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PostPosted: Tue Aug 16, 2016 6:49 pm 
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I went along with the wiki and what tepples had stated in his posts for consistency; in casual conversations I don't dare say things like "mebibyte" out loud.


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PostPosted: Tue Aug 16, 2016 9:06 pm 
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freem wrote:
Would GBA be about as powerful as Neo Geo, apart from the smaller display (240x160 vs. 304x224)?

I thought this was a no brainer... It's like 4 SNES put together! :lol:

Because vertical resolution doesn't impact how much data you can send per line (how many theoretical scanlines does the GBA have? I know it can send a crap ton of data to vram in one frame), you could get 240(4xoverdraw x 4bpp) + 248(4BGs x 8bpp) = 11,776 bits.

With the Neo Geo, it's easier, just do 320(4bpp) + 96(16pixels x 4bpp) = 7,427 bits. That's less than 2/3's as much as the GBA. However, I'm sure the bandwidth of the Neo Geo is actually closer to the GBA in that each sprite is going to have more additional information sent to it than a BG tile on the GBA, but it can't close the gap that much. Me adding the fix layer was also kind of giving the Neo Geo a boost in this comparison.

Plus, like what has been said earlier, the GBA is a lot more flexible in how it can manipulate the graphics in terms of transformation. However, you have to sacrifice a BG layer for every affine transformed one you add. Sprites are fine though. The Neo Geo also doesn't support transparency or (if I'm correct) have window layers, and we don't even know if it supports any sort of sprite multiplexing.

freem wrote:
The core Neo-Geo sprite size is 16px wide, and 16-512px tall.

I'd say this is a loss. the GBA can pull of most reasonable object sizes with either less sprites or less bandwidth. 16x512 is bigger than 64x64, but you really only want a size like that if you're creating "BG layers". I'm not even sure why they settled with a size like 512, it's over twice as tall as the screen and ultimately seems like it just takes up more data in vram.

While the GBA can't beat the Neo Geo at every situation (much like how the SNES can't beat the Turbografx at everything but is generally considered more powerful), I'd say it's more powerful overall by a sizable margin. However, there's one thing that the Neo Geo has a great advantage over, and that's the number of palettes available (just like the Turbografx, actually.) I'm not sure what's up with Nintendo's refusal to add more color palettes to their systems. I guess they observed that most arcade boards with 1024+ colors use less than half of them anyway. :lol:

I think the Neo Geo's biggest problem is the fact that there are no BG layers. Although the hardware was designed to do this for sprites, it's just not the most efficient way to go about it in that a lot of bandwidth is wasted on loading redundant information, like the x and y of every sprite when they're all linked together. The Neo Geo can display a lot onscreen at a time, but not as much as most of the other arcade machines from the time period. I still don't understand the big scare to using 3BG layers, I mean, you have 1.5x overdraw for sprites, and that's more than the SNES, Genesis, or Turbografx. I think the Neo Geo would have looked better if developers were more conscious of the fact that there aren't actually BG layers on the system but sprites instead. If your background doesn't take up the whole screen, just don't put sprites there. You could have a fighting game where the arena is in the woods and has a log cabin on the right as the only thing in the foreground aside from the ground. Although the ground covers the whole ground horizontally, the log cabin doesn't so there don't need to be blank sprites to the left. Doing this will mean you can't do the auto stick feature thing for sprites, but who cares, it's not like the 12MHz 68000 is taking much of a performance hit. :lol:


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PostPosted: Tue Aug 16, 2016 9:18 pm 
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Is it me or after reading the complete thread we still have no conclusion on why 330 megabits? That was the main goal of the thread... Right? :lol:


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PostPosted: Tue Aug 16, 2016 9:33 pm 
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Wasn't that just about answered in the first post? It's not really 330 (it's 329 and a half, but that'd sound lame).

Also, I think you'd know better in that threads here wander wherever they want to... :lol:


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PostPosted: Tue Aug 16, 2016 9:35 pm 
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330 could just be SNK's counterpart to Heinz's 57.


