Rust teaser (sort of) Part II

So my initial plan with the clip I posted last week was just to record a short sequence of the character I've been working on walking around, with everything lit by light volumes, and then do a write up on what had gone into making the sequence. I ended up getting carried away with the sequence and ran out of time so here's the write up!

Main Character

I've made some good progress on the main character but there's still a fair bit to do. I'd say the model is mostly done but the texture still needs work. Areas like the straps, hands and head haven't really been worked on yet so the texture you see here is pretty much a test run.

Still, I like where it's headed and it's been great to get a more complex model in to replace the robot I'd previously been using.

I thought I'd include an offline render of the high poly model as well (right). I haven't done much high poly character work to date so there's definitely been a learning curve but I'm happy with how the model is evolving.

Fun with deferred light types

I'd always planned for the character to wear some sort of light source and for lots of reasons but primarily it just looks cool. It's hard to think of a sci-fi film where the suits don't have some sort of moody light source (often blue) located just under the actors jawline so I wasn't about to buck the tradition :)

I wanted the light source to realistically illuminate both the character and the environment but it was hard to get both those properties without resorting to shadow maps. I thought I'd approach it slightly differently so I ended up using a single light source with two falloff factors (left). An omni directional, short range falloff provides local lighting to the character without affecting areas it shouldn't (like the opposite side of the body) whilst a hemispherical , medium range falloff illuminates the nearby environment.

Post Process Colour Correction

This has been on my list of things to try out for quite a while now so it was great to finally get it implemented. There aren't many resources on how this should be done but I think that's mostly due to it being quite a straightforward process. Using a pixels RGB value as a texture coordinate you simply sample a 3D texture containing the colour correction information. The image shows a few examples.

This opens up a massive range of colour correction options and any number of software packages can be used to create the 3D look up textures, often referred to as LUTs. The process is largely the same regardless of the software used and involves colour shifting both a reference image (usually an uncorrected screenshot of the game) and a flattened version of the LUT. The altered LUT is then sampled at runtime, reproducing the colour alterations made to the reference image. Below you can see how the sequence looked before and after colour correction with the flattened LUTs as overlays.

That's all folks

To wrap up I thought I'd post some un-textured shots of the scene as they always do a good job of showing off the lighting volumes.

Rust teaser (sort of)

Okay so this isn't really a teaser, think of it more as a mood and lighting test maybe :)  I'd initially just wanted a video of the starman character walking around a simple scene but I ended up getting carried away. The scene is loosely based on an existing piece of Tadao Ando architecture and not really indicative of where the project is heading, environment wise at least. The video was captured straight from the engine so editing aside I haven't done any additional post processing on the frames.

The audio samples used are by ERH and were obtained from the Freesound Project. The samples are used under the Creative Commons Sampling Plus 1.0 licence.

Anti aliasing

I've wanted to implement  some form of anti aliasing for a while now so I took a break from playing through the recent Humble Indie Bundle and looked into it. There are several different options when it comes to AA in deferred rendering so I've started with what seemed to be the easiest. The method I've used here is the one outlined in GPU Gems: Deferred Shading in Tabula Rasa and I haven't really deviated from that article with regards to AA.

I also took the opportunity to look into applying a post process sharpen to the overall image. The method is known as unsharp masking and it's an effect a lot of digital artists use to spruce up their images. It goes back further actually and I was surprised to learn that the technique was pioneered in conventional photographic darkrooms.

You can see some examples of AA and unsharp masking below. Be sure to view them full screen without any scaling as the difference is hard to spot when the images are down sampled. In some areas the sharpen effect over sharpens fine details and increases the aliasing problem although for the most part the effect is an improvement.

Fullscreen examples (click for larger versions)

With AA

No AA

With AA

No AA

With AA

No AA

Well that was fun, back to playing Cortex Command... sniping the engines off drop ships never get's boring ;)

Concept Art - Starman

It's concept time again :) This time around it's a concept for Rusts protagonist who for now I'm just calling the Starman. This is my second attempt at the character, you can (sort of) see the first version in this concept. That version was more futuristic looking but I like the lo-fi direction this is heading in, if you can call a space suit lo-fi!

Like most of the concepts I've posted so far I started out with a 3D render, which you can see below. I often find this to be the fastest way to work as it gives you a very solid base to start from.

SSAO

I recently decided it was time to take another look at SSAO as it's a technique that should complement lighting volumes quite well. Due to their sparse nature lighting volumes don't provide mid/high frequency lighting detail so SSAO should help add some of that lost lighting detail back into the scene.

There's already been a heck of a lot written about SSAO and I don't have much more to add so my plan is to keep this post fairly brief. My first implementation attempts were several years ago now and although the results were okay the shaders were pretty complicated. They often involved sampling both normal and depth buffers, reconstructing 3D positions and also required lots of per pixel matrix multiplications. The technique shown here only requires a depth buffer and is quite straight forward to implement. You can read all about it in Rendering techniques in Toy Story III on the Advances in Real-Time Rendering in 3D Graphics and Games  SIGGRAPH 2010 page.

For these shots I'm using a total of 32 SSAO samples per pixel. If that gets to be too much of a frame rate killer I can dial it back but for now it's looking pretty good. The SSAO only affects the ambient light provided by the light volume, direct light remains unaffected.

Isolated SSAO

SSAO with light volumes

Full lighting with textures

The original museum model, complete with some awesome dinosaur skeletons which aren't featured here, was built by Alvaro Luna Bautista and Joel Anderson and can be found at http://www.3drender.com/challenges/. I also used some textures from the crytek sponza scene which you can grab here http://www.crytek.com/cryengine/cryengine3/downloads.