fred_em wrote: > Hi, > > I am confused about how to use PBOs in OSG. I browsed the forum quite a bit > but still can't make my code work. > > 1) GPU -> CPU pixel transfers > > As I understand it, an osg::Image with an osg::PixelBufferObject cannot be > used (yet) to read FBO contents. I have actually checked that and could see > that glReadPixels() still uses a client-side memory pointer. I believe this > scenario is not supported yet. Not a big deal. > > I understand it is possible to do this manually and follow for instance what > is done in the osgscreencapture sample. This sample doesn't make use of > osg::PixelBufferObject, and instead manually creates a GL PBO, manually calls > glReadBuffer with a bound pixel buffer object. > > 2) CPU -> GPU pixel transfers > > I gave this a go but cannot make it work yet. To see if the PBO is > effectively used this time in my GL tracer I look at a current bound PBO and > the last parameter of glTexImage2D, which would reflect an offset and not a > client side pointer. > > My code to create my texture, image and PBO is the following: > > > Code: > Image *image = osgDB:readImageFile(filePath); > > // PBO image binding method 1 - this line has no effect for me > PixelBufferObject *pbo = new PixelBufferObject(image); > > // PBO image binding method 2 - I get a crash in > BufferObject::computeRequiredBufferSize here > image->setPixelBufferObject(new PixelBufferObject()); > > Texture2D *texture = new Texture2D(image); > geode->getOrCreateStateSet()->setTextureAttributeAndMode(0, texture, > StateSet::ON); > > > > > I don't see any PBO created in the GL trace, and glTexImage2D still reads > image data off a client side pointer. > > What I am doing wrong? > > Cheers, > Fred
This looks like a bug to me. The following code works: > Image *image = new Image(); > image->allocate(256, 256, 1, GL_RGBA, GL_UNSIGNED_BYTE, 1); > image->setPixelBufferObject(new PixelBufferObject(image)); > Texture2D *texture = new Texture2D(); > texture->setImage(image); > The following doesn't work: > Image *image = osgDB::readImageFile(...); > image->setPixelBufferObject(new PixelBufferObject(image)); > // I've tried image->dirty(); here, too > Texture2D *texture = new Texture2D(); > texture->setImage(image); > In the second case, a GL tracer shows that glGenBuffers(1, ...); is called, but nothing is done beyond that. Long story short, if you create an Image with osgDB::readImageFile(), things don't work. Surprisingly enough, dirty() makes no difference. Cheers, Fred ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=34534#34534 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
