[Sobek]

Hey guys,

I previously bought this up in another thread, but it wasn't really the right one to ask in I think. Basically, if you have a texture with transparency, on most angles it causes any models or other sprites in line with those transparent areas to appear invisible... I don't know what the technical reason is for this (feel free to enlighten me, I'm very curious), but it's such an irritating little glitch to see. If you're working a fair few models and sprites (as I do) it can start to become a bit of a problem. I like to try and create environment details (such as background features) using a combination of models and sprites, but it seems the further away they are, the worse the problem is. If you turn your view to the left or right a bit you can typically find various angles that stop it from happening, but it's apparent most of the time;



You can see how there's a section of transparency around the edges of the leaves that is rendering the texture of the mountain behind it entirely transparent. Sometimes it's much worse though, like I've shown here previously;

http://forums.duke4.net/index.php?showtopi...amp;#entry28442



In that picture, you can see how there's a large blocking sprite, entirely transparent but which the ENTIRE transparent area renders ANYTHING behind it invisible on almost all angles.

Is this something like Z-fighting, where one surface is fighting to stay in the foreground over another (that seems to only affect transparent sections of a texture it seems)? As I mentioned in that linked post, this is also something that only seems to happen in Polymer, too. If there's something I can do to prevent this from happening, please tell me... Starting to drive me nuts

[Sobek]

No one has any thoughts on this issue? Heck, if I've been doing something wrong all this time then I'd love to know... But otherwise, what causes this? And given that it's Polymer-only (and therefore much easier to pinpoint the cause of), I hope it's something that can be 'fixed'.

[Mblackwell]

Is the mountain a skybox? Is it like that in game?

[Gambini]

I reported this issue as many times and to many people as i have spended time around here. You can workaround this changing your filtering settings to near_mm_near but the problem will persist forever i guess. It used to be irritating in Polymost but seems to be even worse in Polymer (in polymer all this kind of sprites seem to have an aura of background culling). However, TX told me once hthat this is very hard to fix.

[Sobek]

Mblackwell, on Jul 16 2010, 01:08 PM, said:

Is the mountain a skybox? Is it like that in game?

The skybox is the pinkish sky in the background, but the mountains are just a couple of sprites.

Gambini, on Jul 16 2010, 01:13 PM, said:

I reported this issue as many times and to many people as i have spended time around here. You can workaround this changing your filtering settings to near_mm_near but the problem will persist forever i guess. It used to be irritating in Polymost but seems to be even worse in Polymer (in polymer all this kind of sprites seem to have an aura of background culling). However, TX told me once hthat this is very hard to fix.

Interesting... See I've ALWAYS used the trilinear filtering with AF at 16x, so I've never used near_mm_near, but I've NEVER had this issue under Polymost that I can recall.

I'm curious, was your discussion with TX about this something public? I'd be very interested to read the explanation about what's happening (even when I don't understand something, I find it very intriguing to read about). I really hope this can be fixed some day. It seems like one of those fairly 'major' graphical bugs that could do with being corrected. When you've got a lot of sprites / textures working together, it can really destroy the feel of a scene when half of it is covered in transparent outlines and such

[Micky C]

The problem is the edges fade into nothing, but there are many engines for which this isn't the case. For example take Aleph One, the source port for the Marathon Trilogy, and is pretty much its version of eduke32 (they're even on their second openGL renderer which now uses a shader model as well - the similarities are uncanny ) Anyway for their sprites, both in game and in the hud as you can see, there is a definite end, even with texture filtering turned on.

[Gambini]

The problem is not with the ¨end¨ of the sprites, the problem is with the translucent pixels. (ít´s the case in Sobek´s shots because the trilinear filter causes these borders to fade into translucent) According to the angle from where it´s looked the translucent pixels cancel the sprites and maskwalls that are behind, this doesn´t happen with walls and floors (at least in polymost) and it´s the main reason of why i didnt use too many transparent sprites in my map blown fuses, which was meant to be used in Polymost.

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Interesting... See I've ALWAYS used the trilinear filtering with AF at 16x, so I've never used near_mm_near, but I've NEVER had this issue under Polymost that I can recall.

Well, just try and see, if you never had this issue before quite likely your scene didn´t meet the conditions that cause it.

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I'm curious, was your discussion with TX about this something public?

I dont recall the words exactly. It happened on a msn chat, after being ignored by years when questioning this issue, i asked him personally. He told me most engines, even the commercial ones, have problems with translucent textures (i can assure this because Source -the engine that powers half life 2 series- also has some kind of troubles managing multiple translucent masks) and this is the best it could be done. He also said that JonofDuke was worse.

But as you see, this kind of questions seem to be inconvenient, i created threads, sent PMs and asked in the proper threads but never received a suitable answer (besides that one i just mentioned which seems fair enough).

[Micky C]

I was merely saying that the texture filtering for that engine didn't cause sprites to have translucent boundaries, but if what we have at the moment is the best it can be then I guess we can't complain.

[TerminX]

Gambini, on Jul 16 2010, 05:26 PM, said:

I dont recall the words exactly. It happened on a msn chat, after being ignored by years when questioning this issue, i asked him personally. He told me most engines, even the commercial ones, have problems with translucent textures (i can assure this because Source -the engine that powers half life 2 series- also has some kind of troubles managing multiple translucent masks) and this is the best it could be done. He also said that JonofDuke was worse.

That conversation was before Polymer was around and thus doesn't apply to it. Polymer still needs a lot of work in this area and the current result is nowhere near the best that can be done, but I don't think Plagman has any time to work on it anymore for the moment.