check context property

check context property

Hi forum,

I have created an opencl context with the gl-cl interoperability. The context creation was fine and it did not give me any cl error string . But i am getting some trouble while making opencl image buffer from 2D gl texture object. I am getting the cl error string "CL_OUT_OF_RESOURCES"

I suspect that i have problem with context creation. Since i am not getting any cl error string other than CL_SUCCESS, i do not know how else to validate the successful opencl context creation with gl-cl interoperability.

To find the context info i am doing the following :

//now pull out the context infor from the recently created context
size_t contextPropertySize = 0; cl_context_properties *properties = NULL; 
//now extract the context information that we have created
errNum = clGetContextInfo(_m_clContext,CL_CONTEXT_PROPERTIES,0,NULL,&contextPropertySize); 
if(errNum != CL_SUCCESS) { osg::notify(osg::FATAL) << __FUNCTION__ << ": " << __LINE__ << ": " << "Error while clGetContextInfo(..)" << getErrorString(errNum) << std::endl; } 
 properties = new cl_context_properties[contextPropertySize]; 
 errNum = clGetContextInfo(_m_clContext,CL_CONTEXT_PROPERTIES,contextPropertySize,properties,NULL); 
 if(errNum != CL_SUCCESS) { osg::notify(osg::FATAL) << __FUNCTION__ << ": " << __LINE__ << ": " << "Error while clGetContextInfo(..)" << getErrorString(errNum) << std::endl; }

So i have all the information inside properties array . How do i confirm that content of the properties array contain the context properties for gl-cl interoperability ?



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How are you creating the context? Your snippet shows code querrying the context but not the creation. You should create the context by setting the properties to enable CL/GL sharing. Also make sure to get the gl device associated with the gl context


cl_context_properties properties[] =
    CL_CONTEXT_PLATFORM, (cl_context_properties) platform,
    CL_GL_CONTEXT_KHR, (cl_context_properties) g_hRC,
    CL_WGL_HDC_KHR, (cl_context_properties) g_hDC,
cl_int res = pclGetGLContextInfoKHR(properties, CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR, 0, NULL, &devSize);
res = pclGetGLContextInfoKHR( properties, CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR, sizeof(cl_device_id), &device, NULL);
context = clCreateContext(properties,1,&device,0,0,&res);

Of course, you should do the proper error checking at each step.


Thanks for the hint!

I saw many examples where they have not used the function "clGetGLContextInfoKHR(...)" and their context creation is successful. I am confused if it mandatory to use it or not. I am creating the context as follows:

 cl_context_properties contextProperties[] = { #ifdef defined(_WIN32) CL_CONTEXT_PLATFORM, (cl_context_properties) _m_clPlatform, CL_GL_CONTEXT_KHR, (cl_context_properties) windowsContext->getWGLContext(), CL_WGL_HDC_KHR, (cl_context_properties) windowsContext->getHDC(), #elif defined(__GNUC__) CL_CONTEXT_PLATFORM, (cl_context_properties) _m_clPlatform, CL_GL_CONTEXT_KHR, (cl_context_properties) linuxContext->getContext(), CL_GLX_DISPLAY_KHR, (cl_context_properties) linuxContext->getDisplay(), #elif defined(__APPLE__) CGLContextObj glContext = CGLGetCurrentContext(); // get the current GL context CGLShareGroupObj shareGroup = CGLGetShareGroup(glContext); // share group 
 CL_CONTEXT_PROPERTY_USE_CGL_SHAREGROUP_APPLE, (cl_context_properties) shareGroup, #endif 0 }; 
 _m_clContext = clCreateContext(contextProperties,1,&clDevices[clDevUsed],NULL,NULL,&errNum); 
 if(errNum != CL_SUCCESS) { osg::notify(osg::FATAL) << __FUNCTION__ << ": " << __LINE__ << ": " << " OpenCL Context Creation with GL-CL interoperability was not successful :" << getErrorString(errNum) << std::endl; return false; }

I am getting CL_SUCCESS  with the context creation. But later if i try to create 2D opencl image buffer from the valid opengl texture object i get the opencl error "CL_OUT_OF_RESOURCES".  Any idea what might have caused it ?

It will be nice to know some scenarios that cause this type of error.



You get CL_OUT_OF_RESOURCES if for some reason the allocation failed (sorry dont have specifics). But I think the reason your call is failing is because you are creating a shared buffer without a shared context. You need to create the context using a device that is associated with both cl and gl.


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