• 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
yonarw

Shadowmapping in Camera-Space

4 posts in this topic

Hello,
while continuing my work on my deferred shader engine I descided to implement a shadowmapping feature.

Here is the process i do for each light that casts shadows:
1. render the scene from light point of view to create depth-shadowmap
2. store modelview and projection matrix
3. draw light to lightmap using g-buffer and shadowmap
3.1 build transformation matrix that goes from cameraspace to light-view-clipping space by using this matrix:
transformation-matrix = light_projection_matrix * light_modelview_matrix * camera_modelview_matrix_inverse
3.2 In the shader: read fragment position from gbuffer, calculate shadowmap_texture_coordinate with:
shadowmap_texture_coordinate = transformation-matrix * gbuffer_pos
3.3 do the is-in-shadow check stuff

I have several problems:
1. The shadowmap_texture_coordinate does not seem to have an orthographic projection. I fixed this by applying this to the shadowmap_texture_coordinate (sc):
sc.xy = sc.xy / sc.z
This is not correct in any way I think but I have no idea what else could cause the projection-bug.

2. When I read from the shadowmap I get values in [0,1]. How do I transform these to compare them with the distance of a fragment from the light-position since those are given in engine-units.

I hope someone will understand what I am doing [img]http://public.gamedev.net//public/style_emoticons/default/biggrin.png[/img] sometimes I'm not sure my self [img]http://public.gamedev.net//public/style_emoticons/default/happy.png[/img]
0

Share this post


Link to post
Share on other sites
When calculating shadowmap coordinates you have to exactly replicate the "light-camera" transformation.
In your case you have to perform perspective division:

Shadow.xyz = shadow.xyz / shadow.w

Then you have to do the viewport transformation to get proper texture coordinates and depth value:

Shadow.xyz = vec3 (0.5, 0.5, 0.5) + 0.5 * shadow.xyz
0

Share this post


Link to post
Share on other sites
Wow thanks that worked!
Now one step further: Is there a more efficient way of rendering a cubemap than rendering all 6 directions seperately ? I found something that uses a geometry shader to render to all 6 faces of the cube at one time but that looks to complicated for me.
0

Share this post


Link to post
Share on other sites
It is possible to use a spherical mapping. That is, drawing only once, but map the sphere onto a quadratic texture. The advantage is that you only need to do one drawing. The advantage is that you don't get the same resolution in the shadow map everywhere. It will have lowest resolution at the equator, and a singularity at the poles. This may be acceptable, depending on your requirements. Search for "spherical shadowmaps" and you will find a lot.

See also [url="http://www.youtube.com/watch?v=WnNOMTDmYTg"]http://www.youtube.com/watch?v=WnNOMTDmYTg[/url] for an illustration and idea how to improve on the singularities at the poles.
0

Share this post


Link to post
Share on other sites
ok, I guess I will be fine with my cube map for now ... with a little bit of optimization it will only draw visible objects for each side of the cube and I share one FBO for the shadow map. Thanks for your help!
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