The-Powder-Toy/src/simulation/Gravity.cpp

528 lines
14 KiB
C++
Executable File

#include "Gravity.h"
#include <cmath>
#include <iostream>
#include <sys/types.h>
#include "CoordStack.h"
#include "Misc.h"
#include "Simulation.h"
#include "SimulationData.h"
Gravity::Gravity()
{
// Allocate full size Gravmaps
unsigned int size = (XRES / CELL) * (YRES / CELL);
th_ogravmap = new float[size];
th_gravmap = new float[size];
th_gravy = new float[size];
th_gravx = new float[size];
th_gravp = new float[size];
gravmap = new float[size];
gravy = new float[size];
gravx = new float[size];
gravp = new float[size];
gravmask = new unsigned[size];
}
Gravity::~Gravity()
{
stop_grav_async();
#ifdef GRAVFFT
grav_fft_cleanup();
#endif
delete[] th_ogravmap;
delete[] th_gravmap;
delete[] th_gravy;
delete[] th_gravx;
delete[] th_gravp;
delete[] gravmap;
delete[] gravy;
delete[] gravx;
delete[] gravp;
delete[] gravmask;
}
void Gravity::Clear()
{
int size = (XRES / CELL) * (YRES / CELL);
std::fill(gravy, gravy + size, 0.0f);
std::fill(gravx, gravx + size, 0.0f);
std::fill(gravp, gravp + size, 0.0f);
std::fill(gravmap, gravmap + size, 0.0f);
std::fill(gravmask, gravmask + size, 0xFFFFFFFF);
ignoreNextResult = true;
}
#ifdef GRAVFFT
void Gravity::grav_fft_init()
{
int xblock2 = XRES/CELL*2;
int yblock2 = YRES/CELL*2;
int fft_tsize = (xblock2/2+1)*yblock2;
float distance, scaleFactor;
fftwf_plan plan_ptgravx, plan_ptgravy;
if (grav_fft_status) return;
//use fftw malloc function to ensure arrays are aligned, to get better performance
th_ptgravx = reinterpret_cast<float*>(fftwf_malloc(xblock2 * yblock2 * sizeof(float)));
th_ptgravy = reinterpret_cast<float*>(fftwf_malloc(xblock2 * yblock2 * sizeof(float)));
th_ptgravxt = reinterpret_cast<fftwf_complex*>(fftwf_malloc(fft_tsize * sizeof(fftwf_complex)));
th_ptgravyt = reinterpret_cast<fftwf_complex*>(fftwf_malloc(fft_tsize * sizeof(fftwf_complex)));
th_gravmapbig = reinterpret_cast<float*>(fftwf_malloc(xblock2 * yblock2 * sizeof(float)));
th_gravmapbigt = reinterpret_cast<fftwf_complex*>(fftwf_malloc(fft_tsize * sizeof(fftwf_complex)));
th_gravxbig = reinterpret_cast<float*>(fftwf_malloc(xblock2 * yblock2 * sizeof(float)));
th_gravybig = reinterpret_cast<float*>(fftwf_malloc(xblock2 * yblock2 * sizeof(float)));
th_gravxbigt = reinterpret_cast<fftwf_complex*>(fftwf_malloc(fft_tsize * sizeof(fftwf_complex)));
