Directx10 v Directx11

[Greebo]

Honestly it may surprise a few but after the 3D day at overclockers I drastically changed my mind on 3D, for me it’s the next big thing, particularly the 3D Camera, as ‘the man in the street’ will be very impressed – not to mention the gamming for ‘us’ enthusiasts.

I know ATI have given Nvidia a right kicking and that Nvidia have acted disgracefully, but the 3D technology is truly amazing and I hope ATI can somehow get it!

Sorry to go off topic...

Although impressive i prefer dx11 with 3 or 6 screens with ATI for the full on immersion....

Although 3d is going to be the next big thing with sky launching 3d boxes and channels soon and lots of 3d capable tv's coming out.

 

[Rroff]

Tessellation is nothing to do with textures.. Tessellation is the ability for the hardware to increase the number of verticies in an object to give more detail. This has nothing to do with textures.

EX : a mans head. You have

- a texture ( image )
- a 3d model

Basically lets say you create teh head with 1000 verticies ( x, y, z points etc ).

When you render the model to screen and apply the texture you see the head. Now with a 1000 points this head will look basic. Tessellation is adding new points to this model at run time to give more detail. More curves ( take a sphere with 100 verticies or a sphere with 10000 verticies...get the idea )...

Well basically developers can keep models at same size as they have been and use dx11 with new hardware to allow it to add those extra verticies without too much overhead...Result giving more details object...Not textures.

It isn't completely unrelated to the textures... each surface thats been tessellated in the heaven benchmark has a low detail mesh and a normal or displacement map associated with it... the tessellator has extruded extra data based on the data in that normal/displacement texture and the basic mesh. There may be some developers' hints as well as to the final version of the geometry - I've not looked at that part in detail to know what they can and can't do.

The best the tessellator can do is extrude and then smooth the original data to produce more detail in actual 3D space - it can't reproduce missing data so its a bit like upscaling a DVD to HD resolution - it works quite well but it doesn't look anything like as good as if you made the original geometry and textures at a higher detail to start with - and in this day and age its possible to make very high detail worlds offline and crunch them down to acceptable performance levels and still look better than tessellation - there aren't the same restrictions on VRAM, bus bandwidth, etc. as there used to be.

 

[wiak]

Dirt 2 is included with many ATI Radeon HD 5800/5700 cards

 

[rancid_elf]

It isn't completely unrelated to the textures... each surface thats been tessellated in the heaven benchmark has a low detail mesh and a normal or displacement map associated with it... the tessellator has extruded extra data based on the data in that normal/displacement texture and the basic mesh. There may be some developers' hints as well as to the final version of the geometry - I've not looked at that part in detail to know what they can and can't do.

The best the tessellator can do is extrude and then smooth the original data to produce more detail in actual 3D space - it can't reproduce missing data so its a bit like upscaling a DVD to HD resolution - it works quite well but it doesn't look anything like as good as if you made the original geometry and textures at a higher detail to start with - and in this day and age its possible to make very high detail worlds offline and crunch them down to acceptable performance levels and still look better than tessellation - there aren't the same restrictions on VRAM, bus bandwidth, etc. as there used to be.

Yes you are right in many ways. What I was mainly pointing out pointing out was the emphasis on texture memory. For example we are currently adding dx11 tesellation into our 3d engine and the results are superb. This is without any major difference on texture space or model space.

 

[Lightnix]

it looks amazing cant imagine how good an rpg would look with such technology. however developers are focused on consoles and we wont dx11 only games until 2011-2012 when the next gen consoles are estimated to come out.

I'd find it quite amusing if developers suddenly thought the tessellation unit on the 360 was a good idea. I mean that'd translate reasonably well to DirectX 11 (albeit they'd have to transfer the stuff they were doing in vertex shaders on the 360 into the domain shaders on the DX 11 cards).

 

[Rroff]

Yes you are right in many ways. What I was mainly pointing out pointing out was the emphasis on texture memory. For example we are currently adding dx11 tesellation into our 3d engine and the results are superb. This is without any major difference on texture space or model space.

I agree his comments on texture "detail" usage were a bit off the mark.

I still believe that doing your tessellation offline is the better approach - sure you end up with 3x as much geometry data for your level - but you can decimate the final high detail geometry with a progressive detail tool by around 60% compared to tessellation with the same apparent level of detail to the gamer and don't require hardware support on the GPU... aslong as you have a competent LOD system it should also perform better even with the same level of detail. Making decent use of batching should also result in a much lower drop in performance than otherwise.

 

[Orangey]

I'd find it quite amusing if developers suddenly thought the tessellation unit on the 360 was a good idea. I mean that'd translate reasonably well to DirectX 11 (albeit they'd have to transfer the stuff they were doing in vertex shaders on the 360 into the domain shaders on the DX 11 cards).

Correct me if I'm wrong but I think Mass Effect used tessellation on 360 but not PC, for obvious reasons.

edit: Apparently Viva Pinata did use it too, that was a great-looking game.

 

[Lightnix]

Correct me if I'm wrong but I think Mass Effect used tessellation on 360 but not PC, for obvious reasons.

edit: Apparently Viva Pinata did use it too, that was a great-looking game.

Yep, they did, although I wouldn't consider 2 games to be particularly wide spread usage. Although I really like how Viva Pinata used it because it shows it's usable both for practical purposes and to make things more pretty.

