Worksheet 4

Introduction

What is the topic and aim of the project?

The topic being looked at for this project is dynamic ambient occlusion in computer games. The aim is to determine the best method for rendering real time AO in a cost effective manner, while at the same time extending it to simulate indirect lighting as well.

  

Issues

What issues do you want to address?

Probably the main issue to look at will be keeping costs down, since the ambient occlusion will be utilised in applications that already have lighting, shadows, dynamic objects and user interaction, it can't have too great an impact on the framerate. But keeping a balance between the efficiency and the quality will also be important - SSAO can produce noisy output which isn't ideal.

Being able to deal with hidden geometry will also be something to adresss, as SSAO doesn't take into account hidden geometry, especially that outside the camera frustrum.

And of course, adding indirect lighting into the ambient occlusion algorithm, so that global illumination can be better approximated. The two things are closely related so it is a logical step.

Research question

What is your current research question?

What are the best solutions to rendering dynamic ambient occlusion in computer games and how can they be improved/expanded upon to better approximate global illumination? 

Addressing the Question

How do you envisage yourself carrying out the project? - a short exposition of the project.

1. I will look at many different variations of the SSAO algorithm to determine the best way to approach the various problems associated with the method. I've found quite a number of papers and resources on the subject - different techniques solve different issues. I will also look at the newer technique of ambient occlusion volumes (AOV) which I recently found on Nvidia's site, as a potential alternative to SSAO. 

2. I will create a 3D application which simulates a game environment, including things such shadows, lighting, dynamic objects and a user controlled camera. Initially I will test a few different methods of AO and then eventually narrow it down to one technique (which may be an amalgamation of more than one method) which I will then attempt to optimise and expand to include indirect lighting. 

3. Performance will be measured - using the frame-rate, how many passes are needed, etc -  with and without the AO in the scene. Graphical quality will need to be measured with the naked eye.    

 Progress

What have you managed to do so far and how has it influenced your vision?

So far it has all been just research. I've been trawling the web and the library for ambient occlusion resources and found quite a lot of research material. I haven't read everything I've found (though I've skimmed through most)...but I have been trying to get through it, and take notes. I've been looking at static ambient occlusion methods as well, so I can get a wider view of the topic and hopefully a fuller understanding of the theories behind it. My vision has been influenced in a small way by some of the things I've found - i.e. the paper on   

SSDO: Approximating Dynamic Global Illumination in Image Space - made me think about expanding AO into indirect lighting, thus changing my RQ slightly.