Carrier height

[Jel]

In preparation for new catapult work I have been searching to try to find the setting or procedure that raises the carrier airfield to what I think in 64 feet.
For the life of me I cannot find it. Does anyone have any clues?
I need this information to be able to make a catapult airfield at the right height.

Also which airfldXY.3dz file is used for the carrier airfield?

Jel

[Moggy]

Stumped on that one Jel. Looking back ay my 2015/16 early experiments with this:




I got the planes at the right height, but so far as I remember I accepted the default height for the raised carrier deck (invisible) and varied the height of the ship tmod to get the plane to sit on the ramp.

[rotton50]

There are two invisible airfields. One at ground level for seaplane bases and one raised for carriers. In the Airfield.dat file the seaplane airfield is 0 and the carrier airfield is 3.

I don't know who picked those two airfields. And I'm not even sure how the modder knew that neither of those is used in any scenario thus avoiding airfield height conflicts.

I also don't know how the carrier height was decided but I do know that the deck height of the models in 3dz Studio terms is 58 units above sea level. Not sure what the 58 units represents but I suspect meters.

As I wrote over at SimHQ, if a third field is added it should be a new selection not a replacement of an existing field. Otherwise I'm sure we will run into a conflict in some scenario that uses the original airfield.

Taking an education guess here but a third airfield should be raised only about 1/4 of the height of the carrier field. With a bit of finagling of 3dz models I think it would work for both battleship and sub catapults. If it doesn't work for both I would prefer it to work for battleships as there is a lot more playability for that scenario.

It may even be the case that since the sub is so low in the water to begin with that the model could be lowered a few points and then use the seaplane airfield.

I don't know if you all are aware but EAW if pretty forgiving when it comes to putting ships on the water or slightly under the water. A 20 unit drop below ground level is hardly noticeable.

[Jel]

Interesting experiment:
The SPAW Jap carriers use "airfld06.3dz"
I copied "airfld01.3dz", pasted it into the root folder and named it "airfld06.3dz".

This gave me a visible airfield which is clearly drawn at height 0.
However, the aircraft are on top of the carrier, and they take off normally.
So it looks as though the code is positioning the aircraft, and not the airfield.

[Jel]

Continuing with the previous set-up I used the runways.dat editor and changed the "airfld06.3dz" type from 8 (carrier) to 1 (grass):



The aircraft are on the runway, not on the carrier, and as soon as you start an engine you have had it
So runway type is determining the aircraft position.

This gives a few more clues as to where the code might be

[rotton50]

Odd, in my setup the Jap carriers use the 03 airfield, not 06.

I'm referring to columns 21, 23, 25 and 27 as you scroll across the data in the target editor.

Now that I think of it, the runways.dat file enters into this in some way but I've forgotten how.

[Jel]

Switching to the ETO "Allied Carrier" I replaced the carrier with a different TMod



As expected the aircraft are still at their normal (carrier) height which was above the building.

So the EAW source code positions the aircraft with additional height if they are on an airfield with runway type 8.

Odd, in my setup the Jap carriers use the 03 airfield, not 06.

Here is the "runways.dat" editor with Ray's version loaded



If you take it in order the first data line is 0, the second 1, the third 2 and the fourth 3.
On this fourth line the airfield 3dz is "6" and the runway type is "8" (carrier)
The "3" is the value in "airfield.dat" as the reference to this runway in this file

[rotton50]

Heh, I had no idea we had a runway.dat editor that could edit each runway characteristic.

Do you have a text file that explains the data table?

[Jel]

I found the height setting code which has a fixed value (58.0) added to the plane height. It occurred in 32 places
My next step was to make this a variable, so that it can be changed, and it works.
There are some issues with wheel brakes if you make it too high- they cannot be turned off if it is 65.0, so you cannot move.
Here the setting was 40 but you may need to right click on it to view the whole image as it is 1600x900


The planes were rendered after the carrier so although they are really inside it they appear to be outside it.

