public unsafe void Step(float timeStep, Vector2 mousePosition, int buttons)
{
Body *state = (Body *)m_statePtr;
for (int i = 0; i < m_count; i++)
{
var b1 = state + i;
for (int j = i + 1; j < m_count; j++)
{
var b2 = state + j;
var vec = b2->pos - b1->pos;
var distance = vec.magnitude;
vec /= distance;
vec *= (5f / (0.1f + distance * 0.01f)) * m_adjust;
b1->acc += vec;
b2->acc -= vec;
}
}
if (buttons == 1)
{
state[0].pos = mousePosition;
state[0].vel = Vector2.zero;
for (int i = 0; i < m_count; i++)
{
var b = state + i;
var vec = mousePosition - b->pos;
var distance = vec.magnitude;
if (distance > float.Epsilon)
{
vec /= distance;
}
vec *= (3f / (0.1f + distance * 0.001f));
b->acc += vec;
}
}
for (int i = 0; i < m_count; i++)
{
var b = state + i;
if (b->vel.sqrMagnitude > 2500f)
{
b->acc -= b->vel;
}
b->vel += timeStep * b->acc;
b->pos += timeStep * b->vel;
b->acc = Vector2.zero;
}
}
public unsafe void UpdateViews(List <Transform> views)
{
Body *state = (Body *)m_statePtr;
for (int i = 0; i < m_count; i++)
{
views[i].position = state[i].pos;
}
}
public void BenchSetup()
{
bodyPtr = (Body *)Marshal.AllocHGlobal(Marshal.SizeOf <Body>() * 6);
rsPtr = (RS *)Marshal.AllocHGlobal(3 * 1024 * sizeof(double));
nBodyPP = Marshal.AllocHGlobal(Marshal.SizeOf <BodyVector>() * 12);
nBodyPtr = (BodyVector *)((ulong)nBodyPP - ((ulong)nBodyPP + 16) % 16);
rPtr = (R *)Marshal.AllocHGlobal(Marshal.SizeOf <R>() * 1024);
magPtr = (double *)Marshal.AllocHGlobal(sizeof(double) * 1024);
bodySystem = new NBodySystem(bodyPtr);
NBodySystem.Initialize(nBodyPtr);
}
public static void AdvanceStaticIntr1(double dt, R *rPtr, double *magPtr, ref NBodySystem bodySystem, int count = 50000000)
{
Body * items = bodySystem.bodies;
const int N = (BodyCount - 1) * BodyCount / 2;
R * r = rPtr;
double * mag = magPtr;
{
int k = 0;
ref Body iBody = ref items[0];
for (int j = 1; j < 5; ++j, ++k)
{
ref Body jBody = ref items[j];
ref R rf = ref r[k];
public unsafe void Init(int count)
{
m_statePtr = Marshal.AllocHGlobal(count * sizeof(Body));
m_count = count;
Body *state = (Body *)m_statePtr;
for (int i = 0; i < m_count; i++)
{
state[i] = new Body()
{
pos = UnityEngine.Random.insideUnitCircle * 10f,
vel = UnityEngine.Random.insideUnitCircle,
acc = Vector2.zero
};
}
m_adjust = 1f / count;
}
public unsafe void InitializeVerify()
{
double *bvPtr = stackalloc double[sizeof(BodyVector) / sizeof(double)];
NBodySystem.Initialize((BodyVector *)bvPtr);
Body * bodies = stackalloc Body[5];
NBodySystem bodySystem = new NBodySystem(bodies);
var result = NBodySystem.DumpBodyVector(5);
Assert.NotNull(result);
var expected = NBodySystem.DumpBodies(bodies, 5);
Assert.NotNull(expected);
Assert.Equal(expected, result);
}
public unsafe void AdvanceByOne()
{
double *bvPtr = stackalloc double[sizeof(BodyVector) / sizeof(double)];
NBodySystem.Initialize((BodyVector *)bvPtr);
Body * bodies = stackalloc Body[5];
NBodySystem bodySystem = new NBodySystem(bodies);
// Other data structures
RS * rsaPtr = stackalloc RS[1];
R * rPtr = stackalloc R[1024];
double *magPtr = stackalloc double[1024];
double *mag2Ptr = stackalloc double[1024];
NBodySystem.AdvanceStaticIntrSoa(0.01, rsaPtr, magPtr);
var result = NBodySystem.DumpBodyVector(5);
NBodySystem.AdvanceStaticIntr2(0.01, rPtr, mag2Ptr, ref bodySystem);
var expected = NBodySystem.DumpBodies(bodies, 5);
Assert.Equal(expected, result);
}
public NBodySystem(Body *ptr)
{
bodies = ptr;
ref Body p = ref bodies[0];
