You can't help but want to make a 2d overhead or isometric game after looking at some of the art available on OpenGameArt- I'll settle for a little procedural terrain generation:

http://www.openprocessing.org/visuals/?visualID=16704 (click run if it asks about running old java)

The OGA site could use more contributors, as well as better organization to promote the best work- and of course it could be popularized by making use of the content there. I think I'll use this and some variations at the next VJ event I do- I've used recorded video from games before, but even better to generate some game-like imagery live.

Another useful feature would be for terrain tilesets to have a standard connectivity definition file- an ascii file that says which tiles connect best to which neighbors in which direction. Current that's hardcoded into the processing sketch.


Gephex 0.4.3b built on 64-bit Ubuntu 10.10

I haven't found a better graph-based VJ tool than Gephex to use in Linux or Windows (but haven't been looking much either), and it's not trivial to get it running on a modern Ubuntu system- but I've worked through all the compiler messages (with the big exception of leaving out ffmpeg) and have an archive of the results available for download.

Go here for details and a link to the download:


The reconfiguring may screw it up a little, otherwise let it install to my choice of directories and then move the bin and lib etc. files as appropriate.

I'm hoping there is a new and well-supported tool out there that can take the place of gephex- movid is not intended for VJ work but may be retrofittable.


First Steps in Bullet physics

I've played with ODE for several small projects, but recently discovered Bullet physics while looking through ROS (Robot Operating System) documentation. The difference in rigid body simulation between the two is not that obvious, the Bullet rigid body demos seem very impressive and perhaps speedier than ODE. But the soft body physics have no equivalent in ODE, and seem very worthy of investigation- and equally intriguing are the decomposition capabilities, where objects can be shattered into smaller pieces with a function call (it may be more difficult than that, I haven't looked at the code yet).

There is a good forum, not a ton of documentation or second-party dispersed know-how in the form of tutorials especially for the soft body physic, but the demo code is great- and beyond that it comes down to experimentation.

Soft bodies from 3d files

A long time ago I made my own soft body physics simulation code where I would load an .obj file and replace all vertex edges with spring-dampers, and also create a grid of internal springs to give the body volume. It worked okay in the best conditions but would frequently explode in others. Now in bullet there is a toolchain to take a 3d object and turn it volumetric, and then simulate much more robustly than in my amateur effort (though explosions still can occur).

The bunny.inl and cube.inl files in Demos/SoftDemo provide the first clues, they have auto-generated comments like '# Generated by tetgen -YY bunny.smesh'.

Installation of tools

Tetgen is in the Ubuntu repositories, but tetview has to be downloaded as a binary. libg2c isn't in Ubuntu 10.04 lucid lynx, I had to download prebuilt version here http://www.fluvial.ch/d/libg2c.tgz , and also libstdc++.so.5 from http://packages.debian.org/lenny/i386/libstdc++5/download (extract with dpkg-deb file.deb .).

Wings3D is a good program for generating 3d meshes, and is in Ubuntu repositories.

The stl it exports in binary and doesn't work for tetgen ("wrong number of vertices"), use meshlab (also in ubuntu repos) to save it as an stl but uncheck binary. Objects with holes in them didn't work right, tetview kind of locks up on them. Concave areas don't seem quite right either.

I used 'tetgen -p file.stl' and it outputs file.1.ele, file.1.face, file.1.node, and file.1.smesh. 'tetview file.1' will view the output. In the bunny.inl file there is a getElements() and getNodes() function, the data there corresponds to the lists in file.1.ele and file.1.node. Cut and paste the lists into the functions, then use a text editor to put the quotes and line breaks in as seen in bunny.inl.

On trying to use the inl in SoftDemo I get this error
*** glibc detected *** ./AppSoftBodyDemo: malloc(): memory corruption: 0x090f5c38 ***
======= Backtrace: =========

Building the debug version helps out (cmake -DCMAKE_BUILD_TYPE=debug), but I haven't been able to figure it out yet.

