Need for predictable random generator

Question

I\'m a web-game developer and I got a problem with random numbers. Let\'s say that a player has 20% chance to get a critical hit with his sword. That means, 1 out of 5 hits

Answer 1

What you want are not random numbers, but numbers which seem random to a human. Other have already suggested individual algorithms, which can help you, like Shuffle Bad.

For a good detailed and extensive analysis of this domain see AI Game Programming Wisdom 2. The whole book is worth reading for any game developer, the idea of "seemingly random numbers" is handled in chapter:

Filtered Randomness for AI Decisions and Game Logic:

Abstract: Conventional wisdom suggests that the better the random number generator, the more unpredictable your game will be. However, according to psychology studies, true randomness over the short term often looks decidedly unrandom to humans. This article shows how to make random AI decisions and game logic look more random to players, while still maintaining strong statistical randomness.

You may also find another chapter interesting:

The Statistics of Random Numbers

Abstract: Random numbers are used most heavily by Artificial Intelligence and games in general. To ignore their potential is to make the game predictable and boring. Using them incorrectly can be just as bad as ignoring them outright. Understanding how random numbers are generated, their limitations and their capabilities, can remove many difficulties of using them in your game. This article offers insight into random numbers, their generation, and methods to separate good ones from bad.