Actually, I'm rather surprised at how low-end the XBox hardware and graphics 
stuff is. The CPU is surprisingly slow even at simple stuff like 
decompressing an image, and the graphics card pretty much chokes with about 
800 models with a couple hundred vertx each. You really have to work hard to 
make even really simple scenes render fast. I was hoping I could just throw 
simple graphics at it and have it eat easily, or at least close to as well 
as my fairly old PC graphics card.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

Post a reply to this message

Darren New <dne### [at] sanrrcom> wrote:
> Actually, I'm rather surprised at how low-end the XBox hardware and graphics
> stuff is. The CPU is surprisingly slow even at simple stuff like
> decompressing an image, and the graphics card pretty much chokes with about
> 800 models with a couple hundred vertx each.

that's why in Assassin's Creed, while you have plenty of people around in the
streets, once you scale high buildings and can see plenty of the town, you only
see people (in LOD simpler models) in the immediate vicinities.  Far away town
is empty. :)

But shouldn't image decoding be done by the GPU?

also, remember it's a 5 year old hardware already...

Post a reply to this message

On 4/13/2011 19:53, nemesis wrote:
> Far away town is empty. :)

Yeah, that's true of Infamous on the PS3 too. (But, oddly, not of Uncharted 
that I noticed, probably because Uncharted is a string of pearls instead of 
a sandbox.)  It's actually almost distracting.

As well as amusing, when you blow up the gas station, walk 2 blocks away, 
and come back to a resurrected gas station.

> But shouldn't image decoding be done by the GPU?

Hard to say. Can you really decompress jpeg on the GPU?

> also, remember it's a 5 year old hardware already...

True. But still, it's hardware whose primary purpose is rendering graphics.

It's more like "Gee, every other game manages to have really sophisticated 
graphics and stuff like geometry for window ledges instead of just being 
painted on. I wonder what I'm doing that I can't get 1000 flat walls drawn."

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

Post a reply to this message

Darren New <dne### [at] sanrrcom> wrote:
> Hard to say. Can you really decompress jpeg on the GPU?

I thought it'd be a standard operation in GPUs by now.  It's the simplest and
most common operation with images.

> > also, remember it's a 5 year old hardware already...
>
> True. But still, it's hardware whose primary purpose is rendering graphics.

not quite.  It used to be true in the 90's that consoles had faster graphics
capabilities than the PC because they used custom graphics hardware.  Hence,
custom chips for graphics were developed for the PC and many years and heavy
games later, consoles now use that very same hardware.  Except the hardware
never upgrades, while in the PC it does. (or better, you do it)

Post a reply to this message

nemesis <nam### [at] gmailcom> wrote:
> Darren New <dne### [at] sanrrcom> wrote:
> > Hard to say. Can you really decompress jpeg on the GPU?

> I thought it'd be a standard operation in GPUs by now.  It's the simplest and
> most common operation with images.

  Why would you even want to decompress a JPEG image with the GPU? After
all, the processors in the GPU are slower than the main CPU anyways.
(The reason why they are faster at drawing is extreme parallelism and
having hardware that is dedicated to drawing stuff.)

-- 
                                                          - Warp

Post a reply to this message

Darren New <dne### [at] sanrrcom> wrote:
> Actually, I'm rather surprised at how low-end the XBox hardware and graphics 
> stuff is. The CPU is surprisingly slow even at simple stuff like 
> decompressing an image, and the graphics card pretty much chokes with about 
> 800 models with a couple hundred vertx each. You really have to work hard to 
> make even really simple scenes render fast. I was hoping I could just throw 
> simple graphics at it and have it eat easily, or at least close to as well 
> as my fairly old PC graphics card.

  What do you expect of a device that is cheaper than many cellphones?

-- 
                                                          - Warp

Post a reply to this message

> It's more like "Gee, every other game manages to have really
 > sophisticated graphics and stuff like geometry for window ledges instead
 > of just being painted on. I wonder what I'm doing that I can't get 1000
 > flat walls drawn."

When you put it like that, I have to imagine it's something you're 
doing, although I have no idea what it would be. Are you using Direct3D? 
(It is a Microsoft product, after all.) Trying to minimize primitives?

