[T:V Graphics] Spherical clipping

This is one thing that bothers me a bit about ut2k4. It's really annoying when you can see something out of the corner of your eye, but can't see it when it's right in front of you.

To see what I'm talking about, load up t1 or t2 (both implemented this) and have an object where you can just barely see it due to distance. Move your camera so that it appears in each corner of the screen and in the center of your screen. You'll notice that the visibility of that object does NOT change.

Now load up ut2k4. A good illustration is on the onslaught map when you stand on top of the tower with the lightning gun in the base farther from the center obj. If you stand on the edge nearest to the center obj and look towards the top of it, you'll notice that you can't see it. Now move your camera so that it should appear in the corners of your screen, and lo and behold! It appears! Just by putting something in a corner or side of your screen, you can see farther in that direction!

I know it isn't a neat flashy effect, but it makes the overall scene look cleaner. It'd be nice to continue this "tradition" with the next installment of the Tribes franchise :)

this DOES happen in t1/2 if you have your fov at 120

Actually, this thing is present in T1 when you're looking at an oversized sun.

It's present in every game that I've seen. I attribute it to "lazy coding". It's not anything that's really "bad" it just takes slightly less processor power to place a line at distance X from the viewpoint and clip/fogplane there, rather than placing a hemisphere.

I agree it's annoying, but it's not much of a factor in Tribes Gameplay... it matters a lot more in a game like America's Army.

Tycho, somehow I doubt that, but ok... I have the torque engine and have seen the code that does this, and I highly doubt fov has anything to do with it.

This can be very annoying when trying to snipe because you'll be able to see stuff on the sides of your screen, but when you go to snipe something, it just disappears. That's kinda lame, imo.

Actually the effect I see in T1 is somewhat similar, but I think it occurs because of different reasons. When I am zoomed out of a player that is standing behind a hill rather far away, I can sometimes see the top of his/her body through the hill. When I zoom in, I see the actual view of the scene (the player is not visible through the hill).

I think this effect has more to do with the engine taking shortcuts in order to reduce CPU/GPU cycles by not drawing the definitions of the hill as perfectly when you are zoomed out or far away, as when you are zoomed in or close to the hill.

Actually the effect I see in T1 is somewhat similar, but I think it occurs because of different reasons. When I am zoomed out of a player that is standing behind a hill rather far away, I can sometimes see the top of his/her body through the hill. When I zoom in, I see the actual view of the scene (the player is not visible through the hill).

I think this effect has more to do with the engine taking shortcuts in order to reduce CPU/GPU cycles by not drawing the definitions of the hill as perfectly when you are zoomed out or far away, as when you are zoomed in or close to the hill. Yes, this is true.

However it's not the same thing.

Tysoft, somehow I doubt that, but ok... I have the torque engine and have seen the code that does this, and I highly doubt fov has anything to do with it.

This can be very annoying when trying to snipe because you'll be able to see stuff on the sides of your screen, but when you go to snipe something, it just disappears. That's kinda lame, imo.


2 bad tysoft didnt post here

2 bad tycho didnt post here

:lies:


And yeah, apotheosis - there's no "need" to draw fully detailed meshes that are far away. That's the continuous level of detail algorithm that's present in the t1 terrain engine. The t2 terrain engine also implements this. It happens on models too (except non-continuous, they "snap" to LOD's), but you just don't notice it.

You are talking about range based (the spherical one) vs z based fog/clipping. Its not actually laziness from the coders at all :), its a 3d hardware specific thing that you can turn on or off with a single setting. Some cards support it, others don't. Some cards support it really slowly compared to z based, others are faster.

I'm still not sure what we'll use in T:V. The biggest problem with the spherical stuff (other than hardware support) is that in tribes when you get up high, stuff in the distance starts clipping away in a weird spherical shape beneath you... it ends up looking alot worse than using the z based.

That's why you completely fog something out before clipping it, so there's not transition :)

I know torque actually textures the fog onto terrain and interiors. I would guess that unreal just uses default D3D fogging though, so it would be a pain to do it that way.

So that's what the interior texture fog option means

So that's what the interior texture fog option means

Wait, I still dun get it

Fog is textured onto the buildings/terrain instead of going through the graphics API. This gives you some more control over how the fog is applied, i.e. if you want distance based fogging instead of z-based fogging.

You are talking about range based (the spherical one) vs z based fog/clipping. Its not actually laziness from the coders at all :), its a 3d hardware specific thing that you can turn on or off with a single setting. Some cards support it, others don't. Some cards support it really slowly compared to z based, others are faster.

I'm still not sure what we'll use in T:V. The biggest problem with the spherical stuff (other than hardware support) is that in tribes when you get up high, stuff in the distance starts clipping away in a weird spherical shape beneath you... it ends up looking alot worse than using the z based.


so hack the drivers and make it a cylinder.

And also turn up the fps slider.

I'd like distance fog, but it's too iffy for support across the spectrum of cards. Z-fog is much more compatible and you don't have to do extra math to calculate the far clipping plane.

I sure hope the spherical fog isn't used.
It's really annoying for long range weapons, and although I don't think it would be much of a problem in Tribes, it can lead to some strange gameplay situations and exploits.
For example, in America's Army -a game that relies heavily on you spotting the enemy before they do- most of the top teams' machine gunners and snipers scan the landscape with the sides of their monitors, because the fog difference is significant (and I used to play as grenadier/support for a top team... I can tell you, it makes a hell of a difference). Many people have been known to take potshots at targets they spotted this way and land some really devastating blows to the enemy team (and get yourself in a lot of trouble too, since it appears to be cheating on the other side, when it's really just random shooting in someone's general direction).

I seriously don't want to see people in Tribes looking sideways to spot incoming enemies - though given the speeds they should be going at, it shouldn't really be an issue.
Could still be rather annoying from a strictly aesthetic point of view.

There will be a not of no-fog accusations if they use spherical fog. I'm completely against it.

Err. Isn't spherical clipping what *prevents* the problems that Hobbiticus is discussing?

I sure hope the spherical fog isn't used.
It's really annoying for long range weapons, and although I don't think it would be much of a problem in Tribes, it can lead to some strange gameplay situations and exploits.
For example, in America's Army -a game that relies heavily on you spotting the enemy before they do- most of the top teams' machine gunners and snipers scan the landscape with the sides of their monitors, because the fog difference is significant (and I used to play as grenadier/support for a top team... I can tell you, it makes a hell of a difference). Many people have been known to take potshots at targets they spotted this way and land some really devastating blows to the enemy team (and get yourself in a lot of trouble too, since it appears to be cheating on the other side, when it's really just random shooting in someone's general direction).

I seriously don't want to see people in Tribes looking sideways to spot incoming enemies - though given the speeds they should be going at, it shouldn't really be an issue.
Could still be rather annoying from a strictly aesthetic point of view.

I like to think the giant red triangles also help to keep this problem away from the tribes world.