Glow Flicker

#1 Hi Cliff,

There might be an underlying problem to it, but I have always had flicker when using glow. Not 100% sure, but I think so.
However, I have found it to be more of an issue when I am using low-res textures and when facing the texture from further away (probably due to mipmapping).

This and the water flicker around edges is definatly the two biggest cosmetical problems.

#2 This issue seems to have gotten significantly worse as time has gone on... Just upgraded our game to 1.0.3 of TGEA and now the glow just gives me funky little splotchy bits when it renders it at all. I notice that it doesn't really look quite right even in the TGEA demo any more, although there the use of glow is minor enough that it doesn't have as strong an effect.

Is there any intention of fixing the glow feature some day? If it doesn't happen, I'll get 'round to fixing it myself eventually, but it's still pretty low on my own list of priorities.

#3 Does this mean that somehow, somewhere, there exists an implementation of glow that never flickers? My world has just turned upside down.

#4 Dunno if I should say this... But contact Matt Vitelli. He's good at shaders and should I say the guru around here... ;) Sorry Matt

#5 Faucet - Your sarcasm is most useful, thank you very much for your help.

A glow is not supposed to look like this:



Please note that the green lines are supposed to have a solid glow, not the little occasional specks of glowing blobs that they have. When I turn, they sometimes look like the glow is accumulating from faces that are hidden rather than visible, but sometimes the glow vanishes completely.

#6 Not quite what I had envisioned when you said "flicker."

Beyond the obvious check drivers, DX runtime, and make sure AA is not on in the card settings:

Transparency, is there any in the scene?
Is the material set to be emissive?
Custom shader?
Did you bork anything in code?

Do you mind posting up your material definition?

#7 Well, it was flickering in January... but it's gotten worse. The flickering back then was also a lot worse than what you would expect. It is worth noting that the above blobby behavior wasn't exhibited until I upgraded to the newest version of TGEA.

Drivers are up to date, though these days going back often helps, but I don't see this in software written in other engines that exhibits glow. DX runtime is 9.0c, and my card settings are all set to let the application decide.

No transparency, not emissive, no custom shader, and I haven't touched the rendering code.

Here's the material definition, which as you can see is extremely simple:

new Material(gridTex) {
  mapTo = "grid_texture";
  
  baseTex[0] = "data/assets/textures/grid_texture";
  glow = true;
};

#8 What happens if you change it to:

glow[0] = true;
emissive[0] = true;

#9 Hrm... a good thought, but all that really happens is the exact shape of the blobs changes. heh.

Am I the only person getting such messed up glow effects in 1.0.3?

#10 I can only think of two other things:

Debug or release build?
Have you tried doing the glow with a different texture dedicated solely to the glow?

#11 Same behavior for both debug and release. I've actually got glow applied to several textures (including the long cylinder you can see in frame in the screenshot) and get similar behavior. The blobs only seem to show up where there's hidden polys behind the ones that are rendering, otherwise there's no glow at all. The flickering behavior from before was exhibited on multiple systems but I haven't had the opportunity to see if the new behavior is also being exhibited on multiple systems.

Once this becomes a higher priority, I'll probably be able to sort it out, I was just curious if this was something I was going to have to fix myself or if GG planned on addressing it. I noticed that the glow in the TGEA demo was exhibiting similar behavior, not identical but the glow is not as distinct as it used to be in the demo, so I thought it might be a broader problem.

#12 Whats with the "map to" function? last time I played with the glow i think I left that out, but I have to wait til next week to be sure, my computer down and im waiting on parts. The only problem I remember well is when i was far away from the glow it was less obvious, that's probably intended though. So I have to ask is there anything about the scaling of your level and/or objects that are scaled, that might do something.....hmmm I know I had this working, Ill try to get at one of the company computers later if you still need help and don't figure this out:)

#13 The map to is because the textures in question are applied to a DIF, so that tells it what texture on the DIF it is applying to.

With RC3.5, it was as you describe, just faint far away but otherwise it worked correctly. Then, with RC4, it got incredibly flickery... not just a little bit, but really bad. No change with 1.0, but then with 1.0.3, it is as most recently described.

Scaling is normal - the player object at this point is still just the little blue box guy, and things are scaled to that.

It seems to be at its worst when the glow is applied to larger areas.

#14 What flickers for you in the TGEA demo? I just flew around the building in TGEA and it looked fine to me.

Could you get a fraps video of the TGEA flickering or something?

#15 Posting it for you could be a problem, I don't really have a good dump point for videos. I'll see if I can sort something out.

#16 I managed to grab a few screenshots... You can see the blobs on the edge. It's not as pronounced, but it's there. Since knowing my hardware might prove useful, I'm on an FX-62 w/ 2GB of 1.1GHz RAM and a GeForce 7950GX2. Here's the screens:

#17 Oh oh oh. 7950GX2 changes everything. The card always runs in a sort of SLI mode, which is why it took so long for Vista drivers for the 7950 that used the card properly.

You're going to want to dig up nVidia's article on programming for SLI, I remember ages ago back in MS3 I had to do some coding for twin 7600s.

If my memory serves me right, TGEA (TSE at the time, prefers rendering Alternate Frames) you'll want to see if in the driver the 7950 will let you pick its SLI mode. I remember it giving artificats on anything involving the backbuffer and glow as well.

You're also going to want to turn off "KillFramesAhead" in your prefences.

On a side note, is anything going on with DRL or HDR? Do you have either on?

#18 Thanks much for all the help you and everyone else has given me. I'll dig into what you've described above.

Regarding DRL and HDR, I don't have them on right now.

#19 Well, now, this is weird. I set my GPU to multi-display mode and then back, and now everything seems fine. That's VERY odd.

Thanks again.

#20 Glad to see you found a fix, though I can't see how that could have fixed it unless the driver was mucking stuff up.