Frame-rate slowdowns

Discussion in 'Archived Threads 2001-2004' started by Peter D, Jan 5, 2002.

  1. Peter D

    Peter D Stunt Coordinator

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    Having seen a few brief slowdowns in Halo and SSX Tricky in fairly obvious spots on the Xbox, I have to wonder - what the heck? I can understand it in PC games, where you can't rely on the hardware (so it's harder to test the billions of possible configurations), but when you only have one piece of hardware to target, how does this happen?
     
  2. Morgan Jolley

    Morgan Jolley Lead Actor

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    Some games are not programmed to have so many polygons on screen and at such a large scale at once that they will slow down. FFX does this many times, and its either because so many people are on screen and close to the camera or because the landscape goes far into the distance and uses too many polys.

    Thats all that I know (heard explanations like that somewhere). Maybe someone who develops games can elaborate.
     
  3. Gary King

    Gary King Second Unit

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    You build the game engine with a set of specifications for any given frame (amount of world visible, number of enemies/allies on-screen, number of light sources, etc.), and then due to how the player chose to play, that specification is violated.

    Since developers want their games to look as good as possible, their specification is often just a high average case (e.g., 12-15 enemies), and not an extreme case (e.g., 50 enemies).
     
  4. Peter D

    Peter D Stunt Coordinator

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    I dunno - it seems to me that on a console these issues should be largely squashed in playtesting (where testers should be doing whatever can be done in the game to see if there are any problems). The problem is, in both Halo and Tricky, the slowdowns I saw were not from playing in unusual ways. In Halo, it's a scripted event (explosions while you are driving on the last level) that triggers the slowdown. In Tricky, it was just by hitting a spot on the course (Elysium Alps) with the computer racers nearby.
     
  5. Dave Smith

    Dave Smith Stunt Coordinator

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    Basically you only have a certain amount of time per frame to do stuff in (16ms if you're running at 60fps). If you go beyond this for any reason, you're going to get slowdown. The framerate will slow down, anyway - a properly written game will not "feel" slower, at least not until you get down to the 15fps range or so. The game should compensate for the framerate, and not assume the best case.

    You can develop a pretty good looking game on modern consoles which will run at 60fps most of the time. But add a few too many particles, or AIs, or polygons, and eventually you'll push it over the limit and frame out. It's often a choice of the developer - is it better to have an incredible number of events on the screen, or to run at 60fps?

    Also, modern games are not like sprite-based shoot-em-ups running on a SNES. You almost never have exact known quantities on-screen. There's always going to be a situation where a player doesn't kill any enemies, so the maximum number are on screen just as you get to that bit of your level where the artists cheated and exceeded their polygon or texture budget, and oh, he just fired off 20 rounds from his rocket launcher too.

    Slowdowns are a fact of life on today's hardware, and if consumers are going to keep demanding rich gameworlds and interactive everythings (which they should!) then people have to accept the occasional framerate drop. It's mainly that CPUs need to get faster, modern graphics hardware means that the cause of most slowdown in games these days is computational.
     

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