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Alientank

The solution to running Doom 3 on high detail

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I'm pretty sure any present high-end processor can do the job for DOOM III.

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We haven't seen any outdoor areas in that e3 demo so we don't know how it would handle in big areas

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Alientank said:

WHA? That chip will really help with Doom 3


The fact that it's 64bit doesn't mean that processors build on this chip be the perfect solution for DOOM! Like Maonth, said, any present high-end processor can do the job for DOOM III.

I'm not gonna explain now why won't it help, but remember one thing: 64bit is NOT needed! Now 64bit in color depth - that's a totaly different story :)

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Alientank said:

We haven't seen any outdoor areas in that e3 demo so we don't know how it would handle in big areas


Well. The shakycam man didn't get the intro on 'tape'. The intro showed a Mars landscape and noone said it was low on FPS, so i'm pretty sure it handles it ok.

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Dima said:

The fact that it's 64bit doesn't mean that processors build on this chip be the perfect solution for DOOM! Like Maonth, said, any present high-end processor can do the job for DOOM III.

I'm not gonna explain now why won't it help, but remember one thing: 64bit is NOT needed! Now 64bit in color depth - that's a totaly different story :)


It's not the fact that its 64-bit, it's the fact that the chip goes over 3 ghz. I know it's not mentioned in the interview but you have to look around at other previews

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Dima said:

The fact that it's 64bit doesn't mean that processors build on this chip be the perfect solution for DOOM! Like Maonth, said, any present high-end processor can do the job for DOOM III.

I'm not gonna explain now why won't it help, but remember one thing: 64bit is NOT needed! Now 64bit in color depth - that's a totaly different story :)


Hmm. I can hardly tell the difference between 24 and 32bit depth. Why 64?

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Alientank said:

We haven't seen any outdoor areas in that e3 demo so we don't know how it would handle in big areas


We haven't seen them cause they weren't shown in the videos released, even though that 11 minute video should have shown one such area.

We're currently zooming over the Martian landscape, passing over a massive installation of the Union Aerospace Corporation. Inside, a number of guards are chatting as a scientist passes by and sneaks into a nearby room.

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Shaviro said:

Hmm. I can hardly tell the difference between 24 and 32bit depth. Why 64?


Cause Carmack wants so! :)

Seriously, read some of the older Carmack .plan updates and see for youself why it is so needed!

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Dima said:

Cause Carmack wants so! :)

Seriously, read some of the older Carmack .plan updates and see for youself why it is so needed!


I'm too lazy to find them for myself. Do you have links by any chance?

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Shaviro said:

Freaky letters! Now where did i hear that 64bit thing, then? :|


Probably in the NV30 rumour specs :)

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Shaviro said:

Hmm. I can hardly tell the difference between 24 and 32bit depth. Why 64?

That's not strange at all because 24 and 32 bit are the same. Except in 32bit, colors are stored as single 4 byte integers with one dummy/alpha byte rather than 3 separate bytes, which makes 32bit color about 3x faster than 24bit.

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Lemme quote from this article Zaldron wrote:


... Imagine you´re doing 20 passes over a pixel. Why? it doesn´t matter now, but Carmack´s doing it. Now, the only thing you can do to a pixel is changing it´s color. You have the input color, wich is based on the texture you´re using for that polygon. This data is commonly referred as RGB values, and they are often valued as 3 numbers ranging from 0 to 255 (the Red, Green and Blue components). However, in OpenGL, these 256 variations for each tone are expressed in a real number located between 0 and 1 (This was done for greater speed on calculations).

The math involved with pixel lighting and stuff is very complex to act as an example. To show the precision problem, I will use a simple equation. For some reason I want to reduce in half the brightness of a pixel several times. Each time I do it is a pass. We have 1 as the first value, and this will be the result after 5 passes.

