Bullet核心类介绍（Bullet 2.82 HelloWorld程序及其详解，附程序代码）

  1 #include"btBulletDynamicsCommon.h"
  2 #include"omp.h"
  3 
  4 btDiscreteDynamicsWorld* m_DynamicsWorld;
  5 btBroadphaseInterface* m_Broadphase;
  6 btCollisionDispatcher* m_Dispatcher;
  7 btSequentialImpulseConstraintSolver* m_ConstraintSolver;
  8 btDefaultCollisionConfiguration* m_CollisionConfiguration;
  9 btAlignedObjectArray<btCollisionShape*> m_CollisionShapes;
 10 
 11 void bt_rundraw(bool run)
 12 {
 13     if(run){
 14         static double t = omp_get_wtime();
 15         double t2 = omp_get_wtime();
 16         m_DynamicsWorld->stepSimulation(float(t2-t),10);
 17         t = t2;
 18     }
 19 
 20     btCollisionObjectArray& rigidArray = m_DynamicsWorld->getCollisionObjectArray();
 21     for(int i=0; i<rigidArray.size(); ++i){
 22         btRigidBody* body = btRigidBody::upcast(rigidArray[i]);
 23         btTransform trans;
 24         body->getMotionState()->getWorldTransform(trans);
 25         float m[16];
 26         trans.getOpenGLMatrix(m);
 27         GLfloat color[]={.5f, .6f, .7f, 1.0f};
 28         if(i==0){
 29             glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, color);
 30             glMatrixMode(GL_MODELVIEW);
 31             glPushMatrix();
 32             glMultMatrixf(m);
 33             glTranslatef(0,-1,0);
 34             glScalef(100.0f,1.0f,100.0f);
 35             glutSolidCube(1.f);
 36             glPopMatrix();
 37         }else{
 38             if(i%2){
 39                 color[0]=0.0f;color[1]=0.9f;color[2]=0.0f;color[3]=1.0f;
 40             }else{
 41                 color[0]=0.9f;color[1]=0.0f;color[2]=0.0f;color[3]=1.0f;
 42             }
 43             glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, color);
 44             glMatrixMode(GL_MODELVIEW);
 45             glPushMatrix();
 46             glMultMatrixf(m);
 47             glScalef(3.0f,2.0f,4.0f);
 48             glutSolidCube(1.f);
 49             glPopMatrix();
 50         }
 51     }
 52 }
 53 
 54 void bt_start()
 55 {
 56     ///-----initialization_start-----
 57     m_CollisionConfiguration = new btDefaultCollisionConfiguration();
 58     m_Dispatcher = new    btCollisionDispatcher(m_CollisionConfiguration);
 59     m_Broadphase = new btDbvtBroadphase();
 60     m_ConstraintSolver = new btSequentialImpulseConstraintSolver;
 61     m_DynamicsWorld = new btDiscreteDynamicsWorld(
 62         m_Dispatcher,m_Broadphase,m_ConstraintSolver,m_CollisionConfiguration);
 63     m_DynamicsWorld->setGravity(btVector3(0,-10,0));
 64     ///-----initialization_end-----
 65 
 66     { // floor
 67         btCollisionShape* groundShape = new btBoxShape(btVector3(btScalar(50.f),btScalar(0.f),btScalar(50.f)));
 68         m_CollisionShapes.push_back(groundShape);
 69 
 70         btTransform groundTransform;
 71         groundTransform.setIdentity();
 72         groundTransform.setOrigin(btVector3(0,0,0));
 73         btScalar mass(0.f);
 74 
 75         btVector3 localInertia(0,0,0);
 76         if( mass != 0.f )
 77             groundShape->calculateLocalInertia(mass,localInertia);
 78 
 79         //using motionstate is recommended, it provides interpolation capabilities, and only synchronizes ‘active‘ objects
 80         btDefaultMotionState* myMotionState = new btDefaultMotionState(groundTransform);
 81         btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,groundShape,localInertia);
 82         btRigidBody* body = new btRigidBody(rbInfo);
 83 
 84         //add the body to the dynamics world
 85         m_DynamicsWorld->addRigidBody(body);
 86     }
 87 
 88     for(int i=0; i<20; ++i){
 89         btCollisionShape* boxShape = new btBoxShape(btVector3(btScalar(1.5f),btScalar(1.f),btScalar(2.f)));
 90         m_CollisionShapes.push_back(boxShape);
 91 
 92         btTransform groundTransform;
 93         groundTransform.setIdentity();
 94         groundTransform.setOrigin(btVector3(0,i*2.0f+1.0f,i*0.5f));
 95         btScalar mass(6.f);
 96 
 97         btVector3 localInertia(0,0,0);
 98         if( mass != 0.f )
 99             boxShape->calculateLocalInertia(mass,localInertia);
100 
101         //using motionstate is recommended, it provides interpolation capabilities, and only synchronizes ‘active‘ objects
102         btDefaultMotionState* myMotionState = new btDefaultMotionState(groundTransform);
103         btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,boxShape,localInertia);
104         btRigidBody* body = new btRigidBody(rbInfo);
105 
106         //add the body to the dynamics world
107         m_DynamicsWorld->addRigidBody(body);
108     }
109     
110 }
111 
112 void bt_end()
113 {
114     //remove the rigidbodies from the dynamics world and delete them
115     for (int i=m_DynamicsWorld->getNumCollisionObjects()-1; i>=0 ;i--)
116     {
117         btCollisionObject* obj = m_DynamicsWorld->getCollisionObjectArray()[i];
118         btRigidBody* body = btRigidBody::upcast(obj);
119         if (body && body->getMotionState())
120             delete body->getMotionState();
121         m_DynamicsWorld->removeCollisionObject( obj );
122         delete obj;
123     }
124     //delete collision shapes
125     for (int i=0;i<m_CollisionShapes.size();i++)
126     {
127         btCollisionShape* shape = m_CollisionShapes[i];
128         m_CollisionShapes[i] = 0;
129         delete shape;
130     }
131     //delete dynamicsworld and ...
132     delete m_DynamicsWorld;
133     delete m_ConstraintSolver;
134     delete m_Broadphase;
135     delete m_Dispatcher;
136     delete m_CollisionConfiguration;
137     m_CollisionShapes.clear();
138 }