Simplification of fire drawtype

[paramat]

Working on the fire mod i noticed a huge drop in FPS when viewing a forest fire, by far the largest FPS drop i have ever seen in MInetest. The fire drawtype has up to 10 textures displayed, most of the time 6 are displayed: 4 edges and the 2 in a central X shape. Perhaps it is the number of textures used combined with them being animated which is causing the FPS drop?

FIre is usually viewed more from the side than from the top, with 6 textures the effect is extremely dense, i feel the central 2 are not really needed.

There are 4 textures placed against the base of a node, seems overkill for the purpose, perhaps these could be simplified to just 1 that is level and placed a small distance under the node? This texture could be a different texture designed for the purpose, having flames spreading outwards from the centre.

[est31]

Perhaps we should have opaque fire, just like opaque leaves.

[est31]

This is an engine bug, if you complain about the firelike drawtype. But making it be the same as plantllike is a bit pointless, so you could switch to plantlike if you prefer that. Then its no engine bug :)

[paramat]

Hm perhaps a 'simple fire' setting in conf that selects plantlike.

[paramat]

Testing again i don't get such a large drop in FPS as i did before, however i do find the firelike drawtype too dense and overkill, so might open an engine PR to simplify it by removing the 2 central textures.

[Amaz1]

Testing again i don't get such a large drop in FPS as i did before, however i do find the firelike drawtype too dense and overkill, so might open an engine PR to simplify it by removing the 2 central textures.

If you do this, would you be able to make it a setting please? I like firelike as it is now...

[est31]

Might be a good idea, I would change it in my local installation as well.

[paramat]

There's not much difference when removing the central 2, it still has a reasonable density especially when viewed from the side. Currently it's so dense it looks like a random mess and therefore out of character, Minetest's visual style is simple geometric structures.

Working on it last night i realised it has a problem, there are 10 drawtype textures within a limit of 6. The lower 6 flames have priority so some of the top 4 flames are often missing depending on which of the 4 lower side flames are used. Removing the central lower 2 allows up to 2 independant textures for use as top flame textures, these will always appear as the burning underside of the node above.

So it was over-engineered and buggy, i managed to reduce textures from 10 to 5, and further simplified the code, now the code is more than twice as lightweight while also being more effective at doing what firelike was meant to do.

[est31]

What load did you precisely remove? Note that with your changes to fire, there aren't any forest fires anymore, because fire just almost doesn't spread anymore, so no low FPS to be worried about. Also, this is an engine discussion, can you open an engine issue, so that we can discuss this there instead?

Fire is dense, and it is a random mess. That's what fire is, period. If you view fire from angles like 45°, you do notice the missing faces. actually the best idea would be to have a particle spawner here, which spawns "fire" particles. Then, if it still looks acceptable, we can remove those two textures.

[est31]

Minetest is messy, e.g. in the mapgen. Here we neither have "simple" shapes, but rather have an elaborate landscape, with lots of features. It isn't messy everywhere, but at some places you need "mess", so that it doesn't look boring. And right now, fire is one of the exciting nodes of minetest (ore blocks were as well, until pr 548 made them ugly).

[paramat]

PR here minetest/minetest#3171

Note that with your changes to fire, there aren't any forest fires anymore, because fire just almost doesn't spread anymore

If you try it you'll see this is not correct, my recent PR doubled the speed of fire spread, i agree it was too slow for 0.4.13 but that was because the code was so heavy. Spread is exponential so starts slow and speeds up, once a whole tree is on fire it spreads fast enough.

Fire is dense, and it is a random mess.

Yes sure in reality, but this is Minetest, everything is abstracted and simplified, and not over-engineered. The firelike drawtype looks more suitable for an RBA fork.

Particles for fire would be way too heavy for any large fire, particles are currently heavy in Minetest, besides this is overkill when an animated texture is fine.

Minetest is not messy on a small scale, the nodes and drawtypes themselves are very simple.

Firelike is currently very pretty yes, but over-complex and overly concerned with eye-candy instead of simplicity and being lightweight. Those 6 lower textures break the top 4 so we have to reduce the number. Many players are complaining of low FPS caused by fire.

[est31]

Honestly I can't notice an FPS drop caused by fire:

[paramat]

With a large forest fire, much larger than above, i noticed a 10 FPS drop.

[paramat]

Closing for reasons given in the PR minetest/minetest#3171