Tower Simulator

Wilco's Tower Simulator Review

2008-10-09T05:24:00.001-04:00

Well, I can't say I am surprised by what the reviewer found.

Bell 412

2008-09-10T20:53:00.003-04:00

I know, a little boxy here and there. Just saving polys. After all, everyone wants high frames per second, right?

King Air B200

2008-09-08T23:12:00.002-04:00

I am finding it hard to not include every detail, so this has a little bit more of that than the RV-7. I have to watch out for the polygon count, having the simulator's performance in mind, but I figure it is always easier to take a high detail model and scale it down than the opposite.

So far so good regarding the project plan.

RV-7

2008-09-03T22:53:00.009-04:00

So tonight is the second night of work on the first task in the project, creating a 3D model of an RV-7. I have one more night, according to the plan, to finish this up. I plan on creating some basic textures (one of my weaknesses right now) to have some color on it. Can't wait to see what that looks like... For now, here's what the model looks like. I tried keeping the polygon count to a minimum, while adding enough detail. Click on each image for a full-resolution version.

Project Plan

2008-09-03T22:44:00.002-04:00

The Project plan is done. If I am incredibly prescient, and have actually predicted every single activity right, it will take 219.5 days until I have a decently completed version of Tower Simulator. That sounds like a lot (and if that number is anywhere near accurate, I'd be very surprised. It could be a lot less or a lot more, who knows?), but it involves a lot. Here's what I have planned (in bold are the main sections):

Tower Simulator Project Plan

Physics
Collisions
Motion
Taxiing
Parking
Takeoff
Climb
Cruise
Descent
Approach
Landing
Driving
Audio
Aircraft
Jet Engine
Startup
Running
Shutdown
Turboprop Engine
Startup
Running
Shutdown
Piston Engine
Startup
Running
Shutdown
Ground Vehicles
Trucks
Cars
Tractors
Voice Recognition
Models
Airports
KCMH
Runways
Taxiways
Apron
Buildings
LOWI
Runways
Taxiways
Apron
Buildings
Aircraft
Airliners
Embraer 170
Embraer 190
ERJ-135
ERJ-140
ERJ-145
Airbus 319
Airbus 320
Airbus 321
Dash 8-Q400
Boeing 737-300
Boeing 737-700
CRJ-200
CRJ-700
CRJ-900
General Aviation
Lancair Legacy
King Air B200
Bell 412
Falcon 900
Gulfstream V
Cessna 172
Cirrus SR-20
Graphic Interface
Splash Screen
Main Menu
Sub Menus
Graphics Engine
Load Models
Terrain
Skybox
Clouds
Shadows
Rain
Snow
Input
Keyboard
Mouse
Custom Shortcuts
Installation Package

Let's see what happens.

Project Plan

2008-08-28T09:25:00.000-04:00

I make no fuss about the fact that sometimes I find it hard to police myself in regards to following schedules, so I have hired a project manager: my wife. Maybe it sounds crazy to you, but this will keep me much more on track regarding the project plan for Tower Simulator, as she has been very serious about it. I'll be posting a Gantt chart of what the project looks like right now.

Terrain test

2008-07-13T10:56:00.005-04:00

Today I found some time to test loading a heightmap, which I generated from a 10m DEM file, into XNA just to see how easily I could do it, and how good it would look.
The result was pretty good. Some information before you watch it:

The colors are simply based on the height of each vertex, just to have some color. They are not related to anything else from the real world.
The app runs at 60 fps without even sweating, but the video below is running at 30 fps due to compression
The depressions that look like wholes on the opposite side of the mountains are either DEM noise or lakes, I have not investigated it yet

Can you tell where on earth this is? :)

Here's the original heightmap:

WILCO's TowerSim

2008-06-21T17:29:00.002-04:00

I had the opportunity of trying out TowerSim, and have to say I was pretty disappointed. I had a longer list of things I didn't like, but here's the major stuff:

