2005-07-12 19:45:30 UTC
http://www.bizarreonline.net/index.php?action=fullnews&showcomments=1&id=37
The Bizarre Creations technical director, Walter, gives us his opinion on
the upcoming console releases.
Put your thinking caps on and get ready for a crash course in advanced
programming practices - as well as the new techniques necessary for
utilising a new generation of hardware.
Its platform transition time again - that period that keeps game development
fresh and exciting! We have all the rules & limitations we're accustomed to
working with changed as the new generation of game's consoles hit the scene.
As I'm sure you're aware, the two big players this time around are
Microsoft's Xbox 360, and Sony's PlayStation 3. The 360 will see a 2005
release date, whilst the PS3 is rumoured to be available in Spring 2006
(although typically these dates will change).
"Software development is like a gas, it quickly expands to fill the
available space". The question is: how much 'space' do these new machines
give us? How different will they be to each other, and to previous
generations?
This next generation of consoles crosses several important thresholds. This
is the 3rd 'mainstream' generation of console 3d hardware, but what should
be possible visually this time round will be backed up with more in the way
of processing and believability behind the scenes. Less of what's there will
be facades; the styles of game to which photorealism can be applied will be
expanded (pending spiralling production costs).
Whilst the Microsoft & Sony marketing machines are keen to point out the
superiorities of their individual consoles, it's worth pointing out their
similarities. Both get 90% of their claimed processing power from their
Graphics Processing Unit. Both use GPU's based on the same base direct-x9,
shader 3.0 functionality, but somewhat extended in ATI's case. This is much
more similarity than existed between the Xbox and PS2, as both are patterned
around the common DX, shader 3 feature-set (the GameCube was somewhere in
between the two). Whatever their differences, this will make cross-platform
graphical content development easier.
One very valid comment is the implication on their economics... both
platform holders have had to take a call on "power:price" ratio with a
similar architecture. There is only a certain amount of detail which
developers can afford to put in a game - are you really going to see more
sales by hiring another 10 artists to render the buttons on a character's
shirt for example? Production values will be a limiting factor on both
machines, so how much power can developers actually use?
What we have in both cases is extremely capable chips suitable for running
cinematic shaders, with floating point processing per pixel: This is the
backbone of the main visual advancement on both platforms.
The effects only seen in high end PC card tech-demos will become more
prevalent in mainstream games given the predictability of a fixed console
spec that lasts for 5 years. What excites me is not the raw numbers being
thrown around, but the versatility offered. Gone will be the 'distinctive
look' of a 4bit palletized PS2 title or 'cling-film' bump-mapping, replaced
with whatever blend of filters and stylized material effects the developer
chooses. Shader creation will grow as a role in development teams, bringing
real-time ever closer to pre-rendered CG.
The other threshold being crossed is the dawn of the 'near-polygon per pixel
era'. Sony had an interesting take on this during PS3's development cycle.
What we are seeing is 'polygon-texture duality' if you like. On the one hand
geometry gets so detailed that polygons are more evenly distributed across
the screen, (we're regularly using sub-pixel geometry now in PGR3 that we're
having to LOD out), real-time geometry decompression - XPS, CELL-GPU
connection, various shader techniques, practical curved-surface
Tessellation, Displacement Mapping - will mean on true next-gen titles
you'll never see a polygonal boundary. On the other hand, pixel-shader
texture effects beyond bump mapping such as virtual-displacement mapping -
based on ray tracing & voxel approximations - will allow 'image-based
rendering' approaches.
According to rumours, Sony's original plan was to ditch the GPU and simply
merge the two - rely on single pixel polygons to do the job of both - the
'micro-polygon tessellation' of RenderMan - but the reality has not quite
appeared... there's always PS4 and the next Xbox... nonetheless, on paper,
both machines can start counting polygons per pixel rather than pixels per
polygon. One important implication is that it makes 3D scanning approaches
more viable - again with implications for cross platform development. Now
for 3d (like 2d of times past) you can think in terms of scaling the same
content up or down to match the machine.
Display technology is also moving on, with both machines targeting high
definition resolutions, though it remains to be seen what will happen in the
balance between frame-rate, 3d detail, materials, filters, and spatial
resolution. What will people really react to more; a sharper image or a more
realised one?
To summarize on the graphical side - given the ballpark power & versatility,
I would say that overall there's as much scope for production values and
developer talent to show through in a game's visuals as any hardware
differences.
On the CPU side, once again both machines offer a common challenge. Moore's
law is over - the limits of silicon are reached. The speed of light has even
become a consideration in chip design with the physical distances on the die
being a limiting factor!
