Search found 42 matches

by melax
Sun May 03, 2015 11:05 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Interaction with Geometry video now public on GDC Vault
Replies: 3
Views: 3323

Interaction with Geometry video now public on GDC Vault

My 2013 Math Tutorial video on GDC Vault is now publicly accessible: http://www.gdcvault.com/play/1017654/Math-for-Game-Programmers-Interaction I suspect most people here on the Bullet Physics forum are probably very competent with math and geometry already. Nonetheless, being the last Math Tutorial...
by melax
Thu Nov 13, 2014 5:11 am
Forum: Physics authoring tools, serialization, standards and related topics
Topic: StanHull convex hull generation
Replies: 4
Views: 16979

Re: StanHull convex hull generation

I recently had a bit of free time between employers to redo the hull implementation. updated code can be found at: https://github.com/melax/sandbox https://github.com/melax/sandbox/blob/master/include/hull.h Algorithmic-wise its the same. The difference is that the code is tighter and style follows ...
by melax
Mon Nov 04, 2013 6:52 am
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: rigid body Rubik's Cube short video
Replies: 2
Views: 3936

rigid body Rubik's Cube short video

Just for fun...

Ever wonder how a game-physics programmer implements a Rubik's Cube app? Grab some popcorn, turn up the sound, and click on the link below:

http://www.youtube.com/watch?v=uo3QrcZlr_E

enjoy :D
by melax
Sat Jun 15, 2013 12:21 am
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Fully Articulated 3D Skeletal Hand Tracking
Replies: 6
Views: 10574

Re: Fully Articulated 3D Skeletal Hand Tracking

Will this 3D skeletal finger tracking be included
Not an officially supported product, but feel free to try:
http://software.intel.com/en-us/article ... al-release
by melax
Sat Feb 16, 2013 10:25 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Fully Articulated 3D Skeletal Hand Tracking
Replies: 6
Views: 10574

Re: Fully Articulated 3D Skeletal Hand Tracking

I'm extremely sorry about that, we were asked to go "dark" for a few weeks. :(
Same links should work then.

stan
by melax
Mon Feb 04, 2013 9:00 am
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Fully Articulated 3D Skeletal Hand Tracking
Replies: 6
Views: 10574

Re: Fully Articulated 3D Skeletal Hand Tracking

Here's a follow-up gameplay concept video I just made showing how hand tracking might be used in a 3D environment:
http://www.youtube.com/watch?v=sAcTshfZCU8

To interact with stuff it uses a typical powered-ragdoll technique, which i'm sure everybody here is quite familiar with.

-stan
by melax
Wed Jan 30, 2013 9:37 pm
Forum: Career Opportunities
Topic: Interaction Developer Position at Intel Perceptual Computing
Replies: 0
Views: 4914

Interaction Developer Position at Intel Perceptual Computing

Greetings, Intel's perceptual computing team is looking to expand. The specific position is for developing user tracking technology and 3D interactive usages based on it. An Ideal candidate would have a strong simulation background. Search for job requisition number 704329 at http://jobs.intel.com T...
by melax
Sat Jan 12, 2013 9:46 am
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Fully Articulated 3D Skeletal Hand Tracking
Replies: 6
Views: 10574

Fully Articulated 3D Skeletal Hand Tracking

I've posted a couple of youtube videos showing markerless hand and finger tracking based on depth sensor data. Here's the link: http://www.youtube.com/watch?v=8ctQm1VOC6M There are a couple of others on the same youtube channel. The tech provides the 6dof pose of all 17 bones in the hand (palm, wris...
by melax
Wed Jun 02, 2010 6:55 pm
Forum: General Bullet Physics Support and Feedback
Topic: need help about "shortestArcQuat"
Replies: 3
Views: 759

Re: need help about "shortestArcQuat"

let's assume theta = the angle between v0 and v1. from s = btSqrt((1.0f + d) * 2.0f), I know s =2*cos(theta/2); so I think rs should be sin(theta/2), rs = sqrt(1-pow(s/2,2)), and last return value should be like [x*sin(theta/2),y*sin(theta/2),z*sin(theta/2),cos(theta/2)]. but why rs = 1.0f/s ;? and...
by melax
Fri May 07, 2010 8:32 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Structual Analysis with Bullet
Replies: 1
Views: 1114

Re: Structual Analysis with Bullet

It sounds like a reasonable idea. The solver of a physics engine iterates until it arrives at an impulse at each contact/constraint/joint that satisfies the system. Simple example... using a simple physics engine, if you look at the contacts at the bottom of a single stack of blocks then you can see...
by melax
Fri May 07, 2010 7:05 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Matrix vs Quaternion
Replies: 4
Views: 3366

Re: Matrix vs Quaternion

Admittedly there are different opinions on the subject: http://www.gamedev.net/reference/articles/article1199.asp :) my 2c: Anything non rendering is pretty much quaternions for me. From an api perspective it might be easier to specify the placement of a joint/constraint with a matrix (such as axis ...
by melax
Tue Apr 08, 2008 9:09 pm
Forum: General Bullet Physics Support and Feedback
Topic: correction to shortestArcQuat
Replies: 5
Views: 1240

Re: correction to shortestArcQuat

Code I sent to Erwin in case anybody is interested. SIMD_FORCE_INLINE btQuaternion shortestArcQuat(const btVector3& v0, const btVector3& v1) // Game Programming Gems 2.10. make sure v0,v1 are normalized { btVector3 c = v0.cross(v1); btScalar d = v0.dot(v1); if (d < -1.0 + SIMD_EPSILON) { extern SIMD...
by melax
Mon Mar 31, 2008 1:15 am
Forum: Physics authoring tools, serialization, standards and related topics
Topic: StanHull convex hull generation
Replies: 4
Views: 16979

Re: StanHull convex hull generation

I will have to let Stan talk for himself about the algorithm he used in his implementation. My primary contribution was packaging of the source code and doing some pre and post-processing cleanup. I initially wrote the code to use in a 3ds max plugin where the artist could select the number of vert...
by melax
Sat Mar 22, 2008 2:02 am
Forum: General Bullet Physics Support and Feedback
Topic: correction to shortestArcQuat
Replies: 5
Views: 1240

correction to shortestArcQuat

Need to make a small correction to the function shortestArcQuat() in bullet. Any math library that has a similar function might want to also ensure the implementation is correct. The problem is in the special case where the two vectors are collinear, but facing opposite directions. Refer to line 003...
by melax
Sun Feb 24, 2008 9:26 pm
Forum: General Bullet Physics Support and Feedback
Topic: Bullet colission with Enviroments
Replies: 6
Views: 3857

Re: Bullet colission with Enviroments

AABB trees can be a suitable option too. Any hierarchical spatial structure can provide log(n) performance for collision queries. The plane shifting bsp traversal was origianlly designed for translational sweep tests. There is some approximation (false positives) in the result since the separating a...