src/glx/create_context.c

   1 /*
   2  * Copyright © 2011 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #include <limits.h>
  25 #include "glxclient.h"
  26 #include "glx_error.h"
  27 #include <xcb/glx.h>
  28 #include <X11/Xlib-xcb.h>
  29
  30 #include <assert.h>
  31
  32 #if INT_MAX != 2147483647
  33 #error This code requires sizeof(uint32_t) == sizeof(int).
  34 #endif
  35
  36 /* debian stretch still has ancient headers and we're apparently still
  37  * using that for gitlab ci. please delete me when that's fixed.
  38  */
  39 #ifndef X_GLXCreateContextAttribsARB
  40 #warning Please update your GLX protocol headers
  41 #define X_GLXCreateContextAttribsARB 34
  42 #endif
  43
  44 _X_HIDDEN GLXContext
  45 glXCreateContextAttribsARB(Display *dpy, GLXFBConfig config,
  46                            GLXContext share_context, Bool direct,
  47                            const int *attrib_list)
  48 {
  49    xcb_connection_t *const c = XGetXCBConnection(dpy);
  50    struct glx_config *const cfg = (struct glx_config *) config;
  51    struct glx_context *const share = (struct glx_context *) share_context;
  52    struct glx_context *gc = NULL;
  53    unsigned num_attribs = 0;
  54    struct glx_screen *psc;
  55    xcb_generic_error_t *err;
  56    xcb_void_cookie_t cookie;
  57    unsigned dummy_err = 0;
  58    int screen = -1;
  59
  60    if (dpy == NULL)
  61       return NULL;
  62
  63    /* Count the number of attributes specified by the application.  All
  64     * attributes appear in pairs, except the terminating None.
  65     */
  66    if (attrib_list != NULL) {
  67       for (/* empty */; attrib_list[num_attribs * 2] != 0; num_attribs++)
  68          /* empty */ ;
  69    }
  70
  71    if (cfg) {
  72       screen = cfg->screen;
  73    } else {
  74       for (unsigned int i = 0; i < num_attribs; i++) {
  75          if (attrib_list[i * 2] == GLX_SCREEN)
  76             screen = attrib_list[i * 2 + 1];
  77       }
  78       if (screen == -1) {
  79          __glXSendError(dpy, BadValue, 0, X_GLXCreateContextAttribsARB, True);
  80          return NULL;
  81       }
  82    }
  83
  84    /* This means that either the caller passed the wrong display pointer or
  85     * one of the internal GLX data structures (probably the fbconfig) has an
  86     * error.  There is nothing sensible to do, so return an error.
  87     */
  88    psc = GetGLXScreenConfigs(dpy, screen);
  89    if (psc == NULL)
  90       return NULL;
  91
  92    assert(screen == psc->scr);
  93
  94    if (direct && psc->vtable->create_context_attribs) {
  95       /* GLX drops the error returned by the driver.  The expectation is that
  96        * an error will also be returned by the server.  The server's error
  97        * will be delivered to the application.
  98        */
  99       gc = psc->vtable->create_context_attribs(psc, cfg, share, num_attribs,
 100                                                (const uint32_t *) attrib_list,
 101                                                &dummy_err);
 102    }
 103
 104    if (gc == NULL) {
 105 #ifdef GLX_USE_APPLEGL
 106       gc = applegl_create_context(psc, cfg, share, 0);
 107 #else
 108       gc = indirect_create_context_attribs(psc, cfg, share, num_attribs,
 109               (const uint32_t *) attrib_list,
 110               &dummy_err);
 111 #endif
 112    }
 113
 114    gc->xid = xcb_generate_id(c);
 115    gc->share_xid = (share != NULL) ? share->xid : 0;
 116
 117    /* The manual pages for glXCreateContext and glXCreateNewContext say:
 118     *
 119     *     "NULL is returned if execution fails on the client side."
 120     *
 121     * If the server generates an error, the application is supposed to catch
 122     * the protocol error and handle it.  Part of handling the error is freeing
 123     * the possibly non-NULL value returned by this function.
 124     */
 125    cookie =
 126       xcb_glx_create_context_attribs_arb_checked(c,
 127                                                  gc->xid,
 128                                                  cfg ? cfg->fbconfigID : 0,
 129                                                  screen,
 130                                                  gc->share_xid,
 131                                                  gc->isDirect,
 132                                                  num_attribs,
 133                                                  (const uint32_t *)
 134                                                  attrib_list);
 135    err = xcb_request_check(c, cookie);
 136    if (err != NULL) {
 137       gc->vtable->destroy(gc);
 138       gc = NULL;
 139
 140       __glXSendErrorForXcb(dpy, err);
 141       free(err);
 142    }
 143
 144    return (GLXContext) gc;
 145 }