The only way to make computers faster is with deeper pipelines, more
reliance on caches, wider busses, VLIW & SIMD - all common today; - but most
importantly of all, true multiprocessor architectures. GPU's easily
parallelize with independent pixels handled simultaneously, whereas CPU's
game-processing must go back over the same results repeatedly and make
decisions.
This forces a rethink in programming practices and how game engines are put
together. Expect to see a big jump between successive generations of games
on both machines. From the perspective of a programmer working on a title,
this is the biggest change. It should mean one can separate out a fixed,
predictable amount of processing from the chunk taken to manage the visuals;
again helping to deepen the experience. Although the raw 'GFLOPS' provided
by the CPU is only 10% of the overall figure, it's critical to utilize for
the depth of the gaming experience.
Another limiting factor to consider in game-update though is online: this is
another hugely important advancement in console gaming, and it inherently
restricts how much actual game processing is useful to be able to perform on
a machine. The limiting factor becomes not the machines power, but how much
state information can be sent across a broadband network. In practice this
common hardware restriction will limit game design more than the raw CPU
power.
The technical differences between the two consoles will be just as important
as their similarities (if not more so). These will become the unique
strengths that are visible in a platform's exclusive titles as opposed to
multi-format games.
At the time of writing we only have limited information on the PS3 - so it's
too early to say which is more powerful. Sony certainly has a lot of
'GFLOPS' on paper and large amounts of SPE memory, but operates differently
so could be more limited in application.
What I can say for sure is that the Xbox 360 does indeed have a very 'smart'
GPU, with many highly versatile extensions over the common DX9 shader 3
functionality. We're trying to exploit these as much as we can in the time
we have for PGR3, and know we'll be able to build even more into our
next-generation engines. Raw TFLOPS are misleading: there's a big difference
between steamrollering more pixels and REAL improvements such as the number
of separate objects you can handle, what sort of compressed data structures
you can have etc.
The 360 GPU can dynamically target its power at pixels or vertices at will -
allowing it to 'work smarter not harder'. Its EDRAM architecture will most
likely give it the edge in anti-aliasing. It also uses unified memory, so
one has more flexibility in deciding how much memory to devote to textures,
geometry & game-update related resources.
More information is appearing on the RSX chip (the PS3 graphics processor)
which is apparently a little more conventional, but backed up by the option
of pre-processing on the CELL.
The approach offered to CPU side multiprocessing is the biggest difference
between them. Microsoft's machine on paper promises to be the more developer
friendly with 3 identical custom PowerPC cores, 2 hyper threads each. One
can write common code then decide at will how to balance the program across
them. Hyper threading creates some interesting back doors with 2 tasks
sharing the same cache.
In practice, both for optimization and to avoid hard-to-track,
production-schedule-stretching bugs, the best practices mean the more
limited the 'background-tasks' are, the better, which takes forethought in
engine design. Microsoft's customized PowerPC is still reliant on specific
coding to maximize use of its truly powerful vector processing
instructions... although it's worth pointing out it has the fullest featured
SIMD unit I've yet seen!
Sony's contrasting approach has been to take this observation and design a
totally new processing architecture around this. Some talk about it being
like the "RISC revolution all over again". On paper this will be harder to
deal with as you're using non-standard tools. But given the issues above,
the architecture has a certain elegance. An extremely exciting development
in the PC space that I'll be watching closely is the Agiea physics board,
designed explicitly for the sort of 'spatial' processing seen in games -
collision detection and physics. This operates very similarly to the Cell,
surely a vote of confidence for the concept.
However, the first implementations of a new idea rarely get everything
right. Compare the early days of PC 3D cards to their current state of
evolution. Apple have not jumped at the opportunity of using the Cell
processor to power their Macs. I'm only going on limited information and
some speculation so it's too early to tell which will be most powerful in
practice. I keep coming back to the idea of 'polygons' and 'textures'
meeting in the middle, and like the idea of this overlapping with physics
too. It would seem good to have one unit that can handle all 3. Even ATI's
GPU heads towards this with its unified shader model, the same ALU's
sharable between them. We can see the so called "GPGPU" particle & physics
demos appearing (using the GPU to accelerate General Purpose tasks by
placing data in off screen textures). Already some approximations to
real-time global-illumination have appeared on PC's, again an area where
graphics becomes spatially interactive like physics. From a
game/graphics-programming perspective it'll be interesting to see the next
generation which will most likely expand on all these concepts...
So in my eyes, this new generation of consoles is extremely exciting, and on
an open and even playing field - it's all going to come down to the
developers, the games and how it's all marketed!
