Rob Jenkins (robj++at++quid.engr.sgi.com)
Fri, 10 Apr 1998 11:47:24 -0700
The iR clipmap implementatation doesn't support any min filter other than
CLIPMAP_TRILINEAR. The problem you describe could be something else, Don Hatch
had this to say:
"
As for the flickering, I assume it's jumping back and forth between coarser
and finer levels.
It might be helpful to tweak the parameters with:
setDTRFadeCount
setTexLoadTime or setTexLoadTimeFrac
setDTRBlurMargin
or move more slowly.
"
To debug this better the kind of useful info you could give is:
cliptexture 'stats' eg size ( and hence levels ), type.
the values you set with the cliptexture parameters. Can you load your data into
clipfly and manually adjust parameters to see what effect they have ?
Cheers
Rob
On Apr 9, 7:49am, Scott Brabson wrote:
> Subject: ClipTextures and Filters
> Hello All,
>
> I have a cliptexture that consists of luminance values. When I position
> my viewpoint to look at the horizon it looks great. As I fly toward the
> horizon the texture past level 0 appears to be flickering. I figured it
> was the way the Minification filter was being applied. Looking at the
> man page for MPCliptextures and ClipTextures a method to set the Mag
> filter exists but not for Minification. I created this section of code
> to see if I could set the Minfilter through pfTexture. The filter type
> never changes. It always stays at PFTEX_TRILINEAR.
>
> My Questions:
>
> 1. Why is there no Minfilter option for ClipTextures?
> 2. Is there a way to remove this flickering? Has anyone seen this
> flickering?
> 3. Why is the Minfilter set to trilinear?
>
>
> Thanks,
> Scott Brabson
> DCS Corporation
>
>
> Here is the code sample: Is this correct?
>
> {
> pfTexture * text;
> int type;
>
> text = (pfTexture *)pfGetMPClipTextureClipTexture(MPClipTex);
>
> type = pfGetTexFilter(text, PFTEX_MINFILTER);
>
> if(type == PFTEX_POINT)
> cout << "--- Minfilter == POINT" << endl;
> else if(type == PFTEX_TRILINEAR
> cout << "--- Minfilter == TRILINEAR" << endl;
> else
> cout << "---Filter set to: << type << endl;
>
>
> pfTexFilter(text,PFTEX_MINFILTER,PFTEX_MIPMAP_POINT);
>
>
> type = pfGetTexFilter(text, PFTEX_MINFILTER);
>
> if(type == PFTEX_POINT)
> cout << "--- Minfilter == POINT" << endl;
> else if(type == PFTEX_TRILINEAR
> cout << "--- Minfilter == TRILINEAR" << endl;
> else
> cout << "---Filter set to: << type << endl;
>
> //This is always PFTEX_TRILINEAR!!!!
> }
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>-- End of excerpt from Scott Brabson
--
________________________________________________________________
Rob Jenkins mailto:robj++at++sgi.com
Silicon Graphics, Mtn View, California, USA
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This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:57:14 PDT