• 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
SpectreNectar

Distance to collision in AABB world

1 post in this topic

I'm trying to write a function for my game that returns the distance to the nearest collision along a direction. It is fed the following data:

Vector3D origin (Point to start search from)
Vector3D volume (Halfwidths)
Vector3D direction (Direction to check)

The function iterates over a list of "Areas" that are really just axis aligned boundary boxes and attempts to return a distance in the form of a double.

But now I've gone and stirred myself blind on it and need some help. The approach that first came to my mind was to project the boxes to the direction, and when I realized that wouldn't work I thought I'd store the normals of the iterated boundary boxes somewhere instead and then do a separating axis test, like what is common in 2D.
But then it seems I'd be needing an oriented bounding box test. Is that really necessary? I mean considering the boxes are all aligned.

I'd like to know what the correct way to do this would be? Thank you.
0

Share this post


Link to post
Share on other sites
It'd probably be easier to help you correctly if you gave some context on why you need to find the nearest collision along a direction.

I'm going to assume that you're using this to create a coarse and granualar collision detection check. The coarse check would be to perform a distance calculation (somewhat cheap, even with a square root in there). The granular check would be more expensive because you may have many AABB's to check.

My idea is to use a bounding sphere. The center of the sphere is at the center of your cube volume and the sphere radius is the distance to a corner (so that you cover your farthest point). Now you have two or more bounding spheres and the orientation of your AABB doesn't matter. The calculating distance between the bounding spheres is pretty easy: Just measure the distance between the centers and add both their radiuses to the distance. Loop through every collidable object in your game and store the one with the shortest distance.

It'll be an ugly O(n*n) loop though, so if you start to get a lot of objects and slowdown, watch out.

[code]
foreach(CollidableObject obj1 in CollidableObjects)
{
float shortestDistance = infinity;
foreach(CollidableObject obj2 in CollidableObjects)
{
if(obj1 == obj2) //self reference check
continue;

float Dist = MeasureDistance(obj1, obj2); //<--your function to measure distance

if(Dist < shortestDistance)
{
shortestDistance = Dist;
obj1.NearestObject = obj2;
}
}

}
[/code]

If you do start having a lot of collidable objects in your game and its causing performance problems, look into[url="http://en.wikipedia.org/wiki/Quadtree"] quad trees[/url](2D) or [url="http://en.wikipedia.org/wiki/Octtree"]oct trees[/url](3D). Edited by slayemin
1

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