• 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

I dont understand localspace for a particle?

1 post in this topic

I thought only meshs had a localspace?, how can a particle have a local space?




D3DXMatrixInverse(&mInvWorld, 0, &mWorld);

// Compute the change of coordinates matrix that changes coordinates
    // relative to world space so that they are relative to the particle
    // system's local space.


// Get camera position relative to world space system and make it
    // relative to the particle system's local system.
    D3DXVECTOR3 eyePosW = gCamera->pos();
    D3DXVECTOR3 eyePosL;
    D3DXVec3TransformCoord(&eyePosL, &eyePosW, &mInvWorld);





Share this post

Link to post
Share on other sites
A local space is one that is used as a reference for a given set of co-ordinate tuples, so to say. Whether the given set is a mesh, particle system, single particle, skeleton, bone, parented entity frame, ... is irrelevant for this purpose.

To re-interpret the co-ordinates given in a more-local space to a less-local (a.k.a. more-global) space, you multiply the co-ordinates with the transformation build from the placement of the co-ordinate frame of the more-local space with respect to the more-global space (in the following written for row vectors):
pn-1 := pn * Tn-1
This can be done a step further to the next more-global space
pn-2 := pn-1 * Tn-2 = pn * Tn-1 * Tn-2
up until stopping at a space that is in this sense super-ordinated to all the local spaces; then this one is called the global space (or "world").

This can be done in the other direction, too: You can re-interpret co-ordinates given in some more-global space in a more-local space. This is done by using the inverse transformation, because you just need to invert the equations given above. E.g.
pn-1 = pn * Tn-1 <==> pn-1 * Tn-1-1 = pn * Tn-1 * Tn-1-1
so that
pn = pn-1 * Tn-1-1

Something like that is done in the code snippet shown in the OP: You apply the inverse transformation to the camera's position. Assuming that the camera's position was given in global space before, you re-interpret it now in a local space. From the comments I see that the original transformation is the one that places the particle system in the world. So at the end you have transformed the world position of the camera so that is given now w.r.t. the local space of the particle system.

BTW: Notice please that I've written "re-interpret" above. This is because the "world" doesn't really change due to those transformations. You just alter the way you look at it. Edited by haegarr

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