I know the details of your event because you sent me a PM. However, I agree that it was wise to delete them here on the open part of the forum, at least until after this matter is resolved and/or your attorney says it's okay to tell your story. (He won't!
)TPC §46.035(a) makes it unlawful to intentionally fail to conceal a handgun. (Knowingly or recklessly isn't found in that part of the Code.) From your PM, you clearly didn't intend to have it unconcealed, as you just as clearly believed that a combination of darkness and tinted windows rendered the gun "concealed." There is very good evidence that your belief was correct, as the officer didn't even see it until you told him where it was and the second officer opened the passenger door. I'm also less than impressed with the question, "Why do you have a loaded gun in the car?" It implies the officer erroneously thinks that loaded v. unloaded is legally relevant.
There are many methods of concealment folks, and darkness is certainly one of them. I've used it myself on many occasions.
Chas.