Rob Jenkins (robj++at++sgi.com)
Fri, 23 Apr 1999 06:07:41 -0700
Woh ! :-)
I'll suggest a few things in the absence of a good explanation for
everything you describe.
Firstly, make sure you have the latest pf 2.2.3 and Irix 6.5.3
installed. Do you build you pf app linked against OpenGL or IrisGL ?
You'll need to use IrisGL to get shadows but there's some caveats and
things you need to set up described in the man page for pfLightSource.
The saturated lighting you describe indicates you probably are using
IrisGL and are seeing the result of all lights muliplying together, you
can 'normalize' the lighting in the scene with pfLightSource::setVal (
detail in man pfLightSource ), as you sayu, you might have to change
these values as you turn shadows on/off
As for the other things you describe I can guess at a few things that
could givew odd effects, not sure which you're seeing:
o zbuffer size ( see notes in pfLightSource ), might need to reduce the
FBconfig reqs you ask for.
o upgrading pf/Irix will get you recent fixes to GL/pf shadows.
o You're using stencil layers ( not compatible with shadows
o Your channel is smaller than your shadow map.
Do any of the demos work OK ( ie without the strange red square ) ?
Cheers
Rob
Jorge Valencia Loera wrote:
>
> Hi pf`s,
>
> I hope somebody can help me with these problems:
>
> (Even if you`re not sure if it`ll work, send me your ideas, thanks)
> I use pf 2.2 on RE2:
>
> I am currently adding the shadowing functionality to an existing
> application using pf built-in shadowing (shadow map) and I am having
> some strange anomalies appearing on my screens.
>
> 1. When I change the properties of the lights in my application in
> order to cast shadows, a red square about 1/8 the size of my screen
> appears on the lower left corner and there is no way to get rid of
> it!!! I have no idea of what it is BUT I`ve seen that if I increase my
> shadow map size the red square gets bigger too (??????). It is not an
> object of my scene and wherever my viewpoint position is, it always
> appears on the lower left corner.
> ALSO I`ve seen that if I move my viewpoint position in order to
> have an object in front of it (it = the square), the red square will
> be hidden by my object as if it was part of the background.... (???)
> If I move back the viewpoint, the square reappears
>
> 2. I`ve seen that also when I enable the shadows my scene gets
> brighter than it is without shadows, that makes parts of my scene
> completly saturated by WHITE pixels. (???) [too much light]
> I know that I can modify the intensity of each light to avoid that
> behavior but without shadows the intensity of my pfLightSources is OK.
> Does pf needs a higher intensity to cast shadows?
> Should I need to modify the attributes of my lights each time I enable
> & disable shadowing? (that`s something that will happen often in my
> simulation).
>
> 3. The project I'm working on has two main parts (almost totally
> independent), the computation of all the different parts of the
> simulation (dynamics, GUI, ...) & the visual renderer (pf based)
> representing visually the state of the simulation. We are able to run
> the simulation with or without the visuals.
> When I load my simulation with the visuals for the first time,
> everything is OK (the shadows are casted correctly on all my textured
> objects) but if I unload the visuals (only the visuals, the other part
> keeps running) and reload it some minutes after, the shadows will only
> appear on some textures & won`t appear anymore on other textures (none
> of my objects or lights have moved! so the scene should be the same!!)
> It is really strange because a shadow can completly cover an object
> before I kill my visuals, but when I re-run my visuals the same shadow
> appears on parts of the object and doesn`t appear on other parts of
> the same object (the only difference between the parts is the
> texture).
> HINT: If I wait about 30-40 minutes before I load my visuals again
> everything is OK.
>
> If you know ANYTHING about those problems please help me, Thank you.
>
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-- ________________________________________________________________ Rob Jenkins SGI Graphics Consulting Tel 0118 925 7621 mailto:robj++at++sgi.com http://www.sgi.co.uk
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