Viruta Fighters 4
Viruta Fighters 4 Today I checked out Virtua Fighters 4. It seemed mostly like just another fighting game. I couldn't really see any major differences between it and say Tekken Tag Team.

There are minor differences. For example some of the levels have ground clearly made out of polys, not just textures. For example an area made of carved stones. Because Naomi hardware gives you shadow volumes for free the shadows crawl over the polys. Of course this is also true in most Dreamcast games so I suppose it's not that big a deal.

A couple of levels have a height mapped based arena of snow or sand. Although the arena as far as game play is concerned is flat, the characters leave foot prints and body prints in the snow by adusting the height map for the snow where they step or land. Unfortunately the resolution of the height map is not enough and the number of particles thrown up is also not enough so although it's cool it's not that real looking in terms of effects.

There's a couple of levels with reflection mapped water. The cool thing is the relection matches the background perfectly including a couple of boats in the water. Most relection maps I've seen are just a kind of guess.

There's a level with refraction mapped water. I'd like to know how that effect is done. I can think of ways to do it, it's been done on PS1, but not having done it I'm not 100% sure what to do.

One level that's impressive is an arena kind of like the cage at a WWF competition. Outside the cage there are probably 500 animated 3D people. I'm sure they are very low poly and I'm sure they don't have back sides but still it's kind of cool. Only maybe 100 of them are visible at any one time but around the entire rink there are probably about 500 and there's a spot light that shines in the audience.

Some of the levels seem pretty big. The arena itself is pretty much always the same size and unlike Tekken is not unlimited but the some of the background areas around them seem very detailed.

One level has a semi-relective surface. Tekken had one of these too. I don't remember if Tekken's also reflected the players but VF4 does. Of course that's just by putting them under the floor upside down.

On a couple of the areas it's possible to break parts of the floor. For example one arena is made of stones and if you slam an opponent into them they break leaving small ditches etc.

The most amazing thing though and this was probably true of previous VFs. I watched people play and most of them, their entire game lasted less than 30 seconds or so it felt. They were always playing against another person so maybe if you play solitare it's might last longer.

Comments:

Rendering to Texture [ e ]

Hmmm,

I'll have to check out that demo

I always assumed that would be way too slow for most games. The water in Dark Cloud PS2 for example simulates refraction. I always assumed it was done by drawing parts of the previous screen or by drawing the screen once and then drawing the water over it and using the screen as the texture. Or by drawing parts of the previous screen. The same way the wake of the warpball in CTR did it's think. I guess you could call that Rendering to Texture but it doesn't require extra memory and it would work for lots of stuff. The only issue being if stuff got infront of the water before the water surface was rendered

posted by greggmanJuly 16, 2001 at 14:07

Waves Demo [ e ]

NVidia has a demo with source code called Waves that does reflection and refraction by doing render to texture.

The link is:
http://partners.nvidia.com/m
arketing/developer/devrel.ns
f/TechnicalDemosFrame?OpenPa
ge


This demo does not use new stuff like DX8 vertex or pixel shaders or similar OpenGL extensions. It works on old NVidia cards like the GeForce 256.

They might be doing it this way.

posted by tonebyteJuly 16, 2001 at 17:42

other techniques [ e ]

In Hydro Thunder, there was another technique for reflection and refraction. In some parts of the level the water "reflected" by actually drawing the terrain above the water upside down and there was a wiggle applied to the upside down verticies to simulate the undulating effect that moving water would have on the reflection. In other parts of the level the water "refracted" by drawing the underwater geometry and I don't remember if the verticie wiggle was done for this geometry.

This is the non-render-to-texture way to do it, but can look damn good. If the verticie wiggle is done taking in to account water height I suppose it gets even better. And if the verticie wiggle is done taking in to account eye position and water height then it will be a hefty calculation but maybe doable on a PS2.

posted by tonebyteJuly 17, 2001 at 17:46