File:Mandelbrot Set Color Cycling Animation 600px 7.gif

#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <cstdint>
#include <string>
#include <atomic>
#include <omp.h>
#include <cstdio>
using namespace std;
const double PI = 3.14159265358979323846;

#pragma pack(push, 1)
struct BMPHeader {
uint16_t type{0x4D42};
uint32_t size{0};
uint16_t reserved1{0};
uint16_t reserved2{0};
uint32_t offBits{54};
uint32_t structSize{40};
int32_t  width{0};
int32_t  height{0};
uint16_t planes{1};
uint16_t bitCount{24};
uint32_t compression{0};
uint32_t sizeImage{0};
int32_t  xpelsPerMeter{2834};
int32_t  ypelsPerMeter{2834};
uint32_t clrUsed{0};
uint32_t clrImportant{0};};

#pragma pack(pop)
void save_bmp(const string& filename, const vector<uint8_t>& data, int w, int h) {
int rowSize = (w * 3 + 3) & ~3;
BMPHeader header;
header.width = w;
header.height = h;
header.sizeImage = rowSize * h;
header.size = header.sizeImage + 54;
ofstream f(filename, ios::binary);
f.write(reinterpret_cast<char*>(&header), 54);
f.write(reinterpret_cast<const char*>(data.data()), data.size());
f.close();}

int main() {
long double absc = -1.749675773048651182L;
long double ordi = -0.000001140170813768L;
long double size_val = 0.0000000000000021L;
const int targetW = 3840;
const int targetH = 3840;
const int scale = 8;
const int rawW = targetW * scale;
const int rawH = targetH * scale;
cout << "Step 1: Calculating Raw Map (" << rawW << "x" << rawH << ")..." << endl;
vector<uint8_t> iterMap(rawW * rawH);
long double step = size_val / rawW;
long double startX = absc - (size_val / 2.0);
long double startY = ordi - (step * rawH / 2.0);
atomic<int> linesDone{0};

#pragma omp parallel for schedule(dynamic)
for (int b = 0; b < rawH; ++b) {
for (int a = 0; a < rawW; ++a) {
long double m = startX + a * step;
long double n = startY + b * step;
long double c = m, d = n, cc, dd;
int t = 50000;
do { cc = c * c; dd = d * d;
d = (c + c) * d + n;
c = cc - dd + m;
t--; } while (t > 0 && (cc + dd <= 50000.0));
if (t == 0) {
iterMap[b * rawW + a] = 255;} else {
iterMap[b * rawW + a] = (uint8_t)(t % 255); } }
if (++linesDone % 100 == 0) cout << "Progress: " << linesDone << "/" << rawH << "\r" << flush; }
uint8_t pal[256][3];
for (int a = 0; a < 255; ++a) {
pal[a][0] = (uint8_t)round(127 + 127 * cos(2 * PI * a / 255.0));
pal[a][1] = (uint8_t)round(127 + 127 * sin(2 * PI * a / 255.0));
pal[a][2] = (uint8_t)round(127 + 127 * sin(2 * PI * a / 255.0)); }
pal[255][0] = 255; pal[255][1] = 255; pal[255][2] = 255;
cout << "\nStep 2: Rendering frames..." << endl;
int rowSize = (targetW * 3 + 3) & ~3;
for (int frame = 0; frame < 255; ++frame) {
vector<uint8_t> frameData(rowSize * targetH);

#pragma omp parallel for schedule(static)
for (int y = 0; y < targetH; ++y) {
for (int x = 0; x < targetW; ++x) {
uint32_t rSum = 0, gSum = 0, bSum = 0;
for (int j = 0; j < scale; ++j) {
for (int i = 0; i < scale; ++i) {
uint8_t t = iterMap[(y * scale + j) * rawW + (x * scale + i)];
int colorIdx;
if (t == 255) { colorIdx = 255; } else { colorIdx = (t - frame + 255) % 255; }
bSum += pal[colorIdx][0];
gSum += pal[colorIdx][1];
rSum += pal[colorIdx][2]; } }
int outIdx = y * rowSize + x * 3;
frameData[outIdx + 0] = (uint8_t)(bSum >> 6);
frameData[outIdx + 1] = (uint8_t)(gSum >> 6);
frameData[outIdx + 2] = (uint8_t)(rSum >> 6); } }
string filename = "Mandelbrot" + to_string(1000 + frame).substr(1) + ".bmp";
save_bmp(filename, frameData, targetW, targetH);
cout << "Frame " << frame << "/254 saved.   \r" << flush; }
return 0; }