Bridge Commander Universe

MEdelen · Cadet 2nd Class Joined: 26 Aug 2004 Posts: 63

I just had a thought about giving planets and stars gravity. What if you give planets and stars tractorbeams? Just give them no blind spots and make them invisible with no textures. That way if you loose power in your impulse engines and you can't hold your orbit, or if you drift too close to a planet, the "gravity" or low power tractorbeam, will get you. For Stars though it would have to be EXTREMELY long range and the tractorbeam emitters would litterally be every square inch of the suns. You can make a black hole and have the invisible tractorbeams occur in stages. long range would be weak, medium range would be stronger, and the closer you get the stronger the tractorbeam until even a ship with full impulse couldn't escape the pull. What do ya think?

Dante Leonhart · Lieutenant Age: 27 Zodiac: Joined: 18 Jun 2006 Posts: 400

I have to admit, of all the Star Trek games I have played, there was nothing cooler than a skirmish near the event horizon of a MASSIVE black hole in Klingon Academy.

MLeo · **Posted**: 09-12-2006 09:34 PM

The catch with that sollution would be that all tractor beams look the same, no matter how you change it in the hardpoints.
And if you change the texture, you change it for them all.

sfc3fan · **Posted**: 09-12-2006 11:24 PM

MLeo if i remember correctly a while ago you said you might have had an idea for Gravity in Bridge Commander, what ever became of that?

Gravity would be nice: would go spledidly with that black hole i have siting in my system.....

MLeo · **Posted**: 09-13-2006 04:53 PM

The physics/math behind it was to much for me at that point.

I may try again some time in the future, I currently have to much work for big projects.

USS Frontier · **Posted**: 09-14-2006 01:26 AM

i have a better idea:
In a script, you catch the stars, planets, blackholes (and everything else that will have gravity), add a proximity check to them, depending of the type of the object (star = more gravity = longer than planets prox check, planets = normal gravity = normal prox check, and so on), then you get the impulse speed, direction, and everything else needed from the ships inside that prox check to make the math that will subtract( lower) that ships speed, and if she doesnt have the speed or direction to run from the gravity well then the ship will be pulled to that well, with an aceleration rate and so on. Optionally, and would be recommended, some kind of interface or warnings so the player can see/check where there are gravity holes, their strenght, and if he's in one of them.
Actually the baddest problem in that idea is the math part, especialy because it is with vectors and speed.
If i had more experience with vector math, i would try do it. i still didn't learned what those functions in the TGPoint3 class do...cross, unitize, subtract? don't know what they do (i'm not from EUA). Really, if someone explain to me what they do, i would try to do it. i know the how to make the physics and so on, i just dont know how to make that bloody vector math because i don't know what those functions do... I have a list of some special weapons to make for BC, already made 1 of them( but i'm just waiting L_J to give me a piece of code to give a torpedo a tail to release it, and i already made a little program to create the plugins file for it) and them decided to finish my ship(only textures left), but for Gravity i would continue the ship after Gravity is done =P

lol its more cool to make scripts than to make textures (i'm currently making a ship).

MLeo · **Posted**: 09-14-2006 05:27 PM

Those functions are all mathematical functions.
A good book will allow you to find their meanings.
Or try searching here: http://www.gamedev.net/dict/
You can find them there (in the dictionary, linked above, or when you can't find it there, in the articles section, more than enough articles about the subject of vectors and matrices).
If you still can't figure it out, I'll try to explain them.

And you wouldn't even need the proximity checks.
If you look at how gravity works (generally speaking), then it's just a constant force in a directory towards the source. The strength of the force is the inverse square of the distance (times the gravitation force). And for a system, you would just need average all the forces in the system.

USS Frontier · **Posted**: 09-14-2006 08:01 PM

wow.
That's a really useful site Mleo, thank a lot for introducing me to it.
i still didn't read everything in there about vectors, mostly because that will take some time, but i've already discovered what some of those functions do.

So i will begin to make a GravityFX mod, and credit you MEdelen for the idea.
I'll use this topic to post any progress made or questions if help is needed, and check it for new ideas for it.

USS Frontier · **Posted**: 09-25-2006 12:25 AM

Hey just to update:
i've already made various funtions to get the values needed (gravity force, change from km/h to BC's impulse units, etc), the prox checks and some other thingies, right now i'm on the part to apply the force on the ship, looking thru App.py i've found this function ApplyForce (from PhysicsObjectClass), she only needs 1 argument, that i suppose to be the force to apply on the ship, but ANY thing that i put as the arg the console says: "Type Error: expected _p_Force", i tried putting a TGpoint3, a NiPoint3, a TGColorA, numbers(124 and 1235.1124 for example), but always that type error appears... so does anyone here know what this function does or how to use it?

