wgl: dynamically load opengl32.dll and wglGetProcAddress

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
tycho · Dec 28, 2023 · 58576bb · 58576bb
1 parent 68d9e6b
commit 58576bb
Show file tree

Hide file tree

Showing 3 changed files with 117 additions and 11 deletions.
diff --git a/glad/generator/c/templates/loader/gl.c b/glad/generator/c/templates/loader/gl.c
@@ -82,7 +82,7 @@ int gladLoaderLoadGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(
     if (handle) {
         userptr = glad_gl_build_userptr(handle);
 
-        version = gladLoadGL{{ 'Context' if options.mx }}UserPtr({{ 'context,' if options.mx }}glad_gl_get_proc, &userptr);
+        version = gladLoadGL{{ 'Context' if options.mx }}UserPtr({{ 'context, ' if options.mx }}glad_gl_get_proc, &userptr);
 
         if (!version && did_load) {
             gladLoaderUnloadGL{{ 'Context' if options.mx }}({{ 'context' if options.mx }});
@@ -116,9 +116,7 @@ void gladLoaderResetGL{{ 'Context' if options.mx }}({{ template_utils.context_ar
 void gladLoaderResetGL(void) {
     gladLoaderResetGLContext(gladGetGLContext());
 }
-{% endif %}
 
-{% if options.mx_global %}
 int gladLoaderLoadGL(void) {
     return gladLoaderLoadGLContext(gladGet{{ feature_set.name|api }}Context());
 }

diff --git a/glad/generator/c/templates/loader/wgl.c b/glad/generator/c/templates/loader/wgl.c
@@ -1,20 +1,118 @@
 #ifdef GLAD_WGL
 
-static GLADapiproc glad_wgl_get_proc(void *vuserptr, const char* name) {
-    GLAD_UNUSED(vuserptr);
-    return GLAD_GNUC_EXTENSION (GLADapiproc) wglGetProcAddress(name);
+{% include 'loader/library.c' %}
+
+typedef void* (GLAD_API_PTR *GLADwglprocaddrfunc)(const char*);
+struct _glad_wgl_userptr {
+    void *handle;
+    GLADwglprocaddrfunc wgl_get_proc_address_ptr;
+};
+
+{% if not options.mx %}
+static void* {{ template_utils.handle() }} = NULL;
+{% endif %}
+
+static void* glad_wgl_dlopen_handle({{ template_utils.context_arg(def='void') }}) {
+#if GLAD_PLATFORM_APPLE
+    static const char *NAMES[] = {
+        "../Frameworks/OpenGL.framework/OpenGL",
+        "/Library/Frameworks/OpenGL.framework/OpenGL",
+        "/System/Library/Frameworks/OpenGL.framework/OpenGL",
+        "/System/Library/Frameworks/OpenGL.framework/Versions/Current/OpenGL"
+    };
+#elif GLAD_PLATFORM_WIN32
+    static const char *NAMES[] = {"opengl32.dll"};
+#else
+    static const char *NAMES[] = {
+  #if defined(__CYGWIN__)
+        "libGL-1.so",
+  #endif
+        "libGL.so.1",
+        "libGL.so"
+    };
+#endif
+
+    if ({{ template_utils.handle() }} == NULL) {
+        {{ template_utils.handle() }} = glad_get_dlopen_handle(NAMES, GLAD_ARRAYSIZE(NAMES));
+    }
+
+    return {{ template_utils.handle() }};
 }
 