Here is the backtrace:

Program received signal SIGABRT, Aborted.
0x0012d422 in __kernel_vsyscall ()
(gdb) bt
#0 0x0012d422 in __kernel_vsyscall ()
#1 0x003ff651 in raise () from /lib/tls/i686/cmov/libc.so.6
#2 0x00402a82 in abort () from /lib/tls/i686/cmov/libc.so.6
#3 0x0043649d in ?? () from /lib/tls/i686/cmov/libc.so.6
#4 0x00440591 in ?? () from /lib/tls/i686/cmov/libc.so.6
#5 0x00443395 in ?? () from /lib/tls/i686/cmov/libc.so.6
#6 0x00444f9c in malloc () from /lib/tls/i686/cmov/libc.so.6
#7 0x08157d51 in btAllocDefault (size=1195)
at /home/bm/other/bullet-2.77/src/LinearMath/btAlignedAllocator.cpp:24
#8 0x08157e6f in btAlignedAllocInternal (size=1176, alignment=16)
at /home/bm/other/bullet-2.77/src/LinearMath/btAlignedAllocator.cpp:170
#9 0x080b4803 in btCollisionObject::operator new (sizeInBytes=1176)
at /home/bm/other/bullet-2.77/src/BulletCollision/CollisionDispatch/btCollisionObject.h:115
#10 0x080e9e85 in btSoftBodyHelpers::CreateFromTetGenData (worldInfo=...,
ele=0x81707e4 "48 4 0\n 1 26 28 16 12\n 2 28 21 16 12\n 3 25 19 2 20\n 4 28 27 10 14\n 5 17 3 20 1\n 6 20 24 18 19"...,
face=0x0, node=0x81707bb "# Generated by tetgen -YY test.1.smesh \n",
bfacelinks=false, btetralinks=true, bfacesfromtetras=true)
at /home/bm/other/bullet-2.77/src/BulletSoftBody/btSoftBodyHelpers.cpp:957
#11 0x080b0bc5 in Init_TetraCube (pdemo=0x8309c60)
---Type to continue, or q to quit---
at /home/bm/other/bullet-2.77/Demos/SoftDemo/SoftDemo.cpp:1315
#12 0x080b122c in SoftDemo::clientResetScene (this=0x8309c60)
at /home/bm/other/bullet-2.77/Demos/SoftDemo/SoftDemo.cpp:1451
#13 0x080b383f in SoftDemo::initPhysics (this=0x8309c60)
at /home/bm/other/bullet-2.77/Demos/SoftDemo/SoftDemo.cpp:1849
#14 0x080a5b90 in main (argc=1, argv=0xbffff384)
at /home/bm/other/bullet-2.77/Demos/SoftDemo/main.cpp:28

I put the question to the forum here but no responses- not many people are that adept at the soft body physics yet.

Something functional

But I've been able to create a trivial example from scratch that works:

static const char* getNodes() { return(
"8 3 0 0\n"
" 0 1 1 1\n"
" 1 1 1 -1\n"
" 2 1 -1 -1\n"
" 3 1 -1 1\n"
" 4 -1 -1 1\n"
" 5 -1 1 1\n"
" 6 -1 1 -1\n"
" 7 -1 -1 -1\n"
"# \n"); }

static const char* getElements() { return(
"4 4 0\n"
" 0 0 1 3 5\n"
" 1 4 7 5 3\n"
" 2 6 5 1 7\n"
" 3 2 1 7 3\n"
"# \n"); }

Maybe I should try to corrupt the above into provoking the same kind of crash?

Update- Solution Found

tetgen by default is creating 1-based vertex indices, while Bullet is expecting 0-based indices- the -z flag will make tetgen output zero-based. So no more crashing.

Bullet Soft Body Physics from binarymillenium on Vimeo.


