Simple game engine with complete export to scripting language
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Bullet Continuous Collision Detection and Physics Library
Primary author and maintainer: Erwin Coumans
2007 Aug 15
- fixed bug in Extras/GIMPACT 0.2 related to moving triangle meshes
Thanks Thomas,
2007 Aug 14
- added parallel constraint solver. Works on Playstation 3 Cell SPU and multi core (Win Threads on PC and XBox 360).
See Extras/BulletMultiThreaded for SpuSolverTask subfolder and SpuParallelSolver.cpp
Thanks Marten Svanfeldt (Starbreeze Studios)
- fixed some bugs related to parallel collision detection (Extras/BulletMultiThreaded)
Thanks Marten Svanfeldt (Starbreeze Studios)
2007 Aug 2
- added compound and concave-convex (swapped) case for BulletMultiThreaded collision detection, thanks to Marten Svanfeldt
- refactored broadphase and overlapping pair cache. This allows performance improvement by combining multiple broadphases. This helps add/remove of large batches of objects and large worlds. See also Pierre Terdiman forum topic:
2007 July 27
- added Ragdoll Demo
Thanks to Marten Svanfeldt (Starbreeze Studios)
- added Vector Math library for SIMD 3D graphics linear algebra (vector, matrix, quaternion)
See Bullet/Extras/vectormathlibrary
Supports SIMD SSE, PowerPC PPU and Cell SPU (including PS3 Linux and CellBlade), as well as generic portable scalar version
Will be used to improve BulletMultiThreaded performance
Open Sourced by Sony Computer Entertainment Inc. under the new BSD license
- added SIMD math library
4-way SIMD for common math functions like atan2f4, cosf4, floorf4, fabsf4, rsqrtf4 etc. Used by Vector Math library under PPU and SPU.
Supports PowerPC (PPU) and Cell SPU, including PS3 Linux and CellBlade.
See Bullet/Extras/simdmathlibrary
Open sourced by Sony Computer Entertainment Inc. under the new BSD license
2007 July 25
- added several patches: per-rigidbody sleeping threshold. added Assert to prevent deletion of rigidbody while constraints are still pointing at it
Thanks to Marten Svanfeldt (Starbreeze Studios)
2007 July 13
- fixed relative #include paths again. We can't use "../" relative paths: some compilers choke on it (it causes extreme long paths)
Within the libraries, we always need to start with "BulletCollision/" or "BulletDynamics/ or "LinearMath/"
2007 July 10
- Updated Bullet User Manual
2007 July 5
- added btConeTwistConstraint, especially useful for ragdolls. See Demos/RagdollDemo
Thanks to Marten Svanfeldt (Starbreeze Studios)
2007 June 29
- btHeightfieldTerrainShape: Added heightfield support, with customizations
- Upgraded to GIMPACT 0.2, see Extras/GIMPACT and MovingConcaveDemo
- Several patches from Marten Svanfeldt (Starbreeze Studios)
Improved collision filtering (in broadphase and rigidbody)
Improved debug rendering
Allow to set collision filter group/mask in addRigidBody
2007 June 15
- Changed btAlignedObjectArray to call copy constructor/replacement new for duplication, rather then assignment operator (operator=).
2007 June 11
- Added multi-threading. Originally for Playstation 3 Cell SPU, but the same code can run using Win32 Threads using fake DMA transfers (memcpy)
Libspe2 support for Cell Blade / PS3 Linux is upcoming
See Extras/BulletMultiThreaded. Usage: replace btCollisionDispatcher by btSpuGatheringCollisionDispatcher
- Added managed Bullet library, entirely rewritten in C# for Windows and XBox 360 XNA
See Extras/BulletX
Thanks to KleMiX, aka Vsevolod Klementjev
2007 May 31
- sign-bit went wrong in case of 32-bit broadphase, causing quantization problems.
Thanks DevO for reporting.
2007 May 23
- Fixed quantization problem for planar triangle meshes in btOptimizedBvh
Thanks Phil Knight for reporting and helping to fix this bug.
2007 May 20
- btAxisSweep3: Fixed a bug in btAxisSweep3 (sweep and prune) related to object removal. Only showed up when at least one btStaticPlaneShape was inserted.
Thanks tbp for more details on reproducing case.
