Game Developers

void  ApplyGravityForce (const NewtonBody* body, dFloat timestep, int threadIndex)
{
	float mass, ixx, iyy, izz;
 
	NewtonBodyGetMassMatrix(body, &mass, &ixx, &iyy, &izz);
	float gravity[3] = {0.0f, mass * -10.0f, 0.0f};
	NewtonBodySetForce(body, gravity);
}

NewtonBodySetForceAndTorqueCallback(body1, ApplyGravityForce);

#include <cstdlib>
#include <iostream>
 
#include <Newton.h>
 
using namespace std;
 
void  ApplyGravityForce (const NewtonBody* body, dFloat timestep, int threadIndex)
{
	float mass, ixx, iyy, izz;
 
	NewtonBodyGetMassMatrix(body, &mass, &ixx, &iyy, &izz);
	float gravity[3] = {0.0f, mass * -10.0f, 0.0f};
	NewtonBodySetForce(body, gravity);
}
 
int main(int argc, char** argv)
{
    NewtonWorld* nWorld = NewtonCreate();
    NewtonCollision* cball = NewtonCreateSphere(nWorld, 2.f, 2.f, 2.f, 0, 0);
 
    float matrix[4][4] = {0};
    for(int i=0; i<4; i++)
    matrix[i][i] = 1.0f;
    matrix[3][1] = 10.f;
 
    NewtonBody* bball = NewtonCreateBody(nWorld, cball, matrix[0]);
    NewtonReleaseCollision(nWorld, cball);
    NewtonBodySetMassMatrix(bball, 10.f, 12.f, 12.f, 12.f);
 
    NewtonBodySetForceAndTorqueCallback(bball, ApplyGravityForce);
    //NewtonBodySetTransformCallback(bball, )
 
    for(int step=0; step<100; step++)
    {
        NewtonUpdate(nWorld, 1.f/60);
        NewtonBodyGetMatrix(bball, matrix[0]);
 
        if(step%5==0)
        cout << "Position = " << matrix[3][0] << " ; " << matrix[3][1] << " ; " << matrix[3][2] << " ; " << endl;
    }
    return 0;
}