Graphics are sub par - For today's standards, the graphics are really not very good. Some interesting things, such as shadows that fade into transparency as they get away from the object casting them, and point lights for runways and taxiway lights that do get very small at a distance (unlike the light "gobs" that MSFS has) are good ideas, but the texture resolution, aircraft models, terrain resolution, weather conditions (rain and snow) are not very good.
No tower cab - the view from the controller's perspective is simply a point in space, without control panels, monitors, glass or anything else to represent the inside of a tower. It is as if you were floating in space.
Aircraft motion - This is a soar point for me. I think part of a realistic and fun Tower Simulator is aircraft moving as they do in the real world. The aircraft I watched tended to fly a precise approach path, without a single foot of variation, hit the runway exactly at the same point, perform no flare whatsoever, and have unrealistic angles of pitch.
Controller's interface - The radar scope is very similar to the one I am designing, but the text window that allows the user to control aircraft is cumbersome and slow. It could also have been a bit smarter, such as recognizing "cleared for takeoff runway 9" instead of forcing you to type "cleared for takeoff runway 09".
No voice recognition - Controllers don't control via text, they do it via voice. ATCsimulator does a good job at that, so there's no reason these guys couldn't get it right.
Robot-like pilot voices - They used about 8 people to record different pilot voices and accents, but the stitching together of words sounds pretty mechanical and unnatural. I have not cracked the nut on this yet, although I have found a couple of expensive text-to-voice engines that can do a great job. I just have to discover how to do it cheaply.
Performance issues - I left Chicago O'Hare run without controlling aircraft, and the performance quickly dipped below single-digit frame rates. More and more aircraft showed up, and the simulator had no way of deleting older aircraft, or any other means of stopping it from affecting performance.

All in all, it is not a bad effort, but I expected more. I guess this is good news in the sense that the field is still very much wide open for a good Tower Sim, but I could have been a bit more encouraged by stiffer competition ;).

Have you seen this?

2008-04-27T09:08:00.002-04:00

I have known for a long time that there is a community out there just dying to have a good tower simulator. This means that this community is actually pretty sizable, and is great news for everyone! Raising awareness about tower simulations is only one of the good things this software will do.

I like the following features, besides the basic stuff that needs to be in a tower simulator:

- Career mode
- Real-world airline schedules
- Service vehicles

The visuals look quite good, but I am more interested in how realistic it will be. Maybe a demo will be out soon? Here's to hoping.

New airport being considered

2008-04-27T08:47:00.002-04:00

As you have probably noticed from the poll on this site, there were some major airports I was considering including in Tower Simulator. After watching a very well-done documentary on Van Nuys, this airport became a very strong candidate, perhaps even number one!

This airport has everything to make a tower simulation interesting. Beautiful scenery with some pretty high terrain close by, varied traffic (small pistons, flight training, business jets, news helicopters). OK, there are no airlines, but we can fix that by having another airport in this release. Not to mention it is the world's third busiest general aviation airport, as well as the 25th busiest among all world airports, with 1,200 operations per day. That should keep everyone pretty busy :).

Another interesting point is its proximity to LAX and Burbank, which means lots of coordinating between the three facilities. This would allow me to develop the intra-airport communication system that I have been thinking about including. This, of course, exists in real life, and I think adds a lot to a controller's responsibilities and overall perception of realism.

It's tower is pretty interesting looking too, and should be fun to model.

If you have some words on this idea, leave me a comment.

We have arrived!

2008-04-27T08:46:00.001-04:00

Uhuuuuuuu, after a lot of planning and effort, we have arrived in Columbus, OH!!! The good news, as it relates to Tower Simulator, is that I will now be able to resume development, as the dust settles down. Stay tuned.

Eco-house

2008-04-03T17:37:00.003-04:00

So we have decided to build a new house in Columbus, and while this is totally off topic, since it is affecting my work on Tower Simulator, I thought it fair game.

In going over all the deatils you need to pick and choose when buying a house I am finding out a lot about being environmentally sensitive while at it. Here are some really cool solutions:

- Solar water heater
- SunTunnel skylight
- Green roofs
- Geothermal power
- Great reference for all parts of the house: Energy Star

There are so many inexpensive ways to make a house considerably greener, and it will only cost an overall addition of 2 to 3% compared to a "normal" home. Pretty cool, huh?

Back to Columbus

2008-04-02T04:57:00.003-04:00

Flying back to Columbus this Saturday to work on getting a house once again. Workload at the moment is severe, so development has slowed down. Hopefully I'll move soon and be able to resume work.

Space Shuttle Simulator

2008-03-23T12:15:00.001-04:00

Seen this? It looks pretty good. At this point in time, it looks like it's not a very detailed simulator, but more of a mission overview. Graphics looks very good. It is made in France, but I wonder what language they are using. No mention of XNA anywhere...

Feed readers

2008-03-21T07:40:00.003-04:00

I am relatively new to blogging. One of the things that helps me keep up with other blogs I like to read is a feed reader, also called an aggregator. There are many different ones out there, but I really like Google Reader.

