Prey demo on Xbox Live Marketplace

[Dave Baumann]

For Normal Maps, there's not much choice, it's either DXTC5 Texture compression, with or without the Alpha Channel tricks, 3Dc (ATI2) is an "hardwired shader trick" on DXTC5, Palletized or no compression at all.

Prey already does use DXTC5 with the Alpha channel trick, I think, so I don't imagine using 3Dc would change anything from a texture quality/quantity standpoint. It would help a bit from a Shader workload perspective, but I don't see Prey being heavy on the Xenos Shader Arrays, to begin with.

How is 3Dc a shader saving in relation to DXT5?

 

[Farid]

As far as I know the DXTC5 tricks are implemented via Pixel Shader operations. No?

 

[Rys]

Because you have to spend an instruction or two decompressing from DXT5 in the pixelshader, if the hardware doesn't support it. Think of how NVIDIA support 3Dc in the driver.

 

[Platon]

And I don't know where you got the idea that anyone was suggesting otherwise.

Even if they were photos from a camera, that wouldn't change the fact that the 360 isn't rendering any light bloom or using any anti-aliasing.

...

 

[Powderkeg]

They must be hitting texture memory size limitations to need to drop the texture res as much as they did in some spots.

I bet it's a memory bandwidth issue. Only 22.5GB/Sec to split between both the CPU and GPU is a pretty big limitation to try to overcome.

 

[Dave Baumann]

Because you have to spend an instruction or two decompressing from DXT5 in the pixelshader, if the hardware doesn't support it. Think of how NVIDIA support 3Dc in the driver.

I thought they just compress to a two component format.

However, there's should always be a qualative or performance advantage relative to DXt5 formats. You can get the same quality but at a higher sampling cost or you can get the same performance at a lower quality.

 

[Acert93]

Why would it be important?
3Dc is a qualitative format, not a quantitative one.

For Normal Maps, there's not much choice, it's either DXTC5 Texture compression, with or without the Alpha Channel tricks, 3Dc (ATI2) is an "hardwired shader trick" on DXTC5, Palletized or no compression at all.

Prey already does use DXTC5 with the Alpha channel trick, I think, so I don't imagine using 3Dc would change anything from a texture quality/quantity standpoint. It would help a bit from a Shader workload perspective, but I don't see Prey being heavy on the Xenos Shader Arrays, to begin with.

From the press information ATI provided it was made to appear that 3Dc can give either similar normal map quality with a smaller footprint /or/ with the same footprint higher quality. e.g. http://www.tomshardware.com/2004/05/04/ati/page7.html

Based on this picture 3Dc can be used for normal map compression and the summary given is that 3Dc, "[Thanks to the compression] ... allow for more detailed normal maps of the same file size". So my question was, with the gripes about normal mapping quality, were they not using 3Dc? It does require 2 additional shader instructions to use and based on the quality of some PC ports (and the fact 3Dc is not a standard format being used in the PC space) I think it is an interesting question. If anything I wonder if Venom had the time to make the effort to save all the normals in the format to begin with.

However, there's should always be a qualative or performance advantage relative to DXt5 formats. You can get the same quality but at a higher sampling cost or you can get the same performance at a lower quality.

That is what I got out of reading the ATI PR, of course I am a noob I wonder how big a project it would be to convert all a games normals to 3Dc and then to test it?

 

[Rys]

I thought they just compress to a two component format.

However, there's should always be a qualative or performance advantage relative to DXt5 formats. You can get the same quality but at a higher sampling cost or you can get the same performance at a lower quality.

Agreed. As for NVIDIA 3Dc support, I always assumed it was emulate ATI2N via V8U8 and decompress using an instruction or two in the fragment hardware (developer doesn't need to do that, but it's not a 'single cycle' decompression as with ATI hardware).

 

[Richard]

Remember that Doom3 does stencil shadows and performs all skinning on the CPU to do silhouette extraction.

Let me just segway for a sec; if you meant DOOM 3 the game that is correct, but Quake 4 for instance already shifted more skinning work to the GPU.

 

[Farid]

Acert, Ati PR addresses the plain DXTC5 and/or no compression solutions only. They do not address the Alpha channel trick that, interestingly, Ati was among the firsts to publish sample code for it, IIRC.

 

[Skrying]

Can someone tell me why the 360's Prey demo comes in at a HUGE 1.2GB yet the PC version is not even 500MB? If anything, I would have expected the 360 version to be smaller.

