Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
As a long time Virtual Sailor user/idea contributor this thread caught my attention (well... once it said Sailing Ships... in the subject). In fact I've been toying with the idea of attempting to make my own cross-platform sailing simulator for several years. I had thought about using FG as a starting point but more recently I decided Delta3d would suit my needs better. But then again I'm primarily a Perl programmer and it's all vaporware at this point! If there is any movement in this direction I'd be more than happy to help. I'd gladly convert any of my Virtual Sailor boats for use and probably build anything needed. (See www.static-lift.net for examples.) But I do think that wave action upon a boat is THE key to a sailing/boating/ship simulator. Let's face it, regardless of the motive power of the vessel (I too, had downloaded the original Surprise program with the intent of porting it over to Linux), moving up, down, across and through waves is the defining factor of ma ritime travel. --jeff - Original Message - From: Steve Hosgood [EMAIL PROTECTED] To: [EMAIL PROTECTED], FlightGear developers discussions flightgear-devel@lists.sourceforge.net Subject: Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?) Date: Fri, 02 Jun 2006 09:49:04 +0100 GWMobile wrote: What about changing the aerodynamic computation so they take place based on radius from the earth and at what would be sea level change the air density to that of water. Then any object below sealevel flys under those equations. It would allow for surface ships and submarines. And load in the whole terrain map of the world including all bathespheric data I'd considered this, but I don't have the knowledge of hydraulics necessary to try and parameterise a ship's behaviour to suit (say) jsbsim. I think we'd need to spend some time running model hulls through water tanks or flumes if we were ever to gain that sort of data, and that means waiting until some Ph.D ship design students fancy getting into the project! I'm thinking more modestly for now, i.e take Peter Davis's surprise FDM as a starting point. It doesn't handle any of the flotation aspects of a ship - just assumes the ship is at water level (which is OK until you want to try handling behaviour in waves). Davis's sim basically deals with thrust on sails up masts at various heights with yardarms set at given angles. Oh, and a rudder of course. It does consider heeling though, and in a true FDM for a ship I believe a heeled-over hull (as long as it is moving) is a significant contribution to being able to steer the thing. I've not dug in deep enough to see if Davis deals with heeling effects using real data or just fudge-factors. Either way, I think it'll be OK for a starter. FG's world model doesn't even need bathymetric data to start with. Basically you could get away with if (ship within 50m of land) then you've run aground; as a starting point. Worry about bathymetrics *after* getting the rest of it to work. But you're right about submarines of course. They do fly in the water. Boats are the special case. Steve. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel -- ___ Surf the Web in a faster, safer and easier way: Download Opera 8 at http://www.opera.com Powered by Outblaze ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
For craft at sea level over non land turbulence equations could be modified to create rythmic up down motion as well as currents from a direction. If the frequency of the verticla turbulence shift is equal to the speed of the ship times 3 to 20 feet it should provide reasonable wave dip. On Sat, 3 Jun 2006 7:57 am, Jeff Koppe wrote: As a long time Virtual Sailor user/idea contributor this thread caught my attention (well... once it said Sailing Ships... in the subject). In fact I've been toying with the idea of attempting to make my own cross-platform sailing simulator for several years. I had thought about using FG as a starting point but more recently I decided Delta3d would suit my needs better. But then again I'm primarily a Perl programmer and it's all vaporware at this point! If there is any movement in this direction I'd be more than happy to help. I'd gladly convert any of my Virtual Sailor boats for use and probably build anything needed. (See www.static-lift.net for examples.) But I do think that wave action upon a boat is THE key to a sailing/boating/ship simulator. Let's face it, regardless of the motive power of the vessel (I too, had downloaded the original Surprise program with the intent of porting it over to Linux), moving up, down, across and through waves is the defining factor of ma ritime travel. --jeff - Original Message - From: Steve Hosgood [EMAIL PROTECTED] To: [EMAIL PROTECTED], FlightGear developers discussions flightgear-devel@lists.sourceforge.net Subject: Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?) Date: Fri, 02 Jun 2006 09:49:04 +0100 GWMobile wrote: What about changing the aerodynamic computation so they take place based on radius from the earth and at what would be sea level change the air density to that of water. Then any object below sealevel flys under those equations. It would allow for surface ships and submarines. And load in the whole terrain map of the world including all bathespheric data I'd considered this, but I don't have the knowledge of hydraulics necessary to try and parameterise a ship's behaviour to suit (say) jsbsim. I think we'd need to spend some time running model hulls through water tanks or flumes if we were ever to gain that sort of data, and that means waiting until some Ph.D ship design students fancy getting into the project! I'm thinking more modestly for now, i.e take Peter Davis's surprise