th_gravybigt = reinterpret_cast<fftwf_complex*>(fftwf_malloc(fft_tsize * sizeof(fftwf_complex)));
//select best algorithm, could use FFTW_PATIENT or FFTW_EXHAUSTIVE but that increases the time taken to plan, and I don't see much increase in execution speed
plan_ptgravx = fftwf_plan_dft_r2c_2d(yblock2, xblock2, th_ptgravx, th_ptgravxt, FFTW_MEASURE);
plan_ptgravy = fftwf_plan_dft_r2c_2d(yblock2, xblock2, th_ptgravy, th_ptgravyt, FFTW_MEASURE);
plan_gravmap = fftwf_plan_dft_r2c_2d(yblock2, xblock2, th_gravmapbig, th_gravmapbigt, FFTW_MEASURE);
plan_gravx_inverse = fftwf_plan_dft_c2r_2d(yblock2, xblock2, th_gravxbigt, th_gravxbig, FFTW_MEASURE);
plan_gravy_inverse = fftwf_plan_dft_c2r_2d(yblock2, xblock2, th_gravybigt, th_gravybig, FFTW_MEASURE);
//(XRES/CELL)*(YRES/CELL)*4 is size of data array, scaling needed because FFTW calculates an unnormalized DFT
scaleFactor = -M_GRAV/((XRES/CELL)*(YRES/CELL)*4);
//calculate velocity map caused by a point mass
for (int y = 0; y < yblock2; y++)
{
for (int x = 0; x < xblock2; x++)
{
if (x == XRES / CELL && y == YRES / CELL)
continue;
distance = sqrtf(pow(x-(XRES/CELL), 2.0f) + pow(y-(YRES/CELL), 2.0f));
th_ptgravx[y * xblock2 + x] = scaleFactor * (x - (XRES / CELL)) / pow(distance, 3);
th_ptgravy[y * xblock2 + x] = scaleFactor * (y - (YRES / CELL)) / pow(distance, 3);
}
}
th_ptgravx[yblock2 * xblock2 / 2 + xblock2 / 2] = 0.0f;
th_ptgravy[yblock2 * xblock2 / 2 + xblock2 / 2] = 0.0f;
//transform point mass velocity maps
fftwf_execute(plan_ptgravx);
fftwf_execute(plan_ptgravy);
fftwf_destroy_plan(plan_ptgravx);
fftwf_destroy_plan(plan_ptgravy);
fftwf_free(th_ptgravx);
fftwf_free(th_ptgravy);
//clear padded gravmap
memset(th_gravmapbig, 0, xblock2 * yblock2 * sizeof(float));
grav_fft_status = true;
}
void Gravity::grav_fft_cleanup()
{
if (!grav_fft_status) return;
fftwf_free(th_ptgravxt);
fftwf_free(th_ptgravyt);
fftwf_free(th_gravmapbig);
fftwf_free(th_gravmapbigt);
fftwf_free(th_gravxbig);
fftwf_free(th_gravybig);
fftwf_free(th_gravxbigt);
fftwf_free(th_gravybigt);
fftwf_destroy_plan(plan_gravmap);
fftwf_destroy_plan(plan_gravx_inverse);
fftwf_destroy_plan(plan_gravy_inverse);
grav_fft_status = false;
}
#endif
void Gravity::gravity_update_async()
{
int result;
if (!enabled)
return;
bool signal_grav = false;
{
std::unique_lock<std::mutex> l(gravmutex, std::defer_lock);
if (l.try_lock())
{
result = grav_ready;
if (result) //Did the gravity thread finish?
