ClipTextures and Filters

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Scott Brabson (sbrabson++at++southernmaryland.com)
Thu, 09 Apr 1998 07:49:23 -0400


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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