  - Slime

Post a reply to this message

On 4/13/2011 7:28 PM, Darren New wrote:
> Actually, I'm rather surprised at how low-end the XBox hardware and
> graphics stuff is. The CPU is surprisingly slow even at simple stuff
> like decompressing an image, and the graphics card pretty much chokes
> with about 800 models with a couple hundred vertx each. You really have
> to work hard to make even really simple scenes render fast. I was hoping
> I could just throw simple graphics at it and have it eat easily, or at
> least close to as well as my fairly old PC graphics card.
>
Snort. What disappoints me is my hardware. Given that its specs make the 
XBox look like complete shit, despite being a single core, and 5 years 
out of date, but it runs like complete crap, and new version of Linux 
would "improve" the situation enough to not make it still work like 
crap. Why? Because they can't, just to use the obvious example of games, 
make something that runs fine, if *slightly* less pretty, on an XBox, 
run either as well, or even *at all* in some cases, on a better core, 
with 4 times the memory, and a graphics card that.. well, you get the point.

Its like finding that the $20 radio on someone's bicycle has better 
woofers than some $4000 system they just installed in your, slightly out 
of date, Maserati (or equivalent)... Or better yet, discovering that 
some poor shlubs 100 foot sail boat has room for more people on it than 
your new 1,000 foot yacht. I mean, they develop these damn things "on" a 
PC, of some sort, even if they test and tweak the final thing on the 
console. How the hell do you do that and end up needing 2 cores, instead 
of one, a graphics cards that is 2-3 times better, 4 times the memory, 
etc., just to install the fracking thing, never mind run it?

This isn't a bad port (Force Unleashed being the example described), its 
someone making a damn 747, and out of tissue paper no less, when they 
only needed a damn Cessna.

Post a reply to this message

On 4/13/2011 23:40, Warp wrote:
>    Why would you even want to decompress a JPEG image with the GPU?

That's a good point. ALtho I know the set-top boxes I've worked with all 
have MPEG decompression hardware and H.264 decompression hardware, as do 
most of the phone stuff I'm familiar with (which is very little). That's one 
of the arguments about Ogg in HTML5 video tags vs H.264.

> (The reason why they are faster at drawing is extreme parallelism and
> having hardware that is dedicated to drawing stuff.)

I'm pretty sure the individual blocks of jpeg are independent (unlike PNG 
for example). You ought to be able to de-convolve an entire jpeg in parallel 
at least, once you de-huffman it.

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

Post a reply to this message

On 4/13/2011 23:41, Slime wrote:
>  > It's more like "Gee, every other game manages to have really
>  > sophisticated graphics and stuff like geometry for window ledges instead
>  > of just being painted on. I wonder what I'm doing that I can't get 1000
>  > flat walls drawn."
>
> When you put it like that, I have to imagine it's something you're doing,

Yes, exactly. I was hoping i could just be naive and do a 
Wii-quality-graphics game without learning all about how to do complex stuff.

> although I have no idea what it would be.

Apparently, the XBox is slow at restarting the graphics card. If I draw the 
models as 600 individual models, I get about 20FPS.

Switching to instanced drawing (where you draw 100 copies of the same model 
in one draw call by first passing 100 world matrixes to the graphics card 
and then writing basically a shader with nested loops over world matrixes 
and verticies), I get 130FPS.

So, basically, setting the texture and vertex buffers are really slow, even 
tho they're all stored on the GPU without needing to transfer them from the 
CPU other than updating pointers. I think I don't know how the GPU 
interfaces to the CPU at the hardware level very well. If I were serious 
about this, I'd dig up a book on GPU assembly language.

> Are you using Direct3D?

I'm using XNA, which is MS's .NET wrapping of Direct3D (at least on the xbox 
- I don't think it uses D3D on the WinPhone).

Fun fact: XNA stands for "XNA is Not an Acronym."

 > Trying to minimize primitives?

That was basically my complaint. It's a simple enough game I was hoping I 
wouldn't have to do that. There's no sweeping vistas or city-size sandboxes 
or even animated models or (at this point) even *moving* models. :-)

-- 
Darren New, San Diego CA, USA (PST)
   "Coding without comments is like
    driving without turn signals."

Post a reply to this message