Google Reader allows me to check feeds very efficiently on my laptop or on my phone, since they also have a very slick mobile interface. I like the fact Google is smart enough to check what type of browser is accessing their sites. By doing that, they can tell if you are accessing from your phone or laptop and display the proper page (the mobile page is very barren, just text, so it loads very quickly on your phone).

Let me know via the comments if there are other aggregators you like to use, I am always checking new programs out.

Pick up and move

2008-03-21T07:37:00.003-04:00

The latest news are that I have been promoted. I have just returned from France and Monaco, travelled to Vermont the next day, spent one day back at home after that, and am now in Columbus, OH house-hunting. Life moves fast!

One of the cool things about this last trip is the hotel is literally on the airport, it sits between runway 28L and 28R, so I have planes taxiing about 300 feet from my window! Very cool!

Normal Mapping

2008-02-24T22:40:00.006-05:00

One of the things that makes modern games look so good is called Normal Mapping. It's a technique that allows the GPU to deform a simple mesh (an object made of relatively few triangles) with a special image made from a much more detailed mesh of the same model. The result is few triangles, which means faster rendering, but lots of detailed thrown in at render time by the GPU, which means better looking models. Read the Wikipedia article in the link to understand it. I plan on using normal maps a lot in Tower Simulator.

This can be applied in very small-scale object, such as a telephone used to communicate to other ATC all the way to a whole planet, which is what this video is all about. It is not rendered in XNA, as I have not learned to do that yet, but in modo. I just wanted to learn a bit more about normal mapping and the quickest way was to use this software, which is what I use to create models.

The video portraits a perfectly smooth sphere model with 288 polygons with to textures applied. One is a color map of the surface of Mars, the other a normal map of the surface of the same planet. The normal map does not show as color, but instead it allows the GPU to deform the smooth surface I created to show elevation of some major features and craters on the surface of the red planet.

This render is made out of 1500 frames playing at 60 frames per second. The blogger upload came out darker than what I wanted, but you can still see some of the major elevations such as the huge volcano that shows on the beginning and end. Notice how it remains partially lit for a little bit once it moves into the shadow area as Mars rotate. That clearly indicates it is higher than the rest of the surface. You can see this in reverse towards the final seconds as a canyon moves into view.

If you are interested, I got the textures from Planet Pixel Emporium.

Here's the video:

Multiplayer and interfacing with other software

2008-02-17T13:45:00.009-05:00

I have planned to add multiplayer to Tower Simulator. It will work over system link, which means a bunch of computers connected via Local Area Network (LAN), or over the internet. This would allow more than one person with a copy of Tower Simulator to man different positions, such as Clearance Delivery, Ground, and different Tower positions (in big airports it is common to separate the workload between two or more Tower positions, each with a distinct frequency).

That will be really cool, but another option I plan to implement is interfacing with Microsoft Flight Simulator (MSFS). I have not looked into it yet, but I am pretty sure it can be done without much fuss. Tower Simulator would look at the airplane being flown in MSFS and try to do a best match, based on the aircraft that will be available. Communications will happen over a voice channel.

Another cool interaction could be done with ATCSimulator, which is in version 2 at the moment. This simulator covers the enroute, approach, and departure part of the ATC business, and would be a great complement to Tower Simulator. I have not talked to the author yet, and don't plan to until much later in my own development, but it's definitely a goal.

Tech Article #2: XNA's Content Pipeline

2008-02-15T20:49:00.009-05:00

This is pretty cool. Whenever you create a game, one of the hard parts is writing some sort of processor that can, well, process the assets you want in the game. What does that mean?

Let's say I design a kick ass airport in 3DS. I now want to import that into my simulator. How do I do it? My game doesn't just have an "Open file" option, and it sure doesn't understand a .3DS or .MAX extension. So, what are our options?

I could go to Wotsit and take a look at the structure of these file types, meaning their innards, and write some code that can sift through that data and find useful things I need, such as vertices locations, UV map coordinates, etc.

Great, now I can import my cool looking airport and we're in business! Well, not quite. I still need to be able to draw it, and that means I have to write code to run through the vertices and see what textures goes where, load those textures, check everything, then draw.

And what if someone else makes a good airport in another 3D creation tool and I want to add it? What about audio? Can you see how in depth this can get? As a matter of fact, game studios have hordes of people working on just these portions of the code. Lots of work. Boring work, if you ask me.

