View previous topic :: View next topic |
Author |
Message |
goldenboy

Joined: 05 Sep 2008 Posts: 310 Location: Kiel
|
Posted: Wed Jul 14, 2010 6:11 pm Post subject: |
|
|
OK, a problem has surfaced with very large rotating structures.
I have a pretty big rotate_door, which is part of a moving / rotating bridge. Problem is, the thing starts to "flicker" in non-Darkplaces engines, ie from certain angles, the thing becomes invisible.
AFAIK this happens when the thing is in too many vis leafs? portals? It gets much, much worse in a fullvised map. Probably because there are more vis (leafs/portals/whatever).
However: It doesn't happen in Darkplaces. Yay. So there is a way to fix it. (It also doesn't flicker in AguirRe's enhanced GLquake, but that might stem from the fact that BJPquake doesn't support rotating bmodels. The flickering is in my modified Quakespasm - ie a Fitzquake-derived engine). Couldn't test with newest Proquake, which has rotation support, since it can't load the map.
I've also tried turning the rotate_door into a func_wall to see if it still flickers. Nope - the func_wall version does NOT flicker, but of course it also doesn't rotate and hence it can probably not be compared directly.
I'm asking someone like mh, LordHavoc, Baker or other engine capable person to give me a hand here. What does darkplaces do differently when it comes to vis culling? And once we find out, can that fix (I suppose it is a sort of fix) be applied to other engines?
I could probably also chop the thing up into a load of smaller rotate_doors, but I'm afraid this will mess up texturing and/or lighting - I'm glad the thing is textured somewhat correctly.
Why does it work in DP with no flickering, even when fullvised?
What to do? _________________ ReMakeQuake
The Realm of Blog Magic |
|
Back to top |
|
 |
Spike
Joined: 05 Nov 2004 Posts: 944 Location: UK
|
Posted: Wed Jul 14, 2010 6:27 pm Post subject: |
|
|
DP sends bsp ents to all clients regardless of VIS info, last I heard.
So no chance that it can flicker.
Other engines don't quite calculate the absmin/absmax correctly (excessively large), and then drop the ent as it is in half the map (so in too many leafs).
Basically. _________________ What's a signature? |
|
Back to top |
|
 |
Baker

Joined: 14 Mar 2006 Posts: 1538
|
Posted: Wed Jul 14, 2010 6:28 pm Post subject: |
|
|
Could you upload a progs and a sample map so the problem can be examined first hand? _________________ Tomorrow Never Dies. I feel this Tomorrow knocking on the door ... |
|
Back to top |
|
 |
mh

