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//---------------------------------------------------------------------------//
// Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
//
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//
// See http://boostorg.github.com/compute for more information.
//---------------------------------------------------------------------------//
#ifndef BOOST_COMPUTE_INTEROP_OPENGL_CONTEXT_HPP
#define BOOST_COMPUTE_INTEROP_OPENGL_CONTEXT_HPP
#include <boost/throw_exception.hpp>
#include <boost/compute/device.hpp>
#include <boost/compute/system.hpp>
#include <boost/compute/context.hpp>
#include <boost/compute/exception/unsupported_extension_error.hpp>
#include <boost/compute/interop/opengl/cl_gl.hpp>
#ifdef __APPLE__
#include <OpenCL/cl_gl_ext.h>
#include <OpenGL/OpenGL.h>
#endif
#ifdef __linux__
#include <GL/glx.h>
#endif
namespace boost {
namespace compute {
/// Creates a shared OpenCL/OpenGL context for the currently active
/// OpenGL context.
///
/// Once created, the shared context can be used to create OpenCL memory
/// objects which can interact with OpenGL memory objects (e.g. VBOs).
///
/// \throws unsupported_extension_error if no CL-GL sharing capable devices
/// are found.
inline context opengl_create_shared_context()
{
// name of the OpenGL sharing extension for the system
#if defined(__APPLE__)
const char *cl_gl_sharing_extension = "cl_APPLE_gl_sharing";
#else
const char *cl_gl_sharing_extension = "cl_khr_gl_sharing";
#endif
#if defined(__APPLE__)
// get OpenGL share group
CGLContextObj cgl_current_context = CGLGetCurrentContext();
CGLShareGroupObj cgl_share_group = CGLGetShareGroup(cgl_current_context);
cl_context_properties properties[] = {
CL_CONTEXT_PROPERTY_USE_CGL_SHAREGROUP_APPLE,
(cl_context_properties) cgl_share_group,
0
};
cl_int error = 0;
cl_context cl_gl_context = clCreateContext(properties, 0, 0, 0, 0, &error);
if(!cl_gl_context){
BOOST_THROW_EXCEPTION(opencl_error(error));
}
return context(cl_gl_context, false);
#else
typedef cl_int(*GetGLContextInfoKHRFunction)(
const cl_context_properties*, cl_gl_context_info, size_t, void *, size_t *
);
std::vector<platform> platforms = system::platforms();
for(size_t i = 0; i < platforms.size(); i++){
const platform &platform = platforms[i];
// check whether this platform supports OpenCL/OpenGL sharing
if (!platform.supports_extension(cl_gl_sharing_extension))
continue;
// load clGetGLContextInfoKHR() extension function
GetGLContextInfoKHRFunction GetGLContextInfoKHR =
reinterpret_cast<GetGLContextInfoKHRFunction>(
reinterpret_cast<size_t>(
platform.get_extension_function_address("clGetGLContextInfoKHR")
)
);
if(!GetGLContextInfoKHR){
continue;
}
// create context properties listing the platform and current OpenGL display
cl_context_properties properties[] = {
CL_CONTEXT_PLATFORM, (cl_context_properties) platform.id(),
#if defined(__linux__)
CL_GL_CONTEXT_KHR, (cl_context_properties) glXGetCurrentContext(),
CL_GLX_DISPLAY_KHR, (cl_context_properties) glXGetCurrentDisplay(),
#elif defined(_WIN32)
CL_GL_CONTEXT_KHR, (cl_context_properties) wglGetCurrentContext(),
CL_WGL_HDC_KHR, (cl_context_properties) wglGetCurrentDC(),
#endif
0
};
// lookup current OpenCL device for current OpenGL context
cl_device_id gpu_id;
cl_int ret = GetGLContextInfoKHR(
properties,
CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR,
sizeof(cl_device_id),
&gpu_id,
0
);
if(ret != CL_SUCCESS){
continue;
}
// create device object for the GPU and ensure it supports CL-GL sharing
device gpu(gpu_id, false);
if(!gpu.supports_extension(cl_gl_sharing_extension)){
continue;
}
// return CL-GL sharing context
return context(gpu, properties);
}
#endif
// no CL-GL sharing capable devices found
BOOST_THROW_EXCEPTION(
unsupported_extension_error(cl_gl_sharing_extension)
);
}
} // end compute namespace
} // end boost namespace
#endif // BOOST_COMPUTE_INTEROP_OPENGL_CONTEXT_HPP
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