diff --git a/TODO.md b/TODO.md index 1c1bd97..a8c4c59 100644 --- a/TODO.md +++ b/TODO.md @@ -10,6 +10,14 @@ C++ has many major interesting non standard libs. Google unit test framework: +### Vision + +OpenCV. + +Originally by Intel: + +BSD. + ### Linear algebra #### eigen diff --git a/bullet/README.md b/bullet/README.md index 02e2558..4d8e82d 100644 --- a/bullet/README.md +++ b/bullet/README.md @@ -2,10 +2,12 @@ Tested on Bullet 2.83. -1. [Introduction](introduction.md) -1. [Concepts](concepts.md) -1. [Build](build.md) -1. [Users](users.md) +1. Theory + 1. [Introduction](introduction.md) + 1. [Concepts](concepts.md) + 1. [Build](build.md) + 1. [Source code](source-code.md) + 1. [Users](users.md) 1. Examples 1. [Gravity](gravity.cpp) 1. [Ground ball](ground ball.cpp) diff --git a/bullet/TODO.md b/bullet/TODO.md index ec0efb4..c63f3dd 100644 --- a/bullet/TODO.md +++ b/bullet/TODO.md @@ -1,4 +1,13 @@ # TODO +- detect when objects collide + - http://www.bulletphysics.org/mediawiki-1.5.8/index.php?title=Collision_Callbacks_and_Triggers + - http://stackoverflow.com/questions/9117932/detecting-collisions-with-bullet + - http://gamedev.stackexchange.com/questions/22442/how-get-collision-callback-of-two-specific-objects-using-bullet-physics + - http://www.bulletphysics.org/mediawiki-1.5.8/index.php?title=Collision_Callbacks_and_Triggers +- get object rotation: 3 Euler angles. Attempt made at `gravity.cpp` - Stairs physics: http://gamedev.stackexchange.com/questions/74794/make-the-player-run-onto-stairs-smoothly - Voronoi: https://www.youtube.com/watch?v=FIPu9_OGFgc +- what is the point of motion state? +- substeps vs smaller time step on stepSimulation? +- collision primitives: http://www.bulletphysics.org/mediawiki-1.5.8/index.php?title=Collision_Shapes diff --git a/bullet/gravity.cpp b/bullet/gravity.cpp index 822e59b..b2f39d6 100644 --- a/bullet/gravity.cpp +++ b/bullet/gravity.cpp @@ -9,6 +9,8 @@ A sphere falling infinitely to gravity. #include +#define PRINTF_FLOAT "%7.3f" + constexpr float gravity = -10.0f; constexpr float initialY = 10.0f; constexpr float timeStep = 1.0f / 60.0f; @@ -58,12 +60,15 @@ int main() { } else { trans = obj->getWorldTransform(); } - std::printf("%d %d %7.3f %7.3f %7.3f\n", + btVector3 origin = trans.getOrigin(); + // TODO: how to get numbers out of this? + btQuaternion rotation = trans.getRotation(); + std::printf("%d %d " PRINTF_FLOAT " " PRINTF_FLOAT " " PRINTF_FLOAT "\n", i, j, - float(trans.getOrigin().getX()), - float(trans.getOrigin().getY()), - float(trans.getOrigin().getZ())); + float(origin.getX()), + float(origin.getY()), + float(origin.getZ())); } } diff --git a/bullet/ground_ball.cpp b/bullet/ground_ball.cpp index fe4aa50..8c3f30c 100644 --- a/bullet/ground_ball.cpp +++ b/bullet/ground_ball.cpp @@ -7,6 +7,8 @@ A sphere falling and hitting the ground. #include +#define PRINTF_FLOAT "%7.3f" + constexpr float gravity = -10.0f; constexpr float initialY = 10.0f; constexpr float timeStep = 1.0f / 60.0f; @@ -16,17 +18,49 @@ constexpr float groundRestitution = 0.9f; constexpr float sphereRestitution = 0.9f; constexpr int maxNPoints = 500; +static void myTickCallback(btDynamicsWorld *world, btScalar timeStep) { + bool hadCollision = false; + for (int i = 0; i < numManifolds; i++) { + btPersistentManifold* contactManifold = dynamicsWorld->getDispatcher()->getManifoldByIndexInternal(i); + const btCollisionObject* obA = static_cast(contactManifold->getBody0()); + const btCollisionObject* obB = static_cast(contactManifold->getBody1()); + int