Spring Chase Camera

[liamrudel]

Hi guys,

Here's a spring chase camera I did for a recent project. Fell free to use it wherever you like.


SpringCam is a demo app which shows how to use a spring to implement a nice smooth chase camera for driving, flying or third person games.

The demo includes controls to adjust the mass, stiffness and dampening of the spring that attaches the camera to the player.

Source Download:
http://www.liamrudel.com/?page_id=423

[xadhoom]

Very cool! Thanks for sharing! Maybe I can implement your approach with a PhysX Joint and an Actor for correct collsion, too...

xad

[Nauk]

Very useful, thanks for sharing

[SirGolan]

Pairing something like this up with a physics engine for collisions works great as xadhoom mentioned. That's what I've been using lately and it makes for smooth camera moves. Though you have to watch out for instances where the camera gets caught behind something because the player went through a doorway and then strafed to the side before the camera followed them through. I think I have a video of that happening in MV3D somewhere.

Thanks for sharing the code! It was very easy to understand and should be helpful to a lot of people.

[liamrudel]

Cool, Glad I made it easy to understand!

[jacmoe]

Thanks for sharing this! How to setup a camera system is oft requested here.

Which leads me to suggest: how about writing a small wiki article?
And let it not be buried in this forum?

[my.name]

=)

[nikki]

Yay for MyGUI! So, looks like it worked out for you?

[liamrudel]

Ya got it all sorted in the end.

When I get some time I'll turn this into a wiki article

[zarfius]

Very nicely done.

I'm at work so I'm not able to run it at the moment, but looking over the code is enough to get the general idea. Your coding style is very similar to mine, I think I'll also use your GameState class (if that's okay with you )

It'd be interesting to see how much code you have to change in your design if you decide to implement a physics engine. I found that my GameObject class had to change significantly from something very similar to yours.

I second the idea of a wiki article

[liamrudel]

I got the framework from a thread around on the forum. Not sure who I should credit as they adapted it from someone else.

Question: Whats the story with that anyway. If someone posts code like I did is it ok to use it without credit?

Well I'm using Havok physics in another game and am using the same camera code but don't have camera collision, it runs on basically one line of code, can't see it being much different, I suppose after you get the new camera position update it again if there was a collision.

As in:
1. Get camera position from spring
2. Check for collision, and move the camera to uncolided position

As someone else mentioned i'm sure doorways may cause problems. When I get some more time i'll see if i can use a rigidbody in Havok attached to the camera for collision checking.

I also really wanna do the wiki article, will do when i get some free time!

[mickeyren]

Hey liamrudel

I just want to let you know your site is really broken.

[liamrudel]

Can you explain, it all seems fine to me, what do you mean by broken?

[mickeyren]

hmm strange your site does look fine on IE.

broken.jpg (56.93 KiB) Viewed 8534 times

Here's what I see on my firefox. Must be only me or my firebug and web developer toolbar plugins.

[liamrudel]

Can you tell me what version of firefox you are using and what resolution?

[mickeyren]

Hi liamrudel

I manage to track it down. That happens when my firebug's console is enabled. So its me not your site. Sorry for the confusing report.

[liamrudel]

Ok, Thanks all the same

[globalsinner]

Hey there,

Thanks a lot for this. This works great tho I had to get rid of MyGUI as it does not work on my environment. Could be some problem due to differences in the environment in which the dll was compiled and the one I have (VS 2008, using Ogre 1.6). Still it works great and has helped a lot. I'm currently customising it for a small demo I'm workin on..

[liamrudel]

Glad it helped, it's not much but a good starting point!

[Handicap]

Yyym whats da difference? Ive used interpolation for my TPP cam, like:

Code: Select all

cam.DestPos = (calculate point behind player and raycast it to avoid ghosting)
cam.Pos = cam.Pos + (cam.DestPos - cam.Pos) * cam.Interpolation;

Can u tell me what are benefits of ur camera?

[liamrudel]

I'm not claiming this is the best way, so perhaps there are no benifits over your method. It's just one approach. A spring using Hookes Law, gives a nice motion to the camera.

[koirat]

Handicap is your cam interpolation based on time offset or it is just a number, and every frame you are just multiplying difference by interpolation.

I'm askin cuz i made TPP camera with tightness parameter, but my implementation is not time offsest based but frame based. I will change it to spring based camera soon. So it's behavior is not going to be FPS dependant.

[liamrudel]

Just to note, as far as I remember I left my spring frame rate dependent, to fix this just mulitply by time since last frame when getting velocity.

[Handicap]

No, I use constant FPS and accumulator, sth like:

Code: Select all

gameloop
{
  accumulator = accumulator + timeDelta
  while (accumulator > frameTime)
   {
       doGameLogicFrame()
      accumulator = accumulator - frameTime
   }
  render()
}

So I have constant frame Time (i.e. 0.01666) and no fps-relative problems within logic and physics (includin camera)

[koirat]

Just to note, as far as I remember I left my spring frame rate dependent, to fix this just mulitply by time since last frame when getting velocity.

You mean in this place ??

Code: Select all

//Add velocity to old camera position
	mCameraPos = mCameraPos + mVelocity * timeOffset.