Bundler on 64-bit Ubuntu 9.10

It builds fine, but seg faults when run:

[KeyMatchFull] Matching to image 312
[KeyMatchFull] Matching took 71.610s
[KeyMatchFull] Matching to image 313
[KeyMatchFull] Matching took 69.720s
mkdir: cannot create directory `bundle': File exists
[- Running Bundler -]
/home/binarymillenium/bundler-v0.3-source/RunBundler.sh: line 93: 22589 Segmentation fault $BUNDLER list.txt --options_file options.txt › bundle/out
[- Done -]

Program received signal SIGSEGV, Segmentation fault.
0x0000000000522650 in dscal_ ()
(gdb) bt
#0 0x0000000000522650 in dscal_ ()
#1 0x0000000000519d16 in dsytf2_ ()
#2 0x00000000004e9644 in dsytrf_ ()
#3 0x00000000004a6d99 in sba_symat_invert_BK ()
#4 0x00000000004a05ec in sba_motstr_levmar_x ()
#5 0x000000000049d058 in sba_motstr_levmar ()
#6 0x000000000049ae8e in run_sfm ()
#7 0x0000000000415e06 in BundlerApp::RunSFM(int, int, int, bool, camera_params_t*, v3_t*, int*, v3_t*, std::vector‹std::vector‹std::pair‹int, int›, std::allocator‹std::pair‹int, int› › ›, std::allocator‹std::vector‹std::pair‹int, int›, std::allocator‹std::pair‹int, int› › › › ›&, double, double*, double*, double*, double*, bool) ()
#8 0x000000000042a16e in BundlerApp::BundleAdjustFast() ()
#9 0x0000000000405c33 in BundlerApp::OnInit() ()
#10 0x0000000000406f77 in main ()

I'll update this post with results of trying out the 32-bit binaries, and also trying to build it on 64-bit with 32-bit compilation.


There needs to be better buzz blogger integration

The generic rss import gadget sort of works, but the rss headlines of buzz are really useless, only saying that there is a new buzz from username- they should have the first sentence at least of a buzz item:


Xbox Project Natal - Estimated Specs

This video went up yesterday, was pulled down and then restored later for some reason (not before other youtube users posted their own copies and gathered many more views than the official channel)

The video states 30Hz, and there is an interesting shot starting at two minutes.

From the above screenshots it's possible to count the number of pixels horizontally and vertically, and also most of the depth bins (there may be more range beyond the wall behind the person but a minimum count is better than nothing).

So there at least 18 depth bins, counted at 2:01-2:04 in the video. Each is maybe 2 or3 inches spaced.

The resolution looks like 64x64.


Structured Light For 3d Scanning

I learned a little about structured light from the 2008 House of Cards Radiohead video and more since Kyle McDonald created an open source google code implementation- but only very recently really gotten into how it works.

Simulated Structured Light

I had trouble getting good scans initially and I thought it would be good to create a perfectly controlled setup that didn't require a projector or camera- instead generate scenes from software, projecting textures onto 3d objects.

One of the generated input phase images:

Output from the google code ThreePhase processing app:

The obvious improvement is to add in an obj loader to this program, instead of just generating a semi-random blobby shape.

Real World Scans

I was hoping for a lot more but managed to get a few scans of people during a New Year's Eve party:

From 2009.12.31_nextyear

From 2009.12.31_nextyear

From 2009.12.31_nextyear

Those were all made using modified versions of Kyle McDonald's slDecode and slCapture programs. I'll post those somewhere eventually.

Matlab Script

This script is currently very very slow, but it's good to be able to debug in matlab and have easy access to fft and other functions.

Wrapped phase:

Unwrapped phase:

Note the vertical lines where phase propagates vertically in glitchy ways- some filtering (and even slower processing time) ought to be able to clean that during the flood fill.


I hope to go mainly in the direction of high resolution high fidelity scans, as opposed to high frame-rate low sample-time scans, though I think I can access several high frame rate cameras for use in the latter. There is also lots of room for improvements (especially at the phase unwrapping stage) that would benefit either one of those.