id tech 5?
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Hi there, I did a search on this forum and did not come up with any posts. Just watched some Carmack videos and it appears his new magic is layer as much shit as you want using decals and blends and then the engine bakes this down to a very massive texture and then streams in chunks of the massive texture to the user as they move around the world. Is this correct?
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So yeah, the resolution was quite low, but it was helped with detail textures. And it did mean we could do completely unique stuff everywhere with no extra performance overhead of any sort, which was nice. If you look at some of the maps (particularly Refinery) they have the sort of terrain detail - erosion, weathering, blended surface types - that I don't think any FPS has managed before (or since, yet, until Rage comes out!).
The Rage stuff is basically like you described. From what little I know, it seems likely that you start out building up a base of tiling textures blended with unique masks (either painted by hand, or generated from tools like World Machine), you'd use these for stuff like grass, rocks, sand etc - the big details.
I wrote a tutorial for this using the in-game ETQW tools here:
http://wiki.splashdamage.com/index.php/A_Simple_First_Megatexture
You can see how you get some nice heightmap blending options to get more uniqueness out of tiling textures. They were called "distribution pattern" maps.
Hoffa (our lead environment artist) wrote this tutorial for more advanced, detailed terrain texture creation - the end result looks awesome and unique:
http://wiki.splashdamage.com/index.php/An_Advanced_Terrain_and_Megatexture
That includes more complex mask editing.
Then, yes, on top of that, you use decals and overlays (we called them "stamps"), you'd just fly around the level in the game and stamp pre-defined unique textures on top of each other. It seems id Tech 5 improved this technique a little by allowing multiple editable layers of stamps, so you can go back and tweak stuff or toggle parts on and off. In our tools you could just stamp whole sections at once, but once you were done there was no "editing", so you'd either have to erase the stamp, or stamp other stuff over it to hide what you didn't want. It worked pretty well in production though, and artists quite liked doing the stamping work IIRC.
If you read the Sparse Virtual Texturing PDF that Jan Paul van Waveren from id put out recently, it's here - http://s09.idav.ucdavis.edu/talks/05-JP_id_Tech_5_Challenges.pdf - then you will see that they are actually using virtual texturing for everything in id tech 5 where possible. You can use "traditional" textures too, but you will get better performance if you virtualise, since it cuts down on loading time and just streams in when necessary.
I seem to remember reading somewhere that the Rage landscapes use something like 128,000 x 128,000 pixel textures, but I might be wrong there.
it is: http://s09.idav.ucdavis.edu/talks/05-JP_id_Tech_5_Challenges.pdf
you can see different "atlas tiles" on the character models as well
edit: damn mop beat me
Texture streaming/ Virtual textures are a pretty simple concept, I think its the implementation of the technology that's exciting, I'd love to see the quality obtained when using the same amounts of texture space as rage but on a smaller sized world, you'd get an absurd texel density.
Mop I am curious did the megatexture kill your production cycle, ie did artists take a million years to do the terrain texturing or did artists pick up the tech and get productivity boosts. Seems like a lot of work to paint every inch of the world, although I guess you could just put the detail where you need it like anything else. Yeah Carmack said in the video I watched last night rage = 128000 pixels. Thanks for those links that pretty much answered my questions.
@keen, I think one would unify the thing. And have one common atlas system (read 3 textures, diffuse,spec,normal) for everything. Special casing for what in a frame is "character" and what is "environment" wouldn't be efficient. The only thing being different would be the particle stuff, I think that would be rendered old style and after the rest.
Nah, once we had picked up the tools (and our tools guys were refining them based on our feedback where possible), it was pretty fast. We had 2 people working on megatexture terrains full-time (I was one of them) - the leveldesigners created heightmaps initially, then after playtesting we created unique lowpoly meshes from these and marked out areas which could not change for gameplay reasons, then used World Machine to do erosion, detail and all that stuff - it outputs masks for you and you can get some crazy nice detail out of it without much effort once you have some good erosion node settings.
Exactly, detail where needed - a lot of the "distant hills" are just pure world-machine mask based tiling textures with distribution patterns to break up the tiling nature of them. The "stamping" was the final pass which added unique detail where the player would be most, but that took the least time compared with setting up a good solid base of terrain texture.
In the videos they showed up the tools, when he teleported or did a camera jump-cut, it seemed to fetch the entire world in just a few frames. When the camera was on a demo loop, they might have done something smart for the camera cuts like pre-caching ahead or something to get the data ready... not sure.
I had heard of World Machine before but had never really spent the time to check it out. Just downloaded the free version last night, it's pretty awesome.