Blog

DigitalRune Graphics - WIP (SSAO, Atmospheric Scattering, God Rays)

Nov 15

Written by:
Monday, November 15, 2010  RssIcon


Besides DigitalRune Physics we have been working on DigitalRune Graphics for several month now. I thought it would be nice to use a few graphics effects of DigitalRune Graphics to make our physics demos more interesting. – And here is the result: A short video testing screen space ambient occlusion, an atmospheric scattering skydome and god rays in a simple XNA physics demo. (Implementation details follow after the video.)

Video: DigitalRune Graphics WIP #1

 

Implementation Details

This demo uses only a few features of DigitalRune Graphics, which are described below. I didn’t bother to integrate other features, like HDR, shadows, motion blur, etc., in this demo.

Screen space ambient occlusion (SSAO)

Ambient occlusion is a method to approximate global illumination. Especially in such simple physics demos it helps to improve the perception of depth and spatial proximity. The effect used in the video is a pure post-processing effect. A very good article on SSAO is Shader X7, Chapter 6.1 Screen-Space Ambient Occlusion (link refers to book page on Amazon.com).

Atmospheric Scattering

The colorful skydome is computed using atmospheric scattering on the GPU. Atmospheric scattering is explained in GPU Gems 2, Chapter 16 – Accurate Atmospheric Scattering. Currently, we use this scattering model, but we will investigate other scattering formulas in the future.

Crepuscular Rays (God Rays)

The god ray effect in the video is cranked up to make it very obvious. In games we would prefer a more subtle use ;-). The effect in the video is a post-processing effect, similar to the effect described in GPU Gems 3, Chapter 13 – Volumetric Light Scattering as a Post-Process.


Your name:
Gravatar Preview
Your email:
(Optional) Email used only to show Gravatar.
Your website:
Title:
Comment:
Security Code
CAPTCHA image
Enter the code shown above in the box below
Add Comment   Cancel