) {
+    return NULL;
+  }
+
+  edges_len = mathutils_array_parse_alloc_vi((int **)&in_edges, 2, edges, error_prefix);
+  if (edges_len == -1) {
+    goto exit_cdt;
+  }
+
+  faces_len = mathutils_array_parse_alloc_viseq(
+      &in_faces, &in_faces_start_table, &in_faces_len_table, faces, error_prefix);
+  if (faces_len == -1) {
+    goto exit_cdt;
+  }
+
+  in.verts_len = (int)vert_coords_len;
+  in.vert_coords = in_coords;
+  in.edges_len = edges_len;
+  in.faces_len = faces_len;
+  in.edges = in_edges;
+  in.faces = in_faces;
+  in.faces_start_table = in_faces_start_table;
+  in.faces_len_table = in_faces_len_table;
+  in.epsilon = epsilon;
+
+  res = BLI_delaunay_2d_cdt_calc(&in, output_type);
+
+  ret_value = PyTuple_New(6);
+
+  out_vert_coords = PyList_New(res->verts_len);
+  for (i = 0; i < res->verts_len; i++) {
+    item = Vector_CreatePyObject(res->vert_coords[i], 2, NULL);
+    if (item == NULL) {
+      Py_DECREF(ret_value);
+      Py_DECREF(out_vert_coords);
+      goto exit_cdt;
+    }
+    PyList_SET_ITEM(out_vert_coords, i, item);
+  }
+  PyTuple_SET_ITEM(ret_value, 0, out_vert_coords);
+
+  out_edges = PyList_New(res->edges_len);
+  for (i = 0; i < res->edges_len; i++) {
+    item = PyTuple_New(2);
+    PyTuple_SET_ITEM(item, 0, PyLong_FromLong((long)res->edges[i][0]));
+    PyTuple_SET_ITEM(item, 1, PyLong_FromLong((long)res->edges[i][1]));
+    PyList_SET_ITEM(out_edges, i, item);
+  }
+  PyTuple_SET_ITEM(ret_value, 1, out_edges);
+
+  out_faces = list_of_lists_from_arrays(
+      res->faces, res->faces_start_table, res->faces_len_table, res->faces_len);
+  PyTuple_SET_ITEM(ret_value, 2, out_faces);
+
+  out_orig_verts = list_of_lists_from_arrays(
+      res->verts_orig, res->verts_orig_start_table, res->verts_orig_len_table, res->verts_len);
+  PyTuple_SET_ITEM(ret_value, 3, out_orig_verts);
+
+  out_orig_edges = list_of_lists_from_arrays(
+      res->edges_orig, res->edges_orig_start_table, res->edges_orig_len_table, res->edges_len);
+  PyTuple_SET_ITEM(ret_value, 4, out_orig_edges);
+
+  out_orig_faces = list_of_lists_from_arrays(
+      res->faces_orig, res->faces_orig_start_table, res->faces_orig_len_table, res->faces_len);
+  PyTuple_SET_ITEM(ret_value, 5, out_orig_faces);
+
+exit_cdt:
+  if (in_coords != NULL) {
+    PyMem_Free(in_coords);
+  }
+  if (in_edges != NULL) {
+    PyMem_Free(in_edges);
+  }
+  if (in_faces != NULL) {
+    PyMem_Free(in_faces);
+  }
+  if (in_faces_start_table != NULL) {
+    PyMem_Free(in_faces_start_table);
+  }
+  if (in_faces_len_table != NULL) {
+    PyMem_Free(in_faces_len_table);
+  }
+  if (res) {
+    BLI_delaunay_2d_cdt_free(res);
+  }
+  return ret_value;
+}
+
 #endif /* MATH_STANDALONE */
 
 static PyMethodDef M_Geometry_methods[] = {
@@ -1593,6 +1774,10 @@ static PyMethodDef M_Geometry_methods[] = {
      (PyCFunction)M_Geometry_convex_hull_2d,
      METH_O,
      M_Geometry_convex_hull_2d_doc},
+    {"delaunay_2d_cdt",
+     (PyCFunction)M_Geometry_delaunay_2d_cdt,
+     METH_VARARGS,
+     M_Geometry_delaunay_2d_cdt_doc},
     {"box_fit_2d", (PyCFunction)M_Geometry_box_fit_2d, METH_O, M_Geometry_box_fit_2d_doc},
     {"box_pack_2d", (PyCFunction)M_Geometry_box_pack_2d, METH_O, M_Geometry_box_pack_2d_doc},
 #endif