Technical: Polygons, 3D rotation effects, and teh NEO

[Electroman]

OF POLYGONS AND PYRAMIDS:
Many of you may remember similar topics over the early 90's when polygon games were emerging on consoles. You remember the Starfox vs Silpheed debate? Turned out that Nintendo's Starfox spanked the hell out of GameArts' Silpheed in sales, and technical prowess, even while us Sega fans still didn't want to believe that Silpheed's gfx were nothing more than a big FMV movie. Remember the big deal in SNES Zelda with the 3D polygonal triforces in the introduction?

3D MAPPED PIXEL ROTATION/SPIN (if you know the real name/lingo, please say so)
Nintendo wowed us with Donkey Kong Country with its 3D pixel rotations on SNES. As a Sega fanboy I pretended not to be impressed when I really was.

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POLYGONS NEOGEO:
Viewpoint is the only one I know of.
Do you guys think that Sammy actually used mathematical polygon animation for all the polysprites or simply saved each one as a frame and tied them together? AFAIK, with the possible exception of the above, no NEO GEO game has ever used polygonal graphics with x,y,z coordinate math. If you know of any, please show off and tell us.

3D ROTATION/SPIN ON NEOGEO:
The only games I have played that have this 3D rotation fx are Pulstar, Blazing Star, and Shock Troopers 2nd Squad. Do you think that the NEO GEO actually can map and spin sprites like in Pulstar/Blazing Star through SIN/COS math or does the NEO do it with just blunt sprite animation? Do you know of any other NEO GEO games that use this technique?

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I certainly don't know the lingo, and even more certainly don't know what the hardware can really do, outside of what i've observed. But we do know programmers will cheat, mask, and use smoke and mirrors in their programming code to achieve an effect not allowable in hardware. Its this kind of work that really impresses me and gives respect to the programmers.

More of an opened-ended discussion, if you have anything you'd like to say about it, please do.

 

[Visuatrox]

Viewpoint polygons?!. Is it not just drawn/pre-rendered sprites/backgrounds in isometric style?

Blazing Star, I'm sure NeoGeo is capable of spinning sprites around in realtime. I have even seen less powerful machines do that. But spinning around a sprite in real-time has limited use, but I can see it being useful in for example explotions when parts fly spinning around.. As for what is used in Blazing Star I have no idea..

 

[Electroman]

Viewpoint polygons?!. Is it not just drawn/pre-rendered sprites/backgrounds in isometric style?

This is what I wanted to ask teh NEO community here, if anyone that is/was 'in the loop' with Viewpoint's design way back.

As for what is used in Blazing Star I have no idea..

A few of the bosses in Pulstar, Blazing Star have these 3D spinning bosses...

 

[Moose]

I posted a topic like this a while back. I remeber some of the tech gurus reading it and talking about a few things...

Rotation: The neo cannot actually rotate any sprites, rather, all "faux pas" rotation has to be hand drawn, fram by frame.

Polygon: I remember hearing that the Neo has no polygon ability whatsoever.

Going of topic a little, if there any super tech gurus here, I have been reading lately about some guys at www.sonic-cult.org that have found a way to obtain a source code through a genesis emulator. So, they have found the entire source code of Sonic 2! They have been talking about porting the game to Sega CD. So my question regarding this is, could they ever port a sonic game to the NEO, in your oppinion?

 

[madmanjock]

Remmber the neo hardware was made back in '89, little or no interest was in polygons until about 1992 when Viruta Racing came out and really changed the gaming world as we know it quickly followed by Virtua Fighter in '93. This neo = no 3d. In pulstar it was all done prerendered - no real 3D it was done on a pc and then turned into sprites.

 

[Electroman]

The NEO has a processor so therefore it can do polys. It should do them at least as well as its little brother, the Genny.

As for 3D rotation... can a computer be programmed, in a memory map, X, Y, and Z locations for every pixel and have each one move, pixel for pixel on each plane?

 

[Verythrax]

Well, it can do vector math, like Tempest, as example - even a Apple II computer can fo that.. But I don't know how to determine how WELL the Neo could do this kind kind of stuff in realtime, gameplay-wise.

but polygon fill and textures are another thing.

But all polygons (drawn) and sprites were handled frame by frame at the Neo. About polygon rotation, Neo can't do something like Mode 7 stuff, but something like Electroman described in his last post is just what some Amiga and Genesis effects do. Just visual 'tricks' using a 68000 cpu, like that 'melting' and 'waving' effects that we see in that old Amiga games hacks intro

 

[Mushiki]

From a technical standpoint, the Neo-Geo should be able to display polygons, but from a practical standpoint this is worth nothing, since the Neo-Geo hardware lacks of a FPU, and using the main processor's integer unit to perform floating point operations isn't something "acceptable" this days.

 

[JMKurtz]

You guys are confusing 3d math -vs- 3d visual objects. The neo can compute whatever you want, but it can not display 3d polygon objects. 3D graphics are based on per-pixel computation and display. The Neo lacks this.

