[Bf-blender-cvs] SVN commit: /data/svn/bf-blender [54142] trunk/blender/source/blender/ python/mathutils/mathutils_geometry.c: add mathutils function to intersect 2 circles.
Campbell Barton
ideasman42 at gmail.com
Mon Jan 28 12:52:22 CET 2013
Revision: 54142
http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=54142
Author: campbellbarton
Date: 2013-01-28 11:52:17 +0000 (Mon, 28 Jan 2013)
Log Message:
-----------
add mathutils function to intersect 2 circles. Converted to C from a python script by Alex Fraser.
Modified Paths:
--------------
trunk/blender/source/blender/python/mathutils/mathutils_geometry.c
Modified: trunk/blender/source/blender/python/mathutils/mathutils_geometry.c
===================================================================
--- trunk/blender/source/blender/python/mathutils/mathutils_geometry.c 2013-01-28 08:58:20 UTC (rev 54141)
+++ trunk/blender/source/blender/python/mathutils/mathutils_geometry.c 2013-01-28 11:52:17 UTC (rev 54142)
@@ -251,6 +251,86 @@
}
}
+/* Line-Line intersection using algorithm from mathworld.wolfram.com */
+
+PyDoc_STRVAR(M_Geometry_intersect_sphere_sphere_2d_doc,
+".. function:: intersect_sphere_sphere_2d(p_a, radius_a, p_b, radius_b)\n"
+"\n"
+" Returns 2 points on between intersecting circles.\n"
+"\n"
+" :arg p_a: Center of the first circle\n"
+" :type p_a: :class:`mathutils.Vector`\n"
+" :arg radius_a: Radius of the first circle\n"
+" :type radius_a: float\n"
+" :arg p_b: Center of the second circle\n"
+" :type p_b: :class:`mathutils.Vector`\n"
+" :arg radius_b: Radius of the second circle\n"
+" :type radius_b: float\n"
+" :rtype: tuple of :class:`mathutils.Vector`'s or None when there is no intersection\n"
+);
+static PyObject *M_Geometry_intersect_sphere_sphere_2d(PyObject *UNUSED(self), PyObject *args)
+{
+ PyObject *ret;
+ VectorObject *vec_a, *vec_b;
+ float *v_a, *v_b;
+ float rad_a, rad_b;
+ float v_ab[2];
+ float dist;
+
+ if (!PyArg_ParseTuple(args, "O!fO!f:intersect_sphere_sphere_2d",
+ &vector_Type, &vec_a, &rad_a,
+ &vector_Type, &vec_b, &rad_b))
+ {
+ return NULL;
+ }
+
+ if (BaseMath_ReadCallback(vec_a) == -1 ||
+ BaseMath_ReadCallback(vec_b) == -1)
+ {
+ return NULL;
+ }
+
+ ret = PyTuple_New(2);
+
+ v_a = vec_a->vec;
+ v_b = vec_b->vec;
+
+ sub_v2_v2v2(v_ab, v_b, v_a);
+ dist = len_v2(v_ab);
+
+ if (/* out of range */
+ (dist > rad_a + rad_b) ||
+ /* fully-contained in the other */
+ (dist < abs(rad_a - rad_b)) ||
+ /* co-incident */
+ (dist < FLT_EPSILON))
+ {
+ /* out of range */
+ PyTuple_SET_ITEM(ret, 0, Py_None); Py_INCREF(Py_None);
+ PyTuple_SET_ITEM(ret, 1, Py_None); Py_INCREF(Py_None);
+ }
+ else {
+ const float dist_delta = ((rad_a * rad_a) - (rad_b * rad_b) + (dist * dist)) / (2.0f * dist);
+ const float h = powf(fabsf((rad_a * rad_a) - (dist_delta * dist_delta)), 0.5f);
+ float i_cent[2];
+ float i1[2], i2[2];
+
+ i_cent[0] = v_a[0] + ((v_ab[0] * dist_delta) / dist);
+ i_cent[1] = v_a[1] + ((v_ab[1] * dist_delta) / dist);
+
+ i1[0] = i_cent[0] + h * v_ab[1] / dist;
+ i1[1] = i_cent[1] - h * v_ab[0] / dist;
+
+ i2[0] = i_cent[0] - h * v_ab[1] / dist;
+ i2[1] = i_cent[1] + h * v_ab[0] / dist;
+
+ PyTuple_SET_ITEM(ret, 0, Vector_CreatePyObject(i1, 2, Py_NEW, NULL));
+ PyTuple_SET_ITEM(ret, 1, Vector_CreatePyObject(i2, 2, Py_NEW, NULL));
+ }
+
+ return ret;
+}
+
PyDoc_STRVAR(M_Geometry_normal_doc,
".. function:: normal(v1, v2, v3, v4=None)\n"
"\n"
@@ -1376,6 +1456,7 @@
{"intersect_line_sphere", (PyCFunction) M_Geometry_intersect_line_sphere, METH_VARARGS, M_Geometry_intersect_line_sphere_doc},
{"intersect_line_sphere_2d", (PyCFunction) M_Geometry_intersect_line_sphere_2d, METH_VARARGS, M_Geometry_intersect_line_sphere_2d_doc},
{"distance_point_to_plane", (PyCFunction) M_Geometry_distance_point_to_plane, METH_VARARGS, M_Geometry_distance_point_to_plane_doc},
+ {"intersect_sphere_sphere_2d", (PyCFunction) M_Geometry_intersect_sphere_sphere_2d, METH_VARARGS, M_Geometry_intersect_sphere_sphere_2d_doc},
{"area_tri", (PyCFunction) M_Geometry_area_tri, METH_VARARGS, M_Geometry_area_tri_doc},
{"normal", (PyCFunction) M_Geometry_normal, METH_VARARGS, M_Geometry_normal_doc},
{"barycentric_transform", (PyCFunction) M_Geometry_barycentric_transform, METH_VARARGS, M_Geometry_barycentric_transform_doc},
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