GL_REGAL_log https://github.com/p3/regal/blob/master/doc/extensions/GL_REGAL_log.txt GL_REGAL_log GL_LOG_ERROR_REGAL 0x9319 GL_LOG_WARNING_REGAL 0x931A GL_LOG_INFO_REGAL 0x931B GL_LOG_APP_REGAL 0x931C GL_LOG_DRIVER_REGAL 0x931D GL_LOG_INTERNAL_REGAL 0x931E GL_LOG_DEBUG_REGAL 0x931F GL_LOG_STATUS_REGAL 0x9320 GL_LOG_HTTP_REGAL 0x9321 void glLogMessageCallbackREGAL (GLLOGPROCREGAL callback) typedef void (APIENTRY *GLLOGPROCREGAL)(GLenum stream, GLsizei length, const GLchar *message, GLvoid *context)