Re: [osg-users] Using getGlShaderInfoLog
Hi Joel, I think I had assumed to this point that the shader would be compiled once it was loaded and bound to the program object - it seemed the most logical way to manage it. Of course, once you indicated that even compilation doesn't happen until the shader's called for (which makes sense, now that I think of it), I tried retrieving the log after calling viewer.frame() inside the viewer loop and it worked perfectly. Yes, well in conjunction with what I said also, that the main thread often doesn't have a graphics context, it makes even more sense. How would it compile your shader immediately after loading it if there's no graphics context? Glad I could clear things up for you. J-S -- __ Jean-Sebastien Guayjean-sebastien.g...@cm-labs.com http://www.cm-labs.com/ http://whitestar02.webhop.org/ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Using getGlShaderInfoLog
J-S, Thanks for the reply. You told me exactly what I needed to know. I think I had assumed to this point that the shader would be compiled once it was loaded and bound to the program object - it seemed the most logical way to manage it. Of course, once you indicated that even compilation doesn't happen until the shader's called for (which makes sense, now that I think of it), I tried retrieving the log after calling viewer.frame() inside the viewer loop and it worked perfectly. Anyway, thanks for the help! Joel -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=34886#34886 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Using getGlShaderInfoLog
Hi Joel, Just for reference, the error is: "Unhandled exception at 0xcdcdcdcd in OSG-shader.exe: 0xC005: Access violation." This error is a general error on Windows that means something bad happened. Generally the "something bad" is a null pointer being dereferenced, or something like that, but the only way to know for sure is to build the project in debug and run it. Then the Visual Studio debugger will stop exactly where the error happens and you'll be able to pinpoint the cause. In your case, it seems to me that two things may cause the error you're getting: 1. osgDB::readShaderFile() for geometryShader1 returned NULL, i.e. the shader file you specified did not exist / could not be read. So when you call geometryShader1->getGlShaderInfoLog(0, log); you're dereferencing a null pointer. 2. osg::Shader::getGlShaderInfoLog() requires that the context ID you pass (0 in your case) be current, or that the shader have been compiled for that context prior to the call, and that isn't the case. Again that might cause a null pointer dereference. For 2, note that in OSG, unless you run specifically in single threaded mode, you generally don't have a graphics context current in the main application thread. All OpenGL work is done in other threads (GraphicsThread). And shaders are generally compiled only when needed, i.e. when rendering a frame. So if the shader was read correctly, eliminating problem 1, then you probably need to wait for a frame to be rendered before getting the shader info log. You could set a post-frame callback on your camera, or something like that. In any case, building OSG and your app in debug and running it will tell you what's happening better than I could ever hope to. Hope this helps, J-S -- __ Jean-Sebastien Guayjean-sebastien.g...@cm-labs.com http://www.cm-labs.com/ http://whitestar02.webhop.org/ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Using getGlShaderInfoLog
Just as a follow-up, I stumbled across a post which indicated part of the
problem may lie in the compiler. I should point out that I'm using OSG with
VS2010.
I'm also starting to wonder if this has something more to do with OpenGL than
with OSG. I tried accessing the shader info log immediately after loading the
shader and binding it to the program object, with the same result.
Code:
//load shaders
osg::ref_ptr vertexShader1(
osg::Shader::readShaderFile (osg::Shader::VERTEX,
"C:/OpenSceneGraph/OpenSceneGraph-Data-2.8.0/myShaders/pass1.vert"));
osg::ref_ptr geometryShader1(
osg::Shader::readShaderFile (osg::Shader::GEOMETRY,
"C:/OpenSceneGraph/OpenSceneGraph-Data-2.8.0/myShaders/test.geom"));
osg::ref_ptr fragShader1(
osg::Shader::readShaderFile (osg::Shader::FRAGMENT,
"C:/OpenSceneGraph/OpenSceneGraph-Data-2.8.0/myShaders/pass1.frag"));
//set up program
osg::ref_ptr pass1 (new osg::Program());
pass1->addShader(vertexShader1);
pass1->addShader(geometryShader1);
pass1->addShader(fragShader1);
pass1->addBindAttribLocation("osg_Vertex", 0);
pass1->addBindAttribLocation("osg_Normal", 2);
//create stateset
geodePass1->getOrCreateStateSet()->setAttribute(pass1);
//test info log
std::string log="";
geometryShader1->getGlShaderInfoLog(0, log);
Regardless of what's in the info log, it seems to me that it ought to return
something, if only an empty string, but I get the error instead...
Just for reference, the error is: "Unhandled exception at 0xcdcdcdcd in
OSG-shader.exe: 0xC005: Access violation."
--
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=34866#34866
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[osg-users] Using getGlShaderInfoLog
Hello, As I've been playing with shaders in OSG, I've tried to get the shader info log so I can export it directly to a file (largely because it doesn't want to show up in the console when I have a GLSL compilation error). In any case, I've pieced together several snippets of code across a few posts from the forum, but to no avail. The code: Code: osgViewer::ViewerBase::Contexts* c = new osgViewer::ViewerBase::Contexts(); viewer.getContexts(*c); unsigned int contextID; osg::ref_ptr stat; for (osgViewer::ViewerBase::Contexts::iterator itr=c->begin(); itr!=c->end(); ++itr) stat = (*itr)->getState(); contextID = stat->getContextID(); osg::ref_ptr pass1 (dynamic_cast (FindNode(root, "root_geodeShaderGeometry1")->getFirst())); osg::ref_ptr sh1 (dynamic_cast (pass1->getStateSet()->getAttribute(osg::StateAttribute::PROGRAM, 0))); std::string log; osg::Shader* shader = sh1->getShader(0); shader->compileShader(*(stat.get())); bool logFound = shader->getGlShaderInfoLog(contextID, log); if (logFound) std::cout << log; I can retrieve my shader programs fine (I have 3), but i get an unhandled exception (access violation) at 0xcdcdcdcd when I try to call compileShader or getGlShaderInfoLog. That tells me the problem isn't with my parameters, but with accessing the shader object itself. I'm sure it's something simple that I've overlooked, and I imagine it's been covered in another post somewhere, but since my knowledge of OSG overall is pretty much limited to what I've tried to implement, the solution eludes me. Any thoughts? -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=34726#34726 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