- btAxisSweep3: Fixed issue with full 32bit precision btAxisSweep3 (define BP_USE_FIXEDPOINT_INT_32), it used only 0xffff/65536 for quantization instead of full integer space (0xffffffff)
- btRaycastVehicle: Added 'getForwardVector' and getCurrentSpeedKmHour utility functions
- Fixed local scaling issues (btConvexTriangleMeshShape, btBvhTriangleMeshShape, removed scaling from btMatrix3x3).
Thanks Volker for reporting!
- Added second filename search, so that starting BspDemo and ConvexDecompositionDemo from within Visual Studio (without setting the starting path) still works
2007 April 22
- Added braking functionality to btRaycastVehicle
- Removed tons of warnings, under MSVC 2005 compilation in -W4
2007 March 21
- Fixed issues: comma at end of enum causes errors for some compilers
- Fixed initialization bug in LocalRayResult ( m_localShapeInfo(localShapeInfo) )
2007 March 20
- Added refit tree to quantized stackless tree, and updated ConcaveDemo as example.
2007 March 17
- Added constraint solver optimizations, avoiding cross products during iterations, and gather rigidbody/constraint info in contiguous memory (btSolverBody/btSolverConstraint)
- These optimizations don't give large benefit yet, but it has good potential. Turned on by default. Can be switched off using solver->setSolverMode(SOLVER_RANDMIZE_ORDER).
- Enabled anti-jitter for rigid bodies. This is experimental, and can be switched off by setting a global (it is experimental so no proper interface) gJitterVelocityDampingFactor = 1.0;
- Fixed bug in islandmanifold.heapSort(btPersistentManifoldSortPredicate()); , thanks Noehrgel for reporting this (affected Sun Solaris)
2007 March 12
- Added compile-time toggle between on 16-bit and 32-bit fixed-point SAP broadphase.
This allows the number of bodies to exceed 32767
- Enable useQuantizedAabbCompression on btTriangleMesh, see ColladaDemo
2007 March 8
- Fixed bug in constraint/island sorting (caused by replacing STL by dedicated btAlignedObjectArray with heapSort)
Thanks Clemens Unterkofler for pointing this out!
2007 March 6
- removed STL from the Bullet library: replace std::vector by btAlignedObjectArray. Also removed the std::set for overlapping pair set, and turned it into an overlapping pair array. The SAP only adds objects, never removed. Removal is postponed for during traversal of overlapping pairs (duplicates and non-overlapping pairs are removed during that traversal).
- added heap sort and binary search/linear search to btAlignedObjectArray
- fixed wrong cast, thanks Hamstray,
2007 Feb 25
- Improved performance of convex collision shapes, cache local AABB instead of recomputation. This fixes issue with very slow performance in larger .bsp levels
2007 Feb 24
- Added compressed/quantized AABB tree, 16 bytes per node, while supporting 32-bit (triangle) indices.
Should be faster and smaller then original version (quantized aabb check is done in integer space)
Original aabb tree nodes are still supported. They are 44 bytes, with full floating point precision and additional subPart index.