{
if (th_gravchanged && !ignoreNextResult)
{
#if !defined(GRAVFFT) && defined(GRAV_DIFF)
memcpy(gravy, th_gravy, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memcpy(gravx, th_gravx, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memcpy(gravp, th_gravp, (XRES/CELL)*(YRES/CELL)*sizeof(float));
#else
// Copy thread gravity maps into this one
std::swap(gravy, th_gravy);
std::swap(gravx, th_gravx);
std::swap(gravp, th_gravp);
#endif
}
ignoreNextResult = false;
std::swap(gravmap, th_gravmap);
grav_ready = 0; //Tell the other thread that we're ready for it to continue
signal_grav = true;
}
}
}
if (signal_grav)
{
gravcv.notify_one();
}
unsigned int size = (XRES / CELL) * (YRES / CELL);
membwand(gravy, gravmask, size * sizeof(float), size * sizeof(unsigned));
membwand(gravx, gravmask, size * sizeof(float), size * sizeof(unsigned));
std::fill(&gravmap[0], &gravmap[size], 0.0f);
}
void Gravity::update_grav_async()
{
int done = 0;
int thread_done = 0;
unsigned int size = (XRES / CELL) * (YRES / CELL);
std::fill(&th_ogravmap[0], &th_ogravmap[size], 0.0f);
std::fill(&th_gravmap[0], &th_gravmap[size], 0.0f);
std::fill(&th_gravy[0], &th_gravy[size], 0.0f);
std::fill(&th_gravx[0], &th_gravx[size], 0.0f);
std::fill(&th_gravp[0], &th_gravp[size], 0.0f);
#ifdef GRAVFFT
if (!grav_fft_status)
grav_fft_init();
#endif
std::unique_lock<std::mutex> l(gravmutex);
while (!thread_done)
{
if (!done)
{
// run gravity update
update_grav();
done = 1;
grav_ready = 1;
thread_done = gravthread_done;
}
else
{
// wait for main thread
gravcv.wait(l);
done = grav_ready;
thread_done = gravthread_done;
}
}
}
void Gravity::start_grav_async()
{
if (enabled) //If it's already enabled, restart it
stop_grav_async();
gravthread_done = 0;
grav_ready = 0;
gravthread = std::thread([this]() { update_grav_async(); }); //Start asynchronous gravity simulation
enabled = true;
unsigned int size = (XRES / CELL) * (YRES / CELL);
std::fill(&gravy[0], &gravy[size], 0.0f);
std::fill(&gravx[0], &gravx[size], 0.0f);
std::fill(&gravp[0], &gravp[size], 0.0f);
std::fill(&gravmap[0], &gravmap[size], 0.0f);
}
void Gravity::stop_grav_async()
{
if (enabled)
{
{
std::lock_guard<std::mutex> g(gravmutex);
gravthread_done = 1;
}
gravcv.notify_one();
gravthread.join();
enabled = false;
}
// Clear the grav velocities
unsigned int size = (XRES / CELL) * (YRES / CELL);
std::fill(&gravy[0], &gravy[size], 0.0f);
std::fill(&gravx[0], &gravx[size], 0.0f);
std::fill(&gravp[0], &gravp[size], 0.0f);
std::fill(&gravmap[0], &gravmap[size], 0.0f);
}
#ifdef GRAVFFT
void Gravity::update_grav()
{
int xblock2 = XRES/CELL*2, yblock2 = YRES/CELL*2;
int fft_tsize = (xblock2/2+1)*yblock2;
float mr, mc, pr, pc, gr, gc;
if (memcmp(th_ogravmap, th_gravmap, sizeof(float)*(XRES/CELL)*(YRES/CELL)) != 0)
{
th_gravchanged = 1;
