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Detail textures

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Ysaneya

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Many people have been worried by the lack of updates recently. No, we haven't got lazy, in fact quite the contrary :) We've been awfully busy at work.

In this journal I'm going to review some of the recent work, without going too far into details. In a future dedicated update I'll come back more extensively on the recent server side development.

Detail textures

I've added support for detail textures to the game. It was in fact quite easy to implement ( two hours of work ) but that feature was requested by many artists, so I took a bit of time to experiment it. The test scene is Kickman's shipyard as seen in this screenshot:



Now, this station is huge. Really huge. More than 8 kilometers in height. It was textured using spAce's generic texture pack, but despite using tiling textures, the texture still looks blurry when you move the camera close to the hull:



And now here's the difference using a detail texture:



Since I didn't have any detail texture ready, I simply used mtl_5_d.tga ( from spAce's texture pack ), increased the contrast and converted it to grayscale. I then placed this texture into the alpha channel of the misc map ( mtl_5_m.tga ).

Here, I said it: surprise! surprise!, details textures make use of the unused ( so far ) channel of the misc map. The nice "side effect" is that, like the other kind of maps, you can assign a detail texture for each sub material, which means that a single object can use different detail textures in different areas of the object..

The detail texture does not use a secondary UV map though: the shader takes the diffuse UV map and applies a scale factor ( x8 in this picture ) to increase the frequency. The result is that you see "sub-plating" inside the big plates of the texture.

So what does the shader do exactly ? It acts as a modifier to the shading; please remember that the detail texture is a grayscale image.

1. It is additively added ( with a weight ) to the diffuse color. Note that the intensity 128 / 256 is interpreted as the neutral value: all intensities lower than 128 will subtract, while all intensities over 128 will add. The formula is COL = COL + ( DETAIL - 0.5 ) * weight

2. It is additively added ( with a weight ) to the specular value. Formula is the same than above, with a different weight.

3. It is interpreted as a heightmap and converted to a normal ( by computing the gradient ) on the fly. This normal is then used to displace the original normal coming from the normal map, before the lighting / shading computations are done.

If you're going to update existing textures / packs, you should probably think of the detail texture as a detail heightmap added at a higher frequency on top of the surface.

Instead of interpreting the same texture in two different ways ( additively for the diffuse / spec, and as a heightmap for the normal map ), I could have used a new RGBA map storing the detail normal in RGB and the detail color in alpha, and this would have saved the detail normal computation in the shader. However, this would have required one more texture, wasting precious video memory.

It is unlikely that I'll update ASEToBin to support detail textures anytime soon. ASEToBin uses obsolete assembly shaders, so I'd have to port all those shaders to GLSL, which is many days of work.

Recent work

In the past 2 months, I've been working on various tasks. Some of them are secret, so I can't say much about them. They include work on Earth ( which I can't show for obvious reasons ), and work on networking security ( which I can't explain either, to not give precious hints to potential hackers ). I've also done a couple of experiments with spAce, which will hopefully go public once we get nice results.

What I can say, however, is that I've done some nice progress on the infamous terrain engine. No, it's still not finished, but it's getting closer every day. At the moment it's on hold, as I wanted to progress a bit on the gameplay and server side. I'll probably come back on it with a dedicated journal and more details once it's complete.

I've implemented new automatic geometry optimization algorithms into the engine, which are automatically used by ASEToBin. Those involve re-ordering vertices and indices for maximum vertex cache efficiency. For interested programmers, I've been using Tom Forsyth's Linear-Speed Vertex Cache Optimization . It increases the framerate by 10-20% in scenes with simple shading. When shading is more of a bottleneck, like on the planetary surfaces, it didn't help at all, but the good news is that it didn't hurt the framerate either.

I added a couple of performance / memory usage fixes to the terrain engine. Some index buffers are now shared in system memory; the maximum depth level in the terrain quadtree is limited, saving texture memory on the last depth levels. I'm storing the normals of each terrain patch in a LA ( luminance/alpha ) normal map texture, in two 8-bits channels, and recompute the missing component in a shader. Unfortunately, texture compression cannot be used, since the textures are rendered dynamically. I've also introduced new types of noise to give more variety to the types of terrain that can be procedurally generated.