FDM as a starting point. It doesn't handle any of the flotation aspects of a ship - just assumes the ship is at water level (which is OK until you want to try handling behaviour in waves). Davis's sim basically deals with thrust on sails up masts at various heights with yardarms set at given angles. Oh, and a rudder of course. It does consider heeling though, and in a true FDM for a ship I believe a heeled-over hull (as long as it is moving) is a significant contribution to being able to steer the thing. I've not dug in deep enough to see if Davis deals with heeling effects using real data or just fudge-factors. Either way, I think it'll be OK for a starter. FG's world model doesn't even need bathymetric data to start with. Basically you could get away with if (ship within 50m of land) then you've run aground; as a starting point. Worry about bathymetrics *after* getting the rest of it to work. But you're right about submarines of course. They do fly in the water. Boats are the special case. Steve. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel -- ___ Surf the Web in a faster, safer and easier way: Download Opera 8 at http://www.opera.com Powered by Outblaze ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel Bush's family and their Saudi partners make higher profits by preventing Saddam's huge Iraqi oil reserves from ever being sold. They'll Enron the world - George Watson 2001 For Hurricanes www.globalboiling.com For solar wind and earthquakes www.electricquakes.com Typos caused by two inch mobile phone keyboard ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
Martin Doege wrote: Hi Steve! Naval simulations are great, but if integrating tides into the present-day ocean in FG is such a big technical challenge as it seems to be, I would not think that a "real" ocean with rolling waves, reefs, bathymetry, etc. is right around the corner. I think you would want to have something like in Virtual Sailor or Silent Hunter III and that is simply far removed from the blue plane that is currently the sea in FG. Hi Martin. I'm not sure the tides issue is likely to be a "big technical challenge" actually. In the space of about 4 postings here, a workable scheme was proposed of colouring certain triangles "sea" or "mud" according to their datum heights as compared with a local simplified tideheight generator. I can provide the maths for a tideheight generator, the only "problem" is providing a suitable set of triangles (tagged with datum heights) in a known tidal area. Also, on a tile-by-tile basis, a set of (probably four) tidal vectors has to be given. The graphics engine needs to know how to do the colouring on-the-fly, but compared with the magic that the 3D experts on this project have already acheived, that'll be done in an evening as soon as someone sets out to do it! But in general naval simulations don't always need flashy graphics to be fun, so finding a good graphics engine is probably not so important at this point. I ws intimating that I don't have to find one - I've found it! Right here. :-) As with all simulations, what really makes them absorbing is the feeling of "being there", and while good graphics don't hurt, good gameplay matters more. For example, the submarine sim Red Storm Rising mostly had only tactical displays to look at that look about as boring as it gets, and yet it was an engaging game and the suspension of disbelief worked well. That's about what the current "surprise" program (windoze or linux) has. It's really just a wrapper around the "FDM" to let the "FDM" be used for something. So instead of hoping for great seascapes from FG/SimGear in the near (or not so near) future, I would first improve your existing "FDM", add the ocean, include navigation aids, etc. Stars, sun and a stopwatch. That's all you get! Ok. Ok, I'm joking of course. That's all you get in the 18th century, but if sailing ships worm their way into the FG world, they'll be usable in any timeframe. After all, tall ships are still with us in the 21st century. Cannons and a damage model should also be added since you are mentioning Hornblower. As in Sid Meier's Pirates!, the crew should also be simulated, [giant snip] Funny, you've just written almost exactly what I wrote to "The Admiral" (Peter Davis) last year. His comments were that he never planned to make a game of the sim - his sentiments in fact matched closely to those we hear all the time here on the FlightGear discussions group. It's to be an accurate sim first and foremost, but if people want to add guns/missiles etc then that's up to them. I talked about crew, crew morale etc. (I've been a penpaper RPG-er for a long time.) Same sort of response - basically, he (Davis) is only really interested in getting the sim to work well and would be disappointed to see the project "degenerate" into "just a game". Of course, done well then there's no reason why any of the additions you mention would degenerate the project - they should be seen as enhancements. Graphics could initially be fairly minimal, perhaps isometric view or 2D. Dovetailing into FG would allow 3D models from the start. I really don't want to have to build a custom isometric or 2D graphics engine just for "surprise". This would also give you time to develop a good interface. All your points are very valid - especially this one. Unlike aircraft, saling ships don't have a single "point of control". The nearest (in 18th century parlance) is "the quarterdeck" where the master or captain issues the orders, which then have to be relayed through several layers of middlemen to the grunts who pull the ropes. There is of course a "ship's wheel" but it's not a single point of control to compare with (say) an aircraft control column. Try it with "suprise". The ship's wheel does precious little unless the ship is moving at quite a lick. It's the set of the sails (especially the spanker) that really steers the thing. I would also use a higher-level language for faster development and improved flexibility. Python comes to mind and has the advantage that the existing BASIC code should be easily converted to it and that there is Libglade and pyGlade. It is also nicely modular and its sane implementation of object orientation as well as its use of generators are definite boons for simulations. At a later point, 3D graphics could be added if desired, e.g. via PyOpenGL or using code in C/C++. The existing code isn't BASIC, it's 'C' that looks like BASIC :-) As I stated before - Davis wrote the original in BASIC and ported it to 'C' many years
Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
What about changing the aerodynamic computation so they take place based on radius from the earth and at what would be sea level change the air density to that of water. Then any object below sealevel flys under those equations. It would allow for surface ships and submarines. And load in the whole terrain map of the world including all bathespheric data The water surface could then just be a specialized cloud layer. That would give a great start. On Thu, 1 Jun 2006 10:30 am, Steve Hosgood wrote: Martin Doege wrote: Hi Steve! Naval simulations are great, but if integrating tides into the present-day ocean in FG is such a big technical challenge as it seems to be, I would not think that a real ocean with rolling waves, reefs, bathymetry, etc. is right around the corner. I think you would want to have something like in Virtual Sailor or Silent Hunter III and that is simply far removed from the blue plane that is currently the sea in FG. Hi Martin. I'm not sure the tides issue is likely to be a big technical challenge actually. In the space of about 4 postings here, a workable scheme was proposed of colouring certain triangles sea or mud according to their datum heights as compared with a local simplified tideheight generator. I can provide the maths for a tideheight generator, the only problem is providing a suitable set of triangles (tagged with datum heights) in a known tidal area. Also, on a tile-by-tile basis, a set of (probably four) tidal vectors has to be given. The graphics engine needs to know how to do the colouring on-the-fly, but compared with the magic that the 3D experts on this project have already acheived, that'll be done in an evening as soon as someone sets out to do it! But in general naval simulations don't always need flashy graphics to be fun, so finding a good graphics engine is probably not so important at this point. I ws intimating that I don't have to find one - I've found it! Right here. :-) As with all simulations, what really makes them absorbing is the feeling of being there, and while good graphics don't hurt, good gameplay matters more. For example, the submarine sim Red Storm Rising mostly had only tactical displays to look at that look about as boring as it gets, and yet it was an engaging game and the suspension of disbelief worked well. That's about what the current surprise program (windoze or linux) has. It's really just a wrapper around the FDM to let the FDM be used for something. So instead of hoping for great seascapes from FG/SimGear in the near (or not so near) future, I would first improve your existing FDM, add the ocean, include navigation aids, etc. Stars, sun and a stopwatch. That's all you get! Ok. Ok, I'm joking of course. That's all you get in the 18th century, but if sailing ships worm their way into the FG world, they'll be usable in any timeframe. After all, tall ships are still with us in the 21st century. Cannons and a damage model should also be added since you are mentioning Hornblower. As in Sid Meier's Pirates!, the crew should also be simulated, [giant snip] Funny, you've just written almost exactly what I wrote to The Admiral (Peter Davis) last year. His comments were that he never planned to make a game of the sim - his sentiments in fact matched closely to those we hear all the time here on the FlightGear discussions group. It's to be an accurate sim first and foremost, but if people want to add guns/missiles etc then that's up to them. I talked about crew, crew morale etc. (I've been a penpaper RPG-er for a long time.) Same sort of response - basically, he (Davis) is only really interested in getting the sim to work well and would be disappointed to see the project degenerate into just a game. Of course, done well then there's no reason why any of the additions you mention would degenerate the project - they should be seen as enhancements. Graphics could initially be fairly minimal, perhaps isometric view or 2D. Dovetailing into FG would allow 3D models from the start. I really don't want to have to build a custom isometric or 2D graphics engine just for surprise. This would also give you time to develop a good interface. All your points are very valid - especially this one. Unlike aircraft, saling ships don't have a single point of control. The nearest (in 18th century parlance) is the quarterdeck where the master or captain issues the orders, which then have to be relayed through several layers of middlemen to the grunts who pull the ropes. There is of course a ship's wheel but it's not a single point of control to compare with (say) an aircraft control column. Try it with suprise. The ship's wheel does precious little unless the ship is moving at quite a lick. It's the set of the sails (especially the spanker) that really steers the thing. I would also use a higher-level
Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
