Todd Vanderlin » research

Keytweeter Keys

Todd Vanderlin — Mon, 23 Nov 2009 02:16:30 +0000

My friend Kyle has a built an app the tweets every 140 charters he types twitter.com/keytweeter. I thought this was interesting so I built an app to pull his twitter down and visualize the most popular key. Unfortunately twitter only allows you to go 3200 tweets back via paging. So the picture about is Kyle’s last 3200 tweets. Looks like E is the popular letter. I could have just wikied it but this was much more fun.

I just ran the app on just numbers interesting results. Its very linear with zero being the most popular.

Normals

Todd Vanderlin — Tue, 22 Sep 2009 23:36:45 +0000

Finally got normals working for the height map. Brad helped me a ton with the math, thanks brad :). After making sure I had the right points its was pretty simple.

Here is an example to calculate normals for a grid in OpenFrameworks. Obviously this can be applied to any other language.

The image above we have four points on a plane. We need three of those points:

ofxVec3f p1(x1, y1, z1);

ofxVec3f p2(x2, y2, z2);

ofxVec3f p3(x3, y3, z3);

We now need a vector from p1 to p2 and p1 to p3.

ofxVec3f v1 = p1 - p2;

ofxVec3f v2 = p1 - p3;

We need the cross product of v1 and v2. This will give us our normal vector. Next we normalize that vector scale it and add p1.

ofxVec3f normalVec = v1.cross(v2);

normalVec.normalize();

normalVec *= 50.0;

normalVec += p1;

Now render from p1 to normal vector.

ofSetColor(255, 0, 0);

glVertex3f(normalVec.x, normalVec.y, normalVec.z);

glVertex3f(p1.x, p1.y, p1.z);

AR Scratching

Todd Vanderlin — Fri, 24 Apr 2009 17:22:39 +0000

I was playing around with some AR markers the other day and came up with this idea. taking just a plain old vinyl record and attaching an AR marker to the label you can track the record in 3D space. The next question was, can you scratch the record? So by figuring out the velocity of the records rotation and applying it to the payback of the audio you can scratch. There is some digital noise that needs to bee worked out, but sounds pretty good. Its still really hard to scratch, it takes some practice but is super fun. The next step is to figure out some nice triggers for different modes. I like the idea of not needing a turntable but the actual spinning of the record helps with the scratching and playback. I made a couple modes, one where the record is paused and you can just scratch through the song. The other looks for zero velocity for x time and then continues on with the song. If there is velocity you then are scratching and the audio is affected. I think that this project has some legs can't wait to play more. more photos

Delaunay Contour

Todd Vanderlin — Sat, 18 Apr 2009 14:53:52 +0000

I wanted to create a shape within the contour so I used delaunay triangulation. This returned all the triangles that build up the convex hull of the points. This was great but I only wanted the triangles inside the contour. Theo gave me a really great inside polygon test which solved this. I made sure that the center of each triangle was inside the contour. I think this will work if I create static shapes that build up the contour. Zach also had a great idea to check to see if the shape is inside the polygon. I could built a contact listener that checks to see if its inside and if so remove.

Contour

Todd Vanderlin — Sat, 18 Apr 2009 04:29:25 +0000

I used box2d to create a shape out of the contour of the body. There are still some some bugs that I’m trying to work out. Initially the shapes were only colliding with the interior of the contour but simple reversing the points solved that. Some shapes are still being push through but I think I have some ideas to solve this, maybe create fixed shapes inside the contour. Despite the somewhat slow playback of the video due to snapzpro the speed is great. More to come.

Mounds

Todd Vanderlin — Wed, 15 Apr 2009 00:46:40 +0000

These are mounds. They wiggle and wobble and don’t like to have things on top of them.

Plants Attack

Todd Vanderlin — Wed, 08 Apr 2009 18:03:41 +0000

Working on some behaviors for plants. When the mouse gets close enough a stem will jump out a take a nibble, then retract for a rest. I want to get the movement a bit more accurate. I’m finding it hard to move objects in box2d without directly changing the position, which then destroys collisions.

Some Plants

Todd Vanderlin — Wed, 08 Apr 2009 03:53:53 +0000

Fluid Arrows

Todd Vanderlin — Tue, 07 Apr 2009 16:30:23 +0000

Some fun fluid arrows

More Creatures

Todd Vanderlin — Sun, 05 Apr 2009 00:43:34 +0000

I’m starting to like the creatures a bit more. I have figure out a way to keep the bodies separated and have them still collide with one another. When they are smaller, some still get a bit tangled. I have been building creature in both Chipmunk and Box2d for comparison. I’m not sure which one I’m going to stick with, I need to do a bit more research.

Scary Vines

Todd Vanderlin — Sat, 04 Apr 2009 02:23:27 +0000

Working on some plant creatures. The vines are built using box2d and springs. They are really flexible but seem to collapse upon eachother, it turns into a mess. I would like to built up the structure of the vines with box2d segments but I can’t figure out a way to build simple lines that change dimensions, go figure. I know that chipmunk can do this but want to figure out a way to do this with box2d.

iPhone Soft bodies

Todd Vanderlin — Mon, 30 Mar 2009 01:01:33 +0000

Now we have soft bodies on the iPhone.

Soft Bodies

Todd Vanderlin — Sun, 29 Mar 2009 18:22:37 +0000

Working on some soft bodies using box2d. They are working well, but sometimes will break when joints cross over. I might be able to add some more cross joints to help keep the shape. They are super fun check out the video.

Project

Todd Vanderlin — Thu, 08 Dec 2005 02:46:42 +0000

coming soon.