MLeo · **Posted**: 09-25-2006 05:14 PM

Funny thing, I was looking at that exact function a couple of days ago (to for something else).

You need to find the "Force" class somewhere.

Force isn't a class in App.py, so maybe in Appc somewhere.

I had a dump from Appc somewhere, but can't find it.

USS Frontier · **Posted**: 09-25-2006 05:35 PM

If it isn't on App, can it be on any other script, besides Appc?
Because I've already saw that App imports this Appc, and uses various stuff from Appc, but I never did find it, I thougth it was hardcoded in BC.
How could I see the contents of Appc?

MLeo · **Posted**: 09-25-2006 06:30 PM

tiqhud · **Posted**: 09-25-2006 08:39 PM

it is a shame, as a gravity well , would add just that extra touch

USS Frontier · **Posted**: 09-25-2006 10:22 PM

Mleo, i used dir() to get the (5208) atributes of Appc, and then printed it to a file, as it is so much easier to search a term in a file then on BC's console
And i didn't found anything on Appc that was a class or function called "force", the only results i had searching for "force" in the file was "PhysicsObjectClass_ApplyFORCE", "CollisionEvent_GetCollisionFORCE" and stuff like that...

MLeo · **Posted**: 09-26-2006 04:20 PM

I was fearing that. It means it's not exposed to us, and therefor unusable. Sad

And outputting to a file is what I was refering to.
It was simply left behind on my old comp.

USS Frontier · **Posted**: 09-26-2006 05:32 PM

Oh crap... ok then, i'll stick with vectors and stuff to apply the force on the ship.

Sometimes i just want to know what was in the mind of the guys that created this game, making a function that can't be used? just bizarre...

Obs: I can say "crap" here can I? if not, just say so and i'll change it.

lost_jedi · **Posted**: 09-26-2006 05:32 PM

well - if we could capture an instance of the force class then we might be able to find out more about it using it's __dict__ property - you never know - it might have a copy or clone parameter?

MLeo · **Posted**: 09-26-2006 05:36 PM

USS Frontier · **Posted**: 09-26-2006 05:58 PM

If it is possible, how could we capture an instance of the force class?

MLeo · **Posted**: 09-26-2006 06:21 PM

Through advanced hacking techniques, and a lot of guessing.

You would first have to try and find the actual ApplyForce function, in memory, then to find the actual force object, which may, or may not exist of any number of complex subtypes itself.

And then you know of what it exists. But it won't do you any good. Sad

You still can't expose it.

USS Frontier · **Posted**: 09-26-2006 07:32 PM

Hmmm, so, can we like, create a force class? derived from TGPoint3 probably. To try making this applyforce to work.

MLeo · **Posted**: 09-26-2006 09:39 PM

Nope. Unless Force is a typedef of TGPoint3 or NiPoint3, which is extremely doubtfull.

Remember what I said about the reference/proxy/shadow things?

The "this" attribute actuall contains information about the (current) type (this is affected by casting) and the memory address the object is.

So, constructing an object to resemble another is something that's part of what programmers call "generics" and when BC was made, generics did exist as an idea, but not implemented as in out of the labs. So in other words, not in BC.

Besides, we're talking Python->C(++) interfacing here as well. Which adds another layer of complexity.

If it is a typedef of TGPoint3 or NiPoint3, then you *could* try to create a class (no inheritance needed) that takes a this in the init, and takes the memory part and appends it to a Force_p_ (check the real string when you try ApplyForce) string and store it as your own this attribute.

So, something like:

USS Frontier · **Posted**: 09-26-2006 10:15 PM

IT WORKED!!!!

lol just joking...

Ok so let's forget this ApplyForce function... i'll use vectors instead.
I just have 1 question that's been annoying me, what's the best way to change direction/speed of the ship, while still mantaing BC's physics (because whenever i use SetAcceleration the ship begin to accelerate without a max speed, so it just stays there, trying to reach infinite speed...)? with SetAcceleration, SetVelocity or SetSpeed, or maybe another i didn't saw? as whenever the ship is affected by gravity it's direction/speed changes because of gravity. the part to get this new vector leave it with me.

EDIT:
Another update:
The basics are working! yay! yes, all ships within the well are suffering from gravity, and if they are stupid enough they'll make a terrible landing on the planet's surface lol
I used SetVelocity, and with worked just the way it should.

