Real-Time Physics Simulation Forum

Code: Select all

#include <bullet/btBulletDynamicsCommon.h>
#include <vector>
#include <iostream>

using std::cout;
using std::endl;
using std::vector;

class test {
private:
    btDefaultCollisionConfiguration     config;
    btSimpleBroadphase                  broadphase;
    btSequentialImpulseConstraintSolver solver;
    btScalar                            timestep;
    btCollisionDispatcher               dispatcher;
    btDiscreteDynamicsWorld             world;
    vector<btRigidBody>                 bodies;
    btStaticPlaneShape                  plane_shape;
    btSphereShape                       sphere_shape;

public:
    test(btScalar dt) :
        config       (btDefaultCollisionConfiguration()),
        broadphase   (btSimpleBroadphase()),
        solver       (btSequentialImpulseConstraintSolver()),
        timestep     (dt),
        dispatcher   (btCollisionDispatcher(&config)), 
        world        (btDiscreteDynamicsWorld(&dispatcher, &broadphase, &solver, &config)),
        plane_shape  (btStaticPlaneShape(btVector3(0, 0, 1), 0)),
        sphere_shape (btSphereShape(1))
    {
        world.setGravity(btVector3(0, 0, -9.80665));
        btRigidBody::btRigidBodyConstructionInfo plane_params(0, nullptr, &plane_shape, btVector3(0, 0, 0));
        btVector3 inertia;
        sphere_shape.calculateLocalInertia(3, inertia);
        btRigidBody::btRigidBodyConstructionInfo ball_params(3, nullptr, &sphere_shape, inertia);
        plane_params.m_restitution = 0.5;
        ball_params.m_restitution = 0.9;
        bodies.emplace_back(plane_params);
        bodies.emplace_back(ball_params);
        btTransform position;
        position.setIdentity();
        bodies[0].setWorldTransform(position);
        position.setOrigin(btVector3(0, 0, 50));
        bodies[1].setWorldTransform(position);
        world.addRigidBody(&bodies[0]);
        world.addRigidBody(&bodies[1]);
    }

    btScalar step() {
        world.stepSimulation(timestep, 1, timestep);
        return bodies[1].getWorldTransform().getOrigin().z();
    }
};

int main() {
    
    test t1(0.001);
    test t2(0.01);
    
    for (float i = 0; i < 10; i += 0.001) {
        cout << i << " " << t1.step() << endl;
    }
    
    cout << endl;

    for (float i = 0; i < 10; i += 0.01) {
        cout << i << " " << t2.step() << endl;
    }

}

Code: Select all

world->getSolverInfo().m_splitImpulse = true;
world->getSolverInfo().m_splitImpulsePenetrationThreshold = -0.000001;
world->getSolverInfo().m_splitImpulseTurnErp = 1.0;