Gamecube/PS2/Xbox stuff... again

[Exophase]

If you are composing you frame using chunks, you'd need to have cut outs where the other chunks go. Unless you are composing and downsampling the image 100% on the CPU, in which case you wouldn't need alpha, but you are doing work on the CPU.

If you use FSAA, your backbuffer is going to be too large for the 2ish MB, so you have to tile. If you have to tile.

You couldn't get the Gamecube's GPU to downsample a tile anyway, because it can't texture from the framebuffer. At least not without copying the data around, but to even get it in texture memory you'd have to tile the tile. And I don't even know if the 24-bit framebuffer formats are supported texture formats.

I can't find good documentation on what the video interface's capabilities are so I don't know what its maximum resolution is (performing FSAA to go below max resolution would probably not be a good tradeoff) or if it has any kind of downsampling of its own. A simple integer 2:1 downsampler wouldn't be that bad CPU-wise, although the memory bandwidth hit would be large.

Suffice it to say that the system wasn't geared for tiling,

But I'm still not seeing what dest alpha has to do with this, unless you're thinking that the function to copy from the GPU framebuffer RAM to the front buffer in main RAM can perform per-pixel alpha blending and that it'll scan every source pixel and accumulate them on top of each other..

 

[see colon]

Everything I've ever read about GameCube FSAA has said it's 3x Supersample. That would make it 960*720 scaled down to 640*480, right? assuming they use both h+v AA

Regarding alpha, I think I was getting ahead of myself. I assumed you would set your buffer size, block out areas using the alpha channel and only render the pixels you need for the tile, more to system memory and repeat using alpha to block out other parts of the scene, but now that I think about it, that makes no sense, because the buffer would still need to be too large to fit in memory. So yeah, you probably don't need alpha to tile.

 

[HTupolev]

Everything I've ever read about GameCube FSAA has said it's 3x Supersample. That would make it 960*720 scaled down to 640*480, right? assuming they use both h+v AA

No idea, but that would be 2.25x, not 3x.

 

[shredenvain]

Slightly off topic question. Is the difference in power between the Ps4 and Xb1 similar to the difference in power between the Ps2 and Xbox? Less? More? Same? Or not applicable?

 

[Grall]

Decidedly not applicable at all, the two machines are extremely different architecturally. The xbox stomps all over PS2 in both features and performance however. ...Except for the controller, which was pretty bad for xbox.

 

[shredenvain]

The S controller was great though.

 

[Exophase]

Everything I've ever read about GameCube FSAA has said it's 3x Supersample. That would make it 960*720 scaled down to 640*480, right? assuming they use both h+v AA

I don't know what 3x sub-pixels means but I think this is the best guess, that it's downsampling 1.5x1.5, and the "3x" is adding those two terms together. I can't think of anything else that makes sense.

So I guess the hardware resolve downsamples, so doing it via texturing isn't necessary. It should be possible in two tiles, unless there are weird restrictions on resolution for the downsampler (and I don't see why there would be). But you still pay the cost of running the T&L twice, unless you can figure out some world-space culling to cut down on polygons outside the tile, implemented on the CPU.

To get comparable results on PS2, you'd need 5.27MB for the backbuffer (this is assuming neither 16-bit color nor depth are used), plus 1.17MB for the frontbuffer. Since PS2 needs the front buffer stored in VRAM you probably wouldn't have enough space with just two tiles, if you wanted to have any textures. If you wanted to do it in 16-bit color/depth you could fit it in with a modest amount of room left over for texturing, but it'd look considerably worse.

PS2 could use post-transformed vertexes for one of the tiles. But this does still incur the cost of writing back transformed vertexes and then doing a pass-through pass to the GS. And you still get a doubled hit to triangle setup unless you can do culling on the VUs. You could do a full blown tiler on the VUs too, but that'd have its own expenses.

 

[Blazkowicz]

Decidedly not applicable at all, the two machines are extremely different architecturally. The xbox stomps all over PS2 in both features and performance however. ...Except for the controller, which was pretty bad for xbox.

