From 0d483a1c89f6cafe61db858e490c472ee8063542 Mon Sep 17 00:00:00 2001 From: ocornut Date: Tue, 7 May 2024 18:23:29 +0200 Subject: [PATCH] Backends: OpenGL3: Update loader for Linux to support EGL/GLVND. (#7562) + #6983 --- backends/imgui_impl_opengl3.cpp | 1 + backends/imgui_impl_opengl3_loader.h | 114 ++++++++++++++++++++++++--- docs/CHANGELOG.txt | 1 + 3 files changed, 105 insertions(+), 11 deletions(-) diff --git a/backends/imgui_impl_opengl3.cpp b/backends/imgui_impl_opengl3.cpp index ff18a763109c..2d492f750053 100644 --- a/backends/imgui_impl_opengl3.cpp +++ b/backends/imgui_impl_opengl3.cpp @@ -22,6 +22,7 @@ // CHANGELOG // (minor and older changes stripped away, please see git history for details) +// 2024-05-07: OpenGL: Update loader for Linux to support EGL/GLVND. (#7562) // 2024-04-16: OpenGL: Detect ES3 contexts on desktop based on version string, to e.g. avoid calling glPolygonMode() on them. (#7447) // 2024-01-09: OpenGL: Update GL3W based imgui_impl_opengl3_loader.h to load "libGL.so" and variants, fixing regression on distros missing a symlink. // 2023-11-08: OpenGL: Update GL3W based imgui_impl_opengl3_loader.h to load "libGL.so" instead of "libGL.so.1", accommodating for NetBSD systems having only "libGL.so.3" available. (#6983) diff --git a/backends/imgui_impl_opengl3_loader.h b/backends/imgui_impl_opengl3_loader.h index 271e157ac803..71d19f83d5ce 100644 --- a/backends/imgui_impl_opengl3_loader.h +++ b/backends/imgui_impl_opengl3_loader.h @@ -665,31 +665,123 @@ static GL3WglProc get_proc(const char *proc) #else #include -static void *libgl; -static GL3WglProc (*glx_get_proc_address)(const GLubyte *); +static void* libgl; // OpenGL library +static void* libglx; // GLX library +static void* libegl; // EGL library +static GL3WGetProcAddressProc gl_get_proc_address; -static int open_libgl(void) +static void close_libgl(void) { + if (libgl) { + dlclose(libgl); + libgl = NULL; + } + if (libegl) { + dlclose(libegl); + libegl = NULL; + } + if (libglx) { + dlclose(libglx); + libglx = NULL; + } +} + +static int is_library_loaded(const char* name, void** lib) +{ + *lib = dlopen(name, RTLD_LAZY | RTLD_LOCAL | RTLD_NOLOAD); + return *lib != NULL; +} + +static int open_libs(void) +{ + // On Linux we have two APIs to get process addresses: EGL and GLX. + // EGL is supported under both X11 and Wayland, whereas GLX is X11-specific. + + libgl = NULL; + libegl = NULL; + libglx = NULL; + + // First check what's already loaded, the windowing library might have + // already loaded either EGL or GLX and we want to use the same one. + + if (is_library_loaded("libEGL.so.1", &libegl) || + is_library_loaded("libGLX.so.0", &libglx)) { + libgl = dlopen("libOpenGL.so.0", RTLD_LAZY | RTLD_LOCAL); + if (libgl) + return GL3W_OK; + else + close_libgl(); + } + + if (is_library_loaded("libGL.so", &libgl)) + return GL3W_OK; + if (is_library_loaded("libGL.so.1", &libgl)) + return GL3W_OK; + if (is_library_loaded("libGL.so.3", &libgl)) + return GL3W_OK; + + // Neither is already loaded, so we have to load one. Try EGL first + // because it is supported under both X11 and Wayland. + + // Load OpenGL + EGL + libgl = dlopen("libOpenGL.so.0", RTLD_LAZY | RTLD_LOCAL); + libegl = dlopen("libEGL.so.1", RTLD_LAZY | RTLD_LOCAL); + if (libgl && libegl) + return GL3W_OK; + else + close_libgl(); + + // Fall back to legacy libGL, which includes GLX // While most systems use libGL.so.1, NetBSD seems to use that libGL.so.3. See https://github.com/ocornut/imgui/issues/6983 libgl = dlopen("libGL.so", RTLD_LAZY | RTLD_LOCAL); if (!libgl) libgl = dlopen("libGL.so.1", RTLD_LAZY | RTLD_LOCAL); if (!libgl) libgl = dlopen("libGL.so.3", RTLD_LAZY | RTLD_LOCAL); - if (!libgl) + + if (libgl) + return GL3W_OK; + + return GL3W_ERROR_LIBRARY_OPEN; +} + +static int open_libgl(void) +{ + int res = open_libs(); + if (res) + return res; + + if (libegl) + *(void**)(&gl_get_proc_address) = dlsym(libegl, "eglGetProcAddress"); + else if (libglx) + *(void**)(&gl_get_proc_address) = dlsym(libglx, "glXGetProcAddressARB"); + else + *(void**)(&gl_get_proc_address) = dlsym(libgl, "glXGetProcAddressARB"); + + if (!gl_get_proc_address) { + close_libgl(); return GL3W_ERROR_LIBRARY_OPEN; - *(void **)(&glx_get_proc_address) = dlsym(libgl, "glXGetProcAddressARB"); + } + return GL3W_OK; } -static void close_libgl(void) { dlclose(libgl); } - -static GL3WglProc get_proc(const char *proc) +static GL3WglProc get_proc(const char* proc) { - GL3WglProc res; - res = glx_get_proc_address((const GLubyte *)proc); + GL3WglProc res = NULL; + + // Before EGL version 1.5, eglGetProcAddress doesn't support querying core + // functions and may return a dummy function if we try, so try to load the + // function from the GL library directly first. + if (libegl) + *(void**)(&res) = dlsym(libgl, proc); + if (!res) - *(void **)(&res) = dlsym(libgl, proc); + res = gl_get_proc_address(proc); + + if (!libegl && !res) + *(void**)(&res) = dlsym(libgl, proc); + return res; } #endif diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt index 932d74bdd4bb..ca6c29bb293c 100644 --- a/docs/CHANGELOG.txt +++ b/docs/CHANGELOG.txt @@ -80,6 +80,7 @@ Other changes: mitigitate issues with reading vertex indexing limits with 16-bit indices. (#7496, #5720) - Backends: OpenGL3: Detect ES3 contexts on desktop based on version string, to e.g. avoid calling glPolygonMode() on them. (#7447) [@afraidofdark, @ocornut] +- Backends: OpenGL3: Update loader for Linux to support EGL/GLVND. (#7562) [@ShadowNinja, @vanfanel] - Backends: Vulkan: Added convenience support for Volk via IMGUI_IMPL_VULKAN_USE_VOLK define. (you could always use IMGUI_IMPL_VULKAN_NO_PROTOTYPES + ImGui_ImplVulkan_LoadFunctions() as well). (#6582, #4854) [@adalsteinnh, @kennyalive, @ocornut]