💾 Archived View for marginalia.nu › junk › very-old-code.cc.gmi captured on 2021-12-17 at 13:26:06. Gemini links have been rewritten to link to archived content
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A sample of very old code I once wrote, with no thought of ever coming back to maintain it. Then I came back 10+ years later and got it running with a lot of effort.
The result (even if the compression doesn't do it justice):
https://archive.org/details/NebulabrotFractalTumblinginFourDimensions
#include <stdlib.h>
#include <math.h>
#include <fcntl.h>
#include <unistd.h>
#include "SDL.h"
#define WIDTH 1920
#define HEIGHT 1080
#define LENGTH 50000
#define LIMG 50
#define LIMB 1
#define SUBSTEP 0.125
#include <vector>
#include <utility>
#include <iostream>
#include <fstream>
using namespace std;
double mapr[WIDTH][HEIGHT];
double mapg[WIDTH][HEIGHT];
double mapb[WIDTH][HEIGHT];
double theta;
int Z = 0;
int W = 0;
const double SQRT2 = M_SQRT2*2.0;
double angle[6] = { 0, 0, 0, 0, 0, 0, } ;
vector<pair<double,double>> coords;
vector<pair<double,double>> origins;
vector<int> lens;
int li;
void mapbrot(double x, double y, double z, double w) {
double cx = x + z, cy = y + w;
double cx2 = cx*cx, cy2 = cy*cy;
int iter = 0;
double cx0 = cx;
double cy0 = cy;
vector<pair<double,double>> orbit;
// orbit.push_back(make_pair(cy,cx));
while(cx2+cy2 < 4) {
if(iter++ > LENGTH) return;
cy = 2*cx*cy + y;
cx = cx2 - cy2 + x;
cx2 = cx*cx;
cy2 = cy*cy;
orbit.push_back(make_pair(cy,cx));
if(cx == cx0 && cy == cy0) return;
}
coords.insert(end(coords), begin(orbit), end(orbit));
origins.push_back({x+z,y+w});
lens.push_back(iter);
}
void render() {
double ca0 = cos(angle[0]);
double ca1 = cos(angle[1]);
double ca2 = cos(angle[2]);
double ca3 = cos(angle[3]);
double ca4 = cos(angle[4]);
double ca5 = cos(angle[5]);
double sa0 = sin(angle[0]);
double sa1 = sin(angle[1]);
double sa2 = sin(angle[2]);
double sa3 = sin(angle[3]);
double sa4 = sin(angle[4]);
double sa5 = sin(angle[5]);
long iter = 0;
for (int i = 0; i < lens.size(); i++) {
double x = origins[i].first;
double y = origins[i].second;
int li = lens[i];
for (int j = 0; j < li; j++,iter++) {
double xp = coords[iter].first * ca0 - coords[iter].second * sa0;
double yp = coords[iter].first * sa0 + coords[iter].second * ca0;
double zp = x * ca1 - y * sa1;
double wp = x * sa1 + y * ca1;
double cxp = xp * ca2 - zp * sa2;
double czp = xp * sa2 + zp * ca2;
double cyp = yp * ca3 - wp * sa3;
double cwp = yp * sa3 + wp * ca3;
xp = cxp * ca4 - cwp * sa4;
wp = cxp * sa4 + cwp * ca4;
yp = cyp * ca5 - czp * sa5;
zp = cyp * sa5 + czp * ca5;
int xc = (WIDTH - HEIGHT) / 2 + (1.5*yp+2.5)*HEIGHT/4.0;
int yc = (1.5*xp+2)*HEIGHT/4.0;
