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Old 18-Jun-2012, 16:50   #1
Persistantthug
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Default Is programing "to the metal" on XBOX 360 forbidden?

Is it true that when making an XBOX 360 game, DIRECT X must be used/employed and programing without Microsoft's API is forbidden?



I saw a posting where someone may have implied this months ago when my computer was down (my mobile browser will not allow me to post here for some reason), but I've been wanting to clarify this and perhaps get a little more information on this.

Thank you.
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Old 18-Jun-2012, 17:03   #2
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Yes but its much closer to the metal than Windows Direct X
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Old 18-Jun-2012, 17:48   #3
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You have to understand what DirectX really does on a console.
The GPU has a ring buffer (actually this isn't strictly true on all hardware, but it's close enough) When you execute a DirectX command most of the time it just copies the command into the ring buffer.
The place where it gets "fiddly" is that there isn't a 1:1 correspondence between State and Hardware registers and shader constants aren't quite as neat as they appear in the API.
The 360 version of "DirectX", exposes pretty much all of the additional functionality of the chip, including calling precompiled display lists.
You'd get virtually nothing going straight to the hardware, you'd pretty much have to write the same wrapper and manage the circular buffer yourself.
The only thing it has in common with DirectX on a PC is the API looks similar.

On a PC it's different partly because of ring transitions, partly the old pre DX11 driver model and partly because PC Drivers try and optimize/fix bad useage patterns by the application when Draw Prim is called.
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Old 22-Jun-2012, 11:34   #4
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Quote:
Originally Posted by ERP View Post
You have to understand what DirectX really does on a console.
The GPU has a ring buffer (actually this isn't strictly true on all hardware, but it's close enough) When you execute a DirectX command most of the time it just copies the command into the ring buffer.
The place where it gets "fiddly" is that there isn't a 1:1 correspondence between State and Hardware registers and shader constants aren't quite as neat as they appear in the API.
The 360 version of "DirectX", exposes pretty much all of the additional functionality of the chip, including calling precompiled display lists.
You'd get virtually nothing going straight to the hardware, you'd pretty much have to write the same wrapper and manage the circular buffer yourself.
The only thing it has in common with DirectX on a PC is the API looks similar.

On a PC it's different partly because of ring transitions, partly the old pre DX11 driver model and partly because PC Drivers try and optimize/fix bad useage patterns by the application when Draw Prim is called.
I thought exclusive games (when given similar budgets and skilled developers) couldn't be compared because the 360 must use DirectX which would limit performance: for example forza 5 versus GT 5? At least that is what a good friend (who is a developer) told me. He says the 360 should be able to have even better graphics, but it can't because of the direct X overhead.
So is he wrong?
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Old 22-Jun-2012, 11:56   #5
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You use some form of API regardless of the console. Whether it's DirectX, libGCM or whatever else. On consoles these APIs are super thin and penalties are close to none (and you learn where they are not minuscule). There's no "coding to the metal" anymore, it's pretty much a myth. You'd have to build some reasonable layer on top of the "metal" anyways so instead of reinventing the wheel (and making many, many mistakes) you use the API provided. The only thing common between DirectX on Xbox 360 and PC is the look and feel of the API, but the core principals are different. There's no DXGI driver below because you don't need any abstraction for various hardware. There's no dynamic linking to the DLL - it's a static lib AFAIK and since you use WPO unneeded parts are stripped and stuff gets inlined nicely where possible. With PGO you get even more improvements. Your friend probably saw an API and assumed it's the same stack Windows has. It isn't.
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Old 22-Jun-2012, 12:45   #6
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What about on the CPU side? Dot they let you code anything ASM? Or is the compiler considered good enough? I come from the DSP world where not writing ASM seems very foreign, lol.
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Old 22-Jun-2012, 14:25   #7
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Close to the metal programming is not forbidden. It's widely used.

