Re: [Plib-devel] Work outstanding.

[Steve B. <sjb...@ai...>]

Gil Carter wrote:

> >Probably it would be best to
> >have the performance monitor both in the engine and the modeler.
> >In the engine for the developer, so that he can see the performance
> >where it matters, with sound and ai etc going on.
> >In the modeler, the developer can quickly make changes, for example
> >that car model is too slow - lets try it with opaque windows.
> 
> Ok, but keep in mind that you're not just measuring how long it takes to
> render your car - you're really benchmarking the performance of PPE as
> well.  Even though PPE is underpinned by PLIB, if you're developing models
> for a game, your game engine is really the place to benchmark.

PPE (when not actually being given mouse clicks or key events) simply
calls PLIB's SSG  "ssgCullAndDraw" in a pretty tight loop.

If you set it up with the same clip planes, FOV and resolution as the
game, then it will produce identical timings for those graphics that are
done in SSG...obviously, the game's own menu's and icons won't get
timed.

That's as close as a separate application could possibly be.

So, that's why ssgStatistics needs to be a simple class you can add to
your game *as well* as in PPE.  In PPE it'll give the artist a good 'first
look' at the kind of performance he can expect.  Not perfect - nothing can
be - but since it saves him saving the model, shutting down PPE, starting the
game, playing through to the desired spot and *THEN* turning on the stats,
it's MUCH more likely that he'll actually check performance frequently.

I think that's a valuable tool - even if it's "off" by 10%.

> Maybe PPE could have a "preview" mode which goes fullscreen with no menus,

...the menu's don't redraw unless you click on them or something changes.
They impose no load just be 'being there'...hence no need to get rid of them.

> ...and just renders the current model with trace enabled to give you an idea
> of what type of performance you'll get in a standalone app.

Once 'gotcha' is that the very act of measuring stats costs time (a kind of
Heisenberg uncertainty effect!) - so you NEVER can get perfect statistics!

>  There are
> issues of still having all of the other OpenGL resources consumed to keep
> PPE alive in background, but at least you're not rendering four views of
> the model plus the user interface at each frame :-)

PPE can run happily with a single 3D window.  The four-view mode is optional.

You aren't re-displaying the GUI each frame - only if it changes.


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