if(xc>=0 && yc>=0 && xc < WIDTH && yc < HEIGHT) {
mapr[xc][yc]+=j/(double) li;
mapg[xc][yc]+=1 - j/(double) li;
//mapg[xc][yc]++;
mapb[xc][yc]++;
//` mapb[xc][yc]+=1.0 - j/(double) li;
}
xp = -coords[iter].first * ca0 - coords[iter].second * sa0;
yp = -coords[iter].first * sa0 + coords[iter].second * ca0;
zp = x*ca1 + y * sa1;
wp = x*sa1 - y * ca1;
cxp = xp * ca2 - zp * sa2;
czp = xp * sa2 + zp * ca2;
cyp = yp * ca3 - wp * sa3;
cwp = yp * sa3 + wp * ca3;
xp = cxp * ca4 - cwp * sa4;
wp = cxp * sa4 + cwp * ca4;
yp = cyp * ca5 - czp * sa5;
zp = cyp * sa5 + czp * ca5;
xc = (WIDTH - HEIGHT)/2 + (1.5*yp+2.5)*HEIGHT/4.0;
yc = (1.5*xp+2)*HEIGHT/4.0;
if(xc>=0 && yc>=0 && xc < WIDTH && yc < HEIGHT) {
mapr[xc][yc]+=j/(double) li;
mapg[xc][yc]+=1 - j/(double) li;
// mapg[xc][yc]++;
mapb[xc][yc]++;
}
}
}
}
double min(double a, double b) {
if (a < b) {
return a;
}
else {
return b;
}
}
SDL_Surface* s = NULL;
int mval[3] = { 0, 0, 0 };
void paint() {
int x, y;
if (mval[0] == 0) {
for(x = 0; x < WIDTH; x++) {
for(y = 0; y < HEIGHT; y++) {
if(mapr[x][y] > mval[0]) mval[0] = mapr[x][y];
if(mapg[x][y] > mval[1]) mval[1] = mapg[x][y];
if(mapb[x][y] > mval[2]) mval[2] = mapb[x][y];
}
}
}
for(x = 0; x < WIDTH; x++) {
for(y = 0; y < HEIGHT; y++) {
SDL_Rect r;
r.x = x;
r.y = y;
r.w = 1;
r.h = 1;
int R = 255.0 * min(1.0, mapr[x][y] / (double)mval[0]);
int G = 255.0 * min(1.0, mapg[x][y] / (double)mval[1]);
int B = 255.0 * min(1.0, mapb[x][y] / (double)mval[2]);
SDL_FillRect(s, &r, SDL_MapRGB(s->format, R, G, B));
mapr[x][y] = mapg[x][y] = mapb[x][y] = 0;
}
}
SDL_Flip(s);
};
void mbrotsweep() {
int X, Y;
for(X = 0; X < WIDTH; X++) {
for(Y = 0; Y < HEIGHT; Y++) {
mapr[X][Y] = 0;
mapg[X][Y] = 0;
mapb[X][Y] = 0;
}
}
render();
paint();
}
void save() {
static int i = 0;
char filename[16];
sprintf(filename, "out%.4d.bmp.tmp", i);
SDL_WM_SetCaption(filename, NULL);
SDL_SaveBMP(s, filename);
char filename2[16];
sprintf(filename2, "out%.4d.bmp", i++);
rename(filename, filename2);
}
void exportFile() {
ofstream of("out.dat", ios::out | ios::binary | ios::trunc);
printf("%d\n", lens.size());
int sz = lens.size();
of.write(reinterpret_cast<char *>(&sz), sizeof(sz));
// of << lens.size();
for (int i : lens) {
of.write(reinterpret_cast<char *>(&i), sizeof(i));
}
printf("%d\n", origins.size());
sz = origins.size();
of.write(reinterpret_cast<char *>(&sz), sizeof(sz));
for (pair<double,double> p : origins) {
of.write(reinterpret_cast<char *>(&p.first), sizeof(p.first));
of.write(reinterpret_cast<char *>(&p.second), sizeof(p.second));
}
printf("%d\n", coords.size());
sz = coords.size();
of.write(reinterpret_cast<char *>(&sz), sizeof(sz));
for (pair<double,double> p : coords) {
