• 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
mv348

Modified stenciled shadow volumes algorithm - any good for gpu implementation?

3 posts in this topic

Hello all,

 

Since I am not working with an artist I get my my models from sites like turbosquid. This being the case I can't really place constraints on my models so I need to use fairly robust techniques.

 

In my last thread, someone suggested an algorithm proposed in this paper for how to create stencil shadow volumes with no constraints placed on the model.

 

The algorithm essentially comes down to first, creating a unique set of triangle-edges, where each edge has a signed counter variable initialized to 0. You create the shadow volume in two steps. First you render the front facing triangles, and while doing so, you either increment or decrement the counter value of its edges based on a certain condition (specifically, based on whether the edge is directed the same as the rendered triangle).

 

After all triangles have been processed, the silohuette edges are rendered based on the value of the counter in each edge object.

 

The  exact details are not so important, my concern is a good GPU implementation. The shader would need to keep a list of counters for each edge and update them per-triangle render. Then process only those edges who's final counter value is non-zero. Since they potentially update the same value counter variable, there could be some bottleneck I think.

 

Is this technique just not practical for GPU optimization?

 

 

1

Share this post


Link to post
Share on other sites

I'm not sure how such an algorithm would work using classic GLSL, since primitive assembly doesn't really share data across invocations--that is, edges are generated for each polygon that uses them; there's no place for a single value to go.

 

That said, I can think of a number of workarounds, that make this nice for GPU computation.

 

The easiest and most obvious thing is to try OpenCL. An OpenCL kernel operating on vertex indices, for example, could atomically update a counter variable for each edge (and you only need process each edge once, too!). This counter can then be stored in an attribute VBO passed to the shader you use to render the data, on a per-vertex basis. It would be easiest to handle edges at the geometry stage.

0

Share this post


Link to post
Share on other sites

Thanks for your reponse, Geometrian!

 

I haven't really had time to dig into OpenCL just yet. So you think this isn't suitable for GLSL?

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