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      1 /*
      2  Copyright (c) 2008 Apple Inc.
      3 
      4  Permission is hereby granted, free of charge, to any person
      5  obtaining a copy of this software and associated documentation files
      6  (the "Software"), to deal in the Software without restriction,
      7  including without limitation the rights to use, copy, modify, merge,
      8  publish, distribute, sublicense, and/or sell copies of the Software,
      9  and to permit persons to whom the Software is furnished to do so,
     10  subject to the following conditions:
     11 
     12  The above copyright notice and this permission notice shall be
     13  included in all copies or substantial portions of the Software.
     14 
     15  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     16  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     17  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     18  NONINFRINGEMENT.  IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT
     19  HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
     20  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     21  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     22  DEALINGS IN THE SOFTWARE.
     23 
     24  Except as contained in this notice, the name(s) of the above
     25  copyright holders shall not be used in advertising or otherwise to
     26  promote the sale, use or other dealings in this Software without
     27  prior written authorization.
     28 */
     29 
     30 #include <stdbool.h>
     31 #include <stdio.h>
     32 #include <stdlib.h>
     33 #include <dlfcn.h>
     34 
     35 #include "apple_cgl.h"
     36 #include "apple_glx.h"
     37 
     38 #ifndef OPENGL_FRAMEWORK_PATH
     39 #define OPENGL_FRAMEWORK_PATH "/System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL"
     40 #endif
     41 
     42 static void *dl_handle = NULL;
     43 
     44 struct apple_cgl_api apple_cgl;
     45 
     46 static bool initialized = false;
     47 
     48 static void *
     49 sym(void *h, const char *name)
     50 {
     51    void *s;
     52 
     53    s = dlsym(h, name);
     54 
     55    if (NULL == s) {
     56       fprintf(stderr, "error: %s\n", dlerror());
     57       abort();
     58    }
     59 
     60    return s;
     61 }
     62 
     63 void
     64 apple_cgl_init(void)
     65 {
     66    void *h;
     67    const char *opengl_framework_path;
     68 
     69    if (initialized)
     70       return;
     71 
     72    opengl_framework_path = getenv("OPENGL_FRAMEWORK_PATH");
     73    if (!opengl_framework_path) {
     74       opengl_framework_path = OPENGL_FRAMEWORK_PATH;
     75    }
     76 
     77    (void) dlerror();            /*drain dlerror */
     78    h = dlopen(opengl_framework_path, RTLD_NOW);
     79 
     80    if (NULL == h) {
     81       fprintf(stderr, "error: unable to dlopen %s : %s\n",
     82               opengl_framework_path, dlerror());
     83       abort();
     84    }
     85 
     86    dl_handle = h;
     87 
     88    apple_cgl.get_version = sym(h, "CGLGetVersion");
     89 
     90    apple_cgl.get_version(&apple_cgl.version_major, &apple_cgl.version_minor);
     91 
     92    apple_glx_diagnostic("CGL major %d minor %d\n", apple_cgl.version_major, apple_cgl.version_minor);
     93 
     94    if (1 != apple_cgl.version_major) {
     95       fprintf(stderr, "WARNING: the CGL major version has changed!\n"
     96               "libGL may be incompatible!\n");
     97    }
     98 
     99    apple_cgl.choose_pixel_format = sym(h, "CGLChoosePixelFormat");
    100    apple_cgl.destroy_pixel_format = sym(h, "CGLDestroyPixelFormat");
    101 
    102    apple_cgl.clear_drawable = sym(h, "CGLClearDrawable");
    103    apple_cgl.flush_drawable = sym(h, "CGLFlushDrawable");
    104 
    105    apple_cgl.create_context = sym(h, "CGLCreateContext");
    106    apple_cgl.destroy_context = sym(h, "CGLDestroyContext");
    107 
    108    apple_cgl.set_current_context = sym(h, "CGLSetCurrentContext");
    109    apple_cgl.get_current_context = sym(h, "CGLGetCurrentContext");
    110    apple_cgl.error_string = sym(h, "CGLErrorString");
    111 
    112    apple_cgl.set_off_screen = sym(h, "CGLSetOffScreen");
    113 
    114    apple_cgl.copy_context = sym(h, "CGLCopyContext");
    115 
    116    apple_cgl.create_pbuffer = sym(h, "CGLCreatePBuffer");
    117    apple_cgl.destroy_pbuffer = sym(h, "CGLDestroyPBuffer");
    118    apple_cgl.set_pbuffer = sym(h, "CGLSetPBuffer");
    119 
    120    initialized = true;
    121 }
    122 
    123 void *
    124 apple_cgl_get_dl_handle(void)
    125 {
    126    return dl_handle;
    127 }
    128