of.write(reinterpret_cast<char *>(&p.first), sizeof(p.first));
of.write(reinterpret_cast<char *>(&p.second), sizeof(p.second));
}
}
void importFile() {
ifstream ifs("out.dat", ios::in | ios::binary);
int i; double x; double y;
ifs.read(reinterpret_cast<char *>(&i), sizeof(i));
printf("%d\n", i);
fflush(NULL);
lens.reserve(i);
for (int j = 0; j < i; j++) {
int k;
ifs.read(reinterpret_cast<char *>(&k), sizeof(k));
lens.push_back(k);
}
ifs.read(reinterpret_cast<char *>(&i), sizeof(i));
printf("%d\n", i);
fflush(NULL);
origins.reserve(i);
for (int j = 0; j < i; j++) {
ifs.read(reinterpret_cast<char *>(&x), sizeof(x));
ifs.read(reinterpret_cast<char *>(&y), sizeof(y));
origins.push_back({x,y});
}
ifs.read(reinterpret_cast<char *>(&i), sizeof(i));
printf("%d\n", i);
fflush(NULL);
coords.reserve(i);
for (int j = 0; j < i; j++) {
ifs.read(reinterpret_cast<char *>(&x), sizeof(x));
ifs.read(reinterpret_cast<char *>(&y), sizeof(y));
coords.push_back({x,y});
}
}
int main(int argc, char* argv[]) {
SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);
s = SDL_SetVideoMode(WIDTH, HEIGHT, 16, SDL_SWSURFACE);
double x, y;
/* for(x = 0; x < WIDTH; x+=SUBSTEP) {
printf("%2.2f%% - %d - %2.2f Mb \n", (100.0*x)/WIDTH, coords.size(), 8 * coords.size() / 1024 / 1024.);
for(y = 0; y < (HEIGHT)/2; y+=SUBSTEP) {
mapbrot((double)4*(x-WIDTH/2) / (double) WIDTH, (double)4*(y-HEIGHT/2) / (double) HEIGHT, 0, 0);
}
}*/
// exportFile();
importFile();
const double step = M_PI / 40000.0;
double t = M_PI/3.0;
for(t = 0; t < 2*M_PI; t+=step) {
angle[2]=M_PI+M_PI*cos(t);
angle[3]=M_PI+M_PI*cos(2*t);
angle[4]=M_PI+M_PI*cos(3*t);
angle[5]=M_PI+M_PI*cos(5*t);
mbrotsweep();
save();
}
/*
for(angle[2] = 0; angle[2] < 2*M_PI; angle[2]+=step) {
frame(angle);
save();
}
angle[2] = 0;
for(angle[3] = 0; angle[3] < 2*M_PI; angle[3]+=step) {
frame(angle);
save();
}
angle[3] = 0;
for(angle[4] = 0; angle[4] < 2*M_PI; angle[4]+=step) {
frame(angle);
save();
}
angle[4] = 0;
for(angle[5] = 0; angle[5] < 2*M_PI; angle[5]+=step) {
frame(angle);
save();
}
angle[5] = 0;
for(angle[2] = 0; angle[2] < M_PI/2; angle[2]+=step) {
frame(angle);
save();
}
angle[2] = M_PI/2;
for(angle[3] = 0; angle[3] < M_PI; angle[3]+=step) {
frame(angle);
save();
}
angle[3] = M_PI;
for(angle[5] = 0; angle[5] < M_PI; angle[5]+=step) {
frame(angle);
save();
}
angle[5] = M_PI;
for(angle[2] = M_PI/2; angle[2] < M_PI; angle[2]+=step) {
frame(angle);
save();
}
angle[2] = M_PI;
for(angle[3] = M_PI; angle[3] < 2*M_PI; angle[3]+=step) {
frame(angle);
save();
}
angle[3] = M_PI*2;
for(angle[5] = M_PI; angle[5] < M_PI*2; angle[5]+=step) {
frame(angle);
save();
}*/
printf("\nALL DONE\n");
for(;;) SDL_Flip(s);
}
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