Hi David,
thank you. Your advices really helped to solve the problem.
Hi Sebastian
2012/10/30 Sebastian Messerschmidt <[email protected]
<mailto:[email protected]>>
Hello,
I'm trying to implement an advanced HDR lighting algorithm where I
need the average luminance of the last frame(s).
Currently I've encountered two major problems:
1. Is there a possibility to get only the last mipmap-level from
texture/image bound to a FBO?
I can get the whole image via readImageFromCurrentTexture in a
postDrawCallback, but this unfortunately copies the complete texture.
Looking at the code, I see that all mipmap levels are copied, and
my question is if it would be feasible to either create a special
function to copy only a specific mipmap-level or add an additional
parameter to the function to specifiy the mipmap level?
I don't see any code in OSG to just read specific mipmap level, but
with "readImageFromCurrentTexture" code as model, this will not be
difficult to do appropriate function.
2. I have trouble getting correct values from floating point
buffers. It works if get the values as GL_UNSIGNED_BYTE (the
values are indeed scaled to 0 -255) but this, of course, won't be
precise enough as the buffer holds the logarithmic luminance.
check this :
- be sure to bind correct texture in Texture 0 :
state->applyTextureAttribute(0, myTextureToRead);
- be sure to active correct Texture Unit :
state->setActiveTextureUnit(0);
- be sure current texture have FLOAT internal Type :
osg::Image::computeFormatDataType(myTextureToRead->getInternalFormat()) ==
GL_FLOAT
And when you did
double data = *image->getMipmapData(0);
you read the buttom left pixel of the complet image, average luminance
is in the last mipmap level
double averageLuminance = *reinterprete_cast<double*>(
image->getMipmapData(image->getNumMipmapLevels() - 1) );
HTH
David
Below you find a snippet of my PostDrawCallback, maybe I'm doint
something fundamentally wrong.
I'm running on OSG 3.0.1.
virtual void operator () (osg::RenderInfo& render_info) const
{
//state->apply(render_info.getCurrentCamera()->getStateSet());
//state->applyTextureAttribute(0,mTexture);
//mTexture->apply(*state);
osg::ref_ptr<osg::Image> image=new osg::Image();
mTexture->getImage()->readImageFromCurrentTexture(render_info.getContextID(),true,
GL_UNSIGNED_BYTE); //works , doesn't work with GL_FLOAT
double data = *image->getMipmapData(0);
std::cout << "luminance " << data << std::endl;
//osgDB::writeImageFile(*image,"snap.bmp");
}
cheers
Sebastian
_______________________________________________
osg-users mailing list
[email protected]
<mailto:[email protected]>
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