- added meter-unit scaling support in ColladaConverter.cpp
2007 Feb 21
- Build system: updated library names
- Updated EPA comparison integration (missing parameter)
2007 Jan 04
- fixed optimized AABB tree building: in some cases the tree building fails due to unbalanced trees, which generated stack overflow
2006 Dec 15
- added contribution to allow double precision collision detection/dynamics. Define BT_USE_DOUBLE_PRECISION in your project and libraries that include Bullet
2006 Dec 14
- merged contact and non-contact constraint solving into one loop, will improve stability of jointed bodies during collisions
- added first draft for hingeConstraint motor
2006 Dec 8, Erwin Coumans
- preparation for SIMD: added btAlignedAllocator and btAlignedObjectArray, to replace stl std::vector, same interface, but compatible with 16 byte alignment
- cleaned up dependencies in autogenerated msvc projectfiles
- aligned btVector3 on 16 bytes boundary, under win32. see if developers will come up with problems
2006 Dec 04, Erwin Coumans
Added btNearCallback. This is similar to Open Dynamics Engine (ODE) dNearCallback, but important differences:
- contact points are persistent (lifetime more then one frame, for warmstarting/incremental contact point management)
- continuous collision detection, time of impact
Added btRigidBody::isInWorld(), returns true if btRigidBody is inside a btCollisionWorld/btDynamicsWorld derived class
Added angularFactor to btRigidbody, this helps some character control (no angular impulse applied)
2006 Nov 28
Moved StackAlloc from EPA into LinearMath/btStackAlloc
renamed internal class ConcaveShape into btConcaveShape
added btHeightfieldTerrainShape (not completed yet)
2006 Nov 15 Nathanael Presson
Added EPA penetration depth algorithm, Expanding Polytope Algorithm
Added Pierre Terdiman penetration depth comparison/test DEMO
Fixed Bullet's Minkowski sampling penetration depth solver
Contributed by Nathanael Presson
2006 Nov 11 Francisco Le<EFBFBD>n N<EFBFBD>jera
Added GIMPACT trimesh collision detection: concave versus concave,
Contributed by Francisco Le<EFBFBD>n N<EFBFBD>jera
2006 Nov 2
Minor refactoring: btCollisionObject changes from struct into class, added accessor methods
Force use of btMotionState to synchronize graphics transform, disabled old btRigidBody constructor that accepts btTransform
Renamed treshold into threshold throughout the code
2006 Oct 30
Enable decoupling of physics and graphics framerate using interpolation and internal fixed timestep, based on btMotionState
Enabled raycast vehicle demo (still needs tuning)
Refresh contact points, even when they are already persistent.
Fixed debugDraw colors (thanks pc0de for reporting)
Use Dispatcher in ConcaveConvexCollisionAlgorithm (so it uses the registered collision algorithm, not hardcoded convexconcave)
Improved performance of constraint solver by precalculating the cross product/impulse arm
Added collision comparison code: ODE box-box, also sphere-triangle
Added safety check into GJK, and an assert for AABB's that are very large
Fixed kinematic support (deriving velocities for animated objects)
Updated comparison/optional quickstep solver in Extras
UserCollisionAlgorithm demonstrates btTriangleMesh usage (easier trimesh compared to index array version)
Removed scaling from btTransform (we only want to deal with rigid transforms)
2006 Oct 4
Fixed minor leak in btOptimizeBVH
Cleanup of btRigidBody construction
added getW() in btQuaternion
assert when setLinearVelocity is called on btRigidBody
renamed projectfile library from collada-dom to colladadom (to make VC6 happy)
2006 Sept 27
Big Refactoring: renamed and moved files, create a replacement for CcdPhysicsEnvironment/CcdPhysicsController.
All Bullet classes in LinearMath, BulletCollision and BulletDynamics start with bt, and methods start with lowercase.
Moved classes into src folder, which is the only include folder needed.
Added 2 headerfiles in src: btBulletCollisionCommon.h and btBulletDynamicsCommon.h
2006 Sept 23
Fixed 2 bugs, causing crashes when removing objects. Should do better unit-testing. UnionFind and 3D SAP were involved.
2006 Sept 19
Allow programmable friction and contact solver model. User can register their own functions for several interaction types.
Improved performance, and removed hardcoded maximum overlaps (switched from C-array to stl::set)
2006 Sept 16
Added Bullet 2.0 User Manual
Allow registration of custom user collision algorithms
2006 Sept 10
Started cleaning up demos
2006 Sept 4
Fixed concave collision bug (caused instability/missing collisions in meshes/compounds)
Fixed memoryleak in OptimizedBvh, added RayTestSingle to CollisionWorld
Prepared for VehicleDemo
Increased Performance (island generation for sleeping objects took too much time)
Better COLLADA 1.4.1 physics conformance in ColladaDemo
2006 August 11
Added Quake BspDemo
Improved CCD for compound and non-convex objects
2006 August 10
Added per-triangle material (friction/restitution) support for non-convex meshes. See ConcaveDemo for usage.