Now i'm beggining to make the extra stuff, starting from the GUI:
To show where the wells are I was thinking of making a 2D map, showing the wells and ships, BUT if it is possible I woulda make the wells appears on BC's 3D map (you know that one that appears by pressing "m"? and is centered in the player's ship?), so if anyone know how i can make them appear on the 3D map, please tell me how. on 2D plane, i woulda put a circular texture representing the well, centered on the planet (that would be another circular texture), and so on, like ST:Armada 2 mini-map for those that played the game. on the 3D map, i woulda create somehow a sphere around the planet, representing the well.

MLeo · **Posted**: 09-27-2006 04:50 PM

So the ships try and stear away?

Good.

I was going to suggest that you get the velocity (with direction) as a vector and multiply it with the various gravity vectors, then put it back.

USS Frontier · **Posted**: 09-27-2006 05:56 PM

Actually the ships move like they want to, the player's ship, the AI ships, but their velocity and direction are affected by gravity. So if a AI ship stops moving, she will be pulled by gravity. I've also tested this with Orbit Planet, and while kiska orbits the planet the gravity changes the direction and speed of the ship, but kiska automatically repositions the ship, so there's no problem with orbit planet. Now, to make a AI ship realizes that she's being affected by gravity and take actions because of this condition, like moving the ship to counter the gravity force and so on, would require changes in the AI scripts, and to be honest, i don't know a damn thing about the AI scripts.

Here's an example: the ship A has a maximum impulse speed of 5600 Km/h, if she tries to run away from a planet, in a direction that is a straight line from the planet, she'll only reach a maximun speed of 5300 Km/h.

Notice that this was only an example, the gravity force is affected by the planet's mass and the distance between the planet and the ship in question. And there's also a few tweaks to make to the code.

sfc3fan · **Posted**: 10-04-2006 05:00 PM

This though just struck me how does gravity effect Stations or orbital objects, I've currently got all the planets in my Homeworld mod set as ships and the last thing i want is the Planets moons falling into the planet.... Again...

USS Frontier · **Posted**: 10-04-2006 06:38 PM

When setting the gravity wells, the script will create a list of all planets/suns objs(that aren't created by NanoFX AtmosphereFX), and then create a list of all possible objects that will be atracted by gravity, they are ships with genus 1 (genus 1 = ships / genus 2 - 3 = stations - asteroids) and that are not stationary.
So Asteroids and Statons won't be affected by gravity.

And a new update:
- i will quickly rewrite the script so that instead of being a bunch of functions and global lists/dict/variables, it will be made using classes, so things stay more organized and faster.
- You can now set the density of your planets or suns, by using this code:

USS Frontier · **Posted**: 10-10-2006 11:22 PM

Hey to anyone, updating again:

About the main part (handling the grav wells):
- It's all done in classes now, everythng working fine
- Added a support to set in a ship's script if she won't be affected by gravity. I made this because there are some ships that have Genus=1 and are not stationary but shouldn't be affected by grav, or it would cause problems. Like Firepoints, probes, plasma streams.

About the interface part:
- Added a UMM plugin. So now with UMM you can set some settings for GravityFX. Until now they are: If GravityFX should set stock planets density, and a multiplying factor of the grav force, to make the grav force have the real value, or up to 5000 times stronger than the real value. This was added because there are various planets in game that doesn't have a real radius, but other that do (like the planets of the Sol Multisystem), and as radius affects mass, that affects the grav force, this setting was added so that if people want they can make the force stronger easily.
- the Glow Emmiter is completed too, i fixed the error that was causing it to appear about 60-100Km away from the planet.

Sorry about the delay to make the interface, but i'm having some trouble with a stylized window (the one i mentioned in the previous post).

USS Frontier · **Posted**: 10-12-2006 05:36 PM

Okay, i made a 2:30 min trailer of the GravityFX mod.
It's a 17Mb RAR file, containing a 78Mb AVI movie (with no sounds)
Download here
*Note: it is uploaded in sendspace.com, another file i uploaded there some time ago doesn't show up anymore, so i say to everyone that wants to see this trailer: Download ASAP. If you take too long and can't download the file anymore, contact me via email, and i'll try to send it by email to you. or i'll just upload it again.*

Note that, its was meant to just show some features, not everything. the quality might not be very good, the part before entering quickbattle was taken using frame shots, so it passes REALLY fast, it'll be good to pause at the start of the movie, and go frame by frame to see the main menu part, until quickbattle starts.

And remember i said i was having troubles with the interface? noticed that the "Adv Helm/Sensor Options Menu" window's buttons doesn't show their string? that's the problem i'm having, tho i have another window too, that i didn't show on the trailer, and her buttons's strings appear...

MLeo · **Posted**: 10-12-2006 07:02 PM

Are you using a tgl database for the strings?

Then in that case you need to load it first (or load the correct one).