/* * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008) * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice including the dates of first publication and * either this permission notice or a reference to * http://oss.sgi.com/projects/FreeB/ * shall be included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * * Except as contained in this notice, the name of Silicon Graphics, Inc. * shall not be used in advertising or otherwise to promote the sale, use or * other dealings in this Software without prior written authorization from * Silicon Graphics, Inc. */ /** * \file glxcurrent.c * Client-side GLX interface for current context management. */ #ifdef HAVE_PTHREAD #include <pthread.h> #endif #include "glxclient.h" #include "glapi.h" /* ** We setup some dummy structures here so that the API can be used ** even if no context is current. */ static GLubyte dummyBuffer[__GLX_BUFFER_LIMIT_SIZE]; static struct glx_context_vtable dummyVtable; /* ** Dummy context used by small commands when there is no current context. ** All the ** gl and glx entry points are designed to operate as nop's when using ** the dummy context structure. */ struct glx_context dummyContext = { &dummyBuffer[0], &dummyBuffer[0], &dummyBuffer[0], &dummyBuffer[__GLX_BUFFER_LIMIT_SIZE], sizeof(dummyBuffer), &dummyVtable }; /* * Current context management and locking */ #if defined( HAVE_PTHREAD ) _X_HIDDEN pthread_mutex_t __glXmutex = PTHREAD_MUTEX_INITIALIZER; # if defined( GLX_USE_TLS ) /** * Per-thread GLX context pointer. * * \c __glXSetCurrentContext is written is such a way that this pointer can * \b never be \c NULL. This is important! Because of this * \c __glXGetCurrentContext can be implemented as trivial macro. */ __thread void *__glX_tls_Context __attribute__ ((tls_model("initial-exec"))) = &dummyContext; _X_HIDDEN void __glXSetCurrentContext(struct glx_context * c) { __glX_tls_Context = (c != NULL) ? c : &dummyContext; } # else static pthread_once_t once_control = PTHREAD_ONCE_INIT; /** * Per-thread data key. * * Once \c init_thread_data has been called, the per-thread data key will * take a value of \c NULL. As each new thread is created the default * value, in that thread, will be \c NULL. */ static pthread_key_t ContextTSD; /** * Initialize the per-thread data key. * * This function is called \b exactly once per-process (not per-thread!) to * initialize the per-thread data key. This is ideally done using the * \c pthread_once mechanism. */ static void init_thread_data(void) { if (pthread_key_create(&ContextTSD, NULL) != 0) { perror("pthread_key_create"); exit(-1); } } _X_HIDDEN void __glXSetCurrentContext(struct glx_context * c) { pthread_once(&once_control, init_thread_data); pthread_setspecific(ContextTSD, c); } _X_HIDDEN struct glx_context * __glXGetCurrentContext(void) { void *v; pthread_once(&once_control, init_thread_data); v = pthread_getspecific(ContextTSD); return (v == NULL) ? &dummyContext : (struct glx_context *) v; } # endif /* defined( GLX_USE_TLS ) */ #elif defined( THREADS ) #error Unknown threading method specified. #else /* not thread safe */ _X_HIDDEN struct glx_context *__glXcurrentContext = &dummyContext; #endif _X_HIDDEN void __glXSetCurrentContextNull(void) { __glXSetCurrentContext(&dummyContext); #if defined(GLX_DIRECT_RENDERING) _glapi_set_dispatch(NULL); /* no-op functions */ _glapi_set_context(NULL); #endif } _X_EXPORT GLXContext glXGetCurrentContext(void) { struct glx_context *cx = __glXGetCurrentContext(); if (cx == &dummyContext) { return NULL; } else { return (GLXContext) cx; } } _X_EXPORT GLXDrawable glXGetCurrentDrawable(void) { struct glx_context *gc = __glXGetCurrentContext(); return gc->currentDrawable; } static void __glXGenerateError(Display * dpy, XID resource, BYTE errorCode, CARD16 minorCode) { xError error; error.errorCode = errorCode; error.resourceID = resource; error.sequenceNumber = dpy->request; error.type = X_Error; error.majorCode = __glXSetupForCommand(dpy); error.minorCode = minorCode; _XError(dpy, &error); } /** * Make a particular context current. * * \note This is in this file so that it can access dummyContext. */ static Bool MakeContextCurrent(Display * dpy, GLXDrawable draw, GLXDrawable read, GLXContext gc_user) { struct glx_context *gc = (struct glx_context *) gc_user; struct glx_context *oldGC = __glXGetCurrentContext(); /* Make sure that the new context has a nonzero ID. In the request, * a zero context ID is used only to mean that we bind to no current * context. */ if ((gc != NULL) && (gc->xid == None)) { return GL_FALSE; } _glapi_check_multithread(); __glXLock(); if (oldGC == gc && gc->currentDrawable == draw && gc->currentReadable == read) { __glXUnlock(); return True; } if (oldGC != &dummyContext) { if (--oldGC->thread_refcount == 0) { oldGC->vtable->unbind(oldGC, gc); oldGC->currentDpy = 0; } } if (gc) { /* Attempt to bind the context. We do this before mucking with * gc and __glXSetCurrentContext to properly handle our state in * case of an error. * * If an error occurs, set the Null context since we've already * blown away our old context. The caller is responsible for * figuring out how to handle setting a valid context. */ if (gc->vtable->bind(gc, oldGC, draw, read) != Success) { __glXSetCurrentContextNull(); __glXUnlock(); __glXGenerateError(dpy, None, GLXBadContext, X_GLXMakeContextCurrent); return GL_FALSE; } if (gc->thread_refcount == 0) { gc->currentDpy = dpy; gc->currentDrawable = draw; gc->currentReadable = read; } gc->thread_refcount++; __glXSetCurrentContext(gc); } else { __glXSetCurrentContextNull(); } if (oldGC->thread_refcount == 0 && oldGC != &dummyContext && oldGC->xid == None) { /* We are switching away from a context that was * previously destroyed, so we need to free the memory * for the old handle. */ oldGC->vtable->destroy(oldGC); } __glXUnlock(); return GL_TRUE; } _X_EXPORT Bool glXMakeCurrent(Display * dpy, GLXDrawable draw, GLXContext gc) { return MakeContextCurrent(dpy, draw, draw, gc); } _X_EXPORT GLX_ALIAS(Bool, glXMakeCurrentReadSGI, (Display * dpy, GLXDrawable d, GLXDrawable r, GLXContext ctx), (dpy, d, r, ctx), MakeContextCurrent) _X_EXPORT GLX_ALIAS(Bool, glXMakeContextCurrent, (Display * dpy, GLXDrawable d, GLXDrawable r, GLXContext ctx), (dpy, d, r, ctx), MakeContextCurrent)