If you break your Wudu during the prayer, by passing wind or otherwise, you should go and do Wudu, then come back and start the prayer from the beginning all over again according to the more correct view.

Cats do not invalidate the prayer even if they pass in front of you, because the basic guideline is that the prayer is valid and there is no evidence to suggest that cats can invalidate the prayer.

Weeping during prayer is one of the outcomes of humble submission (khushu‘) in prayer. As for making oneself weep, there is a da‘if (weak) hadith that has been narrated concerning it; if it is sahih, what is meant is bringing sorrow into the heart and focusing, not making sounds by weeping artificially.

Taking narcotic drugs is not permissible except in the case when there is no alternative to it, based on medical advice. If someone prays at the time of taking it when he is not fully aware, then his prayer is not valid. But if he is aware and understands what he is saying and doing, then his prayer is valid in that case.

The following are matters that invalidate prayer: 1- that which invalidates Wudu, 2- uncovering the `Awrah, 3- turning away from the Qiblah, 4- excessive continuous movement during the prayer, 5- omitting one of the pillars of the prayer, 6- saying the Salam before completing the prayer, 7- laughing out loud, 8- eating and drinking.

What is prohibited when fasting is inhaling Bukhur, not merely smelling its fragrance, because Bukhur has particles, so if it reaches the throat, it breaks the fast. There is nothing wrong with one who is praying smelling perfume or Bukhur.