Re: [osg-users] osgswig: iterating over a vertex array
Thanks for the response. I'll try tackling it with ctypes, then. Not an elegant solution, but I think I can get it to work. Randolph On Feb 25, 2009, at 11:35 PM, Gerwin de Haan wrote: Hi Randolph, this is a typical problem of (python) wrappers; the getVertexArray returns a general Array, which is currently not wrapped. The trick would be to somewhere cast the general Array back to its specific type in Python, e.g. a Vec3Array. We've used some of these tricks in the wrappings themselves by a dynamic_cast through C++ run-time type information (not accessible to users), and some you can access yourself, e.g. osg.Node.asLOD . To fix your particular problem we might introduce extensions to Array such as osg.Array.asVec3Array etc, or better would be to automatically let SWIG convert all returning values of Array to its real type. In any case this means diving into SWIG specifics. I'll post this as an issue on the list (http://code.google.com/p/osgswig/issues/detail?id=27), but I cannot give guarantees when it will be picked up. Gerwin On Thu, Feb 26, 2009 at 5:19 AM, Randolph Fritz rfr...@u.washington.edu wrote: I'm writing a prototype OSG to Radiance exporter in Python. I've got to the point of code that iterates over all geodes in the scene graph. Problem is--then what? Is the only way to read the elements of the arrays ctype and pointers? Or is there something a bit simpler and safer? Perhaps-relevant bit of code: def apply_Geode(self,ge): for i in range(ge.getNumDrawables()): geom = ge.getDrawable(i).asGeometry() if geom: arr = geom.getVertexArray() for i in range(arr.getNumElements()): # This doesn't seem to work--what does? arr.accept(i,self.val) -- Randolph Fritz design machine group architecture department university of washington rfr...@u.washington.edu ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] osgswig: iterating over a vertex array
The following code appears to work:
def apply_Geode(self,ge):
for i in range(ge.getNumDrawables()):
geom = ge.getDrawable(i).asGeometry()
if geom:
arr = geom.getVertexArray()
if arr.getType() != osg.Array.Vec3ArrayType:
raise LumError, 'Type of vertex array not
three-element vectors'
# aagh!
sz = arr.getDataSize()
pvec =
ctypes.pointer(c_float.from_address(int(arr.getDataPointer(
o = 0
for i in range(arr.getNumElements()):
self.file.write(' %f %f %f\n' % (pvec[o],
pvec[o+1], pvec[o+2]))
o += sz
I do not recommend this as a coding style, but it seems to be the only
way to do this at the moment.
Randolph
Gerwin de Haan wrote:
Hi Randolph,
this is a typical problem of (python) wrappers; the getVertexArray
returns a general Array, which is currently not wrapped. The trick
would be to somewhere cast the general Array back to its specific
type in Python, e.g. a Vec3Array. We've used some of these tricks in
the wrappings themselves by a dynamic_cast through C++ run-time type
information (not accessible to users), and some you can access
yourself, e.g. osg.Node.asLOD .
To fix your particular problem we might introduce extensions to Array
such as osg.Array.asVec3Array etc, or better would be to automatically
let SWIG convert all returning values of Array to its real type. In
any case this means diving into SWIG specifics. I'll post this as an
issue on the list
(http://code.google.com/p/osgswig/issues/detail?id=27), but I cannot
give guarantees when it will be picked up.
Gerwin
On Thu, Feb 26, 2009 at 5:19 AM, Randolph Fritz rfr...@u.washington.edu wrote:
I'm writing a prototype OSG to Radiance exporter in Python. I've got to the
point of code that iterates over all geodes in the scene graph. Problem
is--then what? Is the only way to read the elements of the arrays ctype and
pointers? Or is there something a bit simpler and safer?
Perhaps-relevant bit of code:
def apply_Geode(self,ge):
for i in range(ge.getNumDrawables()):
geom = ge.getDrawable(i).asGeometry()
if geom:
arr = geom.getVertexArray()
for i in range(arr.getNumElements()):
# This doesn't seem to work--what does?
arr.accept(i,self.val)
--
Randolph Fritz
design machine group
architecture department
university of washington
rfr...@u.washington.edu
___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
--
Randolph Fritz
design machine group
architecture department
university of washington
rfr...@u.washington.edu
___
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] osgswig: iterating over a vertex array
Hi Randolph, this is a typical problem of (python) wrappers; the getVertexArray returns a general Array, which is currently not wrapped. The trick would be to somewhere cast the general Array back to its specific type in Python, e.g. a Vec3Array. We've used some of these tricks in the wrappings themselves by a dynamic_cast through C++ run-time type information (not accessible to users), and some you can access yourself, e.g. osg.Node.asLOD . To fix your particular problem we might introduce extensions to Array such as osg.Array.asVec3Array etc, or better would be to automatically let SWIG convert all returning values of Array to its real type. In any case this means diving into SWIG specifics. I'll post this as an issue on the list (http://code.google.com/p/osgswig/issues/detail?id=27), but I cannot give guarantees when it will be picked up. Gerwin On Thu, Feb 26, 2009 at 5:19 AM, Randolph Fritz rfr...@u.washington.edu wrote: I'm writing a prototype OSG to Radiance exporter in Python. I've got to the point of code that iterates over all geodes in the scene graph. Problem is--then what? Is the only way to read the elements of the arrays ctype and pointers? Or is there something a bit simpler and safer? Perhaps-relevant bit of code: def apply_Geode(self,ge): for i in range(ge.getNumDrawables()): geom = ge.getDrawable(i).asGeometry() if geom: arr = geom.getVertexArray() for i in range(arr.getNumElements()): # This doesn't seem to work--what does? arr.accept(i,self.val) -- Randolph Fritz design machine group architecture department university of washington rfr...@u.washington.edu ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
