• 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.

Archived

This topic is now archived and is closed to further replies.

griffenjam

Blending woes

3 posts in this topic

I am using blending but am having some serious problems with a few objects that overlap but shouldn''t be blended. If two things have an alpha value of 1.0f how do I make one simple overlap the other one and not blend? Jason Mickela ICQ : 873518 E-Mail: jmickela@sbcglobal.net ------------------------------ "Evil attacks from all sides but the greatest evil attacks from within." Me ------------------------------
0

Share this post


Link to post
Share on other sites
turn blending off when drawing those objects.

glEnable(GL_BLEND);
glBlendFunc(...);
// draw blended objects

glDisable(GL_BLEND);
// draw non-blended objects

- Mike
0

Share this post


Link to post
Share on other sites
Everybody keeps saying that you should draw the opaque objects first. Then draw the blended objects from furthest to nearest. There''s some kind of logic behind that, but I have no idea what it is.
0

Share this post


Link to post
Share on other sites
Well here''s the procedure:
1) Turn on the depth buffer, depth writes and depth testing. (The latter two are enabled by default if the depth buffer is enabled.)
2) Turn of blending and draw all your opaque objects, preferably in front-to-back order but that''s not necessary.
3) Disable depth writes.
4) Turn on bledning and draw all transparent objects in a back-to-front order. Order is very important here!

Now here''s the logic.
Drawing your opaque objects from front-to-back decreases the amount of unnecessarily rendered pixels. If you render a cube in the background, and then another object in the foreground that obscures it, then you wouldn''t need to draw all those cube pixels.
When blending, we don''t want to write to the depth buffer because transparent pixels should not obscure other pixels entirely. We do keep depth testing enabled because we do want transparent pixels to be obscured by opaque pixels.
The rendering in front-to-back order is necessary for proper blending. If a destination pixel is in front of your pixel to be rendered, you''ll need another blending function than when it''s the other way around. This is not possible in OpenGL in a single pass, so it is better to sort your objects to prevent it from happening.

Did that help?

Dirk =[Scarab]= Gerrits
0

Share this post


Link to post
Share on other sites