float dt = 1.0f / (4.0f * 24.0f);
vec3f gravity = {0.0f, -9.81f, 0.0f};
vec3f dV = {2.0f, 0.0f, 0.0f} - v@v;
float lengthV = length(dV);
float Re = lengthV * @rad / 1.225f;
float C = 0.0f;
if (Re > 1000.0f) C = 24.0f / Re;
else C = 0.424f;
vec3f drag = 0.5f * 1.2f * C * lengthV * dV * 4.0f * 3.14f * pow(@rad, 2.0f);
v@v += (gravity - drag / ((4.0f / 3.0f) * 3.14f * pow(@rad, 3.0f))) * dt;
v@P += v@v * dt;