public static void Initialize()
{
bodies = (Body *)(U8.Base);
pairs = (Pair *)(&bodies[BodyCount]);
InitBody(
0, // Sun
mass: Solarmass
);
InitBody(
1, // Jupiter
x: 4.84143144246472090e+00,
y: -1.16032004402742839e+00,
z: -1.03622044471123109e-01,
vx: 1.66007664274403694e-03 * DaysPeryear,
vy: 7.69901118419740425e-03 * DaysPeryear,
vz: -6.90460016972063023e-05 * DaysPeryear,
mass: 9.54791938424326609e-04 * Solarmass
);
InitBody(
2, // Saturn
x: 8.34336671824457987e+00,
y: 4.12479856412430479e+00,
z: -4.03523417114321381e-01,
vx: -2.76742510726862411e-03 * DaysPeryear,
vy: 4.99852801234917238e-03 * DaysPeryear,
vz: 2.30417297573763929e-05 * DaysPeryear,
mass: 2.85885980666130812e-04 * Solarmass
);
InitBody(
3, // Uranus
x: 1.28943695621391310e+01,
y: -1.51111514016986312e+01,
z: -2.23307578892655734e-01,
vx: 2.96460137564761618e-03 * DaysPeryear,
vy: 2.37847173959480950e-03 * DaysPeryear,
vz: -2.96589568540237556e-05 * DaysPeryear,
mass: 4.36624404335156298e-05 * Solarmass
);
InitBody(
4, // Neptune
x: 1.53796971148509165e+01,
y: -2.59193146099879641e+01,
z: 1.79258772950371181e-01,
vx: 2.68067772490389322e-03 * DaysPeryear,
vy: 1.62824170038242295e-03 * DaysPeryear,
vz: -9.51592254519715870e-05 * DaysPeryear,
mass: 5.15138902046611451e-05 * Solarmass
);
int pi = 0;
for (int i = 0; i < BodyCount - 1; i++)
{
for (int j = i + 1; j < BodyCount; j++)
{
var p = &pairs[pi++];
p->bi = &bodies[i];
p->bj = &bodies[j];
}
}
double px = 0.0, py = 0.0, pz = 0.0;
for (int i = 0; i < BodyCount; i++)
{
var b = &(bodies[i]);
px += b->vx * b->mass;
py += b->vy * b->mass;
pz += b->vz * b->mass;
}
var sol = &bodies[0];
sol->vx = -px / Solarmass;
sol->vy = -py / Solarmass;
sol->vz = -pz / Solarmass;
}
public static void Initialize () {
bodies = (Body*)(U8.Base);
pairs = (Pair*)(&bodies[BodyCount]);
InitBody(
0, // Sun
mass: Solarmass
);
InitBody(
1, // Jupiter
x: 4.84143144246472090e+00,
y: -1.16032004402742839e+00,
z: -1.03622044471123109e-01,
vx: 1.66007664274403694e-03 * DaysPeryear,
vy: 7.69901118419740425e-03 * DaysPeryear,
vz: -6.90460016972063023e-05 * DaysPeryear,
mass: 9.54791938424326609e-04 * Solarmass
);
InitBody(
2, // Saturn
x: 8.34336671824457987e+00,
y: 4.12479856412430479e+00,
z: -4.03523417114321381e-01,
vx: -2.76742510726862411e-03 * DaysPeryear,
vy: 4.99852801234917238e-03 * DaysPeryear,
vz: 2.30417297573763929e-05 * DaysPeryear,
mass: 2.85885980666130812e-04 * Solarmass
);
InitBody(
3, // Uranus
x: 1.28943695621391310e+01,
y: -1.51111514016986312e+01,
z: -2.23307578892655734e-01,
vx: 2.96460137564761618e-03 * DaysPeryear,
vy: 2.37847173959480950e-03 * DaysPeryear,
vz: -2.96589568540237556e-05 * DaysPeryear,
mass: 4.36624404335156298e-05 * Solarmass
);
InitBody(
4, // Neptune
x: 1.53796971148509165e+01,
y: -2.59193146099879641e+01,
z: 1.79258772950371181e-01,
vx: 2.68067772490389322e-03 * DaysPeryear,
vy: 1.62824170038242295e-03 * DaysPeryear,
vz: -9.51592254519715870e-05 * DaysPeryear,
mass: 5.15138902046611451e-05 * Solarmass
);
int pi = 0;
for (int i = 0; i < BodyCount - 1; i++) {
for (int j = i + 1; j < BodyCount; j++) {
var p = &pairs[pi++];
p->bi = &bodies[i];
p->bj = &bodies[j];
}
}
double px = 0.0, py = 0.0, pz = 0.0;
for (int i = 0; i < BodyCount; i++) {
var b = &(bodies[i]);
px += b->vx * b->mass;
py += b->vy * b->mass;
pz += b->vz * b->mass;
}
var sol = &bodies[0];
sol->vx = -px / Solarmass;
sol->vy = -py / Solarmass;
sol->vz = -pz / Solarmass;
}
