// 2>/dev/null; set -e; [ .mb.elf -nt "$0" ] || gcc -o .mb.elf -std=gnu99 -Wall -O3 "$0" -lm; exec ./.mb.elf "$@"

#include <math.h>
#include <complex.h>
#include <linux/fb.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <signal.h>

void quit(int s)
{
	system("tput cnorm");
	exit(s && 1);
}

int main(int argc, char *argv[])
{

	// parameters
	double outside = 16, ox = -0.5, oy = 0, r = 1.5;
	long max_i = 50, rb_i = 30;
	char **p = argv;
	if (*++p) { ox = atof(*p);
	if (*++p) { oy = atof(*p);
	if (*++p) { r = atof(*p);
	if (*++p) { max_i = atoi(*p);
	if (*++p) { rb_i = atoi(*p);
	if (*++p) { outside = atof(*p);
	}}}}}}

	// framebuffer
	signal(SIGINT, quit);
	system("tput civis");
	int fb = open("/dev/fb0", O_RDWR);
	struct fb_var_screeninfo framebuffer_info;
	ioctl(fb, FBIOGET_VSCREENINFO, &framebuffer_info);
	int w = framebuffer_info.xres;
	int h = framebuffer_info.yres;
	if (framebuffer_info.bits_per_pixel != 32)
		return 1;
	uint32_t *v = mmap(NULL, w*h*4, PROT_WRITE, MAP_SHARED, fb, 0);

	// rainbow
	uint32_t rb[360];
#define d2r(a) (M_PI*a/180)
#define rbc(a, b) ((cos(a-d2r(b))+1)/2)
#define byt(v) ((int)(v == 1 ? 255 : 256*v))
#define rgb(r, g, b) (byt(r)<<16 | byt(g)<<8 | byt(b))
	for (int A=0; A<360; ++A) {
		double a = A*M_PI/180;
		rb[A] = rgb( rbc(a, -120), .9 * rbc(a, 0), rbc(a, 120) );
	}

	// smoothing
	int smooth_n = 8; // 32
	double smooth_fac = pow(2, 1.0/smooth_n);
	double smooth_outside[smooth_n];
	for (int i=0; i<smooth_n; ++i)
		smooth_outside[i] = pow(outside, pow(smooth_fac, i));
#define smooth_i(i, z) \
double a = cabs(z); \
i = i * smooth_n + smooth_n-1; \
for (int j=1; j<smooth_n && a >= smooth_outside[j]; ++j, --i);
	int max_i_smooth = max_i * smooth_n, rb_i_smooth = rb_i * smooth_n;

	// mandelbrot set, slowly
	double d = 2*r/h, x0 = ox-d*w/2, y0 = oy+d*h/2;
	for (int y=0; y<h; ++y) {
		complex c = x0 + (y0-d*y)*I;
		for (int x=0; x<w; ++x) {
			complex z = c;
			long i;
			for (i=0; i < max_i && cabs(z) < outside; ++i)
				z = z*z + c;
			smooth_i(i, z);
			*v++ = i < max_i_smooth ? rb[i*359 / rb_i_smooth % 360] : 0;
			c += d;
		}
	}

	getchar();

	if (argc == 1)
		execl(argv[0], argv[0], "-.743643135", ".131825963", ".0000054855", "16000", "400", NULL);

	quit(0);
}