Revision: 37820
http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=37820
Author: campbellbarton
Date: 2011-06-26 07:21:19 +0000 (Sun, 26 Jun 2011)
Log Message:
-----------
math func to find the intersection(s) between a segment and a sphere for
C/python.
from python:
i1, i2 = mathutils.geometry.intersect_line_sphere(l1, l2, sphere, radius)
Modified Paths:
--------------
trunk/blender/source/blender/blenlib/BLI_math_geom.h
trunk/blender/source/blender/blenlib/intern/math_geom.c
trunk/blender/source/blender/python/generic/mathutils_geometry.c
Modified: trunk/blender/source/blender/blenlib/BLI_math_geom.h
===================================================================
--- trunk/blender/source/blender/blenlib/BLI_math_geom.h 2011-06-26
06:05:56 UTC (rev 37819)
+++ trunk/blender/source/blender/blenlib/BLI_math_geom.h 2011-06-26
07:21:19 UTC (rev 37820)
@@ -79,6 +79,7 @@
int isect_line_line_v2(const float a1[2], const float a2[2], const float
b1[2], const float b2[2]);
int isect_line_line_v2_int(const int a1[2], const int a2[2], const int b1[2],
const int b2[2]);
int isect_seg_seg_v2_point(const float v1[2], const float v2[2], const float
v3[2], const float v4[2], float vi[2]);
+int isect_seg_sphere_v3(const float l1[3], const float l2[3], const float
sp[3], const float r, float r_p1[3], float r_p2[3]);
/* Returns the number of point of interests
* 0 - lines are colinear
Modified: trunk/blender/source/blender/blenlib/intern/math_geom.c
===================================================================
--- trunk/blender/source/blender/blenlib/intern/math_geom.c 2011-06-26
06:05:56 UTC (rev 37819)
+++ trunk/blender/source/blender/blenlib/intern/math_geom.c 2011-06-26
07:21:19 UTC (rev 37820)
@@ -349,6 +349,79 @@
return -1;
}
+int isect_seg_sphere_v3(const float l1[3], const float l2[3],
+ const float sp[3], const float r,
+ float r_p1[3], float r_p2[3])
+{
+ /* l1: coordinates (point of line)
+ * l2: coordinates (point of line)
+ * sp, r: coordinates and radius (sphere)
+ * r_p1, r_p2: return intersection coordinates
+ */
+
+
+ /* adapted for use in blender by Campbell Barton - 2011
+ *
+ * atelier iebele abel - 2001
+ * [email protected]
+ * http://www.iebele.nl
+ *
+ * sphere_line_intersection function adapted from:
+ * http://astronomy.swin.edu.au/pbourke/geometry/sphereline
+ * Paul Bourke [email protected]
+ */
+
+ const float ldir[3]= {
+ l2[0] - l1[0],
+ l2[1] - l1[1],
+ l2[2] - l1[2]
+ };
+
+ const float a= dot_v3v3(ldir, ldir);
+
+ const float b= 2.0f *
+ (ldir[0] * (l1[0] - sp[0]) +
+ ldir[1] * (l1[1] - sp[1]) +
+ ldir[2] * (l1[2] - sp[2]));
+
+ const float c=
+ dot_v3v3(sp, sp) +
+ dot_v3v3(l1, l1) -
+ (2.0f * dot_v3v3(sp, l1)) -
+ (r * r);
+
+ const float i = b * b - 4.0f * a * c;
+
+ float mu;
+
+ if (i < 0.0f) {
+ /* no intersections */
+ return 0;
+ }
+ else if (i == 0.0f) {
+ /* one intersection */
+ mu = -b / (2.0f * a);
+ madd_v3_v3v3fl(r_p1, l1, ldir, mu);
+ return 1;
+ }
+ else if (i > 0.0) {
+ const float i_sqrt= sqrt(i); /* avoid calc twice */
+
+ /* first intersection */
+ mu = (-b + i_sqrt) / (2.0f * a);
+ madd_v3_v3v3fl(r_p1, l1, ldir, mu);
+
+ /* second intersection */
+ mu = (-b - i_sqrt) / (2.0f * a);
+ madd_v3_v3v3fl(r_p2, l1, ldir, mu);
+ return 2;
+ }
+ else {
+ /* math domain error - nan */
+ return -1;
+ }
+}
+
/*
-1: colliniar
1: intersection
Modified: trunk/blender/source/blender/python/generic/mathutils_geometry.c