It's hard to find consoles with similar hardware. The Neo Geo and Megadrive/Genesis both ran a 68000 + Z80 and enough to say the Neo Geo was bad ass. But it was largely a matter of throwing a grand worth of ROMs and whatever chips into the game cartridge.

XB one vs PS4 is perhaps like the Gamecube vs Wii.

 

[Grall]

It's hard to find consoles with similar hardware.

Xbone and PS4 are reasonably comparable. Perhaps the most comparable consoles that have ever existed. They're certainly the only consoles to have been constructed out of off-shelf hardware to such an extent (even though neither are off the shelf by any means, really.)

Non-existing and/or extremely obscure consoles such as Phantom etc do not count, naturally.

 

[see colon]

It's hard to find consoles with similar hardware. The Neo Geo and Megadrive/Genesis both ran a 68000 + Z80 and enough to say the Neo Geo was bad ass. But it was largely a matter of throwing a grand worth of ROMs and whatever chips into the game cartridge.

XB one vs PS4 is perhaps like the Gamecube vs Wii.

NeoGeo's video hardware was so much better, though. Scaling, rotation, more sprites, 4000 more colors on screen... Plus the 68k is clocked faster.

Curiously, with SegaCD the CPU gap is closed (and maybe exceeded, if you can manage to get both 68k's working together), more ram and there's extra hardware for scaling and rotation, but it never got a 2d showcase game that would put it on the same stage as the NeoGeo.

 

[Blazkowicz]

With a CD , you have to load stuff into RAM instead of directly using it from ROM chips when possible. That's why a Neo Geo CD came up with an absolutely huge 7 MB RAM, and there was a memory expansion for Sega Saturn to run similar games.

 

[Exophase]

Non-existing and/or extremely obscure consoles such as Phantom etc do not count, naturally.

This is probably too obscure for you, but MSX and Sega SG 1000 were very similar. Colecovision too, although the audio chip back then was a little different. A lot of those early consoles used totally off the shelf parts, much more so than this generation, so you see a lot of the same parts floating around.

 

[Grall]

MSX was a home computer, not a console. And first-generation consoles... A bit outside the scope of our comparison, innit? Those things were so primitive they barely qualified as programmable computers in the first place (in the sense we think of them anyway); the VCS didn't even have a dedicated video chip, it used the main CPU to actually draw the image a line or two at a time on the screen... Wasn't much processing power left in that poor thing after taking care of that!

 

[Reznor007]

NeoGeo's video hardware was so much better, though. Scaling, rotation, more sprites, 4000 more colors on screen... Plus the 68k is clocked faster.

NeoGeo didn't have rotation hardware, it just had so much ROM space that they had room to store rotated sprites for every object that would be rotated.

 

[function]

Like the MD/Genesis the Neo Geo could also do a certain amount of sprite rotation on the CPU.

Whizz-arse programmers could actually do some scaling/rotation effects better on the M68000 than the SNES could with it's cool but limited Mode 7 stuff.

But ... this is getting v.OT.

 

[Reznor007]

Like the MD/Genesis the Neo Geo could also do a certain amount of sprite rotation on the CPU.

Whizz-arse programmers could actually do some scaling/rotation effects better on the M68000 than the SNES could with it's cool but limited Mode 7 stuff.

But ... this is getting v.OT.

Well, in a technical sense the 68K CPU could have done rotation, but not on NeoGeo. The NeoGeo carts contained 2 PCB's, one had the 68K program ROM's and the audio sample ROM's. The 2nd PCB contained the actual graphics ROM's, Z80 program ROM for the sound system, and the S1 ROM which was basically text/font data.

The 68K bus was not connected to the same bus as the graphics ROM's. There's a 3rd party modified BIOS that has many extra features for the real hardware(arcade or home version) and one is a CRC32 check. This check can only access the 68K program ROMs though, it cannot check the graphics ROMs because they aren't connected. The 68K basically tells the graphics chip what to do, and not much else.