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PostPosted: Tue Aug 16, 2016 9:57 pm 
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I was hoping to get something resembling confirmation from anyone who had any more in-depth knowledge, since I managed to rationalize my way to the number 329.5 rather than finding an authoritative answer.

But since none's shown up yet, this is probably the wrong forum to ask. (If, in fact, the answer is even publicly known)


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PostPosted: Wed Aug 17, 2016 9:38 am 
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I decided to remove my last post instead of a double post. I thought I was up to something but maybe it was not the case.

For some reason I decided to check wikipedia for the neogeo but in Japanese. I know wikipedia cannot be trusted but what was written in Japanese instead of english was interesting:

Quote:
MAX 330 MEGA
ネオジオの初期作品から『メタルスラッグ2』まで「(文字列)」の部分を表示していたのがこの言葉で、フォントは「PRO-GEAR SPEC」と同じである。
「MAX 330 MEGA」の意味である「最大330メガ」は当初、搭載できるロムカセットの最大容量と言われていたが、この数字は本体がROMへアクセスする速度が最大330メガビット/秒であることを示している。これはネオジオの箱に記載されている。


They say that until metal slug 2, the "string" that is shown was PRO-GEAR-SPEC. Initially "MAX 330 MEGA" was believed to means the max size of a rom cartridge but on the body (of what, console? box? sometime japanese omit important details) there is string that says "ROM access 330 megabits per seconds". This is written on the box of the neo geo.

I tried to search on the net for the Japanese neo geo box. I found some that shows on the back the specification written in english but with some japanese text scattered around but I cannot find that string, only that it can access 330 megabits. It doesn't seems to be on the console either.

Since wikipedia must be taken with a grain of salt I cannot say that it is the reason until I find the proof. If I find one in the store I will check but in the south of Japan... A little bit hard to find. When I was in Tokyo I could I found one easily.

I found some confidential neo geo dev document by accident but there was no mention on that subject either.

I attached the picture for the back of the box.


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PostPosted: Wed Aug 17, 2016 3:53 pm 
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Banshaku wrote:
...there is string that says "ROM access 330 megabits per seconds".

Thanks for the interesting research; however...

Honestly, this all sounds like marketing wank. I'm no expert, but if you do some really rough math:

Main CPU: 12M (Mhz) ÷ 4 (cycles/read instruction) x 16 (bits/read instruction) = 46 megabits per second.

Sound CPU: 4M ÷ 7 x 8 = 4.36 megabits per second.

GPU: 24M (÷ ?) x 24 (bits) = 549 megabits per second....?

Yamaha YM2610: (1.85–55.5 khz + (6 * 18.5 kHz)) * 8 (bits/adpcm sample) = 1.27 megabits per second.

So, umm... how does one calculate these or add them all up anyway?

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PostPosted: Wed Aug 17, 2016 6:32 pm 
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ccovell wrote:
GPU: 24M (÷ ?) x 24 (bits) = 549 megabits per second....?
Pixel clock is 6MHz. Both tile busses do fetches at 1.5MHz. CROM data bus is effectively 64 bits wide (it's 32 bit with fake DDR). SROM data bus, similarly, is 16 bits wide.

So that's 80 bits at 1.5MHz, or 120mbit/sec ?

Maybe you get to add all the other data that goes via the P bus? That'd include the L0 vertical shrink control and the palettes for both the fix(S) layer and sprite(C) layer too.

ccovell wrote:
Honestly, this all sounds like marketing wank.
Absolutely. I even conceded that in the first post... it's just ... whence the number?


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PostPosted: Wed Aug 17, 2016 10:19 pm 
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After searching more on the subject, I think the information written by the person in japanese is not accurate and didn't read the specification on the box properly.

I have come to the same conclusion as everyone, that 330 was used for marketing purpose. I think the number may have been generated based on the possible size of rom, like Lidnariq mentioned.

