1 /* 2 * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008) 3 * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice including the dates of first publication and 13 * either this permission notice or a reference to 14 * http://oss.sgi.com/projects/FreeB/ 15 * shall be included in all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 20 * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 21 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF 22 * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 23 * SOFTWARE. 24 * 25 * Except as contained in this notice, the name of Silicon Graphics, Inc. 26 * shall not be used in advertising or otherwise to promote the sale, use or 27 * other dealings in this Software without prior written authorization from 28 * Silicon Graphics, Inc. 29 */ 30 31 /** 32 * \file glxcurrent.c 33 * Client-side GLX interface for current context management. 34 */ 35 36 #include <pthread.h> 37 38 #include "glxclient.h" 39 #include "glapi.h" 40 #include "glx_error.h" 41 42 /* 43 ** We setup some dummy structures here so that the API can be used 44 ** even if no context is current. 45 */ 46 47 static GLubyte dummyBuffer[__GLX_BUFFER_LIMIT_SIZE]; 48 static struct glx_context_vtable dummyVtable; 49 /* 50 ** Dummy context used by small commands when there is no current context. 51 ** All the 52 ** gl and glx entry points are designed to operate as nop's when using 53 ** the dummy context structure. 54 */ 55 struct glx_context dummyContext = { 56 &dummyBuffer[0], 57 &dummyBuffer[0], 58 &dummyBuffer[0], 59 &dummyBuffer[__GLX_BUFFER_LIMIT_SIZE], 60 sizeof(dummyBuffer), 61 &dummyVtable 62 }; 63 64 /* 65 * Current context management and locking 66 */ 67 68 _X_HIDDEN pthread_mutex_t __glXmutex = PTHREAD_MUTEX_INITIALIZER; 69 70 # if defined( GLX_USE_TLS ) 71 72 /** 73 * Per-thread GLX context pointer. 74 * 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. 78 */ 79 __thread void *__glX_tls_Context __attribute__ ((tls_model("initial-exec"))) 80 = &dummyContext; 81 82 _X_HIDDEN void 83 __glXSetCurrentContext(struct glx_context * c) 84 { 85 __glX_tls_Context = (c != NULL) ? c : &dummyContext; 86 } 87 88 # else 89 90 static pthread_once_t once_control = PTHREAD_ONCE_INIT; 91 92 /** 93 * Per-thread data key. 94 * 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. 98 */ 99 static pthread_key_t ContextTSD; 100 101 /** 102 * Initialize the per-thread data key. 103 * 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. 107 */ 108 static void 109 init_thread_data(void) 110 { 111 if (pthread_key_create(&ContextTSD, NULL) != 0) { 112 perror("pthread_key_create"); 113 exit(-1); 114 } 115 } 116 117 _X_HIDDEN void 118 __glXSetCurrentContext(struct glx_context * c) 119 { 120 pthread_once(&once_control, init_thread_data); 121 pthread_setspecific(ContextTSD, c); 122 } 123 124 _X_HIDDEN struct glx_context * 125 __glXGetCurrentContext(void) 126 { 127 void *v; 128 129 pthread_once(&once_control, init_thread_data); 130 131 v = pthread_getspecific(ContextTSD); 132 return (v == NULL) ? &dummyContext : (struct glx_context *) v; 133 } 134 135 # endif /* defined( GLX_USE_TLS ) */ 136 137 138 _X_HIDDEN void 139 __glXSetCurrentContextNull(void) 140 { 141 __glXSetCurrentContext(&dummyContext); 142 #if defined(GLX_DIRECT_RENDERING) 143 _glapi_set_dispatch(NULL); /* no-op functions */ 144 _glapi_set_context(NULL); 145 #endif 146 } 147 148 _GLX_PUBLIC GLXContext 149 glXGetCurrentContext(void) 150 { 151 struct glx_context *cx = __glXGetCurrentContext(); 152 153 if (cx == &dummyContext) { 154 return NULL; 155 } 156 else { 157 return (GLXContext) cx; 158 } 159 } 160 161 _GLX_PUBLIC GLXDrawable 162 glXGetCurrentDrawable(void) 163 { 164 struct glx_context *gc = __glXGetCurrentContext(); 165 return gc->currentDrawable; 166 } 167 168 /** 169 * Make a particular context current. 