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Diffstat (limited to 'bin/brot.c')
| -rw-r--r-- | bin/brot.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/bin/brot.c b/bin/brot.c new file mode 100644 index 00000000..69f11e59 --- /dev/null +++ b/bin/brot.c @@ -0,0 +1,151 @@ +/* Copyright (C) 2018 June 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.h" + +static uint32_t rgb(uint8_t r, uint8_t g, uint8_t b) { + return (uint32_t)r << 16 | (uint32_t)g << 8 | (uint32_t)b; +} +static uint32_t gray(uint8_t n) { + return 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; +} |