-int gladLoaderLoadWGL(HDC hdc) {
-    return gladLoadWGLUserPtr(hdc, glad_wgl_get_proc, NULL);
+static struct _glad_wgl_userptr glad_wgl_build_userptr(void *handle) {
+    struct _glad_wgl_userptr userptr;
+
+    userptr.handle = handle;
+#if GLAD_PLATFORM_APPLE || defined(__HAIKU__)
+    userptr.wgl_get_proc_address_ptr = NULL;
+#elif GLAD_PLATFORM_WIN32
+    userptr.wgl_get_proc_address_ptr =
+        (GLADwglprocaddrfunc) glad_dlsym_handle(handle, "wglGetProcAddress");
+#else
+    userptr.wgl_get_proc_address_ptr =
+        (GLADwglprocaddrfunc) glad_dlsym_handle(handle, "glXGetProcAddressARB");
+#endif
+
+    return userptr;
+}
+
+static GLADapiproc glad_wgl_get_proc(void *vuserptr, const char *name) {
+    struct _glad_wgl_userptr userptr = *(struct _glad_wgl_userptr*) vuserptr;
+    GLADapiproc result = NULL;
+
+    if(userptr.wgl_get_proc_address_ptr != NULL) {
+        result = GLAD_GNUC_EXTENSION (GLADapiproc) userptr.wgl_get_proc_address_ptr(name);
+    }
+    if(result == NULL) {
+        result = glad_dlsym_handle(userptr.handle, name);
+    }
+
+    return result;
+}
+
+int gladLoaderLoadWGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(', ') }}HDC hdc) {
+    int version = 0;
+    void *handle;
+    int did_load = 0;
+    struct _glad_wgl_userptr userptr;
+
+    did_load = {{ template_utils.handle() }} == NULL;
+    handle = glad_wgl_dlopen_handle({{ 'context' if options.mx }});
+    if (handle) {
+        userptr = glad_wgl_build_userptr(handle);
+
+        version = gladLoadWGL{{ 'Context' if options.mx }}UserPtr({{ 'context, ' if options.mx }}hdc, glad_wgl_get_proc, &userptr);
+
+        if (!version && did_load) {
+            gladLoaderUnloadWGL{{ 'Context' if options.mx }}({{ 'context' if options.mx }});
+        }
+    }
+    return version;
 }
 
 {% if options.mx_global %}
+int gladLoaderLoadWGL(HDC hdc) {
+    return gladLoaderLoadWGLContext(gladGet{{ feature_set.name|api }}Context(), hdc);
+}
+
 void gladLoaderResetWGL(void) {
     gladLoaderResetWGLContext(gladGetWGLContext());
 }
 {% endif %}
 
+void gladLoaderUnloadWGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(def='void') }}) {
+    if ({{ template_utils.handle() }} != NULL) {
+        glad_close_dlopen_handle({{ template_utils.handle() }});
+        {{ template_utils.handle() }} = NULL;
+    }
+
+{% if not options.mx %}
+    gladLoaderResetWGL();
+{% else %}
+    gladLoaderResetWGLContext(context);
+{% endif %}
+}
+
 void gladLoaderResetWGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(def='void') }}) {
 {% if options.mx %}
     memset(context, 0, sizeof(GladWGLContext));
@@ -35,4 +133,10 @@ void gladLoaderResetWGL{{ 'Context' if options.mx }}({{ template_utils.context_a
 {% endif %}
 }
 
+{%if options.mx_global %}
+void gladLoaderUnloadWGL(void) {
+    gladLoaderUnloadWGLContext(gladGet{{ feature_set.name|api }}Context());
+}
+{% endif %}
+
 #endif /* GLAD_WGL */
diff --git a/glad/generator/c/templates/loader/wgl.h b/glad/generator/c/templates/loader/wgl.h
@@ -1,9 +1,13 @@
+{% import "template_utils.h" as template_utils with context %}
 #ifdef GLAD_WGL
 
-GLAD_API_CALL int gladLoaderLoadWGL(HDC hdc);
+GLAD_API_CALL int gladLoaderLoadWGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(', ') }}HDC hdc);
+GLAD_API_CALL void gladLoaderUnloadWGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(def='void') }});
 GLAD_API_CALL void gladLoaderResetWGL{{ 'Context' if options.mx }}({{ template_utils.context_arg(def='void') }});
-{% if not options.mx_global %}
+{% if options.mx_global %}
+GLAD_API_CALL int gladLoaderLoadWGL(HDC hdc);
+GLAD_API_CALL void gladLoaderUnloadWGL(void);
 GLAD_API_CALL void gladLoaderResetWGL(void);
 {% endif %}
 
-#endif
+#endif