I recently got a job at Crytek, Seoul office as a License Support Engineer.

In the first release of project Allure, a sample add-in application named ‘OpenAll’ is included.

That add-in does a simple thing. When executed, it automatically parse the current solution and list all file items in that solution.
Then, user can type some partial words and filtered list of files that contains those words is shown in the list view.
By double-clicking a file or selecting with arrow-keys, that selected file is just opened by VisualStudio.
For more convenience, you can assign a keyboard shortcut for this add-in.

To download, go to http://allure.codeplex.com.

Nowadays I’m designing a new programming model of Tomato.Graphics to facilitate more features and functionalities from Direct3D 10. 

I’m struggling not to lose the goal of providing an unified programming model, and to achieve that, dramatic changes are being made to interfaces of Tomato.Graphics.

After this refactoring is done, I’m planning to implement some of my ideas on point-based rendering  exploiting the Direct3D 10 features.

Point-based rendering, as the name implies, is to visualize objects using point primitives instead of polygonal primitives such as triangles. This idea of using points as rendering primitive was first suggested by Marc Levoy and Turner Whitted in 1985 (You can find its abstract and the full paper at here). And afterward, a novel technique named QSplat was introduced by Szymon Rusinkiewicz and Marc Levoy in 2000, and that ignited a fire on this subject.

At this point, we should ask ourselves, ‘why do we need alternate primitives other than triangle?’ We can find a good answer for this question here in QSplat paper abstraction.

Advances in 3D scanning technologies have enabled the practical creation of meshes with hundreds of millions of polygons. Traditional algorithms for display, simplification, and progressive transmission of meshes are impractical for data sets of this size.

I think the most important motive of point primtives is an enormous quantity of newly acquired data in practice (due to its increased volume and accuracy). We can think of the simplest case, where more than hundreds of millions of primitives, in a single rendering frame, are projected onto a screen of limited pixel resolution such as 800 by 600. In such a scene, most single primitive will contribute to a single pixel (or to even smaller) in the final displayed image. And that means, triangle primitives are not a good choice then. Anyway, to avoid some redundancies such as triangular-setup stage required for rendering triangular polygon meshes, we can choose points as our rendering primitives.

After the advent of QSplat, many researchers have rushed into this field (I was one of them ),  and more sophisticated and improved techniques were introduced. Surface splatting techniques using EWA (elliptical weighted average) filter provided very high quality anti-aliased images [web site]. And others have focused on exploiting the programmable graphics pipeline. Sequential point trees technique is one of them. They proposed an innovative method of serializing the whole point hierarchy into graphics memory, and then the GPU by itself can apply a level of detail of the object on the fly [full paper].

In 2005, Mario Botsch et al. proposed more advanced GPU technique in their paper, and later they improved their own algorithm using deferred shading technique. Their algorithm was an application of the Phong shading and deferred shading technique (commonly used in polygonal rendering techniques). And, by exploiting the GPU power, they could achieve both high-quality image and the real-time frame rates at the same time.

Undoubtedly, there were many researches on point-based modelling (such as MLS surface technique) as well, and more advanced rendering techniques (including Pajarola’s) . For those techniques, I will continue on the next post on point-based rendering. Thanks.

Lately I had a wierd problem when working with .NET interop. Whenever I tried to load a native .dll file which is located in exactly the same folder as the executive file, ‘DllNotFoundException’ was thrown.

In the end, using Process Monitor (from SysInternals), I could find what real problem was. While loading up that native .dll file, it again tried to load another dependent .dll files, and that other .dll file couldn’t be found by the system.

So, after copying all .dll files required, the problem could be fixed.

For a  m by n matrix A with rank of r, the number of solutions for linear system of Ax = b is 

1. r < m and r < n
   The number of solutions is 0 or infinite.
2. r = m < n
   The number of solutions is 1 or infinite. (The solution EXISTs.)
3. r = n < m
   The number of solution is 0 or 1. (The solution is  UNIQUE if exists.)
4. r = m = n
   The number of solutions always 1. (INVERTIBLE case.) 

I’ve been a big fan of Gilbert Strang, MIT professor, after buying his math book, Linear algebra and its applications.

You can see his video lectures on elementrary linear algebra course on MIT’s open courseware site.
http://ocw.mit.edu/OcwWeb/Mathematics/18-06Spring-2005/CourseHome/

Last week I’ve just started an open source project named Tomato at CodePlex.

Actually the project was started 3~4 years ago, and at that time I named it a ‘MassiveRender’. It was just a 3D rendering application to conduct some experiments for my point-based rendering research. That application was based on Managed DirectX, and up until now the whole project is still .NET based. As I maintain the project, I decided to develop more generic and powerful graphics rendering engine, and that’s how the project ‘Tomato’ started.

The project is designed with some goals in mind.

• Scientific visualization: some geometrical algorithms including the principal component analysis and moving least squares will be provided for scientific applications.
• Multi-platform: though the current version provides Direct3D9 implementation only, but the overall architecture is designed completely abstracted from the lower-level  layers so that other graphics platforms including Direct3D10 (and XNA possibly) can be provided in the future.
• Flexible rendering passes: renderer can rearrange its rendering passes at run-time. That means one can add a new rendering pass between the passes, or exchange two, all actions on the fly. Furthermore, I’m considering adding more flexibilities such as run-time shader composition.

For now, I’m still having some problems in the current implementation, but those will be fixed soon.

Optimizing GPU Volume Rendering by D. Ruijters and A. Vilanova

Transform Coding for Hardware-Accelerated Volume Rendering

Scalable Hybrid Unstructured and Structured Grid Raycasting

Acceleration of direct volume rendering with programmable graphics hardware

Style Transfer Functions for Illustrative Volume Rendering