Bullet 2.47 released, small constraint solver optimizations

[Erwin Coumans]

Bullet 2.47 is available.

Constraint solver has been optimized with a second path. Avoiding cross products during the iterations and gathering rigid body information into contiguous memory are the main changes. No huge benefits yet, but a good step in the right direction.

It can be disabled by removing 'SOLVER_CACHE_FRIENDLY' from

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solver->setSolverMode(SOLVER_RANDMIZE_ORDER | SOLVER_CACHE_FRIENDLY)

Another stability fix is enabled, that adds some damping for rigid bodies with linear/angular velocity below a treshold. This heuristic is experimental, and can be disabled using

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gJitterVelocityDampingFactor = 0.f;

No proper API for this, as it is experimental.

Enjoy,
Erwin

[Codepoet]

Hi!

Compilation fails on linux / systems with case sensitive file names:
Rename
src/BulletDynamics/ConstraintSolver/btsolverbody.h to btSolverBody.h
src/BulletDynamics/ConstraintSolver/btsolverconstraint.h to btSolverConstraint.h

[Hamstray]

is it just me or did setAngularFactor(0.0) become ineffective?

[Erwin Coumans]

Codepoet, compiler issues have been solved in Bullet 2.48a.

Some features like setAngularFactor, and custom friction model callbacks don't work yet with the 'cache friendly' solver mode.

But you can switch to original (non-cache-friendly) solver mode, and then it should works again:

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btSequentialImpulseConstraintSolver* solver = new btSequentialImpulseConstraintSolver;
//default solverMode is  SOLVER_CACHE_FRIENDLY and SOLVER_RANDMIZE_ORDER.

//Switch back to original solver (non-cache friendly):

solver->setSolverMode(btSequentialImpulseConstraintSolver::SOLVER_RANDMIZE_ORDER);

Hope this helps,
Erwin