===================================================================
--- trunk/blender/source/blender/python/generic/mathutils_geometry.c
2011-06-26 06:05:56 UTC (rev 37819)
+++ trunk/blender/source/blender/python/generic/mathutils_geometry.c
2011-06-26 07:21:19 UTC (rev 37820)
@@ -553,6 +553,73 @@
}
}
+
+PyDoc_STRVAR(M_Geometry_intersect_line_sphere_doc,
+".. function:: intersect_line_sphere(line_a, line_b, sphere_co,
sphere_radius)\n"
+"\n"
+" Takes a lines (as 2 vectors), a sphere as a point and a radius and\n"
+" returns the intersection\n"
+"\n"
+" :arg line_a: First point of the first line\n"
+" :type line_a: :class:`mathutils.Vector`\n"
+" :arg line_b: Second point of the first line\n"
+" :type line_b: :class:`mathutils.Vector`\n"
+" :arg sphere_co: The center of the sphere\n"
+" :type sphere_co: :class:`mathutils.Vector`\n"
+" :arg sphere_radius: Radius of the sphere\n"
+" :type sphere_radius: sphere_radius\n"
+" :return: The intersection points as a pair of vectors or None when there
is no intersection\n"
+" :rtype: A tuple pair containing :class:`mathutils.Vector` or None\n"
+);
+static PyObject *M_Geometry_intersect_line_sphere(PyObject *UNUSED(self),
PyObject* args)
+{
+ PyObject *ret;
+ VectorObject *line_a, *line_b, *sphere_co;
+ float sphere_radius;
+
+ float isect_a[3];
+ float isect_b[3];
+
+ if(!PyArg_ParseTuple(args, "O!O!O!f:intersect_line_sphere",
+ &vector_Type, &line_a,
+ &vector_Type, &line_b,
+ &vector_Type, &sphere_co,
+ &sphere_radius)
+ ) {
+ return NULL;
+ }
+
+ if( BaseMath_ReadCallback(line_a) == -1 ||
+ BaseMath_ReadCallback(line_b) == -1 ||
+ BaseMath_ReadCallback(sphere_co) == -1
+ ) {
+ return NULL;
+ }
+
+ if(ELEM3(2, line_a->size, line_b->size, sphere_co->size)) {
+ PyErr_SetString(PyExc_RuntimeError,
"geometry.intersect_line_sphere(...) can't use 2D Vectors");
+ return NULL;
+ }
+
+ ret= PyTuple_New(2);
+
+ switch(isect_seg_sphere_v3(line_a->vec, line_b->vec, sphere_co->vec,
sphere_radius, isect_a, isect_b)) {
+ case 1:
+ PyTuple_SET_ITEM(ret, 0, newVectorObject(isect_a, 3, Py_NEW,
NULL));
+ PyTuple_SET_ITEM(ret, 1, Py_None); Py_INCREF(Py_None);
+ break;
+ case 2:
+ PyTuple_SET_ITEM(ret, 0, newVectorObject(isect_a, 3, Py_NEW,
NULL));
+ PyTuple_SET_ITEM(ret, 1, newVectorObject(isect_b, 3, Py_NEW,
NULL));
+ break;
+ default:
+ PyTuple_SET_ITEM(ret, 0, Py_None); Py_INCREF(Py_None);
+ PyTuple_SET_ITEM(ret, 1, Py_None); Py_INCREF(Py_None);
+ }
+
+ return ret;
+}
+
PyDoc_STRVAR(M_Geometry_intersect_point_line_doc,
".. function:: intersect_point_line(pt, line_p1, line_p2)\n"
"\n"
@@ -917,6 +984,7 @@
{"intersect_line_line", (PyCFunction) M_Geometry_intersect_line_line,
METH_VARARGS, M_Geometry_intersect_line_line_doc},
{"intersect_line_line_2d", (PyCFunction)
M_Geometry_intersect_line_line_2d, METH_VARARGS,
M_Geometry_intersect_line_line_2d_doc},
{"intersect_line_plane", (PyCFunction) M_Geometry_intersect_line_plane,
METH_VARARGS, M_Geometry_intersect_line_plane_doc},
+ {"intersect_line_sphere", (PyCFunction)
M_Geometry_intersect_line_sphere, METH_VARARGS,
M_Geometry_intersect_line_sphere_doc},
{"interpolate_bezier", (PyCFunction) M_Geometry_interpolate_bezier,
METH_VARARGS, M_Geometry_interpolate_bezier_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},
_______________________________________________
Bf-blender-cvs mailing list
[email protected]
http://lists.blender.org/mailman/listinfo/bf-blender-cvs
