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libgdx / gdx-ai

Artificial Intelligence framework for games based on libGDX or not. Features: Steering Behaviors, Formation Motion, Pathfinding, Behavior Trees and Finite State Machines
Apache License 2.0
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Suggestion: allow us to provide our own Random object #53

Closed ASneakyFox closed 8 years ago

ASneakyFox commented 8 years ago

I have a game I'm working on with procedural generation. To make testing easier I like to use the same random seed on every run.

Instead of using MathUtils.random for doing random stuff in things like the Wander steering behavior, it would be great if it used something like GdxAi.random(), and then allow me to do something like GdxAi.setRandomInstance(myRandom); so that the ai will play out the same way every time with all the other aspects of my game.

edit: also to add, this would be useful for games with save/load functionality. Without being able to set the random instance, players could reload their game over and over to get different outcomes and "cheat" the game.

davebaol commented 8 years ago

Well, there's nothing stopping you from setting the MathUtils.random's seed. You can even replace the Random instance since the static field random of MathUtils is not final.

ASneakyFox commented 8 years ago

The problem with doing that to MathUtils is that many things use MathUtils.random in libgdx all over the place. It would mess up the games underlying model because some particle effect or something is in the game.

davebaol commented 8 years ago

This should not happen unless you use the Random instance from multiple threads.

ASneakyFox commented 8 years ago

No this can happen easily and all the time.

For instance, if I have the game running with a specific seed and see how it runs, then I decide it would look cool if the main character has a particle trail when he moves. Now this new visual effect will change the outcome of all the AI because its using the same random number generator.

Anything at all you change in the game of its view/rendering would possibly be changing the game's model.

davebaol commented 8 years ago

Oh now I see what you mean. But I think that even a dedicated random generator instance would not let you accurately reproduce game sequences since FPS is not deterministic. Actually, you use the random generator more frequently when FPS is high and less when is low.

ASneakyFox commented 8 years ago

ah because it uses random inside of update calls. I guess I wasn't thinking it all the way through. I guess this was a pointless suggestion then. It would be cool if it were possible though.