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Comparative sprite capacity of 3rd and 4th gen consoles
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Author:  TmEE [ Wed May 24, 2017 4:22 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

mikejmoffitt wrote:
I can confirm that every Neo-Geo video system (LSPC-1, LSPC-2, NEO-GRZ) outputs 320 active pixels. 304 pixel width is done by blanking on the FIX layer on the left/right columns. 384 pixels constitutes one line, including blanking. I have not done it, but if you were to write a FIX layer rom that is entirely transparent pixels, you might be able to visually confirm this.

The blanking input on the 74245s on the DAC are active during VBlank on LSPC-based systems, while on the GRZ-based systems it is active during both HBlank and VBlank.


That is more or less what I did, I made DACs always output a signal and fed data to FIX inputs that should have made whatever is underlying active but there was never more than black output. Only ever 304 pixels of active video, rest being blanking and porches.

Author:  tepples [ Wed May 24, 2017 4:52 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

Nicole wrote:
tepples wrote:
  • Super NES
    Rearmost 34 slivers (106%) of frontmost 32 sprites, plus 2-3 backgrounds
    Nominal CHR RAM bandwidth: 168 tiles/frame

Are we just talking common configurations here or the full capabilities of the hardware? Mode 0 is not commonly used because of its color tradeoffs, but it did have four BGs.

Common configurations. Modes other than 1 ("normal"), 2 (column scrolling), 3 (title screens), and 7 (texture mapped floor) don't see a lot of use.

TmEE: "Passive" means vertical blank period, right? If so, the DMA bandwidth to the Genesis VDP in H256 mode appears almost identical to that to the S-PPU after deducting time to copy the sprite attribute table and a row or column of background map. The advantage of "Blast Processing" over DMA to the S-PPU is really just the ability to decompress tiles (Nemesis, Kosinski, etc.) directly to VRAM without using any vblank time.

Author:  ccovell [ Wed May 24, 2017 5:42 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

TmEE wrote:
mikejmoffitt wrote:
I can confirm that every Neo-Geo video system (LSPC-1, LSPC-2, NEO-GRZ) outputs 320 active pixels. 304 pixel width is done by blanking on the FIX layer on the left/right columns. 384 pixels constitutes one line, including blanking. I have not done it, but if you were to write a FIX layer rom that is entirely transparent pixels, you might be able to visually confirm this.

That is more or less what I did, I made DACs always output a signal and fed data to FIX inputs that should have made whatever is underlying active but there was never more than black output. Only ever 304 pixels of active video, rest being blanking and porches.

Run Blue's Journey on any Neo-Geo and double-check that the borders around text during the introduction or in-game are all visible. That's 320 pixels.

Author:  Oziphantom [ Wed May 24, 2017 11:10 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

lidnariq wrote:
edit2: During the 5th console generation, SVGA cards actually grew support for one sprite (i.e. composited dynamically during refresh), intended for the mouse cursor.
Quote:
Amiga
OCS or AGA?
That is OCS , although the bolting might be ECS

AGA has 32 or 64 wide sprites ( all must be the same width), hires or superhires resolutions ( as sprite resolution and colours are independent of "window" resolution ), you can have 2 palletes were odd sprites are one and even is another.
You can have Vertical doubling ( each line is repeated twice, useful for interlace modes)
You can reuse the same sprite again on the same X line ( you can do it on ECS, but on AGA it is without cleaver timings, tricks etc )

Author:  TmEE [ Thu May 25, 2017 3:27 am ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

tepples wrote:
TmEE: "Passive" means vertical blank period, right? If so, the DMA bandwidth to the Genesis VDP in H256 mode appears almost identical to that to the S-PPU after deducting time to copy the sprite attribute table and a row or column of background map. The advantage of "Blast Processing" over DMA to the S-PPU is really just the ability to decompress tiles (Nemesis, Kosinski, etc.) directly to VRAM without using any vblank time.

Yes, it means vertical blanking period. I don't think there are many games that touch VRAM from active display. You still get 16 or 18 bytes per line and could use that to transfer some/all of the sprite list during a statusbar etc.

ccovell wrote:
Blue's Journey on any Neo-Geo and double-check that the borders around text during the introduction or in-game are all visible. That's 320 pixels.

