1 //---------------------------------------------------------------------------//
2 // Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
3 //
4 // Distributed under the Boost Software License, Version 1.0
5 // See accompanying file LICENSE_1_0.txt or copy at
6 // http://www.boost.org/LICENSE_1_0.txt
7 //
8 // See http://boostorg.github.com/compute for more information.
9 //---------------------------------------------------------------------------//
10
11 #ifndef BOOST_COMPUTE_INTEROP_OPENGL_CONTEXT_HPP
12 #define BOOST_COMPUTE_INTEROP_OPENGL_CONTEXT_HPP
13
14 #include <boost/throw_exception.hpp>
15
16 #include <boost/compute/device.hpp>
17 #include <boost/compute/system.hpp>
18 #include <boost/compute/context.hpp>
19 #include <boost/compute/exception/unsupported_extension_error.hpp>
20 #include <boost/compute/interop/opengl/cl_gl.hpp>
21
22 #ifdef __APPLE__
23 #include <OpenCL/cl_gl_ext.h>
24 #include <OpenGL/OpenGL.h>
25 #endif
26
27 #ifdef __linux__
28 #include <GL/glx.h>
29 #endif
30
31 namespace boost {
32 namespace compute {
33
34 /// Creates a shared OpenCL/OpenGL context for the currently active
35 /// OpenGL context.
36 ///
37 /// Once created, the shared context can be used to create OpenCL memory
38 /// objects which can interact with OpenGL memory objects (e.g. VBOs).
39 ///
40 /// \throws unsupported_extension_error if no CL-GL sharing capable devices
41 /// are found.
opengl_create_shared_context()42 inline context opengl_create_shared_context()
43 {
44 // name of the OpenGL sharing extension for the system
45 #if defined(__APPLE__)
46 const char *cl_gl_sharing_extension = "cl_APPLE_gl_sharing";
47 #else
48 const char *cl_gl_sharing_extension = "cl_khr_gl_sharing";
49 #endif
50
51 #if defined(__APPLE__)
52 // get OpenGL share group
53 CGLContextObj cgl_current_context = CGLGetCurrentContext();
54 CGLShareGroupObj cgl_share_group = CGLGetShareGroup(cgl_current_context);
55
56 cl_context_properties properties[] = {
57 CL_CONTEXT_PROPERTY_USE_CGL_SHAREGROUP_APPLE,
58 (cl_context_properties) cgl_share_group,
59 0
60 };
61
62 cl_int error = 0;
63 cl_context cl_gl_context = clCreateContext(properties, 0, 0, 0, 0, &error);
64 if(!cl_gl_context){
65 BOOST_THROW_EXCEPTION(opencl_error(error));
66 }
67
68 return context(cl_gl_context, false);
69 #else
70 typedef cl_int(*GetGLContextInfoKHRFunction)(
71 const cl_context_properties*, cl_gl_context_info, size_t, void *, size_t *
72 );
73
74 std::vector<platform> platforms = system::platforms();
75 for(size_t i = 0; i < platforms.size(); i++){
76 const platform &platform = platforms[i];
77
78 // check whether this platform supports OpenCL/OpenGL sharing
79 if (!platform.supports_extension(cl_gl_sharing_extension))
80 continue;
81
82 // load clGetGLContextInfoKHR() extension function
83 GetGLContextInfoKHRFunction GetGLContextInfoKHR =
84 reinterpret_cast<GetGLContextInfoKHRFunction>(
85 reinterpret_cast<size_t>(
86 platform.get_extension_function_address("clGetGLContextInfoKHR")
87 )
88 );
89 if(!GetGLContextInfoKHR){
90 continue;
91 }
92
93 // create context properties listing the platform and current OpenGL display
94 cl_context_properties properties[] = {
95 CL_CONTEXT_PLATFORM, (cl_context_properties) platform.id(),
96 #if defined(__linux__)
97 CL_GL_CONTEXT_KHR, (cl_context_properties) glXGetCurrentContext(),
98 CL_GLX_DISPLAY_KHR, (cl_context_properties) glXGetCurrentDisplay(),
99 #elif defined(_WIN32)
100 CL_GL_CONTEXT_KHR, (cl_context_properties) wglGetCurrentContext(),
101 CL_WGL_HDC_KHR, (cl_context_properties) wglGetCurrentDC(),
102 #endif
103 0
104 };
105
106 // lookup current OpenCL device for current OpenGL context
107 cl_device_id gpu_id;
108 cl_int ret = GetGLContextInfoKHR(
109 properties,
110 CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR,
111 sizeof(cl_device_id),
112 &gpu_id,
113 0
114 );
115 if(ret != CL_SUCCESS){
116 continue;
117 }
118
119 // create device object for the GPU and ensure it supports CL-GL sharing
120 device gpu(gpu_id, false);
121 if(!gpu.supports_extension(cl_gl_sharing_extension)){
122 continue;
123 }
124
125 // return CL-GL sharing context
126 return context(gpu, properties);
127 }
128 #endif
129
130 // no CL-GL sharing capable devices found
131 BOOST_THROW_EXCEPTION(
132 unsupported_extension_error(cl_gl_sharing_extension)
133 );
134 }
135
136 } // end compute namespace
137 } // end boost namespace
138
139 #endif // BOOST_COMPUTE_INTEROP_OPENGL_CONTEXT_HPP
140