I'm religiously preserving the OpenGL state around everything
that I'm doing (glPushAttrib() and glPopAttrib() with
GL_ALL_ATTRIB_BITS).  Is there something more bulletproof?

Glad to know that FlightGear uses non-plib textures, too.  Can
you point me to a place in the source code where this occurs?

To rephrase my initial question, is there a way to limit the
"world" in which FlightGear operates to, say, 100 sq miles
around my home airport and force it to load everything it
needs up front (thus avoiding the '12 GB of data' consequence)?

Thanks for the help.

D
---- Original message ----
>Date: Wed, 26 Jan 2005 09:36:20 -0600
>From: "Curtis L. Olson" <[EMAIL PROTECTED]>  
>Subject: Re: [Flightgear-users] how do I disable 'dynamic'
textures?  
>To: FlightGear user discussions <[email protected]>
>
>D Wysong wrote:
>
>>Can I keep FG from going back into plib and fiddling with
>>textures once the sim is up/initialized!?
>>
>>I'm using a custom texture that I created using OpenGL
>>directly (instead of via plib) and I'm getting HOSED when FG
>>decides to go load new textures (... or when it does whatever
>>it does when it starts making calls to ssgLoadTextures,
>>ssgMakeMipMaps, etc., after the sim is executing).  AArrgh!
>>  
>>
>
>One thing you need to understand in OpenGL is "state
management".   
>FlightGear is a complex program that needs to set different
opengl 
>parameters (i.e. states) in a number of different places in
the code.  
>If one section of the code isn't careful and doesn't reset
things 
>correctly, or makes some other wierd changes, then this could
cause 
>problems later.
>
>Think about it like someone giving you turn by turn
directions.  If they 
>don't tell you to turn at all the right places, and in the
right order, 
>you aren't going to end up where you want to go.
>
>>Are there any reasons why plib wouldn't let me build/use my
>>own textures? (... I posted a similar question on the
>>plib-users list to see if I get any replies)
>>  
>>
>
>This should all work fine.  FlightGear has places where it
loads or 
>builds it's own textures too.
>
>>Why does FG need to load anything once the sim is executing? 
>>Are textures not allocated/created by FG until they're needed? 
>>Can this 'load-it-as-you-go' behavior be replaced with a
>>'load-everything' approach?
>>What are the consequences?
>>  
>>
>
>What are the consequences of loading 12Gb of world data and
associated 
>textures and code all at once into main RAM?
>
>I would hunt for an opengl state management issue in your
code.  Also, 
>don't forget that you must do all your texture loading in the
main 
>thread.  If you mix opengl calls in different threads, they
will get 
>mixed arbitrarily and sent to the single opengl context, and
you will 
>get unpredictable results ... well actually you'll most
likely get a 
>program crash.
>
>Regards,
>
>Curt.
>
>-- 
>Curtis Olson        http://www.flightgear.org/~curt
>HumanFIRST Program  http://www.humanfirst.umn.edu/
>FlightGear Project  http://www.flightgear.org
>Unique text:        2f585eeea02e2c79d7b1d8c4963bae2d
>
>
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