For example you can program your shaders directly in GPU microcode, you can directly write to ring buffer, you can give GPU pure pointers to fetch data (instead of using DirectX managed objects), etc. Coding in assembler/intrinsics is of course allowed. How else could you write vectorized code (VMX128)? You also need asm/intrinsics for manual cache control. So basically you can't live without asm/intrinsics. VMX and manual cache control are both very much required for performance critical parts of the code.
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Old 22-Jun-2012, 15:32   #8
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Quote:
Originally Posted by sebbbi View Post
Close to the metal programming is not forbidden. It's widely used.

For example you can program your shaders directly in GPU microcode, you can directly write to ring buffer, you can give GPU pure pointers to fetch data (instead of using DirectX managed objects), etc. Coding in assembler/intrinsics is of course allowed. How else could you write vectorized code (VMX128)? You also need asm/intrinsics for manual cache control. So basically you can't live without asm/intrinsics. VMX and manual cache control are both very much required for performance critical parts of the code.
Wow! (I looked at your posts and learned you are part of a (great I must add) developer) So it turns out "close to the metal programming is forbidden" was just a hoax .. that's strange. I will confront my friend with this knowledge
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Old 06-Oct-2012, 15:21   #9
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Just came across this:


Quote:
Originally Posted by gamesindustry.biz

http://www.gamesindustry.biz/article...-power-of-xbox

343 Industries: Halo 4 and the untapped power of Xbox

This generation of consoles isn't dead yet, says Frank O'Connor. And his latest game will prove it


[...]

But I would actually strongly contest the fact that the Xbox 360 is at the end of its life cycle, this has already been one of the longest generations and there's a really good reason for it, which is that current consoles are incredibly flexible and still really powerful. The reason that Halo 4 looks good is that that machine has an awful lot of untapped power still and it's going to continue to.

[...]

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Old 06-Oct-2012, 20:19   #10
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Quote:
Originally Posted by user542745831 View Post
Just came across this:





This is the one case where the argument "it's just clever art" actually is true, but the developers now mention "untapped power"?

A real case of untapped power is comparing ZOE1 to ZOE2. Or Halo3 to Halo: Reach.
In the case of Reach to 4; it's art.
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Old 06-Oct-2012, 20:26   #11
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Quote:
Originally Posted by antwan View Post
This is the one case where the argument "it's just clever art" actually is true, but the developers now mention "untapped power"?

A real case of untapped power is comparing ZOE1 to ZOE2. Or Halo3 to Halo: Reach.
In the case of Reach to 4; it's art.
I don't think so... have you seen new gameplay? it doesn't looks like "it is only art".
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Old 06-Oct-2012, 20:32   #12
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I don't think so... have you seen new gameplay? it doesn't looks like "it is only art".
I have only seen the beta footage where they removed the motion blur, the HDR, the lighting from the energy weapons, explosions, while adding some shadows on characters and the player weapon, improving the horizontal resolution by 9-10% and switching AA method. But aside from that, yes, the improvements in the overall graphics are due to art.
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Old 06-Oct-2012, 21:20   #13
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Quote:
Originally Posted by antwan View Post
I have only seen the beta footage where they removed the motion blur, the HDR, the lighting from the energy weapons, explosions, while adding some shadows on characters and the player weapon, improving the horizontal resolution by 9-10% and switching AA method. But aside from that, yes, the improvements in the overall graphics are due to art.
Quote:
There are a lot of improvements, aside IQ, the lighting better than Reach, animations are really good (better than Reach), AA, textures, etc.




