(a) The fact that a person charged with a crime was in an intoxicated condition at the time the alleged crime was committed is a defense only if such condition was involuntarily produced and rendered such person substantially incapable of knowing or understanding the wrongfulness of such person's conduct and of conforming such person's conduct to the requirements of law.
(b) An act committed while in a state of voluntary intoxication is not less criminal by reason thereof, but when a particular intent or other state of mind is a necessary element to constitute a particular crime, the fact of intoxication may be taken into consideration in determining such intent or state of mind.