Simplified glXGetProcAddress logic.

Removed compile-time selection of GLX entry point retrieval mechanism.
Made dlopen a required dependency.

This is a stopgap solution until we start requiring GLX 1.4.

CMakeLists.txt

@@ -372,25 +372,10 @@ if (_GLFW_GLX)
 
     list(APPEND glfw_PKG_DEPS "gl")
 
-    include(CheckFunctionExists)
-
-    set(CMAKE_REQUIRED_LIBRARIES "${OPENGL_gl_LIBRARY}")
-    check_function_exists(glXGetProcAddress _GLFW_HAS_GLXGETPROCADDRESS)
-    check_function_exists(glXGetProcAddressARB _GLFW_HAS_GLXGETPROCADDRESSARB)
-    check_function_exists(glXGetProcAddressEXT _GLFW_HAS_GLXGETPROCADDRESSEXT)
-
-    if (NOT _GLFW_HAS_GLXGETPROCADDRESS AND
-        NOT _GLFW_HAS_GLXGETPROCADDRESSARB AND
-        NOT _GLFW_HAS_GLXGETPROCADDRESSEXT)
-        message(WARNING "No glXGetProcAddressXXX variant found")
-
-        set(_GLFW_HAS_DLOPEN 1)
-        if (CMAKE_DL_LIBS)
-            list(APPEND glfw_LIBRARIES "${CMAKE_DL_LIBS}")
-            list(APPEND glfw_PKG_LIBS "-l${CMAKE_DL_LIBS}")
-        endif()
+    if (CMAKE_DL_LIBS)
+        list(APPEND glfw_LIBRARIES "${CMAKE_DL_LIBS}")
+        list(APPEND glfw_PKG_LIBS "-l${CMAKE_DL_LIBS}")
     endif()
-
 endif()
 
 #--------------------------------------------------------------------

README.md

@@ -72,6 +72,9 @@ GLFW bundles a number of dependencies in the `deps/` directory.
  - [Cocoa] Bugfix: Resizing a window to its minimum size would segfault
  - [Cocoa] Bugfix: Creating or showing a window would make its context current
  - [X11] Bugfix: `glfwInit` would segfault on systems without RandR
+ - [GLX] Added dependency on `libdl` on systems where it provides `dlopen`
+ - [GLX] Removed `_GLFW_HAS_GLXGETPROCADDRESS*` and `_GLFW_HAS_DLOPEN`
+         compile-time options
 
 
 ## Contact

docs/compile.dox

@@ -288,15 +288,8 @@ libraries.
 If you are building GLFW as a shared library / dynamic library / DLL then you
 must also define `_GLFW_BUILD_DLL`.  Otherwise, you may not define it.
 
-If you are using the X11 window creation API then you _must_ also select an entry
-point retrieval mechanism.
-
- - `_GLFW_HAS_GLXGETPROCADDRESS` to use `glXGetProcAddress` (recommended)
- - `_GLFW_HAS_GLXGETPROCADDRESSARB` to use `glXGetProcAddressARB` (legacy)
- - `_GLFW_HAS_GLXGETPROCADDRESSEXT` to use `glXGetProcAddressEXT` (legacy)
- - `_GLFW_HAS_DLOPEN` to do manual retrieval with `dlopen` (fallback)
-
-In addition, support for the following X11 extensions can be enabled:
+If you are using the X11 window creation API, support for the following X11
+extensions can be enabled:
 
  - `_GLFW_HAS_XINPUT` to use XInput2 for high-resolution cursor motion
  (recommended)

src/egl_context.h

@@ -35,11 +35,6 @@
 // extensions and not all operating systems come with an up-to-date version
 #include "../deps/EGL/eglext.h"
 
-// Do we have support for dlopen/dlsym?
-#if defined(_GLFW_HAS_DLOPEN)
- #include <dlfcn.h>
-#endif
-
 #define _GLFW_PLATFORM_FBCONFIG                 EGLConfig       egl
 #define _GLFW_PLATFORM_CONTEXT_STATE            _GLFWcontextEGL egl
 #define _GLFW_PLATFORM_LIBRARY_CONTEXT_STATE    _GLFWlibraryEGL egl

src/glfw_config.h.in

@@ -64,14 +64,6 @@
 #cmakedefine _GLFW_HAS_XINPUT
 // Define this to 1 if the Xxf86vm X11 extension is available
 #cmakedefine _GLFW_HAS_XF86VM
-// Define this to 1 if glXGetProcAddress is available
-#cmakedefine _GLFW_HAS_GLXGETPROCADDRESS
-// Define this to 1 if glXGetProcAddressARB is available
-#cmakedefine _GLFW_HAS_GLXGETPROCADDRESSARB
-// Define this to 1 if glXGetProcAddressEXT is available
-#cmakedefine _GLFW_HAS_GLXGETPROCADDRESSEXT
-// Define this to 1 if dlopen is available
-#cmakedefine _GLFW_HAS_DLOPEN
 
 // Define this to 1 if glfwInit should change the current directory
 #cmakedefine _GLFW_USE_CHDIR

src/glx_context.c

@@ -30,11 +30,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <assert.h>
-
-
-// This is the only glXGetProcAddress variant not declared by glxext.h
-void (*glXGetProcAddressEXT(const GLubyte* procName))();
-
+#include <dlfcn.h>
 
 #ifndef GLXBadProfileARB
  #define GLXBadProfileARB 13
@@ -163,14 +159,17 @@ int _glfwInitContextAPI(void)
     if (!_glfwInitTLS())
         return GL_FALSE;
 