I added support for renderable cube maps, and I have some ideas to improve the space backgrounds and nebulae, which aren't in HDR yet.

I've also done some serious progress on the server side. The global architecture ( meta-server, SQL server, cluster server and node servers ) is set up. The various network protocols are on their way. I'm now working on dynamic load balancing, so that star systems ( managed by a node ) can migrate to another node when the cpu is too busy. I'll probably come back on the architecture in details in a future update.

Darkfall Launch

Darkfall Online ( a fantasy MMO ) has launched. Why do I mention it ? Well, it's a very interesting case of study for us. Like Infinity, it is produced by an independent company ( although they do have millions of dollars of funding ). Like Infinity, it went for a niche market ( twitch-based combat and full PvP ) which isn't "casual". And like Infinity, it took forever to launch and has been labelled as "vaporware" for years ( although we still have some margin compared to them ).

So, what are the lessons learned from Darkfall's launch ? What can we do to prevent the same problems from happening ?

Unfortunately, I'm a bit pessimistic in that area. Of course that doesn't mean that we won't do our best to have a good launch. But, realistically, we won't have the resources to open more than one server, even if we need a lot more to support all the players trying to connect. This means.. waiting queues. A lot of Darkfall players are, understandably, angry: they paid the full price for the client ( 50$, if not more ? ) but can't get into the game, due to waiting queues that are many hours long. The good news is that, for Infinity, the initial download will probably be free ( but don't quote me on that, nothing is 100% set in stone yet ).

Will the server be stable ? Will it crash ? Will it lag ? Nobody can say for sure. As I see it, it depends on three factors:

- the number of players that try to connect, and more accurately, how much stress they cause on the server ( 1000 players connecting within 1 hour causes less stress than 1000 players trying to connect every minute.. ).

- the server ( physical machine ) performance, network quality and bandwidth available.

- the client / server code performance and quality: hopefully, not too many bugs.

On those three factors, the only one we can directly control is the third one. The machine's performance is mostly a financial problem, and as independent developers, we definitely won't be able to afford a large cluster that can handle tens of thousands of players at the beginning. Finally, how many players try to connect is a double-edged sword: more players means more income, but also mean more stress on the server, maintenance, support problems, etc..

The last lesson learned from Darkfall, IMO, is to communicate with your player base, especially at launch. I can understand the frustration of many players when the game has launched, but the most recent news on the website is a month old or more. Of course, I can also understand the developers who are busy trying to fix their code, but it only takes a few minutes..
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Dude... thats just awesome. The difference the detail texture makes is huge. I can't wait to play this game... bags being a beta tester, btw ^^.

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Nice work! The detail textures look great and gave me some ideas for my own project. :-)

Quote:
What I can say, however, is that I've done some nice progress on the infamous terrain engine. No, it's still not finished, but it's getting closer every day. At the moment it's on hold, as I wanted to progress a bit on the gameplay and server side.


I'm glad to hear this! Not knowing anything about you or your game besides your gamedev journal (so, take with a grain of salt), I have always been a little worried that the quest for perfection in visuals would eat up all of your development time and energy before you really had the gameplay ironed out. I think I understand why you worked so heavily on the visual features first -- to attract a community, to keep yourself engaged, and perhaps to prove that continuous rendering of a solar system is indeed feasible -- or maybe it just seems that way because I am only exposed to the eye-candy gamedev posts. Do you care to comment?

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Quote:
The last lesson learned from Darkfall, IMO, is to communicate with your player base, especially at launch. I can understand the frustration of many players when the game has launched, but the most recent news on the website is a month old or more. Of course, I can also understand the developers who are busy trying to fix their code, but it only takes a few minutes..


I have been through many launches and communication (for me at least) is one of the most important things. Darkfall failed in that department, but many other launches have handled it poorly too - even from much larger companies.


Anyways, I have been following your project for years and since this is my first post here, I just want to say thanks for sharing all the information - it have been a great inspiration to me and it is very impressive work.

/Ronzan

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Lookin good, as usual :)
In my project I'm looking at moving from a 'single skin per model' setup to a material-based approach - which sounds like what you use - any tips for moving over/approaches/experiences you can quickly summarise?

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