add sphere2.urdf
move btSpatialAlgebra into LinearMath
remove some warnings, introduce BT_ZERO, BT_ONE, BT_HALF as defines for 0.f/0., 1.f/1., 0.5f/0.5 respectively
contact force problems". The solver needs a lot of iterations, before the quality goes up (~ 1000)
Thanks to Gabor PUHR for the contribution!
Improved the btLemkeSolver.
Remove the sparse optimizations from the btMatrixX.h, replace it with explicit call to rowComputeNonZeroElements (only used in the btSolveProjectedGaussSeidel), it was likely slowing things down, without being useful.
Re-enable SIMD in the solver (was accidently disabled in Bullet 2.82 release)
with permission of the original author.
The Lemke implementation is not fully working yet:
1) we need to convert the lo-high LCP problem into a problem without the lo/high
2) we need to sort out the remaining instabilities, and report a failure if the max loopcount is reached etc.
We replaced the fmatvec library with our own LinearMath/btMatrixX.h, and STL std::vector with btAlignedObjectArray
Removed some warnings/potential issues: use fuzzyZero instead of isZero, and some warnings,
related to this issue 756
Added a PGS solver that uses the sparsity of the A matrix, just for testing (the equivalent sequential impulse solver is much faster, not having to allocate the big matrices)