I quite like this tessellation. I think some of the demos we're seeing of it are a bit limited though. I'd quite like to see tessellation put to use in more of a dynamic way.

Imagine your character is walking through a snow field, in a contemporary game, you might be lucky if the footprints your character lays down have any kind of depth at all, they're usually just flat textures and they'll probably disappear in a few seconds. Now imagine that every footstep your character takes, a real dent is put in the snow in the shape of his shoe, you can see the details of that shoe in the mesh. That is realism, and is perfectly viable with DirectX 11's tessellation techniques. What's more is this won't take a huge toll on performance, as you can tessellate only the patch that the character stepped on. Genius!

 

[titaniumx3]

I agree his comments on texture "detail" usage were a bit off the mark.

I still believe that doing your tessellation offline is the better approach - sure you end up with 3x as much geometry data for your level - but you can decimate the final high detail geometry with a progressive detail tool by around 60% compared to tessellation with the same apparent level of detail to the gamer and don't require hardware support on the GPU... aslong as you have a competent LOD system it should also perform better even with the same level of detail. Making decent use of batching should also result in a much lower drop in performance than otherwise.

Can you provide examples of any games that do this?

 

[rancid_elf]

Can you provide examples of any games that do this?

Just check out the unreal 3 engine. It does exactly as he is saying.

This is an extract from the unreal engine desciption.

Meshes Mesh Loading, Skinning, Progressive, Tessellation, Deformation:
• Most of our characters are built from two meshes: a realtime mesh with thousands of triangles, and a detail mesh with millions of triangles. We provide a distributed-computing application which raytraces the detail mesh and, from its high-polygon geometry, generates a normal map that is applied to the realtime mesh when rendering. The result is in-game objects with all of the lighting detail of the high poly mesh, but that are still easily rendered in real time.

 

[Rroff]

I can't think of any off the top of my head - most developers favor using parallax occlusion mapping or just plain old normal maps instead as its a lot less work.

I don't think the unreal 3 engine uses it extensively... a few engines use simple LOD on certain meshes/object instances but I don't know of any engine that has that implemented as part of the main pipeline.

 

[asoxedri]

this, AMD have had the ability to do a large portion of whats new in DX10, since their 2900xt, Nvidia made a card that simply couldn't do it, and had MS change the DX10 spec.

The thing of it is, you literally can't store bump maps detailed enough for what you can do in a tesselator, without one. Its simply too much info, without hardware acceleration every single little texture in the game will be a lot bigger.

Yes, as I always try to say, DX11, dx10, dx4, the end quality is 100% down to the designers. But in terms of games, almost every single decision involved in building a game, from the engine through the gameplay, comes from a comprismise, if you have hugely high detail textures with ludicrous detail in depth, then well thats a comprimise that means insanely lower framerates, very limited use of a nicer effect, or something as simple as, you can have higher detail textures, but then we can't afford(in terms of performance) to use HDR, or complex lighting.

With tesselation, you're reducing the overhead of such detailed textures immensely, basically with a similar amount of space in memory and power to use, you can run the data through the hardware and end up with a far more detailed image and as you can see, that means less dull/flat walls, floors and everything else.

Why do I think you just explained the difference between 10 and 11?!

 

[varkanoid]

Everything is in place we just NEEEEEEED game developers to move their butts as AMD/Microsoft have,

is that not the problem though. New Graphics cards coming out before the games. Why should a developer do Directx11 game when about 1% of PC owners have DX11 cards. Hardly smacks profit does it not ?

When a new console comes out there are at least 5+ games out there for it. When a new Graphics card comes out like the 5800 series there are 0 Z-E-R-O games out for at least 6 months !

At least its not a totally waste and improvements in speed etc are still there but its like buying a car which runs on electricity and diesel but only being about to run it on diesel until you get the electric charger for it in 6 months time.

How many DX 10.1 games are out now ? How many non OcUK PC users can afford a £200+ 5850 or even know the benefits ? Its all unknown figures.

What I am trying to say is the PC model for Graphic card release needs to change. Developers should be getting DX11 games on the shelves when the cards come out same time. Trouble is it will never happen due to money. Catch 22.

 

[Broken Hope]

5870 takes a big hit using it so I dread to think how it would run on either of those, it probably wouldn't be worth implementing for performance reasons.

I bet those who bought 4870x2 over 5870 in recent weeks are smarting a bit.

I don't think that it will be such a bit hit in actual games, the benchmark isn't using it all that smartly.

I mean there is absolutely no reason to use this level of Tessellation on a door.

http://home.akku.tv/~akku38901/B3D/hosted/doorgp.jpg

 

[Rroff]

I don't think that it will be such a bit hit in actual games, the benchmark isn't using it all that smartly.

I mean there is absolutely no reason to use this level of Tessellation on a door.

http://home.akku.tv/~akku38901/B3D/hosted/doorgp.jpg

Tessellation really ain't that smart... look at the small rocks in the forground - theres loads of places where theres 4 polygons in a square but the angles are so slightly different you could cover the whole thing with 2 ploygons and the player would never notice the difference.

Infact a lot of stuff in that screen shot thats only at a slight distance could be using half the level of detail and you simply wouldn't be able to tell.