• 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
destructivArts

QuadTree traversal

1 post in this topic

Let me preface this by saying that I have never used data trees before so everything I'm saying here is all self taught and google researched over the last week.

Ok with that out of the way:

I have a quad tree set up for my side scrolling game. Each node has two array lists (they are array lists for convenience, they never get to have more than four members), one for data and one for children nodes.

I pass the root node entities (the data) and based on their x and y positions, it passes it to it's children, who pass it to their children and so on, until it is at a leaf node where it is either placed into the nodes data list, or, if the list is full (4 entities), the node is given four children and all 5 entities (original 4 plus the new one) are passed to its children.

My problem now is how do I go through and get them back when I want to use them?
All the traversal algorithms I've seen have given me all the nodes, but I only need the leaf nodes.
In addition, I really only need certain nodes based on which node the player is in.

Any help on this would be very welcome,
Thanks,
Peter
0

Share this post


Link to post
Share on other sites
If you have an algorithm that returns all nodes in the quadtree using recursion, all you have to do is check if a child node is contained in/intersected by the area you want to retrieve entities from. If it is not, you can ignore that entire branch of the tree. Something along the lines of this should work.

[CODE]
getEntitiesInRectangle(Node node, Rectangle rect, List output)
if node is leaf:
for every entity e in node:
if rect contains/intersects e: add e to output;
else
for every child n in node:
if rect contains/intersects n:
call getEntitiesInRectangle(n, rect, output)
[/CODE] Edited by lwm
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