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/* Copyright (C) 2018 Curtis McEnroe <june@causal.agency>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <complex.h>
#include <err.h>
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
#include <unistd.h>
#include "gfx/gfx.h"
static double absSq(double complex z) {
return creal(z) * creal(z) + cimag(z) * cimag(z);
}
static uint32_t depth = 50;
static uint32_t mandelbrot(double complex c) {
double complex z = 0;
for (uint32_t i = 0; i < depth; ++i) {
if (absSq(z) > 4.0) return i;
z = z * z + c;
}
return 0;
}
static uint32_t color(uint32_t n) {
uint32_t gray = (double)n / (double)depth * 255.0;
return gray << 16 | gray << 8 | gray;
}
static double complex translate = -0.75;
static double complex transform = 2.5;
void draw(uint32_t *buf, size_t width, size_t height) {
double yRatio = (height > width) ? (double)height / (double)width : 1.0;
double xRatio = (width > height) ? (double)width / (double)height : 1.0;
for (size_t y = 0; y < height; ++y) {
for (size_t x = 0; x < width; ++x) {
double zx = ((double)x / (double)width - 0.5) * xRatio;
double zy = ((double)y / (double)height - 0.5) * yRatio;
uint32_t n = mandelbrot((zx + zy * I) * transform + translate);
buf[y * width + x] = color(n);
}
}
}
static double translateStep = 1.0 / 128.0;
static double rotateStep = 1.0 / 128.0;
static double scaleStep = 1.0 / 32.0;
bool input(char in) {
const double PI = acos(-1.0);
switch (in) {
case 'q': return false;
break; case '.': depth++;
break; case ',': if (depth) depth--;
break; case 'l': translate += translateStep * transform;
break; case 'h': translate -= translateStep * transform;
break; case 'j': translate += translateStep * I * transform;
break; case 'k': translate -= translateStep * I * transform;
break; case 'u': transform *= cexp(rotateStep * PI * I);
break; case 'i': transform /= cexp(rotateStep * PI * I);
break; case '+': transform *= 1.0 - scaleStep;
break; case '-': transform /= 1.0 - scaleStep;
}
return true;
}
const char *status(void) {
static char buf[256];
snprintf(
buf, sizeof(buf),
"brot -i %u -t %g%+gi -f %g%+gi",
depth,
creal(translate), cimag(translate),
creal(transform), cimag(transform)
);
return buf;
}
static double complex parseComplex(const char *str) {
double real = 0.0, imag = 0.0;
real = strtod(str, (char **)&str);
if (str[0] == 'i') {
imag = real;
real = 0.0;
} else if (str[0]) {
imag = strtod(str, NULL);
}
return real + imag * I;
}
int init(int argc, char *argv[]) {
int opt;
while (0 < (opt = getopt(argc, argv, "f:i:t:"))) {
switch (opt) {
case 'f': transform = parseComplex(optarg); break;
case 'i': depth = strtoul(optarg, NULL, 0); break;
case 't': translate = parseComplex(optarg); break;
default: return EX_USAGE;
}
}
return EX_OK;
}
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