As for the visuals, the Xbox 360 version is pretty obiviously worse, but that means nothing at all for what it can achieve, or what a PC can really if it was given dedicated coding itself. The fact though, is that the coming generation will gets LOTS of ports, more than ever before, so some of you better get use to this unless some dev houses get great tools for porting titles.

 

[Sis]

I recently played this: I absolutely loved it. I agree with the earlier comments about the graphic quality--I'm hoping the released version is of better quality, which seems to be most often the case with Xbox Live demos. Anyway, I thought the voice acting and initial story was very well done. I was immediately drawn to the lead character, Tommy, and was emotionally connected to the characters that he himself was connected to. I also thought the animation was very good, especially in the barroom scenes; can someone with a better eye examine it? I was really impressed with the way the developers used standard dialog and player-driven interaction to move the story; it felt very natural.

I would also add that I generally dislike this kind of FPS; playing Duck Hunt with mindless enemies is generally boring (my daughter calls them "pop-up people", because the tend to just pop up out of nowhere; I think most FPS fans know this as "monster closets").

Anyway, this demo sold me on the game; I will definitely buy this after initially thinking of it as a Turok wannabe.

 

[Proelite]

wrong choice in gpu perhaps? (or do u want a more politically correct answer, ok then now the xb360 gpu is a great idea from a forward thinking perspective but its a prototype/experiment aka something u dont wanna ship, yet they have in the xb360!!! a fixed plaform, why i dont know perhaps the decision taker at ms was a gambler on crack)
we will hear lots about this over the coming years when the xb360 runs games at a lot lower frame rates than pcs/other consoles (*)

(*)dont get me wrong the xb360 gpu is still a good deal for the money, its just far from ideal; ie its a intel p4

How could someone be this ignorant?

 

[overclocked]

Let me just segway for a sec; if you meant DOOM 3 the game that is correct, but Quake 4 for instance already shifted more skinning work to the GPU.

Thats interesting, do you have more info on the specific workloads and task that been brought over from the CPU to VS-programs, or links?

 

[Richard]

Thats interesting, do you have more info on the specific workloads and task that been brought over from the CPU to VS-programs, or links?

Not really, no. When I talked to Raven Software about the enhancements in D3 they were doing for Q4 they specifically mentioned the new skinning path (you can enable it with "r_usenewskinning 1" in the console). They did briefly mentioned that the xbox version had quite a lot more changes though.

 

[Malibu]

Can someone tell me why the 360's Prey demo comes in at a HUGE 1.2GB yet the PC version is not even 500MB? If anything, I would have expected the 360 version to be smaller.

The 360 demo uses packets to load and cache levels and textures.

 

[BenSkywalker]

They must be hitting texture memory size limitations to need to drop the texture res as much as they did in some spots.

My 128MB R9800Pro has significantly higher res textures then the 360 version.

AA is being utilized, most of the horrific aliasing appears to be from normal maps/textures. At first I was thinking AA wasn't enabled also, but if you get to an area not covered with normal maps you can clearly see that the edge AA is actually working quite nicely. I had this game preordered for the 360- that is cancelled now. This is certainly the poorest port I have seen to date. As a point of reference- I picked up Oblivion on the 360 because it ran significantly better then it did on my PC, I picked up TR:Legends for the 360 because it was in an entirely different league then my PC. For Prey, my PC obliterates what the 360 is showing me. This is a very, very poor port.

 

[StefanS]

For Prey, my PC obliterates what the 360 is showing me. This is a very, very poor port.

Well, how is it compared to Quake4 on X360? That probably would make for a better indicator to tell how bad the port really is.

 

[swaaye]

LOL Well if you read the Q4 360 reviews one can only come to the conclusion that it's a terrible experience on the machine. It sounds like it's frequently a slideshow on the console.
http://www.gamespot.com/xbox360/action/quake4/index.html
http://www.gamespot.com/xbox360/action/quake4/player_review.html?id=325301
http://www.gamespot.com/xbox360/action/quake4/player_review.html?id=333803 (<- this guy mentions the console's fan is running low and he thinks that signifies that the CPU is mostly idle. As in it's hardly multithreaded.)

Uhg, Quake 4 was such a disappointment as a game in general. I literally just stopped playing it maybe 1/4 the way thru. And I was playing it smoothly on a 9700 Pro, lol.

 

[kyleb]

At first I was thinking AA wasn't enabled also, but if you get to an area not covered with normal maps you can clearly see that the edge AA is actually working quite nicely.

Not on my 360 or in the 360 shots in this thread.