• 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
Finalspace

Questions about position correction

2 posts in this topic

Hi there,

 

i implemented a simple 2d physics system based on the sequential impulse method presented by Erin Catto (2006).

In that paper, position corrections are resolved by adding a velocity bias to the velocity constraint impulse.

My initial tests for this system was like falling boxes from the sky, apply gravity, let it stack, slide a bit. Everything was working correctly, boxes stacks, penetration gets resolved and it was looking good.

 

Now i added a player rigid body which applies linear impulses to let it move/jump etc. and now the entire system fails.

If the player is penetrating a static body, like moving left and get pushed away to the right, it get half-stucked in the static body and will be pushed apart after a few frames - so that it just touches the static body on the right side.

 

My conclusion is that using velocity bias as position correction is not a good idea for a game after all - therefore i really want to know, what options do i have to solve this issue?

Edited by Finalspace
0

Share this post


Link to post
Share on other sites

Post stabilization seems to be the state of the art. Here's what I think is the original paper on the idea: http://www.cs.rutgers.edu/~dpai/papers/ClinePai03.pdf

 

Erin Catto also talked about this in his last GDC lecture where he referred to the idea as "psuedo impulses". The idea seems to be to take the velocity Jacobian and use it to iteratively solve for position correction, even though the position function is non-linear.

 

This is all implemented in Box2D (look at the comments in b2Island.cpp, search for "NGS" which stands for Nonlinear Gauss-Seidel). There should be a lot of discussion on the Bullet forums about this idea too, like this: http://www.bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=6&t=1644

0

Share this post


Link to post
Share on other sites

Okay, that looks not that easy at all... and porting some parts of box2d seems to be stupid.

In the last 3 years i learned a ton about physics and all that stuff, but now its too much for me - and i know box2d or other physics engines do this much better.

 

I give up - i will use jbox2d instead.

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