And some new lightningt and particles efects:




And plasma cast light as in Reach:



And I guess HDR is still there:

EDIT: I got it, you are the guy from this thread: http://forum.beyond3d.com/showthread.php?t=62394

Last edited by XpiderMX; 06-Oct-2012 at 21:48.
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Old 07-Oct-2012, 02:00   #14
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The AA comparison is a worst case scenario versus a downscaled image.
A 2D godrays effect was already present in a Halo title 11 years ago.
The particle effects super are nice, but you see the missing lighting from the blue shit; though there are some yellow spots on the ground, I thought they were missing completely so thanks for bringing it to my attention.
The really dark screenshots shows the lack of HDR quite nicely.
The last shot is produced using an offline renderer. The lighting-'tech' in that shot does not have to be present in the final game, but it sure would look nice in the really dark screenshot


please remember, nobody is claiming that H4 is NOT the best looking 360 title ever, so take it easy
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Old 07-Oct-2012, 02:37   #15
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Please remember halo 4 has nothing to do with this thread.
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Old 07-Oct-2012, 17:46   #16
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Antwan has something against Halo, this is like the third or fourth thread where he's rambling about it. One had to be closed, I wonder what'll happen next.
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Old 07-Oct-2012, 18:06   #17
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I'm predicting a temp-ban for antwan .... Just sayin'.
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Old 07-Oct-2012, 18:41   #18
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Lol, seems that you guys hate Antwan...

On topic: I always wonder what exclusive devs can bring out of the box! But I guess that Sebbi and his team already hit some metal with their games
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Old 07-Oct-2012, 18:54   #19
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Quote:
Originally Posted by willardjuice View Post
Please remember halo 4 has nothing to do with this thread.
Well, Corrine Yu said that she is programming a lot of things on assembler, including some physics, I guess it is "programming to the metal" xD
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Old 07-Oct-2012, 20:11   #20
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Now that may not be untapped power, but power used differently from a game to another.
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Old 08-Oct-2012, 15:30   #21
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Quote:
Originally Posted by Billy Idol View Post
Lol, seems that you guys hate Antwan...

On topic: I always wonder what exclusive devs can bring out of the box! But I guess that Sebbi and his team already hit some metal with their games
No one hates Antwan, but people do recognize he has some kind of agenda against the game.

Also studios have been hitting the metal with their games for some time now.

Quote:
Originally Posted by Karamazov View Post
Now that may not be untapped power, but power used differently from a game to another.
Pretty much my thought. It's not about hitting more power but using the power you have more efficiently.

I thought the one interview/video with the engineer was surprisingly honest since he commented on giving the illusion of extracting more power out of these boxes.
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Old 09-Oct-2012, 02:51   #22
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Quote:
Originally Posted by antwan View Post
Wow! (I looked at your posts and learned you are part of a (great I must add) developer) So it turns out "close to the metal programming is forbidden" was just a hoax .. that's strange. I will confront my friend with this knowledge
Companies just want you to think that close to the metal is bad thing. Managed code is all the rave now. They have been trying to force silly APIs on people for decades and for the most part it has worked. But as you can see that all dev kits/tools are not created equal and first party game will always look better than third party. Either they know more that 90% of the world's developers or they are coding to the metal. Win for them / fail for you.
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Old 09-Oct-2012, 11:01   #23
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Quote:
Originally Posted by owen View Post
Companies just want you to think that close to the metal is bad thing. Managed code is all the rave now. They have been trying to force silly APIs on people for decades and for the most part it has worked. But as you can see that all dev kits/tools are not created equal and first party game will always look better than third party. Either they know more that 90% of the world's developers or they are coding to the metal. Win for them / fail for you.
API abstract of the underlying hardware, useful on PC, not really on a console.
(Now if you meant that API are unnecessarily fat and ugly, true and unfortunately nothing new, which makes me wonder what those API designers are thinking...)
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Old 09-Oct-2012, 11:15   #24
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APIs come in handy for forwards compatibility though, which could be useful on a console. Or cross device compatibility, such as running your same game on XB3 and Win Mobile phone.
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Old 09-Oct-2012, 14:08   #25
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Quote:
Originally Posted by Rodéric View Post
API abstract of the underlying hardware, useful on PC, not really on a console.
(Now if you meant that API are unnecessarily fat and ugly, true and unfortunately nothing new, which makes me wonder what those API designers are thinking...)
Are you talking about APIs on consoles or PCs being fat?

Based on this and other related threads, I thought APIs were a necessary evil in game development today, even on consoles.
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