1 : 1 / 2 = 0.5
2 : 0.5 / 2 = 0.25
3 : 0.25 / 2 = 0.125
4 : 0.125 / 2 = 0.0625
5 : 0.0625 / 2 = 0.03125

0.03125 would be the real result of the calculation. However, these RGB values don´t have that much precision. Imagine that the system just processes 2 digits after the 0 :

1 : 1 / 2 = 0.5
2 : 0.5 / 2 = 0.25
3 : 0.25 / 2 = 0.12
4 : 0.12 / 2 = 0.06
5 : 0.06 / 2 = 0.03

0.03 is very distant from 0.03125, and that error will be visible in the screen. Since there are many numbers close to "1" that will finish receiving a result of "0.03" many pixels that should look like a gradient of shades will have the same color. This is called "banding" cause the light intensity on the surfaces changes after a couple of pixels, making concentric "rings" of different intensity. This won´t be too noticeable on DooM3, Carmack´s doing everything he can to diminish the effect, although this would be awfully noticeable when several lights are placed almost in the same coords (for more info about this check Carmack´s .plan file).
In conclusion, what good would 64 bit precision do? With these extra bits, developers are able to store the rest of the digits involved in the operation. This is called "mantissa" (this is how ancient romans called fractional portions of a number). This little inconvenience may sound problematic, but the whole new world that dynamic lighting provides to developers, modders and gamers will be so dramatic that the problem will not be a priority until several years.

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We're currently zooming over the Martian landscape, passing over a massive installation of the Union Aerospace Corporation. Inside, a number of guards are chatting as a scientist passes by and sneaks into a nearby room.


Mind if I ask what article this was from? The shakycam footage shows the scientist bumping one guard (who's talking to our character) then walking into the room...doesn't sound like the landscape scene is too long by the sounds of it.

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Sorry, I should have been more specific- I know the shakycam guy misses the intro. I meant that the actual presentation's intro, that shows the massive Martian landscape, according to the text description of it, doesn't seem to be long as it (description) says that it then follows into the scientist sneaking into the room.

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The difference between the normal 32 bits processor and a 64 bits processor is the amount of bits than can be loaded in the CPU per clock cycle. When loaded in the CPU the CPU can do its math (as defined in the instruction set) and return again 32 bits to the memory.

Off course application have to be addapted to make use of 64-bits processors.

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Livo said:

Mind if I ask what article this was from? The shakycam footage shows the scientist bumping one guard (who's talking to our character) then walking into the room...doesn't sound like the landscape scene is too long by the sounds of it.

Just being nitpicky here: The guard is not talking to OUR character (this guy's wearing different armour which isn't green) and that article doesn't explain the specifics, only the rough events - the scientist walks by two guards chatting (doesn't mention that he actually bumbs into one of 'em) and sneaks (well, he doesn't really SNEAK, but he's walking cautiously) into a room...

And I don't give a hoot about current hardware, I'm confident that Doom 3 will run well on what will be standard systems when it's out. I'll wait until Doom 3's released before I upgrade.

So far, the things I need to upgrade:
1. CPU - my current CPU is a Duron 600 Mhz, that's NOT satisfactory.
2. Graphics card - self explanatory.
3. just to get the best experience, sound card - my current soundcard is decent, but it's rather old now and I doubt it'd support Dolby 5.1

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Ah, thanks dsm...I guess I was confused by the first scene guy's armour and his helmet, which I think he was holding underneath his arm. I don't know why I used the phrase "sneaking", its obvious that the scientist is nervous and concerned about something, but he's not doing a very good job of hiding it :)

Back on topic- I suggest saving for the best graphics card that can handle Doom 3 in the future, that card will probably come out next year. (watch out for Carmack's comments on any contenders in the future or next year). Whether that card supports DX 8 better than DX 9 or vice versa depends on any possible DX 9 support for D3 (as Doom 3 will be optimised for one, maybe both but its doubtful).

Keep your RAM and CPU fairly up to date as well, or just wait until a definite release date is confirmed, then just before it, upgrade your computer with all those parts.

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Fredrik said:

Will my 1.4ghz Athlon / 512MB DDR RAM be sufficient? Hmm... yeah.


You will probably need a new GPU, though.

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