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Submitted by George Sealy, posted on June 01, 2001

Image Description, by George Sealy

My submission for IOTD is a collection of screenshots from the project I'm currently working on. My company ( - shameless plug) produces real time animation for sprting events, in my case golf. It's not a game, but the engine driving the graphics is very similar in many respects. We have people out on the course who mark the position of the balls as they land (using GPS), and this data is feed back to the animation machine which produces the live graphics feed for the broadcaster.

Anyway, for the geeks among us (myself included), here's a feature list:
  • Uses OpenGL both by preference and also for platform independance.
  • Written in C and C++.
  • Supports both PAL and NTSC broadcast formats.
  • Maintains constant frame rate of ~30fps, but generally runs at nearer 60fps.
  • Has an implementation of ROAM which will render the entire course at 2m resoultion at 50+ fps, but this isn't used because of popping. Instead heightfields are preprocessed for optimal triangulation.
  • Display of ball flights (both ideal and actual), contours on the green, weather.
  • Interactive setup of cameras, flythroughs, trees, logos etc.
  • Weather effects - rain, sky colour, clouds (no lightening yet!).
  • Other stuff which I won't bore you with...
  • Our web page has more info (, and questions, comments or suggestions are always welcome (

    Image of the Day Gallery


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    Archive Notice: This thread is old and no longer active. It is here for reference purposes. This thread was created on an older version of the flipcode forums, before the site closed in 2005. Please keep that in mind as you view this thread, as many of the topics and opinions may be outdated.

    June 02, 2001, 03:07 AM

    You could, but you don't need to generate per-vertex GPS coordinates... you just need a transform that takes GPS coordinates and gives the corresponding world-space coordinates inside the golf course model, and then you can treat it like any other scene.


    June 02, 2001, 04:44 AM

    ah. ha? eh.

    Cool shot though.


    June 02, 2001, 05:22 AM

    I could think of different approaches. One would be creating the whole computer scene based on GPS coordinates (or GPS transformed into something else), another could be "estimating" and using GPS only as sort of distance meter or something. If there was a transformation of GPS coordinates to vertex values one could of course generate GPS from those vertices.



    June 02, 2001, 05:24 AM

    "First posters suck."

    ...because you're always late :-)))


    Oscar Rydberg

    June 02, 2001, 05:31 AM

    Great work You have there!

    I love golf, and this looks more or less like something I'd wanna do - but as a golfgame!

    How do You do those trees?

    The landscape has a much more realistic feel compared to what's most commonly used in todays broadcasts.

    George Sealy

    June 02, 2001, 06:10 AM

    Hi all,

    Thanks to everyone for the favourable comments about my IOTD submission.
    I'd like to take the chance to clarify / answer a few comments / questions...

    - No it's not a game, but the border is fairly blurry sometimes.
    - Speaking of blurry, this image wasn't using the full quality textures, which require an
    SGI or GeForce 3 - they're 4k x 1k textures, which is almost big enough for my liking. Yes,
    they are actual high detail photos.
    - As far as I know (not being a hardware boffin), the GPS system we use is completely passive,
    so no radiation should be being emitted - at least I hope not as my wife carries one around
    on the course all day!
    - Our product is used as part of a live TV broadcast to increase the audience's understanding of the
    game, and provide the commentator's with a useful tool to demonstrate what's going on. We also
    provide coverage of yachting evnets, and the World Rally Circuit is next - go and have a look at our
    site if you're interested -

    Hope this answers the questions that have been raised,



    June 02, 2001, 08:01 AM

    Guys, don't you have better things to do than flaming each other??? In fact, if we keep going like this we don't need "MC BAXTON"-dudes, we make a better job than he... Why don't you say something about the IOTD? Especially, since it's more original than "just a terrain engine" (I am the right guy saying this *g*). I think the whole idea behind the project is quite interesting. I don't know if this is the main target, but imagine golf fans who are traveling or for another reason can't see the match itself, this system could be used to simulate a golf match almost in real time (on their laptops for example, if they have any of course ;). Or it could be used for educational purposes, when learning playing golf... it has a lot of potential imo, virtual reality is coming ;). And the pics themselves are nice as well =).


    June 02, 2001, 09:55 AM

    Hehe, well I do not know for sure but have you seen these slomo movies of a golfball being hit by a driver or a good wood club? They neatly compress into something that is more like a flat disk ;) If you would happen to have a small receiver in there... well... I do not know if you could build it as flexible as the ball ;) but if you do not.. you get a nicely compressed and broken fm receiver ;)


    June 02, 2001, 11:59 AM

    I was wondering about your actual and ideal flight path. How do you figure out the actual path? You have the start point and the and point of course. Do you also get the club velocity and angle somehow or do you just use some nominal figures that fit the endpoints?

    Speaking of which... you definately couldn't get a GPS into a ball and it wouldn't be useful anyways because the position update rate probably wouldn't give you very good track in flight. Basing the trajectory on a simulation is probably better. Now the FM transmitter that goltrpoat suggested could be fit and survive as they can be made VERY simple.
    However the golf pro association would probably freak out if you even suggested modifying thier precious balls!

    dan ogles

    June 02, 2001, 12:50 PM

    Heh heh heh... you said "precious balls"



    June 02, 2001, 05:34 PM

    a) can you use the ball location GPS to synchronise the real-life camera position to rendered position? Then you could fade between the two shots/overlay, etc.

    b) If you are rendering this for TV, surely you should be using an SGI machine? Preferably with some antialiasing.

    c) Doesn't seem to be very curvy - especially in the bunkers or the shadow for the ball trajectory....

    Still... looks good... /me likes.


    June 02, 2001, 06:32 PM

    About the quake thing, something like that already exists, quake 3 though :) I watched clan9 play against some other clan live from my computer.


    June 02, 2001, 06:32 PM

    About the quake thing, something like that already exists, quake 3 though :) I watched clan9 play against some other clan live from my computer.


    June 03, 2001, 06:57 PM

    Erm, its something like this...

    Golf ball recv's signal from satellites. There's a clock in the sat's and a clock in the golf ball that are mostly sync'd. Time diff from sat to ball gives you the dist from sat to ball.

    Because sat / ball clocks won't be totally in sync you have 4 unknowns - x, y, z, t - so you need 4 sats to give 4 simultaneous equations to solve for 4 unknowns.

    Military stuff has higher precision clock & dunno, maybe more sats?

    So its kind of a passive system, rather than active - wouldn't it be funny if in the middle of desert storm you get "Sorry, network busy" if the ball had to connect to a GPS system.


    June 04, 2001, 07:18 AM

    Why not use a brightly coloured ball, and a couple of video camera's. A bit of image recognition, and interpolation between frames and you could calculate the 3d co-ordinates of the ball.

    Maybe less than live, but "Oh, my. Lets have a re-play of that from the ball's view".

    Might actually make golf watchable.


    June 08, 2001, 04:07 AM

    very cool idea

    i'm seeing alot of sporting events doing similar things now, but most are doing still frames from cameras mounted 360 degrees around the scene. you prolly saw that in the superbowl in it's early beta (not very interesting if you ask me) and now in the nba finals you can see the 180 at both ends of the court (better than superbowl, but still bad quality for tv)

    i like your idea better though, render the entire thing and be able to really walk around the game and step through it at will...

    if you could broadcast the data to people at home with a device capable of saving it, i'm sure lots of people would love to be able to analyze their favorite sporting events this way.

    anyways nice project, hope it's a success for you and your company.

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