Bullet Physics OpenGL Rigid Body Application Template Rigid Simulation in Bullet, bulletrigid

Bullet Physics OpenGL Rigid Body Application Template Rigid Simulation in Bullet, bulletrigid

Use the Bullet physical engine to implement a rigid-body free drop simulation Template

Bullet

Main. cpp

#include <GLUT/glut.h>#include <cstdlib> /* for exit */#include <vector>#include "btBulletDynamicsCommon.h"#include "BulletCollision/Gimpact/btGImpactShape.h"#include "BulletCollision/Gimpact/btGImpactCollisionAlgorithm.h"using namespace std;float zoom = 2000.f;float rotx = 20;float roty = 0;float tx = 0;float ty = 0;int lastx=0;int lasty=0;unsigned char Buttons[3] = {0};float lightPosition[] = { -200, 300, 300, 1.0f};float ambientLight[] = { 0.2f, 0.2f, 0.2f, 1.0f };float diffuseLight[] = { 0.8f, 0.8f, 0.8, 1.0f };float specularLight[] = { 0.5f, 0.5f, 0.5f, 1.0f };btDiscreteDynamicsWorld* mp_btDynamicsWorld = NULL;btRigidBody *cube = NULL;btRigidBody *ground = NULL;void InitWorld(){    btDefaultCollisionConfiguration *config = new btDefaultCollisionConfiguration();    btCollisionDispatcher *dispatcher = new btCollisionDispatcher(config);        btDbvtBroadphase *broadphase = new btDbvtBroadphase();  // Dynamic AABB tree method    btSequentialImpulseConstraintSolver* solver = new btSequentialImpulseConstraintSolver();    mp_btDynamicsWorld = new btDiscreteDynamicsWorld(dispatcher, broadphase, solver, config);    mp_btDynamicsWorld->setGravity(btVector3(0, -9800, 0)); //millimeter 9.8 * 1000}void InitObject(){    //init cube    btCollisionShape *collisionShape = new btBoxShape(btVector3(300,300,300));    //initial position    btVector3 pos = btVector3(0, 600, 0);    btQuaternion qrot(0, 0, 0, 1);        btDefaultMotionState* motion_state = new btDefaultMotionState(btTransform(qrot, pos));        btScalar mass = btScalar(10);    btVector3 inertia = btVector3(0, 0, 0);//guan xing    collisionShape->calculateLocalInertia(mass, inertia);        cube = new btRigidBody(mass, motion_state, collisionShape, inertia);        btScalar restitution = btScalar(0);    cube->setRestitution(restitution);    //default 0.5    btScalar friction = btScalar(0.8);    cube->setFriction(friction);        mp_btDynamicsWorld->addRigidBody(cube);        //init ground    btCollisionShape *groundShape = new btBoxShape(btVector3(2000,5,2000)); //half size        btVector3 groundpos = btVector3(0,-150,0);    btQuaternion groundrot(0, 0, 0, 1);    btDefaultMotionState* groundMotion = new btDefaultMotionState(btTransform(groundrot, groundpos));    ground  = new btRigidBody(0.0, groundMotion, groundShape);//mass = 0 means it is a static object    btScalar rest = btScalar(1);    ground->setRestitution(rest);    mp_btDynamicsWorld->addRigidBody(ground);}void DeleteBullet(){    //cube    delete cube->getMotionState();    mp_btDynamicsWorld->removeRigidBody(cube);    delete cube;    cube = NULL;        //ground    delete ground->getMotionState();    mp_btDynamicsWorld->removeRigidBody(ground);    delete ground;    ground = NULL;        //world    delete mp_btDynamicsWorld->getBroadphase();    delete mp_btDynamicsWorld;    mp_btDynamicsWorld = NULL;}void DrawGrid(int _halfLen, int _gridNum){    glColor3f(1.0f,1.0f,1.0f);        // draw grid    glLineWidth(2);    glBegin(GL_LINES);    for(int i = -_halfLen;i <= _halfLen; i += (_halfLen/_gridNum)) {        glVertex3f(i,0,-_halfLen);        glVertex3f(i,0,_halfLen);                glVertex3f(_halfLen,0,i);        glVertex3f(-_halfLen,0,i);    }    glEnd();}void DrawCoordinate(float _flengthX, float _flengthY, float _flengthZ){    glLineWidth(5);    glBegin(GL_LINES);    glColor3f(1,0,0);    glVertex3f(0,0,0);    glVertex3f(_flengthX,0,0);    glEnd();        glBegin(GL_LINES);    glColor3f(0,1,0);    glVertex3f(0,0,0);    glVertex3f(0,_flengthY,0);    glEnd();        glBegin(GL_LINES);    glColor3f(0,0,1);    glVertex3f(0,0,0);    