2006 August 9
Added CMake support (see
This can autogenerate makefiles, projectfiles cross platform (including MacOS X Xcode )
Just run cmake . in the root folder and it will autogenerate build files
2006 July 26 Erwin Coumans
Upgraded to COLLADA-DOM 1.4.1, latest SVN version
ColladaDemo can export snapshots to .dae
2006 July 24 Erwin Coumans
Added Compound CollisionShape support
(this is still low performance -> requires stackless tree-versus-tree traversal for better performance)
2006 July 15 Erwin Coumans
Added initial support for Parallel execution (collision detection, constraint solving)
See ParallelPhysicsEnvironment in Extras\PhysicsInterface\CcdPhysics
2006 July 10 Erwin Coumans
Added MacOS X support (some build issues mainly)
2006 July 5 Erwin Coumans
Improved COLLADA 1.4 physics import, both COLLADA-DOM and FCollada
2006 June 29 Erwin Coumans
Refactoring of the broadphase
Moved some optional files to Extras: Algebraic ccd and EPA, quickstep
Moved the limits on bodies/overlap to 32k and 65k
2006 June 25 Erwin Coumans
Added basic Collision Filtering, during broadphase
Allow adding meshes to the TriangleIndexVertexArray,
(input for TriangleMeshShape)
Preparation for CompoundShape
2006 June 19 Erwin Coumans
Added support for COLLADA Physics Import.
Both jam and Visual Studio can compile ColladaDemo
2006 June 18 Dirk Gregorius <>
Started implementing Generic6DOF joint and setup basic interface
2006 June 17 Frank Richter <>
Bumped version in to 1.5.6 (assuming that "1.5f" is
the next version released).
Updated files in mk/autoconf and mk/jam with copies from CS; fixes a
GLU detection issue on MinGW.
Set msvc/bullet_ico.ico as the default application icon.
Disabled exceptions for gcc builds.
Applied a patch from Michael D. Adams to fix a warning with gcc.
2006 jUNE 16 Erwin Coumans
Constraints now merge simulation islands.
2006 May 24
Improved GJK accuracy, fixed GjkConvexCast issue, thanks to ~MyXa~ for reporting
2006 May 19
Added restitution support
Moved out Friction and Dynamics info from ManifoldPoint (removed logical dependency)
Added a void* m_userPersistentData in ManifoldPoint.
Added a ContactDestroyedCallback, to allow user to handle destruction of m_userPersistentData
2006 May 13
Fixed some bugs in friction / jacobian calculations. Reported by Dirk Gregorius. Thanks!
2006 May 9
Fixed raycasting filtering
Moved repository to SVN at
2006 April 27
Moved raycasting to CollisionWorld, to make it more generic
Added basic CCD option in the CcdCollisionDemo
Fixed 'noResponse' mode, for triggering rigidbodies (useful for Artificial Intelligence queries)
Improved Bullet/ODE sample (in Extras)
2006 April 10
Separating Axis Test (SAT) convex hull collision detector, contribution by Simon Hobbs
Added SIMD SSE Math classes (for above SAT)
Added Mouse picking in CcdPhysicsDemo
Improved penetration depth estimation in MinkowskiPenetrationDepthSolver, both accuracy and performance
Added Hinge constraint
Added quickprof profiling (see )
2006 March 21 Frank Richter <>
Removed VC manifest files.
Removed superfluous "grpplugins" projects.
2006 March 20 Erwin Coumans
Clamped the acculumated impulse rather then intermediate impulse (within the iteration)
Use the persistent contacts for reusing the impulse
Separated friction and normal solving for better stability
Decreased the default number of iterations of the constraint solver from 10 to 4
2006 March 19 Frank Richter <>
Removed a couple of CSisms from the VC projects.
Fixed VC include & lib paths to go to the Addtional* options
instead the command line arguments.
Added pkgconfig support.
2006 March 14 Frank Richter <>
Added support for shipped GLUT on MinGW.
Fixed GLUT support on MinGW.
2006 March 13 Frank Richter <>
Bolted on Jam-based build system.
Generated VC project files.
Fixed GCC warnings.
Fixed Linux build issues.
2006 March 13
Added 3D Sweep and Prune Broadphase Collision Detection, Contribution from Simon Hobbs.
2006 March 2
Minor change in license to ZLib/LibPNG
This makes it legally a bit easier to deploy on Playstation 3
Prepared for more generic constraints, added ConstraintsDemo
2006 Feb 23
Rearranged files and dependencies to allow for easier standalone Collision Detection without Bullet Dynamics.
See Demos/CollisionInterfaceDemo and Extras/ode/ode/test/test_BulletGjk.cpp for examples how to use.
... todo: add history
2003 Initial version (continuous collision detection)