Enter the Content Pipeline. XNA Game Studio was created by guys who created games for a living, so they know where the pains of the process are. With that in mind, they have created a very cool and streamlined "pipeline" through which we can import all kinds of files. OK, so it's not any kind, they are limited to:

- 3D Files: .X and .FBX
- 2D Files: .DDS, .BMP, .JPG, .PNG, .TGA
- Material files: .FX
- Audio files: .XAP (XACT)

The Content Pipeline takes you all the way from step one, importing, to the last step, loading the asset in memory, ready for use. Check out this graphical description of the pipeline:

How do you use it in code? Very, very simple:

ContentManager myManager = new ContentManager(GameServices);
model = myManager.Load<Model>("ship");

You can now call "ship" in your Draw code and bam!, it's on the screen.

Of course there are shortcomings. The pipeline, as shipped, is pretty limited, but it was meant to be so, since the XNA Team cannot think of all different ways you need to import and convert assets. So they made this a very easy class to inherit and change, adapt, gut, add to, whatever you need, to get exactly what you want out of it. Nice, huh?

FAA ATC Documentation

2008-02-13T08:54:00.003-05:00

This is pretty cool. I am a pilot by schooling, but have never studied for or been a controller. So I need to learn. Where do you go? FAA.gov, of course. Check this out.

OK, looks like the latest FAA Order for Air TRaffic Control is 7110.65S, which came out February 14. Scrap the previous one.

Tech Article #1: Data structures

2008-02-13T08:12:00.007-05:00

Once in a while I will post entries that are more technical in nature. This is the first of them. You should read it anyways, as you'll see the benefit for users at the end.

Last night I was reading about data structures. The folks over at XNA Game Studio have written a four-part article on these, and it made for some excellent reading. Well, I haven't read Part IV yet, but the first three were very cool.

Data structures have to do with storing, retrieving, analysing, and modifying data. In my case, these structures will hold things such as all the aircraft that are in the air, their position, altitude, flightplans (I am considering having overhead traffic at both high and low altitude), etc., as well as anything else that gets bunched up in collections of the same kind.

There are different types of data structures and, like aything else in life, each has its pros and cons. The existing data structures in C# and XNA, and their brief descriptions, are:

- Arrays: A size-defined sequence of data types. Imagine a specific-sized box. Now add, say, 17 of them side by side, glued together. That would be a 17-item array. It is very fast to add and retrieve information, but if you have to change its size by suddenly adding another item in the middle, things get slow. Good for a collection of a static number of items (i.e. number of taxiways in an airport. Those don't change very often).
- Lists: Similar to arrays, except the number of "boxes" is not defined, so they are a little more flexible. Better to hold a collection of items whose total number is unknown or changing over time (i.e. number of arriving flights)
- Collections: Very similar to Lists, except these are good for inheritance (for object-oriented programming, inheriting is making a copy of an object that you can then customize for your own needs)
- Linked Lists: These are very interesting. They are like an array, except instead of being boxes that are glued side-to-side, these are boxes that know where the previous and next are. They could be half a world apart, but if you looked at one box, it would have the address of its predecessor and its successor. The cool thing about this is if you have to add a new itemin the middle of the existing items, you just put it in and change the addresses of predecessors/successors accordingly. The bad part is if you are looking for the last box, your code has to run through every box, starting with the first one, before it can find the last.
- Stacks: Exactly as their name says, these are stacks where you add an object and it goes on top of the stack. When you retrieve an object, they come out in LIFO order. LIFO is Last In First Out. Think of a narrow dead end street being used to park cars. You can only remove the car that was parked first after all the previous ones behind it have been removed. How does this help TowerSIm? Not sure yet, I'm not planning on having vallet parking :).
- Queues: Same as Stacks, but FIFO. You guessed it, First In First Out (i.e. a list of aircraft that have requested clearance).
- Dictionaries: Part IV which I still haven't read.
- Trees: Part IV which I still haven't read.

Pretty cool right? Well, for me it is :). Understanding these will ensure that I use the proper ones for different things, and will give you, the user, the highest possible frame rate.

from DELLicious to HighPerformance

2008-02-04T09:37:00.000-05:00

OK, so maybe the title did not turn out to be as clever as I thought it would. What's happening is I am upgrading my development machine. I am switching from a Dell XPS 1710 to an HP dv9700t. The XPS has been wonderful, and has a videocard that absolutely rocks (GeForce Go 7900 GTX), but it is starting to age a bit on the CPU side (mine is one of the first ones, it only has a Core Duo 2GHz).

