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How to switch between RNG methods


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Hi all,

 

I'm working on a TAS of LeafGreen (on an emulator), and as part of my route, I need to catch a Pokemon with specific IVs generated by Method H4 at a specific RNG frame (frame 93395, to be exact). However, I am only able to make the encounter generate with IVs generated by Method H2. I know that it is theoretically possible to change the RNG Method for the encounter because I have done it before, but not in any sort of reliable way. I just sort of threw inputs at it until something different happened. That has not been successful thus far. Is there a way that I can get this encounter to happen with the RNG Method that I want? It's been driving me insane

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You'd need to influence the vblank to occur at a different time while the game code is executing. Emulators don't all behave the same way (timing/efficiency). Different inputs on prior frames may cause extra/less code to be executed, altering the timing in which the vblank interrupt occurs relative to the PIDIV loop code.

Think of it as two parallel processes; vblank and game-loop. vblank executes X frames per second, and the game loop gets paused whenever vblank is triggered, and a rand call happens.

There is no reliable advice besides input spam on prior frames, to shift when a vblank happens. Nobody has profiled the game loop to show what player inputs can modify the assembly instructions executed per frame, or estimating when a vblank will occur based on the game loop code.

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