[Script] How to hide NPC's until they are needed

[Scotian]

In FireRed, when you walk out of your house, you pass by a hidden Prof. Oak sprite on your way out of Pallet Town. Stepping on the script block to leave Pallet Town triggers the script that calls the showsprite command, and Prof. Oak walks up to you and takes you to his Lab.

How is Prof. Oak hidden by default? There's no flags set to him in AMap, the player does not pass any script blocks in the house to set any flags with a script, he doesn't have a script associated with his sprite, and even if he did, you'd have to talk to him to trigger it.

I want to create an NPC similar to how Oak acts, he is hidden until someone steps on his script block, and then he comes running into the screen. However, my sprite, is just standing in the map when I walk out of the house, and if someone talks to him, it crashes the game.

Any help would be greatly appreciated!

 

[Asith]

There are flags automatically set when the game begins. Oak's flag may be one of those

 

[Pyxal]

In FireRed, when you walk out of your house, you pass by a hidden Prof. Oak sprite on your way out of Pallet Town. Stepping on the script block to leave Pallet Town triggers the script that calls the showsprite command, and Prof. Oak walks up to you and takes you to his Lab.

How is Prof. Oak hidden by default? There's no flags set to him in AMap, the player does not pass any script blocks in the house to set any flags with a script, he doesn't have a script associated with his sprite, and even if he did, you'd have to talk to him to trigger it.

I want to create an NPC similar to how Oak acts, he is hidden until someone steps on his script block, and then he comes running into the screen. However, my sprite, is just standing in the map when I walk out of the house, and if someone talks to him, it crashes the game.

Any help would be greatly appreciated!

Set a flag corresponding to the person event in A-Map in a previous script (preferably a level script). Or just use Oak's flag (0x2C). Here's is a detailed list of [FR] flags: https://github.com/pret/pokefirered/blob/master/include/constants/flags.h