Hierarchy textures

So, it's been a while. I was so busy at SIGGRAPH that I never had the time to share anything.

In this post, I'm showing you some of the last textures I've been working on. These are build as a hierarchy. We use again our variation of the Voronoi diagram to create weird shapes. But this time, instead of using simply one level, we introduce many levels.

On the first level, again, the Voronoi cells are computed and once we know in which cell we are, if that cell has a sub-level, we can then continue the visit in the structure into that sub-level. Each level has can have a small or big influence on the final color of the pixel.

So, here's some outputs:

One of the first output made. It has two cells on the first level. One is the circle-like shape in the middle and then the rest. In the "rest", there's a sub level with a simple small division of the plane in two.

Exactly as the previous one, but here, there's a sub-level in the circle-like shape. As you can see, the fact that there's a new sub-level only affects the part where that sub-level is.

The actual first output that I got with the hierarchy.

In the next images, I start playing with colors inside the cells. Naturally, all of these images where made from random point distribution.

In these images, I simply played with the hierarchy. Each cell has a random chance to get a sub-level and so on. Until a maximal depth was reached. In some of them, I played also with the feature that at each level, you can influence the final color by accumulating a value.

Finally, there's two big step to do before we consider that project finished. First, we want to investigate various patterns. So, how can we do a particular shape for a cell. For this part, we don't need the hierarchy because we know it works. When we are able to control properly the patterns, we will be able to used them at various level.

Second, we want to be more dynamic for the color. Right now, each cell use a function f:[0;1]->[0;1] to control its value that will influence all the other levels. But those functions are a bit static. I can add more, but it will never be enough. So we turn to use something like the shaders in OpenGL. Literally, each cell could have its own function (coded in CUDA-C) and that function would be used to control the contribution of that cell and its sub-level to the final color of the pixel.

Live Wallpaper (some progress)

So, I progressed a lot in developing my first Live Wallpaper for Android. For now, I call this app "Weird Voronoi" because it uses the concept of the Voronoi diagram with some tweaks to create various visual effects.

I had a bit of difficulties to convert directly my fragment shader used on my machine to a fragment shader that can be used on Android with OpenGL ES 2.0. There's some restriction over the language that requires a certain adaptation. But in the end, the result is mostly the same.

Other problem in development, the emulators available cannot run shaders. So I have to debug completely on my Galaxy S. This mean that I know it's working on my phone, but I don't know about any other. I suspect that any phones more recent than the Galaxy S won't have any problem running it.

For now, in the project, I made the majority of the test I wanted to do. To see what are the limits. And actually, compared to a desktop, it's very limited. On my phone, running more than 4 points can be tricky while on the desktop, hundred points is not really a problem. So the objective was also to use this limited amount of points to be able to create some nice effect and I think I managed to do this.

Here's a first images of what the Live Wallpaper will look like:

I took this images from an app I'm developing on my desktop, but the visual effect is mostly the same.

Now that I know the limitation and the possibilities, the main thing left to be able to produce a first version to put on the Android Market is the settings to control the Live Wallpaper.

For now, the common options would be to choose the number of points. Even if 4 on my phone is the limit, there's some benchmark showing that some phones might be able to handle 16 points without a problem. The users will be able to choose if the points are moving, and at which speed. Same thing of the spirals (or if they want a spiral or not).

A variety of functions will be available to choose the right distribution of color. And the possibility to choose between a colored version or a gray scale version.

When the app will be available on the Market, I will give more detail about the features.

Meanwhile, I might post other images of other functions to show other visual effects.