From the "Product Development Component Specifications", in the "sample cassette board" example they show that fix (s rom) could be 1m, characters (c rom) 8m or 16m, program (p rom) 4/4/8/16m, music (n rom?) 1m and pcm (v rom?) 1/8/16m. A combination of those size and you could have 42m (1/16/8/1/16), max 50m (1/16/16/1/16) which would give something like 336 mbits and 400 mbits.

I gave 8m in first sample since usually program code is smaller than data. To get to 330mbits, since fix shouldn't be big either, if I set 256KiB for it, I would have 41.256 x 8 = 330.048 mbits, after rounding it would give 330.

This is just guess work but hey, I had fun reaching that assumption :D


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PostPosted: Thu Aug 18, 2016 6:24 pm 
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Banshaku wrote:
I attached the picture for the back of the box.

I see the 330 in the right end of that statblock, "DIRECT ROM ACCESS CAPABILITY"…but no units.


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PostPosted: Thu Aug 18, 2016 7:12 pm 
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The box never say anything like what is written in the wiki so my conclusion is the person didn't read the box properly. My guess is the picture I found is from the japanese version since there is japanese text on it but i'm not 100% sure. But with other knowledgeable people who gave opinion on the subject regarding this theory... I think that lead was a false positive. My bad ;)


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PostPosted: Sat Aug 27, 2016 7:59 am 
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Quote:
The core Neo-Geo sprite size is 16px wide, and 16-512px tall. Graphics are stored in 16x16 chunks.

Sprites can be attached and the system see them like only one (practical to scroll a background and less CPU usage).

Quote:
Does the Neo Geo have any raster effects, because I imagine that would help too. I'm only asking because I haven't seen any.

Of course it does(a little TF4 demo):
https://www.youtube.com/watch?v=t9NqKXxS9Cw


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PostPosted: Sat Aug 27, 2016 8:48 am 
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Additionally, Sengoku Denshou 2 does raster effects on the title screen for a 3-D skew.

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PostPosted: Mon Aug 29, 2016 12:16 pm 
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Espozo wrote:
I think the Neo Geo's biggest problem is the fact that there are no BG layers. Although the hardware was designed to do this for sprites, it's just not the most efficient way to go about it in that a lot of bandwidth is wasted on loading redundant information, like the x and y of every sprite when they're all linked together. The Neo Geo can display a lot onscreen at a time, but not as much as most of the other arcade machines from the time period. I still don't understand the big scare to using 3BG layers, I mean, you have 1.5x overdraw for sprites, and that's more than the SNES, Genesis, or Turbografx. I think the Neo Geo would have looked better if developers were more conscious of the fact that there aren't actually BG layers on the system but sprites instead. If your background doesn't take up the whole screen, just don't put sprites there. You could have a fighting game where the arena is in the woods and has a log cabin on the right as the only thing in the foreground aside from the ground. Although the ground covers the whole ground horizontally, the log cabin doesn't so there don't need to be blank sprites to the left. Doing this will mean you can't do the auto stick feature thing for sprites, but who cares, it's not like the 12MHz 68000 is taking much of a performance hit. :lol:


I'm thinking you have a bias against the NeoGeo or something like that. I didn't realize that the NeoGeo had a problem with no background layers. Every NeoGeo game I played certainly had a background and it even scrolled! Seems like the system they went with worked out ok. The system had support for over 10 years too.

Everyone can have their own opinion on what games they think look good. But I certainly don't remember anyone talking about NeoGeo and saying how they wished it looked as good as the SNES, Genesis, or TurboGrafx 16. The systems certainly work quite differently. If you want to see a similar era system that did use background layers you have the CPS2 from Capcom. It featured 3 scrolling background layers. I don't think game players cared which method the hardware uses to draw the picture.

Maybe I just don't understand your criticism of the NeoGeo. Are you just going off specs you read somewhere or actual games?


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