Hi, i am creating doom2 clone without using wad files in my part-time. i have created my own map designer and the rendering system using openGL. now i want to put some monsters around and want them to attack player. i don't know a single thing about AI like, targeting player, checking whether the player is insight or even petrolling. the one thing i don't know is how can i animate the monsters over time. like if the player is insight to monster how can i start attacking until the monster or player dies over time. thanks to everyone in advance. -rksingh

You should use a finate state machine. there's a great tutorial on this at mat's (fup) ai-junkie website.