The new HP has a GeForce Go 8600M GS, which is not the top of the market as far as mobile nVidia chips go, but it's not too bad. It isn't as fast as the one in the Dell, but it does have several advantages:

- Shader model 4.0
- DirectX 10
- HDR
- nVidia PureVideo
- PowerMizer (to save power for using it on the go)

The new laptop also has a 2.5GHz, 6MB L2 cache Intel Core 2 Duo T9300, which should be a nice upgrade for me. Like anything in life, this upgrade is a compromise. I lose some screen resolution (Dell's screen runs at an awe-inspiring 1900x1200), but gain a bit in weight (I do normally take my dev machine with me in my travels), and catch up with times in many different areas.

The best part is I am probably going to be even Steven once it is all done, for I got a great $500 off coupon for the HP. Thanks Slickdeals.

I will shortly post some benchmark comparisons of TowerSim once I put these two machines face-to-face.

Access ain't so bad

2008-01-31T20:27:00.000-05:00

I have been working on an app for work. It's written in C#, and it's a data app. One database, and several instances of the app connecting at possibly the same time. I haven't really developed anything with data integration before, so I went hunting for info.

I was really surprised at how hard it was to find what I needed. Starting simple, all I wanted to do was to type some text in a text box, then save it to the database. It IS really simple to do, but the hard part was finding how. I eventualy got it.

I started by using SQL Express, without really thinking about it much, but I realized that it was overkill. I switched to Access, since all company computers have that (just in case, I still don't know if the client app needs to run on a computer that does have Access. My guess is no, but better safe than sorry. Call me lazy, I am). Due to ADO.NET, the type of database doesn't really matter, so most of my calls remained the same between using SQL and Access. Cool. I hear LINQ goes even further than ADO.NET, but I'll leave that learning curve for the future.

I also had to share data between a parent and a child form. That was actually a lot harder than it had to be. MS should really have some pipeline between parent to child and child to child. Once you set up an event handler it works great, but it truly is a pain compared to what I think it should be (declare the variable in either form and using syntax, explain to the compiler "this variable belongs to this form, but that, that, and that form can access it". Would be great).

I have the interface almost ready, and the form for adding a new record to the database is working great. Next will be figuring out how to have several instances working at once without corrupting the database. I could have looked it all up before I started but I have been finding out that is not the most efficient way to work, at least for me. I rather get going, get something working somewhat, then fine tune it and add what's left. Seeing something up and running, even in a preliminary stage, is key to keeping me motivated.

Why am I talking about this? Well, C# skills will definitely help me out in TowerSim. That and it's for work. Work pays bills, which allow me to sit in my idle time and code TowerSim. Logic is a beautiful thing.

Charged particle precipitation

2008-01-23T08:03:00.000-05:00

I guess they could have chosen this title as their company name, but Electric Rain sounds a lot cooler. I have been super busy at work, creating a pretty important presentation for this Thursday. Instead of the beat-to-the-ground PowerPoint approach, I decided to branch off into the unknown and try Eletric Rain's StandOut. It's still in beta, but it's very cool. It's a presentation software (don't let them catch you calling it a "slide" presentation, in their workflow, slides don't exist) that kicks butt, done completely in WPF. Can you say sharp? Yep, you can, and you should, for that's how everything will look.

The learning curve can be somewhat steep, but by using Blend to build the DLL components you then integrate into layouts, which are the bits you can make a presentation from, you can rock in no time. You're only bound by your creative spirit on this one. Awesome.

Back to work. And more coffee.

Text-to-speech

2008-01-09T11:58:00.000-05:00

This is something I will have to implement for a realistic Tower simulator, the planes will have to talk to the user, and vice-versa. On the planes side, their calls are coming from text and will need to be transformed into voice. There are several text-to-speech egines out there, but I came upon one (NeoSpeech) that completely blew me away. It almost sounds like a human being, scary!

I'll be looking into this and other engines.

XNA in a WinForm

2008-01-08T15:47:00.000-05:00

Following up on the thinking of a full 3D interface or a WInForm to run the program in, I bumped into this article. Very cool stuff, including WPF!

Interface thoughts

2008-01-05T18:51:00.001-05:00

As I sit at EWR airport, on my way to LIT, the thought struck me if I should have a completely 3D interface or if the 3D stuff should run in a window inside a bigger WinForm.

Some of the pros/cons that come to mind are:

3D Interface

This to me is by far the more immersive environment, where you have the outside world as well as the inside of the tower all rendered in 3D. In this case, the user would have to "walk" around in the tower floor to go see different computer screens, to look at different areas of the airport, etc. This also means the input interface would have to be built a little more robust that with the other alternative being discussed here, which could extend the development time a bit, when coupled to actually building the inside of the tower and making it interactive.

