Dynamic Weather System

[PaulMesh]

Hey guys,
I just saw a nice video about the effects of weather on objects like static meshes or the ground.
Just wondered if something like this could be implemented in openMW?

http://www.youtube.com/watch?v=8YPgVlBbtcs

http://www.youtube.com/watch?v=2X1vFVGAlwk

[Tarius]

The height map one might be possible. The water one wont be without alot of additional work that probably wont take place for a long time.

[Br0ken]

I've always liked these weather effects in UDK. A whole scene can be covered by one dynamic shader. It would be great to see such thing in OpenMW.
Another dynamic snow implementation - [Unity] UniStorm, and also there is a realistic storm transitions

[Ace (SWE)]

The flow map water is very nice, I remember watching a talk Valve did about how they made their flowmaps for Portal 2 and Left 4 Dead 2. If I recall correctly they basically took the bsp map, separated only the water and anything touching it from the rest of the map, baked anything the water collided with into one huge model that they then fed into another program (houdini?), where they let that program build a flow map. They then take the flow map and apply it back onto the main map in hammer.

Not really something that's done dynamically, though I guess support for flowmaps wouldn't be too hard to create. What would take time is actually flowmapping the water in Morrowind, since that would be up to mods.

The weather on the other hand certainly seems like something we could implement, though since it's not really needed for the big 1.0 it'll probably take a seat somewhere in the back of the list. Unless a shader god (scrawl?) decides we have an urgent need of weather effects that is.

[WeirdSexy]

I've always wanted to see "distant weather". Like it might be clear and sunny where you are, but you can see a storm way off in the distance.

[Mistahtokyo]

I've always wanted to see "distant weather". Like it might be clear and sunny where you are, but you can see a storm way off in the distance.

Correct me if I'm wrong, but wasn't this implemented in Assassin's Creed: Black Flag? Might be interesting to see how they did it.

[SquireNed]

They also had something like it in Just Cause 2, though I don't remember them using dynamic weather for it and just using it for places where the weather is always the same.

One thing to consider for a dynamic weather system is to simply draw the whole map as a grid and use some sort of Perlin noise modified by HSV values of the terrain (i.e. more likely to have ash storms in certain places, rain storms in others, and snow storms in yet others; and they could be of varying intensity based on the darkness and color of the final noise), and just have that feed into the game world and renderer, though it's important to note that my familiarity is in animation stuff and not programming, so I might be suggesting something impossible/lag inducing.

[Chris]

A big problem with distant weather is that Morrowind's landmass is scaled really small. In many cases, it would be pretty silly to see region-specific weathers in the respective distant regions because those areas are small enough that you can see all of it from some vantage points. It'd also make the region's boundaries painfully obvious. Real distant weather would need a game world the size of Daggerfall, and even then you'd need to be careful about having too many weather zones.

What we could do, however, is use distant weather as a way to transition weather types. Like, you walk into the ashlands, and an ash storm comes rolling in from the direction of the center. You won't see the ash storm from outside the ashland region (except for the time it takes to fully go away when leaving), but it would make transitions nicer and more natural looking than just fading the sky texture and enabling/disabling particle effects.

[Rhys]

What Chris say would be cool, where weather effects on some days roll in from a particular direction, rather than just generally fade in.
However then you would probably need a procedural cloud system to be rolling instead of static textures.


Real cloud shadows would be cool.

[sirherrbatka]

I suspect that morrowind is to small for this as well.