-#ifdef _GLFW_DLOPEN_LIBGL
-    _glfw.glx.libGL = dlopen("libGL.so.1", RTLD_LAZY | RTLD_GLOBAL);
-    if (!_glfw.glx.libGL)
+    _glfw.glx.handle = dlopen("libGL.so.1", RTLD_LAZY | RTLD_GLOBAL);
+    if (!_glfw.glx.handle)
     {
-        _glfwInputError(GLFW_API_UNAVAILABLE, "GLX: Failed to find libGL");
+        _glfwInputError(GLFW_API_UNAVAILABLE, "GLX: %s", dlerror());
         return GL_FALSE;
     }
-#endif
+
+    _glfw.glx.GetProcAddress =
+        dlsym(_glfw.glx.handle, "glXGetProcAddress");
+    _glfw.glx.GetProcAddressARB =
+        dlsym(_glfw.glx.handle, "glXGetProcAddressARB");
 
     if (!glXQueryExtension(_glfw.x11.display,
                            &_glfw.glx.errorBase,
@@ -257,14 +256,11 @@ int _glfwInitContextAPI(void)
 //
 void _glfwTerminateContextAPI(void)
 {
-    // Unload libGL.so if necessary
-#ifdef _GLFW_DLOPEN_LIBGL
-    if (_glfw.glx.libGL != NULL)
+    if (_glfw.glx.handle)
     {
-        dlclose(_glfw.glx.libGL);
-        _glfw.glx.libGL = NULL;
+        dlclose(_glfw.glx.handle);
+        _glfw.glx.handle = NULL;
     }
-#endif
 
     _glfwTerminateTLS();
 }
@@ -527,7 +523,12 @@ int _glfwPlatformExtensionSupported(const char* extension)
 
 GLFWglproc _glfwPlatformGetProcAddress(const char* procname)
 {
-    return _glfw_glXGetProcAddress((const GLubyte*) procname);
+    if (_glfw.glx.GetProcAddress)
+        return _glfw.glx.GetProcAddress((const GLubyte*) procname);
+    else if (_glfw.glx.GetProcAddressARB)
+        return _glfw.glx.GetProcAddressARB((const GLubyte*) procname);
+    else
+        return dlsym(_glfw.glx.handle, procname);
 }
 
 

src/glx_context.h

@@ -34,29 +34,9 @@
 // This path may need to be changed if you build GLFW using your own setup
 // We ship and use our own copy of glxext.h since GLFW uses fairly new
 // extensions and not all operating systems come with an up-to-date version
+#define GLX_GLXEXT_PROTOTYPES
 #include "../deps/GL/glxext.h"
 
-// Do we have support for dlopen/dlsym?
-#if defined(_GLFW_HAS_DLOPEN)
- #include <dlfcn.h>
-#endif
-
-// We support four different ways for getting addresses for GL/GLX
-// extension functions: glXGetProcAddress, glXGetProcAddressARB,
-// glXGetProcAddressEXT, and dlsym
-#if defined(_GLFW_HAS_GLXGETPROCADDRESSARB)
- #define _glfw_glXGetProcAddress(x) glXGetProcAddressARB(x)
-#elif defined(_GLFW_HAS_GLXGETPROCADDRESS)
- #define _glfw_glXGetProcAddress(x) glXGetProcAddress(x)
-#elif defined(_GLFW_HAS_GLXGETPROCADDRESSEXT)
- #define _glfw_glXGetProcAddress(x) glXGetProcAddressEXT(x)
-#elif defined(_GLFW_HAS_DLOPEN)
- #define _glfw_glXGetProcAddress(x) dlsym(_glfw.glx.libGL, x)
- #define _GLFW_DLOPEN_LIBGL
-#else
- #error "No OpenGL entry point retrieval mechanism was enabled"
-#endif
-
 #define _GLFW_PLATFORM_FBCONFIG                 GLXFBConfig     glx
 #define _GLFW_PLATFORM_CONTEXT_STATE            _GLFWcontextGLX glx
 #define _GLFW_PLATFORM_LIBRARY_CONTEXT_STATE    _GLFWlibraryGLX glx
@@ -86,7 +66,12 @@ typedef struct _GLFWlibraryGLX
     int             eventBase;
     int             errorBase;
 
+    // dlopen handle for libGL.so.1
+    void*           handle;
+
     // GLX extensions
+    PFNGLXGETPROCADDRESSPROC              GetProcAddress;
+    PFNGLXGETPROCADDRESSPROC              GetProcAddressARB;
     PFNGLXSWAPINTERVALSGIPROC             SwapIntervalSGI;
     PFNGLXSWAPINTERVALEXTPROC             SwapIntervalEXT;
     PFNGLXSWAPINTERVALMESAPROC            SwapIntervalMESA;
@@ -102,11 +87,6 @@ typedef struct _GLFWlibraryGLX
     GLboolean       EXT_create_context_es2_profile;
     GLboolean       ARB_context_flush_control;
 
-#if defined(_GLFW_DLOPEN_LIBGL)
-    // dlopen handle for libGL.so (for glfwGetProcAddress)
-    void*           libGL;
-#endif
-
 } _GLFWlibraryGLX;
 
 

src/x11_init.c

@@ -797,15 +797,6 @@ const char* _glfwPlatformGetVersionString(void)
 #elif defined(_GLFW_EGL)
         " EGL"
 #endif
-#if defined(_GLFW_HAS_GLXGETPROCADDRESS)
-        " glXGetProcAddress"
-#elif defined(_GLFW_HAS_GLXGETPROCADDRESSARB)
-        " glXGetProcAddressARB"
-#elif defined(_GLFW_HAS_GLXGETPROCADDRESSEXT)
-        " glXGetProcAddressEXT"
-#elif defined(_GLFW_DLOPEN_LIBGL)
-        " dlsym(libGL)"
-#endif
 #if defined(_POSIX_TIMERS) && defined(_POSIX_MONOTONIC_CLOCK)
         " clock_gettime"
 #endif