README.md

mandelbrot

build & run

make clean && make && ./mandelbrot

command

• awsd * for moving camera;
• qe * for zoom in/out;
• QE * for rotate camera.

Makefile

CC=cc
LIBS=-lncurses -lm
CFLAGS=-Wall -O3
SRC=$(wildcard *.c)
OBJ=$(SRC:.c=.o)
TARGET=mandelbrot

all: ${OBJ}
	${CC} $(CFLAGS) $(LIBS) $^ -o ${TARGET}

%.o: %.c
	${CC} ${CFLAGS} -c $< -o $@

clean: 
	rm -f *.o ${TARGET}

mandelbrot.c

#include <curses.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#define PI 3.1415926538

static const char tone[] = "$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\\|()1{}[]?-_+~<>i!lI;:,\"^`'. ";
static const int tone_size = 70;

char get_tone(int esc, int limit) {
  return tone[tone_size * (limit - esc) / limit];
}

int escape(double x, double y, int limit, double range) {
  double a=0, b=0, step;
  for(step=0;step<limit-1 && a*a+b*b<range;step++) {
    double tmp = a*a - b*b + x;
    b = 2*a*b + y;
    a = tmp;
  }
  return step;
}

int main(void) {
  WINDOW * mainwin;
  if ((mainwin = initscr()) == NULL) {
    fprintf(stderr, "Error initialising ncurses.\n");
    exit(EXIT_FAILURE);
  }
  
  cbreak();
  noecho();
  // nodelay(mainwin, TRUE);
  int key = -1;
  double cx = -0.75, cy = 0, 
         scalar_x=0.037, scalar_y=scalar_x*1.5, 
         angle = 0;
  double mv_x = 0.15, mv_y = 0.3, mv_a = PI / 6, mv_z = 1.3;
  int limit = 255;
  double range = 1000.0;
  char title[1024];
  do {
    // get screen size
    int win_x, win_y;
    getmaxyx(mainwin, win_y, win_x);
    // move
    switch (key) {
      case 65:
      case 'w':
        cx += win_x * scalar_x * mv_x * sin(angle);
        cy -= win_y * scalar_y * mv_y * cos(angle);
        break;
      case 66:
      case 's':
        cx -= win_x * scalar_x * mv_x * sin(angle);
        cy += win_y * scalar_y * mv_y * cos(angle);
        break;
      case 68:
      case 'a':
        cx -= win_x * scalar_x * mv_x * cos(angle);
        cy -= win_y * scalar_y * mv_y * sin(angle);
        break;
      case 67:
      case 'd':
        cx += win_x * scalar_x * mv_x * cos(angle);
        cy += win_y * scalar_y * mv_y * sin(angle);
        break;
      case 'q':
        scalar_x *= mv_z;
        scalar_y *= mv_z;
        break;
      case 'e':
        scalar_x /= mv_z;
        scalar_y /= mv_z;
        break;
      case 'Q':
        angle -= mv_a;
        if (angle < 0) angle += PI * 2;
        break;
      case 'E':
        angle += mv_a;
        if (angle > PI * 2) angle -= PI * 2;
        break;
    }
    // draw
    double sn = sin(angle), cs = cos(angle);
    for (int y=0;y<win_y;y++) {
      move(y, 0);
      for (int x=0;x<win_x;x++) {
        double oy = (y - win_y/2) * scalar_y;
        double ox = (x - win_x/2) * scalar_x;
        double py = cy + ox * sn + oy * cs;
        double px = cx + ox * cs - oy * sn;
        int esc = escape(px, py, limit, range);
        addch(get_tone(esc, limit));
      }
    }
    int deg = (int) (angle/PI*180);
    sprintf(title, "X:%.2f Y:%.2f Z:%.8f A:%3d", cx, cy, scalar_x, deg);
    mvaddstr(0, 0, title);
    refresh();
    key = getch();
  } while (TRUE);

  delwin(mainwin);
  endwin();
  refresh();

  return EXIT_SUCCESS;
}