On Thu, 1 Jun 2006 12:21:31 -0400, GWMobile wrote in message [EMAIL PROTECTED]: The water surface could then just be a specialized cloud layer. ..in a way, it is. ;o) ..has anyone tried this idea by now? -- ..med vennlig hilsen = with Kind Regards from Arnt... ;o) ...with a number of polar bear hunters in his ancestry... Scenarios always come in sets of three: best case, worst case, and just in case. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
Jim A wrote: All very good, and a great technical challenge. But, maybe a branch called FloatGear would be in order? ;-) I love it! Thanks - that made me smile first thing in the morning. then there are land vehicles -- for transportation, sport, and defenseDriveGear? Or TopGear (or IntoGear) :-) It would be cool to have the Nimitz (and others) respond to sea state, and the visual eye candy of the water to look appropriate to the sea state condition. These thoughts all seem daunting, but seeing what this community has accomplished thus far, it could very well happen. Indeed - however my suggestion would be that should the world-system of FG get used for things other than flight simulation, that it doesn't get branched. Branching just makes maintainance more difficult and breeds flamewars. It is probably best that people wanting to use FlightGear as a world engine for other things (like ship sims) just get on with it using the code as is, but keep talking on this list so that mainline code developers can try and avoid doing things that deliberately break those side-projects. Should something like a ship-sim become popular (and people have asked about ship sims on here before) then maybe its code might enter FG's CVS repository, just like a new flight-sim engine might. (There are at least three flight-sim engines in there already.) It might even happen that FlightGear code becomes three or more conceptual lumps, rather than the two is is now (SimGear FlightGear). SimGear is already starting to look like a great load of astronomy stuff could be broken out into - er - EphemGear? :-) I shall keep an interested eye on whatever improvements are suggested (and made) to the oceans in FG. The development people will probably already want to allow for things like aircraft carriers to behave more naturally - if they keep that in mind, hooking in a sailing ship later should be straightforward. Steve. ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] Sailing Ships (was Re: Tides in FlightGear?)
Martin Doege wrote: By having the water as a separated mesh, we could finally simulate the plane-water interaction properly. I feel that this method would move us into the right direction. And since one of the major selling points of "Flight Simulator X" will be, at least according to the screenshots and trailers, the more realistic depiction of water in all its pixel shader-rendered glory, it would be great if the water in FG would also be a little more than just the big blue parking lot it is right now. :-) Martin D. If there's an interest in improving FG's handling of water, might it be good to take in the idea that maybe one day the FG engine could be used for sailing ship simulation too? After all, FG's already got the 3D graphics engine, world scenery and a weather engine. Add in a sailing ship simulator "FDM", and a proper concept of water (tides, currents, depths, waves, 50-ft sea monsters etc) and you'd have it. Last year, I discovered Peter Davis's Tallship simulator "surprise.exe" and made a partial port to linux. Davis's website (for the original windoze program) is: http://home.wxs.nl/~pdavis My RPMs of the linux port are here: ftp://tallyho.bc.nu/pub/steve/surprise/surprise-20030924-2.i386.rpm My port is nowhere near complete in terms of options and eye-candy, but it does run. Mine only simulates the three-masted frigate (the original does that plus a two-masted brig). Mine doesn't have the "map" display nor any concept of land. The original modelled some "islands" to provide some entertainment trying to navigate. Mine doesn't yet show the "thrusts" diagram which tells you what forces are being provided by which sails. Mine doesn't yet have configurable weather, the original does. Porting it required me to tease out the "FDM" for Davis's ship simulator - it had been somewhat intertwined with the calls to the windoze API needed for his GUI. My version uses his "FDM" but with the GUI implemented with "Glade", the GTK+ GUI writer. I was actually using the project to teach myself Glade. Funnily enough, Peter Davis taught himself Visual Basic (and later Visual C) in order to write his ship-sim in the first place. His inexperience with computer programming does show in the code (along with its rather BASIC-like layout due to its heritage), but it does at least work. I've seen various people post queries about ship simulators on this list before, all to no avail. See here for a (commercial) 3D model of an 18th century frigate: http://www.turbosquid.com/FullPreview/Index.cfm/ID/240860/Action/FullPreview FG can't use this (obviously) but the FG project's got quite a few excellent 3D modeller experts in need of a challenge :-) If you get the "The Making of Hornblower" book that went with the UK's "Carlton TV" dramatisation of Forrester's books, then on the inner cover flysheets and the centre-spread there's a reproduction of a set of technical drawings for the "Grand Turk" (the ship used in the TV series, and used in the BBC's "Longitude" TV programme). To answer one obvious comment before it happens: yes, Peter Davis's source code (and my existing work on a linux port) are all GPL! I asked Davis last year if he would consider some sort of formal licence for his work, and he GPL-ed it last August. Steve ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
