Particle effects development

[LagMaster]

discuss here about the particle evects problem, i will try to make in this first post a sumary of everything we know about particle efects



Topic Start: now , what about particle evects, how can we add them to game? and then how to create them?

[pistacja]

True Particle Effects.

Particles are rendered on small 3d meshes or more typically on single quads with a billboard effect (they always face the camera). Another method is using point-sprites. Some older hardware are very good with point-sprites, but modern GPU's usually render them in software. Hardware instancing could be used to speed up rendering of geometry based particles, but that is a bit hi-end for fonline. Either way both methods use textures with transparencies if anything more complex then a pixel in needed, if they need to be animated series of images (usually stored side by side in one file). Particles like this are rendered in hundreds and thousands and are controlled by a physic script that determine their behaviour (mass, speed, time to live, birthrate, collisions, starting angle, etc).
   
....for fonline it's an overkill, and somehow I don't see it as becoming a part of the engine.


Pre-Rendered Particles

This is something much simpler.  It's just a 2d animation of blood, fire or smoke put on top of the 3d model. Alpha testing and depth sort is still kind of needed but no advanced physic is needed and it only takes 2 triangles to draw.


I says we don't do a particle system at all, just use prerendered effects.  It's only blood, gore, smoke and muzzle flashes.   

[Haraldx]

Indeed, Quake 3 and other good old games used pre rendered effects for muzzleflashes and stuff. It might not look very good for gore animations tho.

[LagMaster]

how about we make some scuzrers or tris and that are painted in red(i trig/blood drop) it will be probably a +20 tris in frame if we use 20 on ech death anim

[Haraldx]

how about we make some scuzrers or tris and that are painted in red(i trig/blood drop) it will be probably a +20 tris in frame if we use 20 on ech death anim

Nah, it's better to have that animated polygon thingy then.

[Graf]

I've asked Cvet about particle effects. He said, that (obviously) there's no actual particle effects system at the moment, but we can use the RunEffect function of the engine. What is necessary to do - is to create a 3D animation, containing stuff that we need (e.g. blood, muzzle flashes, flying rockets, explosions etc.), then create a prototype for each animation (whatever that meant) and after all rig it to the model. Cvet said that this is how it is now works for the 2D, but it is applicable to the 3D as well. Length of the animation will be the same as the lifetime of the particle in that case.

[pistacja]

em, why not just a flat 2d animation on top of the 3d model? It can even ba a native fallout .frm with 1-bit(?) alpha.

[Graf]

Well, if it's possible to combine 2D and 3D, then yes, why not. Though I'm not sure if it works or not. But if it does, it can give even better results.

[Jotisz]

I'm not sure if it would work out well though surely it can be tried.
Personally I would use some morphing on the characters then adding bloods that would be another object will show an example.

[Johnnybravo]

Well, if it's possible to combine 2D and 3D, then yes, why not. Though I'm not sure if it works or not. But if it does, it can give even better results.

It'd look much better, but would suffer from low framerate. However it is not likely anyone would do that complex animations which are used by Fallout so it wouldn't be that bad choice. In fact for the more violent animations it'd be better not to have anything in 3D, because they'd be impossible to do with lowpoly models (like death from electrical) or requires delicate effect that would be really hard to achieve without some scientific imput (flame death) or just really delicate morphing (plasma death).
Don't think it'd be problem to spray particles to get blood and smoke for explosion deaths or maybe even those burst animations.

[Luther Blissett]

I was looking through the .x files of some of the weapons earlier, and running their animations. Notably, some of the assault rifles etc contain little bullet cases which fly out the side when firing (I'm sure you remember seeing these on the example videos).

Anyway, they're basically a bunch of small bits hidden inside the main model. The gun has its own burst and single shot animation - which fire one or lots of little cases out the side. They're invisible when hidden inside (I'm not sure if they actually exist when not being animated... but that's maybe a little philosophical for bullets), then appear as necessary when the animation runs.

Knowing that :
a) We can put loads of little things inside a model and chuck them out as needed with an animation
b) We can put png and other formats as the texture, with working transparency

Could we use a similar method for some of the blood splurts - basically hide a bunch of "red chunks" inside the model - as tiny triangles, painted as wobbly blood splats? Similarly, as the bones can change in size during animation, could we hide a "tiny blood pool" inside, which would expand underneath the character when they're killed normally i.e. HP below -20 will currently make the "blood pool animation" run?

With some of the transparencies I tested previously, I cut a hole through a model by making the texture transparent - could this be used in combination with the above to add a few of the "big hole shot through ribs" style animations?

I don't know whether these extra bits would just need to be put in with the death animation, or whether they would need to live inside the bodies at all times i.e. the human model constantly walks around with tiny red bits hidden inside it.

Also, I can't yet see any obvious method of solving the flame / electric / plasma stuff, unless of course we manage to play a partial 2D animation over a 3D animation - in which case we can scrap all the wobbly blood cubes and do the same for the rest.

[Johnnybravo]

Voxel based models are currently the only way to get faithful replica of those effects in 3D ( and useless because there're no additional angles to view from )
Think that you don't really need per armor animation for those fatalities ( they're in fact the same except perhaps first two-three frames ), so that in fact only framerate is limiting ( smooth animation will turn low in the case of those animations ), but given the animation on scenery (nearly non-existant) this won't be problem at all.

Using transparent model will probably be ok for singleshot bullet critical kills, however the model itself is empty inside and it might be visible.

[Lexx]

I was just thinking about the flamethrower attack animation-- maybe this one could be realized with cutting out the flame from the original 2D animation and showing it then as particle effect in front of the flamer when the animation is played + highlighting the critter with orange / red lights. This could give the animation at least the original feeling and we wouldn't have to care for any fancy flame particle effects.

[LagMaster]

hmm, can we do that will all the projectile animations?(probably rocket fly animation will be changed)

i mean instead of replacing the good old 2D anim with some improvized 3D, we can keep it original

[Lexx]

I don't think it makes much sense with all other attack animations. There isn't much visible in the 2D animations and it probably would be better to give weapons (different rifles, etc.) more unique muzzleflash and stuff. The flamer is the only attack animation that uses a really obvious and known effect.