The Bizarre Creations technical director, Walter, gives us his opinion on
the upcoming console releases.
Put your thinking caps on and get ready for a crash course in advanced
programming practices - as well as the new techniques necessary for
utilising a new generation of hardware.
Its platform transition time again - that period that keeps game development
fresh and exciting! We have all the rules & limitations we're accustomed to
working with changed as the new generation of game's consoles hit the scene.
As I'm sure you're aware, the two big players this time around are
Microsoft's Xbox 360, and Sony's PlayStation 3. The 360 will see a 2005
release date, whilst the PS3 is rumoured to be available in Spring 2006
(although typically these dates will change).
"Software development is like a gas, it quickly expands to fill the
available space". The question is: how much 'space' do these new machines
give us? How different will they be to each other, and to previous
generations?
This next generation of consoles crosses several important thresholds. This
is the 3rd 'mainstream' generation of console 3d hardware, but what should
be possible visually this time round will be backed up with more in the way
of processing and believability behind the scenes. Less of what's there will
be facades; the styles of game to which photorealism can be applied will be
expanded (pending spiralling production costs).
Whilst the Microsoft & Sony marketing machines are keen to point out the
superiorities of their individual consoles, it's worth pointing out their
similarities. Both get 90% of their claimed processing power from their
Graphics Processing Unit. Both use GPU's based on the same base direct-x9,
shader 3.0 functionality, but somewhat extended in ATI's case. This is much
more similarity than existed between the Xbox and PS2, as both are patterned
around the common DX, shader 3 feature-set (the GameCube was somewhere in
between the two). Whatever their differences, this will make cross-platform
graphical content development easier.
One very valid comment is the implication on their economics... both
platform holders have had to take a call on "power:price" ratio with a
similar architecture. There is only a certain amount of detail which
developers can afford to put in a game - are you really going to see more
sales by hiring another 10 artists to render the buttons on a character's
shirt for example? Production values will be a limiting factor on both
machines, so how much power can developers actually use?
What we have in both cases is extremely capable chips suitable for running
cinematic shaders, with floating point processing per pixel: This is the
backbone of the main visual advancement on both platforms.
The effects only seen in high end PC card tech-demos will become more
prevalent in mainstream games given the predictability of a fixed console
spec that lasts for 5 years. What excites me is not the raw numbers being
thrown around, but the versatility offered. Gone will be the 'distinctive
look' of a 4bit palletized PS2 title or 'cling-film' bump-mapping, replaced
with whatever blend of filters and stylized material effects the developer
chooses. Shader creation will grow as a role in development teams, bringing
real-time ever closer to pre-rendered CG.
The other threshold being crossed is the dawn of the 'near-polygon per pixel
era'. Sony had an interesting take on this during PS3's development cycle.
What we are seeing is 'polygon-texture duality' if you like. On the one hand
geometry gets so detailed that polygons are more evenly distributed across
the screen, (we're regularly using sub-pixel geometry now in PGR3 that we're
having to LOD out), real-time geometry decompression - XPS, CELL-GPU
connection, various shader techniques, practical curved-surface
Tessellation, Displacement Mapping - will mean on true next-gen titles
you'll never see a polygonal boundary. On the other hand, pixel-shader
texture effects beyond bump mapping such as virtual-displacement mapping -
based on ray tracing & voxel approximations - will allow 'image-based
rendering' approaches.
According to rumours, Sony's original plan was to ditch the GPU and simply
merge the two - rely on single pixel polygons to do the job of both - the
'micro-polygon tessellation' of RenderMan - but the reality has not quite
appeared... there's always PS4 and the next Xbox... nonetheless, on paper,
both machines can start counting polygons per pixel rather than pixels per
polygon. One important implication is that it makes 3D scanning approaches
more viable - again with implications for cross platform development. Now
for 3d (like 2d of times past) you can think in terms of scaling the same
content up or down to match the machine.
Display technology is also moving on, with both machines targeting high
definition resolutions, though it remains to be seen what will happen in the
balance between frame-rate, 3d detail, materials, filters, and spatial
resolution. What will people really react to more; a sharper image or a more
realised one?
To summarize on the graphical side - given the ballpark power & versatility,
I would say that overall there's as much scope for production values and
developer talent to show through in a game's visuals as any hardware
differences.
On the CPU side, once again both machines offer a common challenge. Moore's
law is over - the limits of silicon are reached. The speed of light has even
become a consideration in chip design with the physical distances on the die
being a limiting factor!