numContacts = contactManifold->getNumContacts(); + for (int j = 0; j < numContacts; j++) { + if (!hadCollision) + std::printf("1 "); + hadCollision = true; + btManifoldPoint& pt = contactManifold->getContactPoint(j); + if (pt.getDistance() < 0.0f) { + const btVector3& ptA = pt.getPositionWorldOnA(); + const btVector3& ptB = pt.getPositionWorldOnB(); + const btVector3& normalOnB = pt.m_normalWorldOnB; + std::printf( + PRINTF_FLOAT " " PRINTF_FLOAT " " PRINTF_FLOAT " " + PRINTF_FLOAT " " PRINTF_FLOAT " " PRINTF_FLOAT " " + PRINTF_FLOAT " " PRINTF_FLOAT " " PRINTF_FLOAT " ", + ptA.getX(), ptA.getY(), ptA.getZ(), + ptB.getX(), ptB.getY(), ptB.getZ(), + normalOnB.getX(), normalOnB.getY(), normalOnB.getZ()); + } + } + } + if (!hadCollision) + std::printf("0 "); + puts(""); +} + int main() { int i, j; - btDefaultCollisionConfiguration* collisionConfiguration + btDefaultCollisionConfiguration *collisionConfiguration = new btDefaultCollisionConfiguration(); - btCollisionDispatcher* dispatcher = new btCollisionDispatcher(collisionConfiguration); - btBroadphaseInterface* overlappingPairCache = new btDbvtBroadphase(); + btCollisionDispatcher *dispatcher = new btCollisionDispatcher(collisionConfiguration); + btBroadphaseInterface *overlappingPairCache = new btDbvtBroadphase(); btSequentialImpulseConstraintSolver* solver = new btSequentialImpulseConstraintSolver; - btDiscreteDynamicsWorld* dynamicsWorld = new btDiscreteDynamicsWorld( + btDiscreteDynamicsWorld *dynamicsWorld = new btDiscreteDynamicsWorld( dispatcher, overlappingPairCache, solver, collisionConfiguration); dynamicsWorld->setGravity(btVector3(0, gravity, 0)); + dynamicsWorld->setInternalTickCallback(myTickCallback); btAlignedObjectArray collisionShapes; // Ground. @@ -77,7 +111,7 @@ int main() { } // Main loop. - std::printf("step body x y z\n"); + std::printf("step body x y z collision a b normal\n"); for (i = 0; i < maxNPoints; ++i) { dynamicsWorld->stepSimulation(timeStep, 10); for (j = dynamicsWorld->getNumCollisionObjects() - 1; j >= 0; --j) { @@ -89,12 +123,14 @@ int main() { } else { trans = obj->getWorldTransform(); } - std::printf("%d %d %7.3f %7.3f %7.3f\n", + btVector3 origin = trans.getOrigin(); + std::printf("%d %d " PRINTF_FLOAT " " PRINTF_FLOAT " " PRINTF_FLOAT " ", i, j, - float(trans.getOrigin().getX()), - float(trans.getOrigin().getY()), - float(trans.getOrigin().getZ())); + float(origin.getX()), + float(origin.getY()), + float(origin.getZ())); + int numManifolds = dynamicsWorld->getDispatcher()->getNumManifolds(); } } diff --git a/bullet/ground_ball.gnuplot b/bullet/ground_ball.gnuplot index 189ef35..d121711 100644 --- a/bullet/ground_ball.gnuplot +++ b/bullet/ground_ball.gnuplot @@ -1,3 +1,4 @@ #!/usr/bin/env gnuplot set key autotitle columnheader -plot 'ground_ball.tmp' using 1:($2 == 1 ? $4 : 1/0) +plot 'ground_ball.tmp' using 1:($2 == 1 ? $4 : 1/0), \ + '' using 1:($2 == 1 ? $6 : 1/0) diff --git a/bullet/introduction.md b/bullet/introduction.md index 04c3faf..ac13060 100644 --- a/bullet/introduction.md +++ b/bullet/introduction.md @@ -1,5 +1,11 @@ # Introduction +## Documentation + +Very little besides the Doxygen: + +Good luck. + ## C API Bullet is written in C++, and exposes only a C++ API. diff --git a/bullet/source-code.md b/bullet/source-code.md new file mode 100644 index 0000000..5df75e6 --- /dev/null +++ b/bullet/source-code.md @@ -0,0 +1,8 @@ +# Source code + +## Style + +Bullet is ugly :-) + +- bt hard-coded prefix instead of C++ namespace +- tabs, including in the middle of lines