WinForm

This would definitelly allow a faster development, as a lot of the information being displayed to the user (such as flight strips) could simply be done via buttons, list boxes, etc.

I am undecided right now and think will be for some time. A decision does not need to be made soon, as I am still coming to grips with XNA and game logic.

Let's keep thinking.

Cool tutorials

2008-01-05T09:57:00.000-05:00

In my never-ending search for more information, I bumped into a couple of tutorial sites that are excellent for XNA. CampElmXNA has tutorials on both C# and XNA. Riemer has been known for his DirectX tutorials, and now has a very extensive series (substitute "a very extensive" for "60"!) of XNA tutorials. Nice job guys!

By the way, Riemer's explanation of what is XNA was a breath of fresh air. Perhaps for people involved with it for some time the following statement is obvious, but it took me some time before I figured this out:

Released in December 2006, XNA is intended to push the ease of game programming to the extreme. XNA is new wrapper around native DirectX. As development on a new version of Managed DirectX has been cancelled, XNA can be thought of as the new version of Managed DirectX.

Pre-Development Test

2008-01-01T23:52:00.000-05:00

OK, I am pretty happy. I just created a runway (a plane in 3DS) and a tower cab (pretty simple, really, 18 polygons), and using the Grumman J2F, hooked a very simple (but important) pre-development test. I have some keyboard inputs controlling the direction the plane moves in, and the camera located inside the tower cab. The camera tracks the plane, and it looks pretty good. I know, it's a small step, but it's one that gives a lot back. It's very cool to see the plane moving, the camera tracking, I'm excited!

Next I start work on a preliminary, basic flight model.

Render Test

2008-01-01T06:42:00.000-05:00

This is a render test I have just cooked up. It uses a free model I got from Turbo Squid of a Grumman J2F Duck. A very nice model with around 8800 polys. I did not use any shaders for multiple instances, just simply loaded each model as if it was different, and drew it, so there are no optimizations at all.

This was to see what kind of performance I got. With the 21 models you see here, fraps (which I used for measuring the frame rates and recording this video) shows I was still rendering at 60 fps. This is in a Dell XPS M1710 laptop (GeForce Go 7900 GTX). Not bad at all!

Google is not the only one that's good at maps

2008-01-01T05:58:00.000-05:00

Check this out. ProFX and MaPZone seem to allow procedural texturing on the fly, so that you don't need the gigabytes of textures to ship with your game. More than that, MaPZone can make diffuse, specular, normal, and other maps all fit together effortlessly. Alright, I'm interested. Oh, and did I mention they are an XNA partner, so they have a special (read dumbbed down) version of MaPZone free. Did I mention I was interested?

The target flight model

2007-12-30T10:50:00.000-05:00

Being an aerospace engineer, I will be interested in reproducing some very faithful flight models for the aircraft in this simulation. One of the things I hate about some simulators I have seen is how artificial their flying has been. A good way to see this is on takeoffs or landings, where, more often than not, a plane will basically switch game states from "plane.state(runningDownTheRunway)" to "plane.state(liftOff)" to "plane.state(climb)". This works fine, but the visual result is the plane snapping from being straight and level, accelerating down the runway, to 10 or so degrees of nose-up, to suddenly climbing out. There's no transition in between, so it looks fake.

My aim is to actually have a somewhat detailed flight model for each aircraft, which is something the guys at Eagle Dynamics did for Lock On: Modern Air Combat. Their AI traffic actually uses a slightly dumbed down version of the highly detaild flight model the user aircraft has. That means takeoffs, landings, and every other phase of flight look very real (they even improved on this in Flaming Cliffs by pretty much using the detailed flight model from LOMAC for AI, and going even deeper for the user aircraft).

A good simulation of flight models that is out there is X-Plane. Here's how Austin Meyer describes the process:

X-Plane reads in the geometric shape of any aircraft and then figures out how that aircraft will fly. It does this by an engineering process called "blade element theory", which involves breaking the aircraft down into many small elements and then finding the forces on each little element many times per second. These forces are then converted into accelerations which are then integrated to velocities and positions... of course, all of this technical theory is completely transparent to you... you just fly! It's fun!

X-Plane goes through the following steps to propagate the flight:

1: Element Break-Down
Done only once during initialization, X-Plane breaks the wing(s), horizontal stabilizer, vertical stabilizer(s), and propeller(s) (if equipped) down into a finite number of elements. The number of elements is decided by the user in Plane-Maker. Ten elements per side per wing or stabilizer is the maximum, and studies have shown that this provides roll rates and accelerations that are very close to the values that would be found with a much larger number of elements.

