Thursday, August 20, 2009

More Threads

X-Plane 940 beta 1 is out...it will take a little bit to get the release notes and docs on the website completely up-to-date. We're still dealing with loose ends from our migration to the new web site, and most of my office is packed up for a move to the Boston area. I'll try to get docs up as fast as I can given the chaos flying about.

Given the interest multi-core stirred up in previous notes, I will mention one change to 940: with this build we've added yet more multi-core to X-Plane.

In 931, X-Plane will use as many cores as you have to load textures, but only one to build "3-d scenery" (a loose category for the work we do when we make airport taxiways and lines, build forests, and extrude roads).

In 940, this "3-d scenery" is also done on as many cores as you have. This should speed up load times a bit, particularly under very heavy tree settings, and hopefully keep the forest engine running faster for users with more cores.

It also sets us up for long-term growth; X-Plane's visual quality is sometimes limited by the time to build 3-d meshes...being able to do this work on many cores means we can use higher quality algorithms.

Consider for example the roads: my original "road extruder" (the code that converts a vector road into a 3-d model, called an extruder because it builds a 3-d road from a cross section like one of those play-dough toys) made beautiful intersections with stop-lines and cross walks and lots of other great stuff.

It was also really slow. And at the time the sim wouldn't fly at all while roads were extruded, so speed was of primary concern. So I replaced it with the much dumber extruder you see today, where intersections are basically ignored.

Now that we have 3-d scenery build on multiple cores, we can begin to provide rendering options that take more CPU time but produce higher quality results. The trees and airport layouts already do this (in that they take more time and produce slower, more detailed, higher triangle count sceneery at higher rendering setting for the same input DSF ad apt.dat file). With more cores, we can continue this strategy with roads and other parts of the sim without worrying about overloading the one core that was doing this work.

Of course just because we can use 8 cores doesn't mean we do...you won't see 8 cores maxed out very often, particularly if you have simple scenery and a very fast machine.

6 comments:

Anonymous said...

Great progress!

By leveraging threads more will you be able to increase the visual range that XPlane renders?

Would it be possible to extend visibility out to say 100 NM instead of the 25 NM that exists now?

Also, is it possible to add an option that disables the "autogen" objects but still leaves airport objects visible. I like to see the airports objects maxed out but not have "autogen" objects elsewhere.

Kind regards, Matthew.

Dan31 said...

"Also, is it possible to add an option that disables the "autogen" objects but still leaves airport objects visible. I like to see the airports objects maxed out but not have "autogen" objects elsewhere."

+1

garrettm30 said...

I too agree with Matthew. The objects such as houses, etc., look nice when turned to a higher level than what most computers can do, but the sparse look of the default level of objects makes it better without them, in my opinion. I would turn them off completely if it were not for the custom airports. If such an option is reasonably feasible, I would love to see airport objects separated from the other objects in the settings. Airports, after all, are where we spend the most time that close to the ground.

Anonymous said...

I'm looking forward to more eye candy especially the auto-generated airport terminals.

Anonymous said...

Another reason why I don't like the "autogen" is that I think the models look out of place in areas such as Asia.

Seeing so many IKEA buildings is just not realistic looking.

So I prefer to turn them off completely but unfortunately you lose all the custom 3D airport objects.

There are some great custom airports out there (including a lot of FS9 conversions).

Subic Bay, Philippines (RPLL) is a great convert with very high FPS, and a fantastic experience in Xplane.

Please address this autogen issue. FS9/FSX offers the same ability, to turn off the "autogen".

Adding this tweak would be very much appreciated by a lot of users I think!

Kind regards, Matthew

Rob said...

I agree with Matt, seeing the IKEA store model outside of North America is very awkward. Furthermore it would be nice to see a greater variety of generic house shapes, because most of the 3d building look like tiny apartment.