Escape бамп - это карта высот (хейтмап). А нормалмап - это продифференцированная карта высот, на основе которой получены нормали к точкам карты. Для пиксельных рассчетов нужны именно нормали.
__________________
So she began again: 'Où est ma chatte?' which was the first sentence in her French lesson-book. The Mouse gave a sudden leap out of the water, and seemed to quiver all over with fright. 'Oh, I beg your pardon!' cried Alice hastily, afraid that she had hurt the poor animal's feelings. 'I quite forgot you didn't like cats.'