170 * 171 * \note This is in this file so that it can access dummyContext. 172 */ 173 static Bool 174 MakeContextCurrent(Display * dpy, GLXDrawable draw, 175 GLXDrawable read, GLXContext gc_user) 176 { 177 struct glx_context *gc = (struct glx_context *) gc_user; 178 struct glx_context *oldGC = __glXGetCurrentContext(); 179 180 /* Make sure that the new context has a nonzero ID. In the request, 181 * a zero context ID is used only to mean that we bind to no current 182 * context. 183 */ 184 if ((gc != NULL) && (gc->xid == None)) { 185 return GL_FALSE; 186 } 187 188 _glapi_check_multithread(); 189 190 __glXLock(); 191 if (oldGC == gc && 192 gc->currentDrawable == draw && gc->currentReadable == read) { 193 __glXUnlock(); 194 return True; 195 } 196 197 if (oldGC != &dummyContext) { 198 if (--oldGC->thread_refcount == 0) { 199 oldGC->vtable->unbind(oldGC, gc); 200 oldGC->currentDpy = 0; 201 } 202 } 203 204 if (gc) { 205 /* Attempt to bind the context. We do this before mucking with 206 * gc and __glXSetCurrentContext to properly handle our state in 207 * case of an error. 208 * 209 * If an error occurs, set the Null context since we've already 210 * blown away our old context. The caller is responsible for 211 * figuring out how to handle setting a valid context. 212 */ 213 if (gc->vtable->bind(gc, oldGC, draw, read) != Success) { 214 __glXSetCurrentContextNull(); 215 __glXUnlock(); 216 __glXSendError(dpy, GLXBadContext, None, X_GLXMakeContextCurrent, 217 False); 218 return GL_FALSE; 219 } 220 221 if (gc->thread_refcount == 0) { 222 gc->currentDpy = dpy; 223 gc->currentDrawable = draw; 224 gc->currentReadable = read; 225 } 226 gc->thread_refcount++; 227 __glXSetCurrentContext(gc); 228 } else { 229 __glXSetCurrentContextNull(); 230 } 231 232 if (oldGC->thread_refcount == 0 && oldGC != &dummyContext && oldGC->xid == None) { 233 /* We are switching away from a context that was 234 * previously destroyed, so we need to free the memory 235 * for the old handle. */ 236 oldGC->vtable->destroy(oldGC); 237 } 238 239 __glXUnlock(); 240 241 /* The indirect vertex array state must to be initialised after we 242 * have setup the context, as it needs to query server attributes. 243 */ 244 if (gc && !gc->isDirect) { 245 __GLXattribute *state = gc->client_state_private; 246 if (state && state->array_state == NULL) { 247 glGetString(GL_EXTENSIONS); 248 glGetString(GL_VERSION); 249 __glXInitVertexArrayState(gc); 250 } 251 } 252 253 return GL_TRUE; 254 } 255 256 257 _GLX_PUBLIC Bool 258 glXMakeCurrent(Display * dpy, GLXDrawable draw, GLXContext gc) 259 { 260 return MakeContextCurrent(dpy, draw, draw, gc); 261 } 262 263 _GLX_PUBLIC 264 GLX_ALIAS(Bool, glXMakeCurrentReadSGI, 265 (Display * dpy, GLXDrawable d, GLXDrawable r, GLXContext ctx), 266 (dpy, d, r, ctx), MakeContextCurrent) 267 268 _GLX_PUBLIC 269 GLX_ALIAS(Bool, glXMakeContextCurrent, 270 (Display * dpy, GLXDrawable d, GLXDrawable r, 271 GLXContext ctx), (dpy, d, r, ctx), MakeContextCurrent) 272