The only way to make computers faster is with deeper pipelines, more
reliance on caches, wider busses, VLIW & SIMD - all common today; - but most
importantly of all, true multiprocessor architectures. GPU's easily
parallelize with independent pixels handled simultaneously, whereas CPU's
game-processing must go back over the same results repeatedly and make
decisions.
This forces a rethink in programming practices and how game engines are put
together. Expect to see a big jump between successive generations of games
on both machines. From the perspective of a programmer working on a title,
this is the biggest change. It should mean one can separate out a fixed,
predictable amount of processing from the chunk taken to manage the visuals;
again helping to deepen the experience. Although the raw 'GFLOPS' provided
by the CPU is only 10% of the overall figure, it's critical to utilize for
the depth of the gaming experience.
Another limiting factor to consider in game-update though is online: this is
another hugely important advancement in console gaming, and it inherently
restricts how much actual game processing is useful to be able to perform on
a machine. The limiting factor becomes not the machines power, but how much
state information can be sent across a broadband network. In practice this
common hardware restriction will limit game design more than the raw CPU
power.
The technical differences between the two consoles will be just as important
as their similarities (if not more so). These will become the unique
strengths that are visible in a platform's exclusive titles as opposed to
multi-format games.
At the time of writing we only have limited information on the PS3 - so it's
too early to say which is more powerful. Sony certainly has a lot of
'GFLOPS' on paper and large amounts of SPE memory, but operates differently
so could be more limited in application.
What I can say for sure is that the Xbox 360 does indeed have a very 'smart'
GPU, with many highly versatile extensions over the common DX9 shader 3
functionality. We're trying to exploit these as much as we can in the time
we have for PGR3, and know we'll be able to build even more into our
next-generation engines. Raw TFLOPS are misleading: there's a big difference
between steamrollering more pixels and REAL improvements such as the number
of separate objects you can handle, what sort of compressed data structures
you can have etc.
The 360 GPU can dynamically target its power at pixels or vertices at will -
allowing it to 'work smarter not harder'. Its EDRAM architecture will most
likely give it the edge in anti-aliasing. It also uses unified memory, so
one has more flexibility in deciding how much memory to devote to textures,
geometry & game-update related resources.
More information is appearing on the RSX chip (the PS3 graphics processor)
which is apparently a little more conventional, but backed up by the option
of pre-processing on the CELL.
The approach offered to CPU side multiprocessing is the biggest difference
between them. Microsoft's machine on paper promises to be the more developer
friendly with 3 identical custom PowerPC cores, 2 hyper threads each. One
can write common code then decide at will how to balance the program across
them. Hyper threading creates some interesting back doors with 2 tasks
sharing the same cache.
In practice, both for optimization and to avoid hard-to-track,
production-schedule-stretching bugs, the best practices mean the more
limited the 'background-tasks' are, the better, which takes forethought in
engine design. Microsoft's customized PowerPC is still reliant on specific
coding to maximize use of its truly powerful vector processing
instructions... although it's worth pointing out it has the fullest featured
SIMD unit I've yet seen!
Sony's contrasting approach has been to take this observation and design a
totally new processing architecture around this. Some talk about it being
like the "RISC revolution all over again". On paper this will be harder to
deal with as you're using non-standard tools. But given the issues above,
the architecture has a certain elegance. An extremely exciting development
in the PC space that I'll be watching closely is the Agiea physics board,
designed explicitly for the sort of 'spatial' processing seen in games -
collision detection and physics. This operates very similarly to the Cell,
surely a vote of confidence for the concept.
However, the first implementations of a new idea rarely get everything
right. Compare the early days of PC 3D cards to their current state of
evolution. Apple have not jumped at the opportunity of using the Cell
processor to power their Macs. I'm only going on limited information and
some speculation so it's too early to tell which will be most powerful in
practice. I keep coming back to the idea of 'polygons' and 'textures'
meeting in the middle, and like the idea of this overlapping with physics
too. It would seem good to have one unit that can handle all 3. Even ATI's
GPU heads towards this with its unified shader model, the same ALU's
sharable between them. We can see the so called "GPGPU" particle & physics
demos appearing (using the GPU to accelerate General Purpose tasks by
placing data in off screen textures). Already some approximations to
real-time global-illumination have appeared on PC's, again an area where
graphics becomes spatially interactive like physics. From a
game/graphics-programming perspective it'll be interesting to see the next
generation which will most likely expand on all these concepts...
So in my eyes, this new generation of consoles is extremely exciting, and on
an open and even playing field - it's all going to come down to the
developers, the games and how it's all marketed!