membwand(th_gravmap, gravmask, (XRES/CELL)*(YRES/CELL)*sizeof(float), (XRES/CELL)*(YRES/CELL)*sizeof(unsigned));
//copy gravmap into padded gravmap array
for (int y = 0; y < YRES / CELL; y++)
{
for (int x = 0; x < XRES / CELL; x++)
{
th_gravmapbig[(y+YRES/CELL)*xblock2+XRES/CELL+x] = th_gravmap[y*(XRES/CELL)+x];
}
}
//transform gravmap
fftwf_execute(plan_gravmap);
//do convolution (multiply the complex numbers)
for (int i = 0; i < fft_tsize; i++)
{
mr = th_gravmapbigt[i][0];
mc = th_gravmapbigt[i][1];
pr = th_ptgravxt[i][0];
pc = th_ptgravxt[i][1];
gr = mr*pr-mc*pc;
gc = mr*pc+mc*pr;
th_gravxbigt[i][0] = gr;
th_gravxbigt[i][1] = gc;
pr = th_ptgravyt[i][0];
pc = th_ptgravyt[i][1];
gr = mr*pr-mc*pc;
gc = mr*pc+mc*pr;
th_gravybigt[i][0] = gr;
th_gravybigt[i][1] = gc;
}
//inverse transform, and copy from padded arrays into normal velocity maps
fftwf_execute(plan_gravx_inverse);
fftwf_execute(plan_gravy_inverse);
for (int y = 0; y < YRES / CELL; y++)
{
for (int x = 0; x < XRES / CELL; x++)
{
th_gravx[y*(XRES/CELL)+x] = th_gravxbig[y*xblock2+x];
th_gravy[y*(XRES/CELL)+x] = th_gravybig[y*xblock2+x];
th_gravp[y*(XRES/CELL)+x] = sqrtf(pow(th_gravxbig[y*xblock2+x],2)+pow(th_gravybig[y*xblock2+x],2));
}
}
}
else
{
th_gravchanged = 0;
}
// Copy th_ogravmap into th_gravmap (doesn't matter what th_ogravmap is afterwards)
std::swap(th_gravmap, th_ogravmap);
}
#else
// gravity without fast Fourier transforms
void Gravity::update_grav(void)
{
int x, y, i, j, changed = 0;
float val, distance;
th_gravchanged = 0;
#ifndef GRAV_DIFF
//Find any changed cells
for (i=0; i<YRES/CELL; i++)
{
if(changed)
break;
for (j=0; j<XRES/CELL; j++)
{
if(th_ogravmap[i*(XRES/CELL)+j]!=th_gravmap[i*(XRES/CELL)+j]){
changed = 1;
break;
}
}
}
if(!changed)
goto fin;
memset(th_gravy, 0, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memset(th_gravx, 0, (XRES/CELL)*(YRES/CELL)*sizeof(float));
#endif
th_gravchanged = 1;
membwand(th_gravmap, gravmask, (XRES/CELL)*(YRES/CELL)*sizeof(float), (XRES/CELL)*(YRES/CELL)*sizeof(unsigned));
for (i = 0; i < YRES / CELL; i++) {
for (j = 0; j < XRES / CELL; j++) {
#ifdef GRAV_DIFF
if (th_ogravmap[i*(XRES/CELL)+j] != th_gravmap[i*(XRES/CELL)+j])
{
#else
if (th_gravmap[i*(XRES/CELL)+j] > 0.0001f || th_gravmap[i*(XRES/CELL)+j]<-0.0001f) //Only calculate with populated or changed cells.
{
#endif
for (y = 0; y < YRES / CELL; y++) {
for (x = 0; x < XRES / CELL; x++) {
if (x == j && y == i)//Ensure it doesn't calculate with itself
continue;
distance = sqrt(pow(j - x, 2.0f) + pow(i - y, 2.0f));
#ifdef GRAV_DIFF
val = th_gravmap[i*(XRES/CELL)+j] - th_ogravmap[i*(XRES/CELL)+j];
#else
val = th_gravmap[i*(XRES/CELL)+j];
#endif
th_gravx[y*(XRES/CELL)+x] += M_GRAV * val * (j - x) / pow(distance, 3.0f);
th_gravy[y*(XRES/CELL)+x] += M_GRAV * val * (i - y) / pow(distance, 3.0f);
th_gravp[y*(XRES/CELL)+x] += M_GRAV * val / pow(distance, 2.0f);
}
