void *libgl_handle;
void *wrapper_handle;
+#define STRNCMP_LITERAL(str, literal) strncmp (str, literal, sizeof (literal) - 1)
+
static void
open_libgl_handle (void)
{
static void *
resolve (const char *name)
{
+ static int before_first_gl_call = 1;
void *symbol;
+ if (before_first_gl_call &&
+ STRNCMP_LITERAL (name, "gl") == 0 &&
+ STRNCMP_LITERAL (name, "glX") != 0)
+ {
+ char *callback_name = getenv ("GLAZE_FIRST_GL_CALL_CALLBACK");
+ if (callback_name) {
+ void (*callback) (void) = dlsym (wrapper_handle,
+ callback_name);
+ if (callback) {
+ (callback) ();
+ } else {
+ fprintf (stderr,
+ "Error: Failed to find function %s "
+ "in GLAZE_WRAPPER library.\n",
+ callback_name);
+ }
+ }
+ before_first_gl_call = 0;
+ }
+
/* The wrapper gets first choice on all symbols. */
symbol = dlsym (wrapper_handle, name);
if (symbol)
void
glaze_execute (int argc, char *argv[], const char *wrapper);
+/* Register a callback function to be called when the first GL
+ * function, (not glX function) is called.
+ *
+ * It's common for Glaze-using libraries to need to do some
+ * initialization that can only be done once a valid OpenGL context is
+ * initialized. For example, the library may need to query what kind
+ * of context has been created.
+ *
+ * This function can be used for this purpose. It arranges for a
+ * function in the wrapper library to be called immediately before the
+ * first call to an OpenGL function by the application. Note that any
+ * window-system-sepecific function calls (such as glX functions) are
+ * not considered "an OpenGL function" for this purpose.
+ *
+ * The 'function_name' argument here should be the name of an exported
+ * function in the wrapper library passed to glaze_exectute, (or
+ * specified in the GLAZE_WRAPPER variable). The function must have a
+ * return type of void and must accept no arguments, so should have a
+ * signature such as:
+ *
+ * void function (void);
+ */
+void
+glaze_set_first_gl_call_callback (const char *function_name);
+
#endif /* GLAZE_H */