glVertex3f(0,0,_flengthZ);    glEnd();}void DrawBulletObject(){    //cube    btTransform trans = cube->getWorldTransform();    btScalar m[16];trans.getOpenGLMatrix(m);    glColor3f(0, 0, 1);glPushMatrix();glMultMatrixf((GLfloat*)m);    glutSolidCube(300);glPopMatrix();        //ground    glColor3f(0, 1, 0);    glPushMatrix();    glTranslatef(0, -5, 0);    glScalef(1, 0.005, 1);    glutSolidCube(2000); //half size    glPopMatrix();    }void Simulate(){    double dt = 1.f/60.0f;    if(mp_btDynamicsWorld)        mp_btDynamicsWorld->stepSimulation(dt,1);}//-------------------------------------------------------------------------------///void Display(){    Simulate();        glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);            glLoadIdentity();        glTranslatef(0,0,-zoom);    glTranslatef(tx,ty,0);    glRotatef(rotx,1,0,0);    glRotatef(roty,0,1,0);            glLightfv(GL_LIGHT1, GL_AMBIENT, ambientLight);    glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuseLight);    glLightfv(GL_LIGHT1, GL_SPECULAR, specularLight);    glLightfv(GL_LIGHT1, GL_POSITION, lightPosition);        glEnable(GL_LIGHT1);    glEnable(GL_LIGHTING);        glColorMaterial(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);    glEnable(GL_COLOR_MATERIAL);        DrawBulletObject();    glDisable( GL_LIGHTING );    glDisable(GL_COLOR_MATERIAL);        DrawGrid(1000, 10);    //DrawCoordinate(1000,1000,1000);        glutPostRedisplay();    glutSwapBuffers();}void Init(){    glShadeModel(GL_SMOOTH);    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);    glClearDepth(1.0f);    glColor4f(1.0f, 1.0f, 1.0f, 1.0f);    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);    glDepthFunc(GL_LEQUAL);    glEnable(GL_DEPTH_TEST);        glEnable(GL_CULL_FACE);        glEnable(GL_NORMALIZE);            InitWorld();    InitObject();}void Reshape(int w, int h){    // prevent divide by 0 error when minimised    if(w==0)        h = 1;        glViewport(0,0,w,h);    glMatrixMode(GL_PROJECTION);    glLoadIdentity();    gluPerspective(45,(float)w/h,0.1,5000);    glMatrixMode(GL_MODELVIEW);    glLoadIdentity();}//-------------------------------------------------------------------------------//void Motion(int x,int y){    int diffx=x-lastx;    int diffy=y-lasty;    lastx=x;    lasty=y;        if( Buttons[2] )    {        zoom -= (float)  1* diffx*2;    }    else        if( Buttons[0] )        {            rotx += (float) 1 * diffy;            roty += (float) 1 * diffx;        }        else            if( Buttons[1] )            {                tx += (float) 1 * diffx;                ty -= (float) 1 * diffy;            }    glutPostRedisplay();}//-------------------------------------------------------------------------------//void Mouse(int b,int s,int x,int y){    lastx=x;    lasty=y;    switch(b)    {        case GLUT_LEFT_BUTTON:            Buttons[0] = ((GLUT_DOWN==s)?1:0);            break;        case GLUT_MIDDLE_BUTTON:            Buttons[1] = ((GLUT_DOWN==s)?1:0);            break;        case GLUT_RIGHT_BUTTON:            Buttons[2] = ((GLUT_DOWN==s)?1:0);            break;        default:            break;    }    glutPostRedisplay();}void Keyboard(unsigned char key, int x, int y){    switch(key) {        case 'q':        case 'Q':        case 27: // ESC key            exit(0);        break;        case 'r':            DeleteBullet();            InitWorld();            InitObject();        break;        default:        break;    }}int main(int argc,char** argv){    glutInit(&argc,argv);    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH);    glutInitWindowSize(640,480);    glutInitWindowPosition(100,100);    glutCreateWindow("Bullet Framework");    glutDisplayFunc(Display);    glutReshapeFunc(Reshape);    glutMouseFunc(Mouse);    glutMotionFunc(Motion);    glutKeyboardFunc(Keyboard);    Init();        glutMainLoop();        return 0;}