Stefan Viljoen <spa### [at] polardcom> wrote:
> Hmm I've often wondered how much control the game developer has over that,
> even on the PC. (On consoles I'm guessing you're even more "locked in" to a
> set of tools...)

  The things that most affect the rendering speed of a game is the amount
of visual effects and details.

  Game developers, graphic artists and level designers always have to make
compromises between visual quality and performance. In an optimal world
every model would consist of millions of triangles, every texture, bump map
and light map would have a humongous resolution, every pixel would be
post-processed with the most advanced shaders which give the best visual
quality, every single piece of geometry would exhibit subpixel-detailed
fully dynamic soft shadows, all reflections would depict the entire reflected
scene in full quality, and the game would render the entire world in full
detail regardless of distance.

  Of course if you do that, you will have to start counting seconds per
frame instead of frames per second.

  So the vast majority of performance optimization happens at the design
and modeling stage: How much can polygon models be reduced without them
starting to look crappy? How much can texture resolutions be reduced?
Can complex shaders be replaced with simpler and faster ones, but which
give virtually the same result? In general, can complicated visual effects
be replaced with simpler and faster ones without noticeable degradation in
visual quality?

  The graphics engine (which in the vast majority of cases, including this
one, means Unreal Engine 3) is also at a key position for performance. While
most developers probably won't be touching the engine itself, the engine
probably has a huge bunch of control knobs that the developers can fine-tune
to reach an optimal compromise between visual quality and speed.

  Of course non-rendering issues can also affect performance, most
importantly the physics engine. You probably don't want to have a couple
million of tiny physics objects in your field of view at the same time,
unless you want to again start counting seconds per frame, so levels need
to be designed so that you don't end up in such situations.

-- 
                                                          - Warp

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