• 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.


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


reflection matrix

3 posts in this topic

Multiply matrices A * B * C * D * E, where each does the following:
A: translate the plane to the origin.
B: rotate the plane to the XY plane.
C: invert the Z coordinate.
D: inverse of matrix B
E: inverse of matrix A

Don''t listen to me. I''ve had too much coffee.

Share this post

Link to post
Share on other sites
If you really want the matrix and not something much simpler described to me here, I can send you scans of my paper on which I developed the said matrices (I''m not going to type them off)

Share this post

Link to post
Share on other sites
If the plane is through the origin the reflection if given by

x'' = x - 2(x.n)n

where n is the unit normal to the plane. This is a linear function of x, so it has a matrix representation,

x'' = Mx

where M is the matrix

( 1 - 2aa, -2ab, -2ac)
( -2ab, 1 - 2bb, -2bc)
( -2ac, -2bc, 1 - 2cc)

where (a, b, c) is the unit vector n, aa = a * a, i.e. ''a'' squared.

This is a 3x3 matrix reflecting in a plane through the origin. Note it is NOT a rotation matrix, so do not try to check it as such. E.g. it''s determinant is not 1 but -1.

If the plane is not through the origin it requires a 4x4 matrix with a translation element. The translation part equals what happens to the origin when reflected, and the origin is reflected though a distance twice it''s distance from the plane along the direction of the plane normal, i.e. just work out the position of the origin after the reflection to complete the matrix.

Share this post

Link to post
Share on other sites