HelloWorld
自由落下のサンプル
ヘッダの読み込み
#include <BulletDynamics/btBulletDynamicsCommon.h> #include <stdio.h>
main関数始まります
int main(int argc, char** argv) { int i;
世界(World)の設定の前準備
///衝突設定はデフォルト、自分で設定することもできる btDefaultCollisionConfiguration* collisionConfiguration = new btDefaultCollisionConfiguration(); ///衝突計算のディスパッチャー // 他のディスパッチャーを用いて並列計算することもできるよ (Extras/BulletMultiThreaded 見てね) btCollisionDispatcher* dispatcher = new btCollisionDispatcher(collisionConfiguration); ///btDbvtBroadphase is a good general purpose broadphase. You can also try out btAxis3Sweep. btBroadphaseInterface* overlappingPairCache = new btDbvtBroadphase(); ///the default constraint solver // 他のソルバーを用いて並列計算することもできるよ (Extras/BulletMultiThreaded 見てね) btSequentialImpulseConstraintSolver* solver = new btSequentialImpulseConstraintSolver; //上記の設定を用いて、世界を作成 btDiscreteDynamicsWorld* dynamicsWorld = new btDiscreteDynamicsWorld(dispatcher,overlappingPairCache,solver,collisionConfiguration); //重力設定 dynamicsWorld->setGravity(btVector3(0,-10,0));
物体(rigid body)の生成
//keep track of the shapes //rigid bodyが存在するあいだは使うよ btAlignedObjectArray<btCollisionShape*> collisionShapes;
受け止める方の物体を生成
{ //とりあえず、50x50x50の立方体を生成(地面用) btCollisionShape* groundShape = new btBoxShape(btVector3(btScalar(50.),btScalar(50.),btScalar(50.))); collisionShapes.push_back(groundShape); //初期化 btTransform groundTransform; groundTransform.setIdentity(); //座標の設定 groundTransform.setOrigin(btVector3(0,-56,0)); btScalar mass(0.); //0ならstatic(静止)、それ以外ならDynamicにする bool isDynamic = (mass != 0.f); btVector3 localInertia(0,0,0); if (isDynamic) groundShape->calculateLocalInertia(mass,localInertia); //using motionstate is recommended, it provides interpolation capabilities, and only synchronizes 'active' objects btDefaultMotionState* myMotionState = new btDefaultMotionState(groundTransform); btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,groundShape,localInertia); btRigidBody* body = new btRigidBody(rbInfo); //物体を世界に追加する dynamicsWorld->addRigidBody(body); }
落ちてくる方の物体を生成
{//次に、1x1x1の立方体を生成(地面用) //create a dynamic rigidbody btCollisionShape* colShape = new btSphereShape(btScalar(1.)); collisionShapes.push_back(colShape); /// 初期位置を設定 btTransform startTransform; startTransform.setIdentity(); btScalar mass(1.f);//重さ //0ならstatic(静止)、それ以外ならDynamicにする bool isDynamic = (mass != 0.f); btVector3 localInertia(0,0,0); if (isDynamic) colShape->calculateLocalInertia(mass,localInertia); startTransform.setOrigin(btVector3(2,10,0));//座標の設定 //using motionstate is recommended, it provides interpolation capabilities, and only synchronizes 'active' objects btDefaultMotionState* myMotionState = new btDefaultMotionState(startTransform); btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,colShape,localInertia); btRigidBody* body = new btRigidBody(rbInfo); dynamicsWorld->addRigidBody(body); }
シミュレーション開始
for (i=0;i<100;i++) { dynamicsWorld->stepSimulation(1.f/60.f,10); //print positions of all objects for (int j=dynamicsWorld->getNumCollisionObjects()-1; j>=0 ;j--) { btCollisionObject* obj = dynamicsWorld->getCollisionObjectArray()[j]; btRigidBody* body = btRigidBody::upcast(obj); if (body && body->getMotionState()) {//位置を取得して表示 btTransform trans; body->getMotionState()->getWorldTransform(trans); printf("world pos = %f,%f,%f\n",float(trans.getOrigin().getX()),float(trans.getOrigin().getY()),float(trans.getOrigin().getZ())); } } }
お片づけ
//remove the rigidbodies from the dynamics world and delete them for (i=dynamicsWorld->getNumCollisionObjects()-1; i>=0 ;i--) { btCollisionObject* obj = dynamicsWorld->getCollisionObjectArray()[i]; btRigidBody* body = btRigidBody::upcast(obj); if (body && body->getMotionState()) { delete body->getMotionState(); } dynamicsWorld->removeCollisionObject( obj ); delete obj; } //delete collision shapes for (int j=0;j<collisionShapes.size();j++) { btCollisionShape* shape = collisionShapes[j]; collisionShapes[j] = 0; delete shape; } //delete dynamics world delete dynamicsWorld; //delete solver delete solver; //delete broadphase delete overlappingPairCache; //delete dispatcher delete dispatcher; delete collisionConfiguration; //next line is optional: it will be cleared by the destructor when the array goes out of scope collisionShapes.clear(); }