2: Velocity Determination
This is done twice per cycle. The aircraft linear and angular velocities, along with the longitudinal, lateral, and vertical arms of each element are considered to find the velocity vector of each element. Downwash, propwash, and induced angle of attack from lift-augmentation devices are all considered when finding the velocity vector of each element.
Propwash is found by looking at the area of each propeller disk, and the thrust of each propeller. Using local air density, X-Plane determines the propwash required for momentum to be conserved.
Downwash is found by looking at the aspect ratio, taper ratio, and sweep of the wing, and the horizontal and vertical distance of the "washed surface" (normally the horizontal stabilizer) from the "washing surface" (normally the wing), and then going to an empirical look-up table to get the degrees of downwash generated per coefficient of lift.

3: Coefficient Determination
The airfoil data entered in Part-Maker is 2-dimensional, so X-Plane applies finite wing lift-slope reduction, finite-wing CLmax reduction, finite-wing induced drag, and finite-wing moment reduction appropriate to the aspect ratio, taper ratio, and sweep of the wing, horizontal stabilizer, vertical stabilizer, or propeller blade in question. Compressible flow effects are considered using Prandtl-Glauert, but transonic effects are not simulated other than an empirical mach-divergent drag increase. In supersonic flight, the airfoil is considered to be a diamond shape with the appropriate thickness ratio... pressures behind the shock waves are found on each of the plates in the diamond-shaped airfoil and summed to give the total pressures on the foil element.

4: Force Build-Up
Using the coefficients just determined in step 3, areas determined during step 1, and dynamic pressures (determined separately for each element based on aircraft speed, altitude, temperature, propwash and wing sweep), the forces are found and summed for the entire aircraft. Forces are then divided by the aircraft mass for linear accelerations, and moments of inertia for angular accelerations.

5: Get Back to Work
Go back to step 2 and do the whole thing over again at least 15 times per second. Aren't computers great?

This is pretty much the approach I am planning on implementing.

XNA beta is not the same as XNA final

2007-12-30T08:50:00.000-05:00

Doh! I was trying to run two very interesting samples found at the XNA Creators Club and was having problems. The build was, for some reason, not building the Content, and this was straight out of the .ZIP. Strange. So I posted on the Creators Club forum, and Shawn came to the rescue, as well as a couple of other people, including Neil Pryde and Machaira (otherwise known as Jim Perry).

Turns out no one had heard of such a problem. Shawn posted a very helpful, step-by-step troubleshooting that lead to some textual output from Visual C# Express, which he was going to look through, but as I sat at the Appleton Airport and worried about the weather, lightning struck: I was still using XNA 2.0 Beta. Could it be? So I paid $7 for a day's access to their WiFi (when will we have free WiFi like we have free drinking water?), downloaded the final release, uninstalled beta, installed final, restart, F5, and....VOILA! It worked!

I feel embarrassed I didn't think of this before. So if you are out there, having the same problem, that's the solution. I am still not clear what the culprit was inside the beta, but I have decided to move on and continue learning XNA.

My legs are fine!

2007-12-28T09:22:00.000-05:00

Hard to believe, but I have survived both downhill as well as cross country ski without getting hurt! That's not to say my body doesn't hurt.

I am going back home today, getting back in the swing of things. I got up really early this morning and spent a couple of hours getting to know Shawn. I am really impressed with his background, but even more impressed by the amount of posts he has written, as well as samples in the XNA Creators Club. His expertise is incredible (he's of MotoGP fame), but even better, it seems he writes exactly about the things I want to know of. I think I have become addicted to his blog.

I heard of Shawn when he responded (in less than 15 minutes) to my first post in the XNA Creator's Club forum. I am having issues running some of the samples posted there, and Shawn is trying to help.

It will be nice to get back home and start doing a little more coding and modelling. I am also going to start planning exactly what road the development will take, with target milestones, not as much as dates, but as acomplishments.

I am liking XNA more and more.

Bah, Humbug!

2007-12-25T09:15:00.000-05:00

Merry Christmas, Happy Kwanza, Happy Hanukka, so overall Happy Holidays to all. Here's where I am for the season, skiing for the first time. Wish my legs good luck!

The book I was using to learn XNA was written for XNA 1.0. I have switched to 2.0, which came out not long ago, and am re-learning some of the basics, since even some of the infastructure setup automatically when you create a Windows Game project has changed. Big ups to the guys behind XNA Game Studio, the help files are very well written. I know how hard it is to write documentation to go along with your development, so congrats on a job well done!

