Hi Mathias,
I've used the following python snippet to make hi-res screenshots
using a slave camera and an FBO. I'm sure you could (or should) do
this with a draw callback, but I started with explicitly calling this
function myself to do some experimentation first. I did have some
trouble on one machine, where the context (and so the image) would
only contain the clear color. You could fill a numpy array from the
image I guess. I would be interested in that.
regards,
Gerwin
---
def fboshot(pFileName="screenshot.png", pWidth=1024,pHeight=768):
"""
screenshot experiment with a frame buffer object
creates a new slave camera, attached to the viewer, draws, saves
to image, removes the camera again
"""
import osg
import osgDB
viewer= __main__.viewer
cam = viewer.getCamera()
#prepare an image, to which a camera can render
shot = osg.Image()
shot.allocateImage(pWidth,pHeight,1, osg.GL_RGB, osg.GL_UNSIGNED_BYTE)
#create a camera with an fbo render target
hicam = osg.Camera()
hicam.setGraphicsContext(cam.getGraphicsContext())
hicam.setRenderTargetImplementation(osg.Camera.FRAME_BUFFER_OBJECT)
hicam.attach(osg.Camera.COLOR_BUFFER,shot)
hicam.setViewport(0,0,pWidth,pHeight)
#add a slave camera
viewer.addSlave(hicam)
#render one frame
viewer.frame()
#store the shot taken
osgDB.writeImageFile(shot,pFileName)
#remove this camera again
viewer.removeSlave(0)
On Fri, Feb 20, 2009 at 4:54 PM, Mathias Franzius
<[email protected]> wrote:
> Dear ng,
>
> first of all thanks for the support for my last questions!
>
> I try to get a scene snapshot into a numpy array.
> In pure OpenGL I used a QT or glut context and glReadPixels and converted
> that to a numpy array using scipy.
> My problem on osg is that the context seems to be deactivated after a
> viewer.frame() call - glReadPixels returns only zeros.
> So I guess either I need to keep the context active, reactivate it, or
> register a callback somehow in a post render phase (?).
> Furthermore, if I want to use the osg method with a camera-attached
> osg.Image, I'll need to convert the Image.data() to numpy format.
> Has sb got an idea (or even a code snippet) that would work in osgswig?
>
> Thanks a lot!
> Mathias
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