Physics Simulation Forum

// Enter these commands, followed by <Return>, to control the player:
// "l" - Left
// "r" - Right
// "u" - Up

#include <btBulletDynamicsCommon.h>
#include <stdio.h>
#include <time.h>
#include <boost/timer/timer.hpp>
#include <boost/thread.hpp>

boost::mutex playerBodyLock;

void reader(btRigidBody *body);

int main() {
   btDefaultCollisionConfiguration config;
   btCollisionDispatcher dispatcher(&config);
   btDbvtBroadphase broadphase;
   btSequentialImpulseConstraintSolver solver;
   btDiscreteDynamicsWorld world(&dispatcher, &broadphase, &solver, &config);
   world.setGravity(btVector3(0, -10, 0));

   btStaticPlaneShape environmentShape(btVector3(0.0f, 1.0f, 0.0f), -3);
   btDefaultMotionState environmentMotionState;
   btCapsuleShape playerShape(1.0f, 2.0f);
   btDefaultMotionState playerMotionState;
   btVector3 playerInertia;
   playerShape.calculateLocalInertia(30, playerInertia);

   btRigidBody::btRigidBodyConstructionInfo environmentBodyCI(0.0f, &environmentMotionState, &environmentShape);
   btRigidBody environmentBody(environmentBodyCI);
   btRigidBody::btRigidBodyConstructionInfo playerBodyCI(30.0f, &playerMotionState, &playerShape, playerInertia);
   btRigidBody playerBody(playerBodyCI);

   playerBody.setAngularFactor(btVector3(0.0f, 0.0f, 0.0f));
   playerBody.setLinearFactor(btVector3(1.0f, 1.0f, 0.0f));
   world.addRigidBody(&environmentBody);
   world.addRigidBody(&playerBody);

   boost::thread readThread(reader, &playerBody);
   boost::timer::cpu_timer timer;
   timer.start();
   float lastUpdate = timer.elapsed().wall / 1e9;
   btTransform playerTransform;
   while(true) {
      {
         boost::lock_guard<boost::mutex> lock(playerBodyLock);
         float now = timer.elapsed().wall / 1e9;
         world.stepSimulation(now - lastUpdate, 5);

         playerBody.getMotionState()->getWorldTransform(playerTransform);
         printf("%f\t%f\t%f\n", playerTransform.getOrigin().x(), playerTransform.getOrigin().y(), playerTransform.getOrigin().z());
         lastUpdate = now;
      }
      boost::this_thread::sleep(boost::posix_time::millisec(40));
   }
}

void reader(btRigidBody *body)
{
   while(true) {
      char command[5];
      fgets(command, sizeof(command), stdin);
      switch(command[0]) {
      case 'l': {
         boost::lock_guard<boost::mutex> lock(playerBodyLock);
         body->applyCentralImpulse(btVector3(-30, 0, 0));
         break;
      }
      case 'r': {
         boost::lock_guard<boost::mutex> lock(playerBodyLock);
         body->applyCentralImpulse(btVector3(30, 0, 0));
         break;
      }
      case 'u': {
         boost::lock_guard<boost::mutex> lock(playerBodyLock);
         body->applyCentralImpulse(btVector3(0, 100, 0));
         break;
      }
      }
   }
}