> > Message: 8 > Date: Thu, 05 Jul 2007 17:12:49 +0200 > From: Ralf Gerlich <[EMAIL PROTECTED]> > Subject: Re: [Flightgear-devel] How to apply different texturing to > the terrain mesh? > To: FlightGear developers discussions > <flightgear-devel@lists.sourceforge.net> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset=us-ascii > > Hello Sebastian! > > Sebastian Bechtold wrote: > >> > [...] but my plan would, for example, make it possible >> > to render markings onto them, or draw softly rounded curves. >> > > I'm specifically interested in the "markings" part (although I'm also > curious at how you want to implement softly rounded curves without > breaking the current concept of texture display). > I -want- to break the current concept of texture display. I don't want to break anything else, but I definitely want to break this. It's all about breaking this ;).
I want to use large patches of texture which are applied to the ground mesh, completely ignoring the materials of the triangles. All I need is to place them correctly, so that a road which is drawn onto a texture file which represents a certain area in the world apperes at the correct place in the simulator. > This might require information which is currently not in the scenery > files, such as the actual position of the centerline and width of the > linear features. The triangles don't represent this information anymore, > however it is available from the scenery sources (e.g. the scenery > database). In general, making this information available in a suitable > format shouldn't be a technical problem (maybe one of available manpower > for implementing the stuff required, but that only means that it may > take longer). > Exactly this is the idea. I have already talked with Martin about this off-list. The plan would be to include the raw (meaning not compiled/digested into the .btg files) vector data into a scenery file and auto-generate the textures using this data. Then you could achieve things like road markings and smooth curves with some more or less simple 2D graphics programming. But however - first, I have to realise this texture mapping stuff. Without that, all further thoughts about how to generate the textures are useless. > Another possibility - at least for simple roads - would be to add a > centerline to the road texture and make TerraGear create an appropriate > texture mapping similar to how it is done currently in genapts for the > taxiways. Unfortunately, the part of TerraGear which creates the texture > coordinates does not know anymore that the polygon it is currently > operating on originally was a linear feature (blown up according to its > width to a polygon). So this approach might require some reorganisation > of the TerraGear architecture. Given that the current architecture is > quite complex (mainly due to the fact that the task at hand is complex) > I don't think this is feasible without risking to break anything to a > larger extent. > That's one reason why I don't want to touch terragear. The second is that I would like to make it possible to modify the ground textures without having to regenerate the scenery. > When we're discussing about runtime creation of textures we might also > get into discussing blending of ground textures. In that case, we should > keep in mind that in reality not all types of landcovers actually blend > into each other. > > When flying overhead forest areas - especially dense forest - these > typically do not blend with surrounding agricultural or greenland areas, > at least not in "civilised" areas where man tends to create sharp > corners by land usage. That's actually not related to this specific > discussion, but I wanted to note that before I forget. > Yeah, I know. But well, that's more an artistic question, not so much a technical one. And as said by you (and also by me above), it's not related to this first step of the plan. But anyway, you are surely right. I have quite a number of thoughts about how to create realistic looking "pseudo aerial photographs". If I should ever be successful with step 1, I'll come back to you with these. Cheers, Sebastian ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
