summary refs log tree commit diff
path: root/bin/brot.c
blob: 576ca77013262effb582833f64ec3819b958b382 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/* 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 <string.h>
#include <sysexits.h>
#include <time.h>
#include <unistd.h>

#include "gfx/gfx.h"

#define RGB(r, g, b) ((uint32_t)(r) << 16 | (uint32_t)(g) << 8 | (uint32_t)(b))
#define GRAY(n) RGB(n, n, n)

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 double complex translate = -0.75;
static double complex transform = 2.5;

static uint32_t samples = 1;

static void sample(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;

	memset(buf, 0, 4 * width * height);
	size_t superWidth = width * samples;
	size_t superHeight = height * samples;
	for (size_t y = 0; y < superHeight; ++y) {
		for (size_t x = 0; x < superWidth; ++x) {
			double zx = (((double)x + 0.5) / (double)superWidth - 0.5) * xRatio;
			double zy = (((double)y + 0.5) / (double)superHeight - 0.5) * yRatio;
			uint32_t n = mandelbrot((zx + zy * I) * transform + translate);
			buf[(y / samples) * width + (x / samples)] += n;
		}
	}
}

static void color(uint32_t *buf, size_t width, size_t height) {
	for (size_t i = 0; i < width * height; ++i) {
		buf[i] = GRAY(255 * buf[i] / samples / samples / depth);
	}
}

static double frameTime;
void draw(uint32_t *buf, size_t width, size_t height) {
	clock_t t0 = clock();
	sample(buf, width, height);
	color(buf, width, height);
	frameTime = (double)(clock() - t0) / (double)CLOCKS_PER_SEC;
}

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) {
		break; case 'q': return false;
		break; case '.': depth++;
		break; case ',': if (depth > 1) 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;
		break; case '0': translate = -0.75; transform = 2.5;
		break; case ']': samples++;
		break; case '[': if (samples > 1) samples--;
	}
	return true;
}

const char *status(void) {
	static char buf[256];
	snprintf(
		buf, sizeof(buf),
		"brot -s %u -i %u -t %g%+gi -f %g%+gi # %.6f",
		samples, depth,
		creal(translate), cimag(translate),
		creal(transform), cimag(transform),
		frameTime
	);
	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:s:t:"))) {
		switch (opt) {
			break; case 'f': transform = parseComplex(optarg);
			break; case 'i': depth = strtoul(optarg, NULL, 0);
			break; case 's': samples = strtoul(optarg, NULL, 0);
			break; case 't': translate = parseComplex(optarg);
			break; default: return EX_USAGE;
		}
	}
	return EX_OK;
}