The video hardware inside the neo has a fixed capability of only displaying 2D sprite strips. Someone would need to come up with a new hardware add-on to do 3D on the Neo. So, anything you see on the Neo now that "appears" to be 3d, it's either pre-rendered graphics or hand-drawn.

However, I wonder if something can be done on the Neo CD. I think there is a way to write data to the sprite area, so you could compute your own data and write it to this area -- effectively, a bitplane emulation of sorts.

Jeff

 

[Electroman]

You guys are confusing 3d math -vs- 3d visual objects. The neo can compute whatever you want, but it can not display 3d polygon objects. 3D graphics are based on per-pixel computation and display. The Neo lacks this.

The video hardware inside the neo has a fixed capability of only displaying 2D sprite strips. Someone would need to come up with a new hardware add-on to do 3D on the Neo. So, anything you see on the Neo now that "appears" to be 3d, it's either pre-rendered graphics or hand-drawn.

However, I wonder if something can be done on the Neo CD. I think there is a way to write data to the sprite area, so you could compute your own data and write it to this area -- effectively, a bitplane emulation of sorts.

Jeff

This is interesting Jeff... so in other words, are you saying that NEO could compute vectors but not display them?

Oh yea... any polygonal FX on NEO would be deemed laughable by today's standards, its just interesting to think of the possibilites.

But with NEO's X and Y scaling abilities, one can do something clever however. From the platforms in SS3 and MS5 that compress, to full-screen scaling we see in many of the fighters (you have to admit, how many other arcade fighting games had zoom functions like Samurai Shodown x and Last Blade x)

I have no doubt that a different group of programmers could conjure up some cool shit FX with the neo, homebrew that is.

 

[kernow]

talking of homebrew, stay tuned for my paper I'm writing on an open MVS specification

 

[Diggerman]

Viewpoint has no polygons, despite the ignorant magazines at the time saying it did. I think it was Gamefan who originally printed that misinformation, probably others too. Viewpoint just has nicely designed sprites that look like polygons.

Jeff Kurtz already went into tech details and I tip my hat to him on that stuff, so I won't bother saying anymore. But nope, no real polygons in Neo games - and personally that's just fine with me.

 

[Baseley09]

I'm convinced some sort of 3D effect could be used on Neo Geo via software emulation. See some examples on the Amiga (Mercenary, flight sims), X6800 (Geograph Seal), which both run on the M6800. These games produce the "effect" of being in an expanse, or 3D open field. Even the 8bit microcomputers had such games as Sentiel & 3D Construction kit.

As said above though, Neo Geo has never used any true 3D gaphic, just FMV and renders given frames of animation.

 

[kernow]

you're correct, using bresenham line functions and software 3d geometry/viewpoint calculations, you could indeed spin a wireframe cube of pixels around if you wanted to, you're limited by the software rendering, and the fact you're on a 68000, plus you'd need to double buffer the screen, but I guess theres probably enough vram to do that anyway.

definately possible.

 

[MrLonghair]

Viewpoint was just pre-rendered low-poly sprites.

 

[JMKurtz]

There are no "bitplane" modes on the Neo, so you can not do any per-pixel graphics. You are limited to hardware sprites strips and the fix layer. There is no way to read/write individual pixels on the screen.

In order to make any sort of 3d display, you would need a way to "fill" the graphics region with data from a program, which you can not do on the Neo -- remember, the graphics on the Neo are in ROMS.

The Video RAM on the neo only holds tile numbers (and attributes of the tile). It is not a bitplane representation of what you see on the screen.

You would need new hardware to do 3d rendering on the Neo.

Jeff

 

[Blaine]

Kurtz knows the hardware better than I do so I won't disagree with him.

Let me set some stuff up first though:

The important thing to remember is that, at it's heart, a 3D game is no different than Tempest or Asteroids or Battlezone.

3D is a vector based technology. In generic and simplified terms a 3D engine is little more than a set of co-ordinates (vectors) being run through a math matrix (which while complex, well within the computational powers of neo hardware.) and then drawn to the screen.*

Now the reason it's impossible, as JMKurtz has been pointing out, is that the neo isn't equiped to 'draw' anything to the screen. That is you can't just give it a bunch of co-ordinates and allow it to draw onto the screen.

The Neo can easily calculate a 3D model (of modest scale no doubt) it just lacks any method to display it.

You can do 3D on almost any computer because almost any computer will allow the programer to directly access the Video RAM (JM pointed out that the Neo doesn't have a traditional video RAM that you'd see in a computer) and therefore draw to a screen.

Honestly 3D isn't that mathematically complex.

What is then? Why do we need all this horsepower for Half-Life 2?

Lighting, textures, bump mapping, reflection mapping, bi-linear and tri-linear filtering, anti-aliasing, skelatal animation, sounds, AI and the sheer massive amount of polygons games these days have. That requires power.

But just generic '3d'... you could do it on the Vectrex .


*Modern 3D engines also incorporate other calculations such as occluding which is used to determine exactly what will be displayed on screen in order to save calculations.