2 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
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33 * Client-side GLX interface for current context management.
38 #include "glxclient.h"
43 ** We setup some dummy structures here so that the API can be used
44 ** even if no context is current.
47 static GLubyte dummyBuffer
[__GLX_BUFFER_LIMIT_SIZE
];
48 static struct glx_context_vtable dummyVtable
;
50 ** Dummy context used by small commands when there is no current context.
52 ** gl and glx entry points are designed to operate as nop's when using
53 ** the dummy context structure.
55 struct glx_context dummyContext
= {
59 &dummyBuffer
[__GLX_BUFFER_LIMIT_SIZE
],
65 * Current context management and locking
68 _X_HIDDEN pthread_mutex_t __glXmutex
= PTHREAD_MUTEX_INITIALIZER
;
70 # if defined( GLX_USE_TLS )
73 * Per-thread GLX context pointer.
75 * \c __glXSetCurrentContext is written is such a way that this pointer can
76 * \b never be \c NULL. This is important! Because of this
77 * \c __glXGetCurrentContext can be implemented as trivial macro.
79 __thread
void *__glX_tls_Context
__attribute__ ((tls_model("initial-exec")))
83 __glXSetCurrentContext(struct glx_context
* c
)
85 __glX_tls_Context
= (c
!= NULL
) ? c
: &dummyContext
;
90 static pthread_once_t once_control
= PTHREAD_ONCE_INIT
;
93 * Per-thread data key.
95 * Once \c init_thread_data has been called, the per-thread data key will
96 * take a value of \c NULL. As each new thread is created the default
97 * value, in that thread, will be \c NULL.
99 static pthread_key_t ContextTSD
;
102 * Initialize the per-thread data key.
104 * This function is called \b exactly once per-process (not per-thread!) to
105 * initialize the per-thread data key. This is ideally done using the
106 * \c pthread_once mechanism.
109 init_thread_data(void)
111 if (pthread_key_create(&ContextTSD
, NULL
) != 0) {
112 perror("pthread_key_create");
118 __glXSetCurrentContext(struct glx_context
* c
)
120 pthread_once(&once_control
, init_thread_data
);
121 pthread_setspecific(ContextTSD
, c
);
124 _X_HIDDEN
struct glx_context
*
125 __glXGetCurrentContext(void)
129 pthread_once(&once_control
, init_thread_data
);
131 v
= pthread_getspecific(ContextTSD
);
132 return (v
== NULL
) ? &dummyContext
: (struct glx_context
*) v
;
135 # endif /* defined( GLX_USE_TLS ) */
139 __glXSetCurrentContextNull(void)
141 __glXSetCurrentContext(&dummyContext
);
142 #if defined(GLX_DIRECT_RENDERING)
143 _glapi_set_dispatch(NULL
); /* no-op functions */
144 _glapi_set_context(NULL
);
149 glXGetCurrentContext(void)
151 struct glx_context
*cx
= __glXGetCurrentContext();
153 if (cx
== &dummyContext
) {
157 return (GLXContext
) cx
;
161 _X_EXPORT GLXDrawable
162 glXGetCurrentDrawable(void)
164 struct glx_context
*gc
= __glXGetCurrentContext();
165 return gc
->currentDrawable
;
169 __glXGenerateError(Display
* dpy
, XID resource
,
170 BYTE errorCode
, CARD16 minorCode
)
174 error
.errorCode
= errorCode
;
175 error
.resourceID
= resource
;
176 error
.sequenceNumber
= dpy
->request
;
177 error
.type
= X_Error
;
178 error
.majorCode
= __glXSetupForCommand(dpy
);
179 error
.minorCode
= minorCode
;
180 _XError(dpy
, &error
);
184 * Make a particular context current.
186 * \note This is in this file so that it can access dummyContext.
189 MakeContextCurrent(Display
* dpy
, GLXDrawable draw
,
190 GLXDrawable read
, GLXContext gc_user
)
192 struct glx_context
*gc
= (struct glx_context
*) gc_user
;
193 struct glx_context
*oldGC
= __glXGetCurrentContext();
195 /* Make sure that the new context has a nonzero ID. In the request,
196 * a zero context ID is used only to mean that we bind to no current
199 if ((gc
!= NULL
) && (gc
->xid
== None
)) {
203 _glapi_check_multithread();
207 gc
->currentDrawable
== draw
&& gc
->currentReadable
== read
) {
212 if (oldGC
!= &dummyContext
) {
213 if (--oldGC
->thread_refcount
== 0) {
214 oldGC
->vtable
->unbind(oldGC
, gc
);
215 oldGC
->currentDpy
= 0;
220 /* Attempt to bind the context. We do this before mucking with
221 * gc and __glXSetCurrentContext to properly handle our state in
224 * If an error occurs, set the Null context since we've already
225 * blown away our old context. The caller is responsible for
226 * figuring out how to handle setting a valid context.
228 if (gc
->vtable
->bind(gc
, oldGC
, draw
, read
) != Success
) {
229 __glXSetCurrentContextNull();
231 __glXGenerateError(dpy
, None
, GLXBadContext
, X_GLXMakeContextCurrent
);
235 if (gc
->thread_refcount
== 0) {
236 gc
->currentDpy
= dpy
;
237 gc
->currentDrawable
= draw
;
238 gc
->currentReadable
= read
;
240 gc
->thread_refcount
++;
241 __glXSetCurrentContext(gc
);
243 __glXSetCurrentContextNull();
246 if (oldGC
->thread_refcount
== 0 && oldGC
!= &dummyContext
&& oldGC
->xid
== None
) {
247 /* We are switching away from a context that was
248 * previously destroyed, so we need to free the memory
249 * for the old handle. */
250 oldGC
->vtable
->destroy(oldGC
);
260 glXMakeCurrent(Display
* dpy
, GLXDrawable draw
, GLXContext gc
)
262 return MakeContextCurrent(dpy
, draw
, draw
, gc
);
266 GLX_ALIAS(Bool
, glXMakeCurrentReadSGI
,
267 (Display
* dpy
, GLXDrawable d
, GLXDrawable r
, GLXContext ctx
),
268 (dpy
, d
, r
, ctx
), MakeContextCurrent
)
271 GLX_ALIAS(Bool
, glXMakeContextCurrent
,
272 (Display
* dpy
, GLXDrawable d
, GLXDrawable r
,
273 GLXContext ctx
), (dpy
, d
, r
, ctx
), MakeContextCurrent
)