sid::plot* sid::plots::get_plot_at(plot::plot_offset pofs) {
plot* pltFirst = this->first();
plot::plot_offset pofsFirst = pltFirst->get_plot_offset();
plot::plot_offset pofsDelta = pofs - pofsFirst;
plot* pltRetVal = this->__m_plots[coords_to_index(pofsDelta)];
return pltRetVal;
}
//-----------------------------------------------------------------------------
void Heightfield::set_altitude(uint32_t x, uint32_t y, float altitude)
{
const uint32_t adjusted_altitude = (altitude < m_min_altitude) ? m_min_altitude : (altitude > m_max_altitude) ? m_max_altitude : altitude;
m_altitudes[coords_to_index(x, y)] = adjusted_altitude;
}
//-----------------------------------------------------------------------------
float Heightfield::altitude(uint32_t x, uint32_t y) const
{
return m_altitudes[coords_to_index(x, y)];
}
sid::plot* sid::plots::at(uint index_X, uint index_Z) {
return (__m_plots[coords_to_index(index_X, index_Z)]);
}
sid::plot* sid::plots::at(const plot::plot_offset& pofs) {
return (__m_plots[coords_to_index(pofs.get_x(), pofs.get_z())]);
}
//==================================================
// simulation
//==================================================
void simulate(int seed){
ran_seed(seed);
int N = 18*512;
double radius = 1.0;
double L = sqrt(1.02*pi*radius*radius*N);
int Npercell = 50;
int pbc[] = {1,1};
double epsilon = 180.0;
double damp_coeff = 0.3;
double kickforce = 20.0;
double dt = 1e-1;
double t = 0.0;
double R = 2*radius;
double R2 = R*R;
int i, j, k;
int *key;
int *type = (int*)malloc(sizeof(int)*N);
int *neigh = (int*)malloc(sizeof(int)*N);
double *rad = (double*)malloc(sizeof(double)*N);
double *col = (double*)malloc(sizeof(double)*N);
for (i=0; i<N; i++){ type[i] = neigh[i] = rad[i] = 0;}
double *x = (double*)malloc(sizeof(double)*2*N);
double *v = (double*)malloc(sizeof(double)*2*N);
double *f = (double*)malloc(sizeof(double)*2*N);
double *w = (double*)malloc(sizeof(double)*2*N);
double *o = (double*)malloc(sizeof(double)*2*N);
for (i=0; i<2*N; i++){o[i] = x[i] = v[i] = f[i] = w[i] = 0.0;}
#ifdef PLOT
double time_end = 1e20;
#else
double time_end = 1e2;
#endif
#ifdef PLOT
plot_init();
plot_clear_screen();
key = plot_render_particles(x, rad, type, N, L,col);
#endif
//-------------------------------------------------
// initialize
for (i=0; i<N; i++){
rad[i] = radius;
x[2*i+0] = L*ran_ran2();
x[2*i+1] = L*ran_ran2();
v[2*i+0] = 0.0;
v[2*i+1] = 0.0;
type[i] = BLACK;
if (i==0) type[i] = RED;
}
//-------------------------------------------------------
// make boxes for the neighborlist
int size[2];
int size_total = 1;
for (i=0; i<2; i++){
size[i] = (int)(L / (R));
size_total *= size[i];
}
int *count = (int*)malloc(sizeof(int)*2*size_total);
int *cells = (int*)malloc(sizeof(int)*2*size_total*Npercell);
for (i=0; i<size_total; i++){
for (j=0; j<Npercell; j++)
cells[i*Npercell + j] = 0;
count[i] = 0;
}
//==========================================================
// where the magic happens
//==========================================================
int frames = 0;
#ifdef FPS
struct timespec start;
clock_gettime(CLOCK_REALTIME, &start);
#endif
int STRESS = 1;
double T = 0.0;
for (t=0.0; t<time_end; t+=dt){
double colmax = 0.0;
int index[2];
for (i=0; i<size_total; i++)
count[i] = 0;
for (i=0; i<N; i++){
col[i] = 0.0;
coords_to_index(&x[2*i], size, index, L);
int t = index[0] + index[1]*size[0];
cells[t*Npercell+count[t]] = i;
count[t]++;
}
int tt[2];
int tix[2];
int image[2];
double dx[2];
for (i=0; i<N; i++){
f[2*i+0] = 0.0;
f[2*i+1] = 0.0;
coords_to_index(&x[2*i], size, index, L);
for (tt[0]=-1; tt[0]<=1; tt[0]++){
for (tt[1]=-1; tt[1]<=1; tt[1]++){