I have also been spending time learnign 3DS Max, as I am going to create all of my 3D models myself. The textures are still an unkown at this time, but we'll see.

Season greetnigs,

I am now a librarian

2007-12-09T10:18:00.000-05:00

That's because I have now started to move some helper game components to a library (DLL) and use it as a resource in the game project. Things like user input, cameras, a framerate counter are all in there, and I'll keep adding. Pretty cool, and very effective, as well as organized.

Pictures of the Air & Space Museum

2007-12-03T07:54:00.001-05:00

Find them here.

Visiting the capital (and Capitol)

2007-12-02T19:30:00.000-05:00

I am in Washington, DC this weekend, for the first time. My parents came in to visit and we took a trip down. Today my Dad and I went to the National Air & Space museum. Wow. They even have SpaceShipOne hanging above the main entrance. I will upload pictures to Flickr and post a link here. Phenomenal stuff.

Which he then guided

2007-11-26T23:21:00.000-05:00

OK, this is getting cooler and cooler, after a 30-minute session of watching another tutorial and then studying the code a bit so I understood it, I was able to give the model some speed and control it's direction in the XZ plane. Very cool! XNA is growing on me, and I can definitely see how you bypass a bunch of low-level coding by having a lot of helper classes already done. Of course these will add to the overhead, but I am not aiming to make the visuals as complex as Crysis or Far Cry, so I should be OK. "Should" is the key word here.

And on the second day, he made a model rotate

2007-11-26T21:38:00.000-05:00

My investigation into XNA is going well. I found out some good video tutorials at the XNA Creators Club. The first one showed me how to get a model in your app and rotate it. The shot to the left is of a free Ferrari model I got from Turbo Squid rotating around it's Y axis and rendering at 60 frames per second. Not too shabby, considering it took me all of three minutes to get this done, from the moment I opened Visual Studio C# Express. Now, to the next tutorial... Oh, by the way, the frame counter on the top left is Fraps.

And yet another programming twist

2007-11-25T09:17:00.000-05:00

I spent the day yesterday reading about the possibility MS is going to release a managed API for DirectX10. Although that is not looking very promising (even though some inside the DirectX team state they are indeed working on it), I found out that XNA support and development seems to be on the rise. XNA is Microsoft's new API for creating games for Windows and the XBOX. The fact it includes the XBOX made me think this might not be a really good platform for a tower simulator which will run in Windows, but upon further reading, it seems that there's a lot I can benefit from this API. Several things you need for creating games, such as timers, access to graphics, audio, and input hardware, networking, etc., have been standardized and made available through XNA. It looks interesting enough that I am taking a look at it today. Oh, and what impressed me quite a bit was a short video of games made with XNA that I found in Michael Klucher's blog. Michael is one of the team members at XNA Game Studio. Time to roll my sleeves up and dig in...

Reading material

2007-11-24T08:51:00.000-05:00

So my language of choice will be C#. I am not 100% sure this will work as far as I can tell, but I like managed code a lot and feel it deserves a go at it. The graphics API of choice is DirectX. I have worked with OpenGL a little in the past, and chose DirectX simply to try and learn something new. Since I don't really know anything about this API, I am reading a couple of books that cover both C# and DirectX. One is Beginning C# Game Programming, a book written with humor, which I appreciate, and that covers the very basics of C# and then moves into DirectX. Another is Managed DirectX 9 Kick Start. Both use DirectX in its managed API, which is still non-existent in DirectX 10. I am not sure if Microsoft will publish a managed API for the latest version of DirectX, but once again, I am trying to stick with managed code. If it doesn't work, no worries, we move on to unmanaged DirectX. The dice are rolled, let's hope it's not snake eyes!

Testing posting from my email

2007-11-24T08:50:00.001-05:00

Cool, apparently this works well. This should allow me to post from mobile phones, in case I become obsessed to that point...

Welcome one and all!

2007-11-24T08:42:00.000-05:00

Well, this is it! I have decided to bite the bullet and commit to creating a tower simulator. As a pilot and former Microsoft Flight Simulator user and add-on developer, I have always felt the lack of a good ATC Tower sim since the good old BAO Tower. Couple that with my interest in programming and here we are. I don't really know what else to say, since this is my first blog, but from reading other blogs I have learned one thing: I am not going to say "I'll try to update this as frequently as possible", as that seems to be pretty much an assurance that it won't happen. So, without making any promises, check back when you can and see if there's anything new.