Joined: 12 Jan 2008 Posts: 910
|
Posted: Wed Jul 14, 2010 6:36 pm Post subject: |
|
|
I fixed this in DirectQ a while back, and - if I'm guessing right - you're on the right track with the entity being in too many leafs. Basically what happens is that leafs not in the PVS fill up the allocation of 16 leaf slots that an entity can be in, so it doesn't get sent.
The stock code (SV_WriteEntitiesToClient in sv_main.c, taken from Fitz so it should be relevant to your engine) looks something like: Code: | // ignore if not touching a PV leaf
for (i=0 ; i < ent->num_leafs ; i++)
if (pvs[ent->leafnums[i] >> 3] & (1 << (ent->leafnums[i]&7) ))
break;
if (i == ent->num_leafs)
continue; // not visible |
My replacement looks like: Code: | // link to PVS leafs - deferred to here so that we can compare leafs that are touched to the PVS.
// this is less optimal on one hand as it now needs to be done separately for each client, rather than once
// only (covering all clients), but more optimal on the other as it only needs to hit one leaf and will
// start dropping out of the recursion as soon as it does so. on balance it should be more optimal overall.
ent->touchleaf = false;
SV_FindTouchedLeafs (ent, sv.worldmodel->brushhdr->nodes, pvs);
// if the entity didn't touch any leafs in the pvs don't send it to the client
if (!ent->touchleaf && !sv_novis.integer)
{
//NumCulledEnts++;
continue;
} |
With my SV_FindTouchedLeafs looking like: Code: | /*
===============
SV_FindTouchedLeafs
moved to here, deferred find until we hit actual sending to client, and
added test vs client pvs in finding.
note - if directq is being used as a server, this may increase the server processing
===============
*/
void SV_FindTouchedLeafs (edict_t *ent, mnode_t *node, byte *pvs)
{
mplane_t *splitplane;
int sides;
int leafnum;
loc0:;
// ent already touches a leaf
if (ent->touchleaf) return;
// hit solid
if (node->contents == CONTENTS_SOLID) return;
// add an efrag if the node is a leaf
// this is used for sending ents to the client so it needs to stay
if (node->contents < 0)
{
loc1:;
leafnum = ((mleaf_t *) node) - sv.worldmodel->brushhdr->leafs - 1;
if ((pvs[leafnum >> 3] & (1 << (leafnum & 7))) || sv_novis.integer)
ent->touchleaf = true;
return;
}
// NODE_MIXED
splitplane = node->plane;
sides = BOX_ON_PLANE_SIDE (ent->v.absmin, ent->v.absmax, splitplane);
// recurse down the contacted sides, start dropping out if we hit anything
if ((sides & 1) && !ent->touchleaf && node->children[0]->contents != CONTENTS_SOLID)
{
if (!(sides & 2) && node->children[0]->contents < 0)
{
node = node->children[0];
goto loc1;
}
else if (!(sides & 2))
{
node = node->children[0];
goto loc0;
}
else SV_FindTouchedLeafs (ent, node->children[0], pvs);
}
if ((sides & 2) && !ent->touchleaf && node->children[1]->contents != CONTENTS_SOLID)
{
// test for a leaf and drop out if so, otherwise it's a node so go round again
node = node->children[1];
if (node->contents < 0)
goto loc1;
else goto loc0; // SV_FindTouchedLeafs (ent, node, pvs);
}
} |
The old SV_FindTouchedLeafs in world.c (and the call to it in SV_LinkEdict) is then removed from the codebase.
A more quick and dirty solution would be to increase the define of MAX_ENT_LEAFS to something like 32, but you're going to get some extra memory usage overhead from that. _________________ DirectQ Engine - New release 1.8.666a, 9th August 2010
MHQuake Blog (General)
Direct3D 8 Quake Engines
Last edited by mh on Wed Jul 14, 2010 10:33 pm; edited 1 time in total |
|
Back to top |
|
 |
Spike
Joined: 05 Nov 2004 Posts: 944 Location: UK
|
Posted: Wed Jul 14, 2010 6:54 pm Post subject: |
|
|
q2 tracks the headnode when it overflows.
though alternatively just set some flag that says 'too many' and just ignore which nodes its in. _________________ What's a signature? |
|
Back to top |
|
 |
goldenboy

Joined: 05 Sep 2008 Posts: 310 Location: Kiel
|
Posted: Wed Jul 14, 2010 7:07 pm Post subject: |
|
|
Right, first off thanks you guys for being so helpful. It's cool knowing you.
This bridge has quietly waited for two years until the day we would finally have proper rotation... now we have, and it's rotating brilliantly (even properly textured, which seems odd and might be coincidence), only to be intercepted by the next problem ah well, that is life.
OK. I tried the quick and dirty way that mh suggested first. I had to raise MAX_ENT_LEAFS to 128 before it worked in the fullvised map. But yeah, that does fix it.
So it can be fixed. I'll try mh's cleaner solution next.
Baker, I'll mail it to you. It's a key section of an RMQ map, so I'd rather not link it atm, but I'll send it to any engine coder who's interested. Makes a good test case I guess.
Quote: | DP sends bsp ents to all clients regardless of VIS info, last I heard. |
That sounds like the cleanest possible solution, but it's probably above my skill level to implement that. I only have a basic understanding of the things involved. Engine coding is only done to get maps running in my case.  _________________ ReMakeQuake
The Realm of Blog Magic |
|
Back to top |
|
 |
Spike
Joined: 05 Nov 2004 Posts: 944 Location: UK
|
Posted: Wed Jul 14, 2010 7:12 pm Post subject: |
|
|
From memory, halflife raised the limit to 64. The cheats. :P _________________ What's a signature? |
|
Back to top |
|
 |
mh

Joined: 12 Jan 2008 Posts: 910
|
Posted: Wed Jul 14, 2010 7:15 pm Post subject: |
|
|
I wouldn't mind a copy of it, just to test that my fix actually does work with it, before you make any changes to your own engine.
(deleted stuff that wasn't actually needed; mental note to self: read the original code first!!! )
Also note the nifty "sv_novis" cvar.  _________________ DirectQ Engine - New release 1.8.666a, 9th August 2010
MHQuake Blog (General)
Direct3D 8 Quake Engines
Last edited by mh on Wed Jul 14, 2010 9:50 pm; edited 1 time in total |
|
Back to top |
|
 |
Baker

