Good splash fx in idtech4?

[Springheel]

I really dislike our water splash fx, but don't understand particles well enough to replace them. Is anyone aware of idtech4 games or mods that have good splash particles that I could use as a reference?

[Bikerdude]

+1 -

 

- I too have always found our existing splash fx overkill on anything above a big splash.

[Obsttorte]

Do youhave an example video of how it might should look like?

[Springheel]

Not a great example at the moment--here's something though it's a bit hard to see:

 

https://youtu.be/fU9P4PCie9k?t=4m35s

[Springheel]

This is a little overdone but it's still far better than ours.

 

[Bikerdude]

the spalshing in the above video is even still to much, you would just see ripples and water displacement with a bit of splashing..

[Arcturus]

I once had been thinking about it. In modern games there are realistic ripples on water. We could use particles with normalmap but there's a problem. Particles are square but ripples need to be round. You could make a round normalmap like this:

Particles can grow with time however the heat haze effects don't blend. There are flat spots like those in the corners that would negate the wave effect on water and other ripples which would reveal the square shape of a particle. One solution could be to rotate the particle very quickly so that it appears round, but I never tested it.

Witcher 3:

https://youtu.be/VKE1Fn1Yrhk?t=2m22s

[Obsttorte]

Can alphatesting be applied on bumpmaps, too. This way we could get rid off the corners. Otherwise it could also be possible to use a function instead of an image to provide the distortion.

 

The water effects in W3 really look awesome.

[Arcturus]

I doubt you can have alpha on heat haze effect.

[Springheel]

There are two parts to the splash effect--one is the actual "splash" (water being thrown into the air) and the other is ripples. Both of ours are not good, though I find our splash worse than the ripples. I mean, THIS is our splash effect as an AI falls into the water. It's even more terrible when you see it in a screenshot--the splash doesn't even overwrite the water!

[nbohr1more]

I was looking at other Id Tech 4 games last night. I think Enemy Territory: Quake Wars has some alright splash effects from the

little I could glean from youtube. Since it uses basically the same material structure we could probably crack open the pack files

and see reference examples. Anyone own it?

[Springheel]

Other issues include AI not making any splash effects when walking through shallow water. Even though the water in the above sewers isn't high enough to cover their feet, there are still no splash effects when they walk. That's why I said even the video above would be a big improvement on our water--forget anything as realistic as the Witcher effects.

[grayman]

I noticed the sewer guards in W3 not causing splash or ripple effects when walking in the water, but decided not to worry about it too much. The rats give off a nice ripple effect, but they're up to their waists in the water, which allows the effect.

[Springheel]

I noticed the sewer guards in W3 not causing splash or ripple effects when walking in the water, but decided not to worry about it too much.

 

 

I don't think it's a WS3 issue; it's something that needs to be improved mod-wide.

 

The rats give off a nice ripple effect, but they're up to their waists in the water, which allows the effect.

 

 

How is this determined? It seems to me that you'd be less likely to make splashes the higher the water goes on your body.

[grayman]

I don't think it's a WS3 issue; it's something that needs to be improved mod-wide.

Right. The fix is in the code, not in WS3. I chose not to worry about it at the time.

 

How is this determined? It seems to me that you'd be less likely to make splashes the higher the water goes on your body.

It's very simplified. If in water that's below the waist, there's no splash or ripple effects. Fixing this is a bit more complex than simply saying "Splash if water's less than ankle height" because the effect originates at the AI's origin, not at his foot. This is probably why the original coders decided not to bother with it.

 

In other words, an AI walking through shallow water would not emit splashes and ripples where his feet were, but at a spot between them.

 

It's certainly fixable, but requires a knowledge of exactly where the foot is in the animation at the moment it touches the water.

[Arcturus]

I thought it would look worse.

 

 

Effects actually blend nicely and corners are not noticeable. There are some drawbacks however. It doesn't work with coloured water:

 

 

The effect is one-sided and I don't know how do another stage with faces flipped. Also particle don't fade, they disappear abruptly.

There are 3 particles spawned at random positions in one cycle. Z axis is also slightly random to avoid z-fight. Along the heat haze effect there is also specular map, just like the water in the video. Here are the files.

[Springheel]

That looks fantastic in the clear water!

[Springheel]

AI walking through shallow water would not emit splashes and ripples where his feet were, but at a spot between them.It's certainly fixable, but requires a knowledge of exactly where the foot is in the animation at the moment it touches the water.

Does the code know when the foot hits the water for the footstep sound, or is that faked?

[SteveL]

I'm going to have to have a look how you did that! I didn't think it'd be possible to see a bump effect on top of heat haze.

[Arcturus]

I learned it from one of our water shaders, which has that effect barely noticeable.

[grayman]

Does the code know when the foot hits the water for the footstep sound, or is that faked?

When the foot hits the ground is determined by the animation ("frame NN footstep"). The code looks at what the material is beneath the AI's origin, and how deep the AI is in any water. If there's water, a splash sound replaces the normal "footstep on material" sound.

 

This is why, when the AI crosses a threshold between floor materials, say from tile to carpet, his forward foot might step on the carpet, but you still get the tile sound if the origin is still back over the tile material.

 

We could enhance this by:

 

- defining offsets for the left and right feet when they are the stepping foot (aka the 'leading' foot). we would need to look at the animations because they don't indicate whether the left or right foot is the current stepping foot.

 

- define separate offsets for running

 

- define separate offsets for creeping (as in slow searching, though I don't remember if slow searching generates footstep sounds)

 

- check the material and for water at the offset

 

- enhance all this for creatures with more than 2 feet (i.e. the horse)

[Springheel]

When the foot hits the ground is determined by the animation ("frame NN footstep")

 

 

If we know when the foot hits the ground from the animation, couldn't we play the splash at that moment, and center the effect on the appropriate foot joint, if the water is appropriately shallow enough? If the water is high enough the AI would be wading instead of stepping, so no splash effect would be needed. Ripples would probably look fine played at the origin if they spread out enough.

[grayman]

If we know when the foot hits the ground from the animation, couldn't we play the splash at that moment, and center the effect on the appropriate foot joint, if the water is appropriately shallow enough?

Yes, that's what I was saying above, if the coordinates of the foot joint are known, and we know which foot is causing the sound.

 

If the water is high enough the AI would be wading instead of stepping, so no splash effect would be needed. Ripples would probably look fine played at the origin if they spread out enough.

Having said all I said about not splashing or rippling in shallow water, I discovered that AI create ripples and splashes when running through water 16 deep, which is certainly not waist level. Maybe that's different code than what I was looking at. Needs a thorough investigation, which I don't have time for atm.

 

The ripples looked okay, but the splash particles didn't paint properly, always painting behind the AI. (He was chasing me as I was running backward.) Maybe that's due to the splash originating behind the leading foot. Dunno.

[SteveL]

The game can access joint coordinates. I had to do that for the blood decals fix. So it shouldn't be too complicated to work out which is the forward foot and use that as the origin of the sound and splash.

[Springheel]

That would be cool, but that's actually not the problem that most needs fixing, IMO. The first thing is simple to replace the existing particle effects with better ones. Arcturus' ripples are fantastic if we can get them working on all types of water. The actual splash effect also needs fixing, but I'm not even sure where to find it.