Re: [hlcoders] HLVIS (Warning, technical details and code)

[Chris Blane]

Had a feeling I might start seeing this topic crop up on the list Zipster.
:) Still no luck with that last bug eh?

:Tal-N
----- Original Message -----
From: Skyler York <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, April 16, 2002 7:56 AM
Subject: [hlcoders] HLVIS (Warning, technical details and code)


> [ Converted text/html to text/plain ]
> I've been working on a few new features for HLVIS, and I have been making
good
> progess.  One of the features is a new maximum VIS option.  In addition to
> being able to compile the map the first time around with this new feature,
you
> can chose to run a MaxDistVis on an already compiled map.
>
> This is my problem.  If you run a MaxDistVis during the initial compile,
the
> the code flags the correct leafs to be invisible:
>
> ------------------------------------------------
> // i = leafnum of first leaf, j = leafnum of second leaf
> offset_l = i >> 3;
> bit_l = (1 << (i & 7));
> offset_tl = j >> 3;
> bit_tl = (1 << (j & 7));
>
> for(k = 0; k < l->numportals; k++)
> {
>      for(m = 0; m < tl->numportals; m++)
>      {
>           l->portals[k]->mightsee[offset_tl] &= ~bit_tl;
>           tl->portals[m]->mightsee[offset_l] &= ~bit_l;
>      }
>  }
>
> ----------------------------------------------
> It basically eliminates leafs before they are even fully VISed.
>
> However, if you run a MaxDistVis on an already compiled map, for the most
> part, the leafs rendered in game are correct, except for a few oddball
leafs
> that aren't "unset" in the code for some unknown reason.  The detection is
the
> same, but it doesn't unset them.  What I have to do first is decompress
all
> the vis information:
> -------------------------------------------------
> void   DecompressAll(void)
> {
>      int i;
>      byte *dest;
>      for(i = 0; i < g_portalleafs; i++)
>      {
>           dest = g_uncompressed + i * g_bitbytes;
>           DecompressVis((const unsigned char*)(g_dvisdata +
(byte)g_dleafs[i +
> 1].visofs), dest, g_bitbytes);
>      }
> }
> ------------------------------------------------
>
> I use this code to "unset" leafs:
> -----------------------------------------------
> // i = leafnum of first leaf, j = leafnum of second leaf
> byte* base_vis_l = g_uncompressed + i * g_bitbytes;
> byte* base_vis_tl = g_uncompressed + j * g_bitbytes;
> offset_l = i >> 3;
> bit_l = (1 << (i & 7));
> offset_tl = j >> 3;
> bit_tl = (1 << (j & 7));
> base_vis_l[offset_tl] &= ~bit_tl;
> base_vis_tl[offset_l] &= ~bit_l;
>
> ------------------------------------------------
>
> ...and this code to recompress the vis info:
> ------------------------------------------------
> void   CompressAll(void)
> {
>      int i, x = 0;
>      byte *dest;
>      byte *src;
>      byte compressed[MAX_MAP_LEAFS / 8];
>      vismap_p = vismap;
>
>      for(i = 0; i < g_portalleafs; i++)
>     {
>         memset(&compressed, 0, sizeof(compressed));
>         src = g_uncompressed + i * g_bitbytes;
>
>        // Compress all leafs into global compression buffer
>        x = CompressVis(src, g_bitbytes, compressed, sizeof(compressed));
>        dest = vismap_p;
>        vismap_p += x;
>        if (vismap_p > vismap_end)
>       {
>            Error("Vismap expansion overflow");
>        }
>
>        g_dleafs[i + 1].visofs = dest - vismap;            // leaf 0 is a
> common solid
>        memcpy(dest, compressed, x);
>      }
> }
> --------------------------------------------------
>
> It works at around a 90% - 95% success rate, but those oddball leafs annoy
me.
>
> Before I forget, here are some pics of what I mean.
>
> This is the map compiled normally:
> http://144.132.16.252/zipster/[2]mdv0.jpg
>
> This is the map compiled the first time around with a max distance of 128:
> http://144.132.16.252/zipster/[4]mdv1.jpg
>
> And here is a picture of the original map being MaxDistVis'd after a
regular
> compile (w/ 128 limit):
> http://144.132.16.252/zipster/[6]mdv2.jpg
>
> As you can see, that blasted leaf in the distance is screwing me over!  I
> don't know how many of you know much about HLVIS procedures, but I hope
I've
> given you enough information.  I would go into more detail, but there's
just
> too much if you don't have an idea of what's happening.
>
> --------------------------------------------------------------------------
----
> MSN Photos is the easiest way to share and print your photos: Click
Here[7]
>
> ===References:===
>   1. http://144.132.16.252/zipster/mdv0.jpg
>   2. http://144.132.16.252/zipster/
>   3. http://144.132.16.252/zipster/mdv1.jpg
>   4. http://144.132.16.252/zipster/
>   5. http://144.132.16.252/zipster/mdv2.jpg
>   6. http://144.132.16.252/zipster/
>   7. http://g.msn.com/1HM505401/15
>
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