Joined: 14 Mar 2006 Posts: 1538
|
Posted: Wed Jul 14, 2010 7:41 pm Post subject: |
|
|
goldenboy wrote: | That sounds like the cleanest possible solution, but it's probably above my skill level to implement that. |
My bsp understanding is limited, but I'd guess it is probably just commenting out this in SV_WriteEntitiesToClient in sv_main.c
Code: | for (i=0 ; i < ent->num_leafs ; i++)
if (pvs[ent->leafnums[i] >> 3] & (1 << (ent->leafnums[i]&7) ))
break;
if (i == ent->num_leafs)
continue; // not visible |
mh wrote: | Also note the nifty "sv_novis" cvar.  |
Hmmm  _________________ Tomorrow Never Dies. I feel this Tomorrow knocking on the door ... |
|
Back to top |
|
 |
mh

Joined: 12 Jan 2008 Posts: 910
|
Posted: Wed Jul 14, 2010 7:50 pm Post subject: |
|
|
It's BSP entities only isn't it, so you'd need to get the model name (something like pr_strings + ent->v.model), check if the first char is '*', then ignore the PVS test if so.
It's a solution to this problem for sure, but one I'd be dubious about as there is a possibility of alias or instanced brush models also being big enough enough to need a fix. Add enough models to the mix, take a map that's well stocked with even just inline brush models (like ne_tower for example) and you're entering a world of hurt. I just prefer the more general fix, it seems cleaner overall.
Edit: my code works with this one. _________________ DirectQ Engine - New release 1.8.666a, 9th August 2010
MHQuake Blog (General)
Direct3D 8 Quake Engines |
|
Back to top |
|
 |
goldenboy

Joined: 05 Sep 2008 Posts: 310 Location: Kiel
|
Posted: Wed Jul 14, 2010 9:48 pm Post subject: |
|
|
Confirmed, adapted mh's fix to FitzSDL/QS/RMQ engine. Works like a charm. Giant rotating bmodels, here I come. _________________ ReMakeQuake
The Realm of Blog Magic |
|
Back to top |
|
 |
mh

Joined: 12 Jan 2008 Posts: 910
|
Posted: Wed Jul 14, 2010 10:19 pm Post subject: |
|
|
Oddly enough, it also works perfectly with Enhanced GLQuake (aguirRe's engine) and he doesn't seem to have done anything to particularly fix this one - although I haven't looked too far yet. It does suffer from a "keyname too long" Sys_Error when parsing globals though, on account of the fact that he reduced the max key name length to 32 (from 64). _________________ DirectQ Engine - New release 1.8.666a, 9th August 2010
MHQuake Blog (General)
Direct3D 8 Quake Engines |
|
Back to top |
|
 |
goldenboy

Joined: 05 Sep 2008 Posts: 310 Location: Kiel
|
Posted: Wed Jul 14, 2010 11:20 pm Post subject: |
|
|
Yeah, but I guess it doesn't rotate there.
There is also no flicker when the offending thing is turned into a simple func_wall.
The problem only appears if the thing rotates, and the engine actually supports the rotation, I think. _________________ ReMakeQuake
The Realm of Blog Magic |
|
Back to top |
|
 |
mh

Joined: 12 Jan 2008 Posts: 910
|
|
Back to top |
|
 |
Spike
Joined: 05 Nov 2004 Posts: 944 Location: UK
|
Posted: Wed Jul 14, 2010 11:47 pm Post subject: |
|
|
Quote: |
if (ent->v.solid == SOLID_BSP &&
(ent->v.angles[0] || ent->v.angles[1] || ent->v.angles[2]) )
{ // expand for rotation
float max, v;
int i;
max = 0;
for (i=0 ; i<3 ; i++)
{
v =fabs( ent->v.mins[i]);
if (v > max)
max = v;
v =fabs( ent->v.maxs[i]);
if (v > max)
max = v;
}
for (i=0 ; i<3 ; i++)
{
ent->v.absmin[i] = ent->v.origin[i] - max;
ent->v.absmax[i] = ent->v.origin[i] + max;
}
}
|
that code will pick the biggest axis and assume that all are that large.
On a long thin (bridge) thing, your absmin/absmax is huuuge. It also extends up and down too, by the same distance...
This is even worse if you didn't change the origin in qbsp.
This is why a func_wall is fine, but anything bsp with rotation will flicker, and also why you need so many leafs. _________________ What's a signature? |
|
Back to top |
|
 |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
Powered by phpBB © 2004 phpBB Group
|