 

[Exophase]

MSX was a home computer, not a console. And first-generation consoles... A bit outside the scope of our comparison, innit? Those things were so primitive they barely qualified as programmable computers in the first place (in the sense we think of them anyway); the VCS didn't even have a dedicated video chip, it used the main CPU to actually draw the image a line or two at a time on the screen... Wasn't much processing power left in that poor thing after taking care of that!

Well, I don't really know what's considered too obscure or not.. but I'd actually call the ones I listed something more like second generation, or at least Wikipedia does. As for MSX not being a console, I think the line was kind of blurred back then, with these computers that plugged into a TV and could run cartridges. I'd kind of consider MSX both a computer and a console.

And sure Atari 2600 had a video chip. It just could only do one scanline at a time, so you had to setup the registers every line. Still better than having the CPU render every pixel, it wouldn't have been fast enough to do that Now, the first gen stuff that didn't even have a CPU would fit your description..

 

[HMBR]

Well, I don't really know what's considered too obscure or not.. but I'd actually call the ones I listed something more like second generation, or at least Wikipedia does. As for MSX not being a console, I think the line was kind of blurred back then, with these computers that plugged into a TV and could run cartridges. I'd kind of consider MSX both a computer and a console.

And sure Atari 2600 had a video chip. It just could only do one scanline at a time, so you had to setup the registers every line. Still better than having the CPU render every pixel, it wouldn't have been fast enough to do that Now, the first gen stuff that didn't even have a CPU would fit your description..

MSX was a computer, just like IBM PC, or Apple II or whatever... you had by default MSX basic, you can program things, run any general purpose software, expand the hardware with third party stuff, it's no locked to MS or anything... pure computer IMO, cartridges are not a gaming console only thing...

 

[Exophase]

MSX was a computer, just like IBM PC, or Apple II or whatever... you had by default MSX basic, you can program things, run any general purpose software, expand the hardware with third party stuff, it's no locked to MS or anything... pure computer IMO, cartridges are not a gaming console only thing...

I agree, it was a computer. Why exactly does computer and console have to be mutually exclusive? For many products of that time I think they weren't, especially for the ones that bundled game controllers. I consider the qualities of a console to be more what it is than what it isn't - a platform with proper gaming hardware that comes standard, that lets you plug in and boot immediately into game cartridges, and where gaming inputs were a standard thing. All things that differentiate it from 80s IBM PCs.

 

[HMBR]

There's at least one very highly regarded developer who did optimisation work on both who thinks the PS2 is more powerful.

GC made some nice looking games, and I prefer the "look" of GC games to PS2, but I have no problem with the PS2 being more powerful in lots of ways.

PS2 could well be more powerful in some areas, or with theoretical numbers,
but I prefer to let the games speak for themselves, and I think the GameCube was a more advanced platform with higher quality graphics,

specially considering a lot more money and hours were spent developing for the PS2, since it was the more popular platform.

I agree, it was a computer. Why exactly does computer and console have to be mutually exclusive? For many products of that time I think they weren't, especially for the ones that bundled game controllers. I consider the qualities of a console to be more what it is than what it isn't - a platform with proper gaming hardware that comes standard, that lets you plug in and boot immediately into game cartridges, and where gaming inputs were a standard thing. All things that differentiate it from 80s IBM PCs.

as far as I know not all MSX came with a joystick, but they all came with a keyboard and MSX basic...
sure the MSX was also a gaming platform, but it was not designed as just a gaming platform, like the Atari 2600 and well, the Gamecub; it was designed as personal computer, to run software, be it games or something else...

when you have a platform with a keyboard, and you can program, store, load with keyboards commands the way you want, I think calling it a gaming console is simply incorrect
surely it was used exclusively (or almost) for gaming by some people, but you could say the same about a current PC...

MSX was designed, sold and advertised as a computer (and also very capable as a gaming platform)
I think there is a clear difference to what we call a console (like the atari 2600 or NES)