}
}
}
}
fin:
memcpy(th_ogravmap, th_gravmap, (XRES/CELL)*(YRES/CELL)*sizeof(float));
}
#endif
bool Gravity::grav_mask_r(int x, int y, char checkmap[YRES/CELL][XRES/CELL], char shape[YRES/CELL][XRES/CELL])
{
int x1, x2;
bool ret = false;
try
{
CoordStack cs;
cs.push(x, y);
do
{
cs.pop(x, y);
x1 = x2 = x;
while (x1 >= 0)
{
if (x1 == 0)
{
ret = true;
break;
}
else if (checkmap[y][x1-1] || bmap[y][x1-1] == WL_GRAV)
break;
x1--;
}
while (x2 <= XRES/CELL-1)
{
if (x2 == XRES/CELL-1)
{
ret = true;
break;
}
else if (checkmap[y][x2+1] || bmap[y][x2+1] == WL_GRAV)
break;
x2++;
}
for (x = x1; x <= x2; x++)
{
shape[y][x] = 1;
checkmap[y][x] = 1;
}
if (y == 0)
{
for (x = x1; x <= x2; x++)
if (bmap[y][x] != WL_GRAV)
ret = true;
}
else if (y >= 1)
{
for (x = x1; x <= x2; x++)
if (!checkmap[y-1][x] && bmap[y-1][x] != WL_GRAV)
{
if (y-1 == 0)
ret = true;
cs.push(x, y-1);
}
}
if (y < YRES/CELL-1)
for (x=x1; x<=x2; x++)
if (!checkmap[y+1][x] && bmap[y+1][x] != WL_GRAV)
{
if (y+1 == YRES/CELL-1)
ret = true;
cs.push(x, y+1);
}
} while (cs.getSize()>0);
}
catch (std::exception& e)
{
std::cerr << e.what() << std::endl;
ret = false;
}
return ret;
}
void Gravity::mask_free(mask_el *c_mask_el)
{
if (c_mask_el == nullptr)
return;
delete[] c_mask_el->next;
delete[] c_mask_el->shape;
delete[] c_mask_el;
}
void Gravity::gravity_mask()
{
char checkmap[YRES/CELL][XRES/CELL];
unsigned maskvalue;
mask_el *t_mask_el = nullptr;
mask_el *c_mask_el = nullptr;
if (!gravmask)
return;
memset(checkmap, 0, sizeof(checkmap));
for (int x = 0; x < XRES / CELL; x++)
{
for(int y = 0; y < YRES / CELL; y++)
{
if (bmap[y][x] != WL_GRAV && checkmap[y][x] == 0)
{
// Create a new shape
if (t_mask_el == nullptr)
{
t_mask_el = new mask_el[sizeof(mask_el)];
t_mask_el->shape = new char[(XRES / CELL) * (YRES / CELL)];
std::fill(&t_mask_el->shape[0], &t_mask_el->shape[(XRES / CELL) * (YRES / CELL)], 0);
t_mask_el->shapeout = 0;
t_mask_el->next = nullptr;
c_mask_el = t_mask_el;
}
else
{
c_mask_el->next = new mask_el[sizeof(mask_el)];
c_mask_el = c_mask_el->next;
c_mask_el->shape = new char[(XRES / CELL) * (YRES / CELL)];
std::fill(&c_mask_el->shape[0], &c_mask_el->shape[(XRES / CELL) * (YRES / CELL)], 0);
c_mask_el->shapeout = 0;
c_mask_el->next = nullptr;
}
// Fill the shape
if (grav_mask_r(x, y, checkmap, reinterpret_cast<char(*)[XRES/CELL]>(c_mask_el->shape)))
c_mask_el->shapeout = 1;
}
}
}
c_mask_el = t_mask_el;
std::fill(&gravmask[0], &gravmask[(XRES / CELL) * (YRES / CELL)], 0);
while (c_mask_el != nullptr)
{
char *cshape = c_mask_el->shape;
for (int x = 0; x < XRES / CELL; x++)
{
for (int y = 0; y < YRES / CELL; y++)
{
if (cshape[y * (XRES / CELL) + x])
{
if (c_mask_el->shapeout)
maskvalue = 0xFFFFFFFF;
else
maskvalue = 0x00000000;
gravmask[y * (XRES / CELL) + x] = maskvalue;
}
}
}
c_mask_el = c_mask_el->next;
}
mask_free(t_mask_el);
}