• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Angus Hollands

Where to render object positions and animations

5 posts in this topic

Hey everyone,

 

I'm a little indecisive when choosing how to render the gamestate on the client. 

I can forward extrapolate the other clients to where they would be on the server, but then things like playing animations would need to be forwarded to compensate. As a result, the animation would "jump" into a frame; such that if the latency was half a second and the animation framerate was 60 frames per second, 30 frames would be skipped. 

 

How should I deal with the timing issues?

  1. Extrapolate forwards by the downstream latency to get the current position of the object
  2. Render at time of receipt but still run client itself ahead using prediction

Forgetting about the jitter buffer, I'm concerned about hit detection; The first option would potentially be out by some margin, but the latter option would technically be incorrect as it was aiming at the client's old positions. Any thoughts?

0

Share this post


Link to post
Share on other sites

This is a game design question. Games have shipped using both the "display guessed forward state at the right time" method, and the "display only known data, but late" method. Pick the one that you feel will work better with your game.

In my opinion, I'd rather pick "display known data, late" for most cases, as it leads to easier to manage simulation code; hit testing can be authoritative using the same data on all clients and the server, for example.

0

Share this post


Link to post
Share on other sites

So, for the sake of ease it is best to treat the latest incoming data as the current data.

How would one run a jitter buffer for this without doing something involving clock sync?

The predictions I send to the server will be the results of the inputs, therefore I'd only need to timestamp them to help prevent speed-hacking (I'd only need to know how long the inputs were processed for.)

 

In light of the fact that I'd need to re-simulate physics, I've decided to temporarily switch to another Python-based engine which gives me this ability, so that I can get the foundations working. Does this look like a permissible gameloop?

 

  1. Receive network data.
  2. Apply any corrections to physics data - there would have to be "real" positions and "render" positions, although this would make things more complex so I may just use interpolated positions for non-authority gameobjects.
  3. Tick physics (perhaps a number of times if there are a number of saved moves).
  4. Run simulation from inputs.
  5. Tick Physics 
  6. Send results to server (with timestamp) -> delta = last_timestamp - current timestamp
Edited by Angus Hollands
0

Share this post


Link to post
Share on other sites

How would one run a jitter buffer for this without doing something involving clock sync?

 
The sender should put their clock / time step number into each packet. That way, you know at what rate to play back the packets on the receiving end. Then, settle on a relation between sender clock and your own clock. If the delay ends up either wanting to play packets before they arrive, or holding on to packets for too long before they're played out, then you adjust it (this also adjusts for clock rate skew.)
0

Share this post


Link to post
Share on other sites

Here I'm wondering how Unreal does it. By default, the replication statements are applied as soon as they're received. This would include physics. However the physics system scrapes the replicated data so It may choose to implement a jitter buffer. Would it then be sensible for the Physics "system" (that which iterates over the actors and scrapes the data) to implement the jitter buffer; sending a timestamp with the attributes? 

0

Share this post


Link to post
Share on other sites

How would one compensate for the scenario when physics are deliberately omitted from the replication (e.g when the object isn't moving)?
The two solutions I foresee would be a boolean "isIdle" that is replicated with the physics, or just sending it every replication regardless (or just reading the velocity value).

 

Furthermore, have you any suggestions on how to create the buffer? Because my attempts haven't been altogether succesful.

Edited by Angus Hollands
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0