int goodcell = 1;
for (j=0; j<2; j++){
tix[j] = mod_rvec(index[j]+tt[j],size[j]-1,pbc[j],&image[j]);
if (pbc[j] < image[j])
goodcell=0;
}
if (goodcell){
int ind = tix[0] + tix[1]*size[0];
for (j=0; j<count[ind]; j++){
int n = cells[ind*Npercell+j];
double dist = 0.0;
for (k=0; k<2; k++){
dx[k] = x[2*n+k] - x[2*i+k];
if (image[k])
dx[k] += L*tt[k];
dist += dx[k]*dx[k];
}
//===============================================
// force calculation - hertz
if (dist > 1e-10 && dist < R2){
double r0 = R;
double l = sqrt(dist);
double co = epsilon * (1-l/r0)*(1-l/r0) * (l<r0);
for (k=0; k<2; k++){
f[2*i+k] += - dx[k] * co;
if (STRESS==1) col[i] += co*co*dx[k]*dx[k];//100*co*dx[k];//sqrt(co*co*dx[k]*dx[k]);
}
if (STRESS==2) col[i] += dx[1] * co*co*dx[1];
if (STRESS==3) col[i] += dx[0] * co*co*dx[0];
if (STRESS==4) col[i] += dx[1] * co*co*dx[0];
}
}
}
} }
//====================================
// damping
f[2*i+0] -= damp_coeff*v[2*i+0];
f[2*i+1] -= damp_coeff*v[2*i+1];
//=====================================
// noise
f[2*i+0] += T*(ran_ran2()-0.5);
f[2*i+1] += T*(ran_ran2()-0.5);
//=====================================
// kick force
f[2*i+0] += o[2*i+0]; o[2*i+0] = 0.0;
f[2*i+1] += o[2*i+1]; o[2*i+1] = 0.0;
//=======================
// color norm
if (col[i] > colmax) colmax = col[i];
}
// now integrate the forces since we have found them
for (i=0; i<N;i++){
// Newton-Stomer-Verlet
if (key['h'] != 1){
v[2*i+0] += f[2*i+0] * dt;
v[2*i+1] += f[2*i+1] * dt;
x[2*i+0] += v[2*i+0] * dt;
x[2*i+1] += v[2*i+1] * dt;
}
// boundary conditions
for (j=0; j<2; j++){
if (pbc[j] == 1){
if (x[2*i+j] >= L-EPSILON || x[2*i+j] < 0)
x[2*i+j] = mymod(x[2*i+j], L);
}
else {
const double restoration = 1.0;
if (x[2*i+j] >= L){x[2*i+j] = 2*L-x[2*i+j]; v[2*i+j] *= -restoration;}
if (x[2*i+j] < 0) {x[2*i+j] = -x[2*i+j]; v[2*i+j] *= -restoration;}
if (x[2*i+j] >= L-EPSILON || x[2*i+j] < 0){x[2*i+j] = mymod(x[2*i+j], L);}
}
}
// just check for errors
if (x[2*i+0] >= L || x[2*i+0] < 0.0 ||
x[2*i+1] >= L || x[2*i+1] < 0.0)
printf("out of bounds\n");
//col[i] += v[2*i+0]*v[2*i+0] + v[2*i+1]*v[2*i+1];
if (STRESS == 1) col[i] = col[i]/8;
if (STRESS == 2) col[i] = col[i]/16;
if (STRESS == 3) col[i] = col[i]/16;
if (STRESS == 4) col[i] = col[i]/4;
if (STRESS > 1) col[i] = fabs(col[i])+0.5;
}
#ifdef PLOT
const int FRAMESKIP = 1;
if (frames % FRAMESKIP == 0){
char filename[100];
sprintf(filename, "screen_%05d.png", frames/FRAMESKIP);
plot_clear_screen();
key = plot_render_particles(x, rad, type, N, L,col);
#ifdef IMAGES
plot_saveimage(filename);
#endif
}
#endif
frames++;
if (key['1'] == 1) STRESS = 1;
if (key['2'] == 1) STRESS = 2;
if (key['3'] == 1) STRESS = 3;
if (key['4'] == 1) STRESS = 4;
if (key['q'] == 1)
break;
if (key['w'] == 1){
for (i=0; i<N; i++){
if (type[i] == RED)
o[2*i+1] = -kickforce;
}
}
if (key['s'] == 1){
for (i=0; i<N; i++){
if (type[i] == RED)
o[2*i+1] = kickforce;
}
}
if (key['a'] == 1){
for (i=0; i<N; i++){
if (type[i] == RED)
o[2*i+0] = -kickforce;
}
}
if (key['d'] == 1){
for (i=0; i<N; i++){
if (type[i] == RED)
o[2*i+0] = kickforce;
}
}
if (key['9'] == 1)
T -= 0.01;
if (key['0'] == 1)
T += 0.01;
if (key['8'] == 1)
T = 0.0;
if (key['o'] == 1)
L -= 0.01;
if (key['p'] == 1)
L += 0.01;
}
// end of the magic, cleanup
//----------------------------------------------
#ifdef FPS
struct timespec end;
clock_gettime(CLOCK_REALTIME, &end);
printf("fps = %f\n", frames/(end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec)/1e9);
#endif
free(cells);
free(count);
free(x);
free(v);
free(f);
free(w);
free(o);
free(neigh);
free(rad);
free(type);
#ifdef PLOT
plot_clean();
#endif
}