Unfortunately I don't have that game (and it seems way out my budget too), I only have the Metal Slugs, Neo Turf Masters and Riding Hero and none of those do more than 304 no matter what I tried. My TV shows almost all the image from sync to sync with only few pixels worth clipped off on left side in the porch so it isn't a matter of me not seeing the pixels if they were there, plus I had scope running simultaneously and it never showed any activity at the edges of regular active display area when I was testing around.
EDIT: When I looked through my chat log with Furrtek I saw that I did manage to get some noise show up in the sides of screen when I toyed around with some control signals but there was never any actual graphics there.
I'll remain unconvinced about the 320 pixels until I see them myself. I don't plan to take up NG programming yet and I'm not very familiar with the machine to write a small test ROM anyway that would set up things so that in theory there will be stuff visible at the sides. I could swap out the 68K program ROM in one of my carts for sake of testing.

Author:  mikejmoffitt [ Thu May 25, 2017 10:56 am ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

Real Bout Fatal Fury Special uses 320 pixels as well. I suppose I'll have to go home and take some pictures of it to convince you.

Author:  Espozo [ Thu May 25, 2017 11:02 am ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

Yeah, I thought it was well known the Neo Geo outputs 320 pixels horizontally, but that 8 pixels on either side are commonly blackened out by plain black tiles in the fix layer? It'd be no different than putting a plain black window on both sides of the screen on the SNES or any other thing to block part of the screen in software (Not natively supporting reducing the rendering area, like on the NES).

Author:  psycopathicteen [ Thu May 25, 2017 12:02 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

I think most of the later games used the smaller resolution for some reason.

Author:  tepples [ Thu May 25, 2017 12:06 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

Perhaps the smaller res (304x224) was more compatible with marginal monitors, particularly aging MVS monitors and the TVs used with the AES.

If you compare the AES's output timing to that of a standard TV, you find that only 315x240 pixels are in the 4:3 frame, the rest in what Rec. 601 calls the "nominal analog blanking" area. (The AES pixel aspect ratio is 65:64.) Assuming 3.5% overscan on all sides, you end up with close to 64/65*.93*320 by .93*240 = 293x223 visible.

Author:  TmEE [ Thu May 25, 2017 2:41 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

Arcade cab monitors tend to have bunch of manual controls in them so you can set the screen size and other parameters to suit the particular board you have installed, there was no need for any tight timings or signal levels and everything used the most convenient timebases and resistor values for their video output frequencies and levels.
AES uses a different master clock just so that the video output would play nicer with TVs which are supposed to follow some particular standards.

All places cite 320 pixels but it seemed that everything was using no more than 304 and only 320 shots I saw were from emulators so that's where the curiosity began and after a bunch of experiments I could never get more than 304 pixels to show up on my MV1 (with LSPC-A0) board. I have a MV1-FZ (with LSPC2-A2) that is yet to be tested in any meaningful way (will get a chance to look at it again once I am back from Norway, which happens next month).

mikejmoffitt wrote:
Real Bout Fatal Fury Special uses 320 pixels as well. I suppose I'll have to go home and take some pictures of it to convince you.

Yes please if it isn't too much trouble ~

Author:  tepples [ Wed May 31, 2017 1:58 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

True, but as a monitor ages, those controls become less effective at hiding the signs of aging.

You might be able to count pixels by replacing a game's fix ROM with direct wires from low address lines to the data lines.

Is it still spelled "coverage", or is it officially "covfefe" now?

Author:  mikejmoffitt [ Wed May 31, 2017 2:17 pm ]
Post subject:  Re: Comparative sprite capacity of 3rd and 4th gen consoles

TmEE wrote:
Arcade cab monitors tend to have bunch of manual controls in them so you can set the screen size and other parameters to suit the particular board you have installed, there was no need for any tight timings or signal levels and everything used the most convenient timebases and resistor values for their video output frequencies and levels.
AES uses a different master clock just so that the video output would play nicer with TVs which are supposed to follow some particular standards.

All places cite 320 pixels but it seemed that everything was using no more than 304 and only 320 shots I saw were from emulators so that's where the curiosity began and after a bunch of experiments I could never get more than 304 pixels to show up on my MV1 (with LSPC-A0) board. I have a MV1-FZ (with LSPC2-A2) that is yet to be tested in any meaningful way (will get a chance to look at it again once I am back from Norway, which happens next month).

mikejmoffitt wrote:
Real Bout Fatal Fury Special uses 320 pixels as well. I suppose I'll have to go home and take some pictures of it to convince you.

Yes please if it isn't too much trouble ~


Here's an emulator screenshot first:
Image
Pay careful attention to the distance between the "Credits" stuff and the edges.

Now this is captured off of the MVS pixel bus with an FPGA as part of my line doubler:
Image

This is how it would look if it was cropped to 304:
Image

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