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Comment by glandium | Hacker News Reader

If I remember correctly, after I upgraded my PC, Alone in the Dark was the only game where I had to turn the Turbo button off to be playable... otherwise it would be so fast that the first monster would come at you from the window within seconds. And of course, walking was running like Usain Bolt.

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As a kid, I never understood how the CPU could be too fast for the software. I'm not sure I do now either though. I get timing issues on ROM emulators for the old games using quirks due to NTSC/PAL issues. I know there were other programs that did not work with the Turbo button engaged that were not games where timing might be much more crucial.

You have to explicitly write your code to prevent this from happening. You typically have an engine that is executing all of your logic (rendering, game logic, AI, etc.) in cycles. By default, it will execute these cycles as quickly as possible. So for anything with real-time components, faster CPU = enemies move faster.

I forget which game first introduced a fix for this, but the solution is to have the engine run on time-based ticks -- you wait to execute the next cycle until the requisite time has passed.

Another alternative is to say, "How much time has passed since the last frame?" and update the game state based on that.

When your computer can't hold a constant framerate, the game doesn't slow down.

The developers didn't use fixed time points to update their games logic, they just updated the logic at the same speed of the proc, which leads to some interesting things.

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