• 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
ATC

Different approach to "Camera" design?

2 posts in this topic

I was just considering what the implications of a different approach to designing a camera base class might be...

[source lang="csharp"]
// Traditional approach ::
class CameraTraditional
{
public Vector3 Up { get; set; }

public Vector3 Target { get; set; }

public Vector3 Position { get; set; }
};

// A different approach ::
class CameraDifferent
{
public Vector3 Position { get; set; }

public Quaternion Orientation { get; set; }
};
[/source]

The pseudo-code example says it all... Normally, we implement a "camera" object with the properties "Up", "Target" and "Position" for creating a view matrix. But what if we toss that notion out and go with something more akin to any other 3D game entity, which has a "Position" and "Orientation" rather than calculating everything in terms of what direction is up and where the target is...?

What problems might this pose in game design? What advantages might it have? I was just curious about this idea so figured I'd ask...

Regards,

--ATC--

EDIT:

Also, what is the easiest way to decompose a projection matrix to retrieve the fov, aspect ratio and near/far clipping planes? Edited by ATC
0

Share this post


Link to post
Share on other sites
To construct a view matrix you'll always require those three vectors, but you could very well construct them each frame by transforming the local unit axes for the camera by the orientation quaternion. There's no real gain in the method you proposed except for the fact that you use a little less memory in only storing a 3-vector and a quaternion instead of 3 3-vectors.

If I remember correctly a left-handed perspective projection matrix is laid out like this (don't shoot me if I get something wrong here):

X 0 0 0
0 Y 0 0
0 0 Z 1
0 0 W 0

Y = 1.0 / (tan(field_of_view*0.5))
X = Y / aspect_ratio
Z = far_value/(far_value - near_value)
W = -(near_value * far_value)/(far_value - near_value)

Extracting the field of view and aspect ratio is quite trivial, extracting near and far values might require some trickery (almost 3AM here, not in a mood to solve this now)
0

Share this post


Link to post
Share on other sites
I am usually constructing my cameras the second way - although instead of position + quaternion I use full matrix.

The motivation behind it is that now camera is completely "normal" 3D object (scenenode or whatever) and you can use all your standard object transformation and query methods on it. It has bounding box too - it is just the bbox of projection frustum.
Specific camera controllers are built on top of this basic camera and are modifying directly the camera matrix.

Of course in that case you will want to write handful of convenience methods to rotate your camera around target, query position and orientation etc.
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