Ray
In the source code there are lists of values in files like "Runways.dat", indicating the order of the data, the data type (boolean, byte, integer, etc) so I can build an app to read the files, and then extend it so that it can edit the files.
Sometimes the names make sense, but most of the time I have no idea what the values really are, and what they do.
Hence, I have very little documentation

[Moggy]

I played with the runways.dat yonks ago, probably when I first did Midway, and did this old data page: http://mogggy.org/tech/techairfields.htm it sets out what the values do (at least as we understood then).

Don't we now have the possibility for 32 airfield types in runways.dat? That was implemented back in 2008/9

[Jel]

In the table there are 32, over half of which we have never used. The order matches the original order,hence the 0, 10, 9, 6 ..... for the 3dz numbers.
In the source code there is a "point over carrier" check which tests if a point is over a runway type 8.
If it is true then certain things happen, such as the aircraft being raised.

[Jel]

This morning's work



In the exe there is now a variable "RaiseMe" with the default set to 58.0
It can now be read from an external "Carrier.mpf" file which can be in the root folder or a theatre folder.
In the screenie "RaiseMe"was set to 40.0 in the"Carrier.mpf" file which was in the "Default Theatre" folder.

It is now up to you guys to decide on our next move, bearing in mind that we have these possibilities:
One of the unused runways could be used as the battleship runway.
There would be a "Point over Battleship" routine to test if the plane is over this new runway.
There could be a second variable such as "RaiseMe2" also in the"Carrier.mpf" file and read from it to set the height of the aircraft on the battleship runway.

To test it I would need to add a target with a battleship that has an airfield (similar to the "Allied carrier" in ETO), so I need the appropriate TMod, and an appropriate suggestion for the height.

Jel

[rotton50]

Lots to digest.

A number of comments, not in any order or importance:

- I didn't know we had unused airfields so obviously my earlier request for an additional airfield is moot. If no one objects, I plan to use the last one (32) for a battleship airfield, It seems least likely to have been used in any other scenario thus avoiding conflicts. if that works I'll use (31) for a submarine airfield. if I read your post correctly a sub airfield would require a raiseme3 entry.

- As to the data that tells the exec you are over a certain airfield, that must be how the tailhook action code is activated. Not sure what we'd do with it for a battleship but suggestions are welcome.

- One thing that has to be watched for is that planes on the deck of a carrier will explode upon engine start if the TMOD.dat for the deck is too high. This would also apply to a battleship deck. As far as I can tell it's purely a trial and error process.

- I can put together a battleship model and target for testing this, just give me a day or so to figure out how to proceed.

- Any though as to how to move the carrier planes forward on the deck before the catapult effect takes place? As I wrote earlier, as it sits now, the planes are launched from the deck from their original start points. This is Ok for the battleship since there's only one plane involved but for the carriers it doesn't look right.
I wonder if looking a Ralf's code for lining up the planes on the deck after landing would give you a clue for implementing this. Originally, the planes landed and moved forward in a helter skelter fashion with some of them falling off the deck. After his mod they moved forward and lined up almost perfectly.

- Isn't it nice in here?

[Jel]

We should just focus on the battleship. Once we get that right we can so the sub.
With the battleship I would assume that it is selected as a base, with the single aircraft, and you launch using the catapult.
In this situation piloting manually does not use the catapult code, but it kicks in with AI planes. The trick with a single plane is to use Alt-N.
I will also need to write some code to make the number of planes to 1

Check my post re- host only multiplayer
I will test it, but I expect that I could select a carrier as the secondary base and fly escort from another. With a ground-start the AI plane would be launched by catapult. This cannot be done in single missions because the exe selects the secondary base.

[rotton50]

In this situation piloting manually does not use the catapult code, but it kicks in with AI planes. The trick with a single plane is to use Alt-N.

It also works if you select autopilot.