margen v1.2.4

* feat: Github CI

* add verbose to gcc

* reorder jobs

* add extra warnings and small fix

.github/workflows/ci.yml

@@ -0,0 +1,33 @@
+name: C-lang CI
+
+on:
+  push:
+    branches: ["master"]
+  pull_request:
+    branches: ["master"]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: gcc
+        run: mkdir -p build && gcc -v -Wall -Wextra -Werror src/*.c src/*.h -lm
+
+  build-release:
+    needs: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: aclocal
+        run: aclocal
+      - name: autoconf
+        run: autoconf
+      - name: automake
+        run: automake --add-missing
+      - name: configure
+        run: ./configure
+      - name: make
+        run: make
+      - name: make distcheck
+        run: make distcheck

.gitignore

@@ -2,3 +2,25 @@ build
 .vscode
 *.bmp
 !images/*
+*.cache
+.deps
+Makefile
+*.log
+*.o
+*.h.gch
+*.out
+.dirstamp
+aclocal.m4
+compile
+install-sh
+missing
+depcomp
+Makefile.in
+configure~
+config.status
+margen
+*.tar.gz
+configure
+src/margen*
+*.pkg.tar.zst
+pkg

Makefile

@@ -1,24 +0,0 @@
-TARGET ?= margen
-INSTALL_DIR ?= $(HOME)/.local/bin
-TEST_ARGS ?=
-SHELL := /bin/bash
-
-.PHONY: build
-clean:
-	@rm -rf build
-
-build:
-	@mkdir -p build
-	gcc -Wall src/*.c src/*.h -lm -o build/$(TARGET)
-
-.PHONY: install
-install: build
-	cp -f build/$(TARGET) $(INSTALL_DIR)/$(TARGET)
-
-.PHONY: time
-time: build
-	time ./build/$(TARGET) $(TEST_ARGS)
-
-.PHONY: valgrind
-valgrind: build
-	valgrind --leak-check=full -s ./build/$(TARGET) $(TEST_ARGS)

Makefile.am

@@ -0,0 +1,5 @@
+AUTOMAKE_OPTIONS = foreign subdir-objects -Wall
+bin_PROGRAMS = margen
+margen_SOURCES = src/main.c src/args.c src/bmp.c src/generator.c src/rand.c
+margen_CFLAGS = -Ofast -march=native -flto -funroll-loops -fprefetch-loop-arrays -fno-exceptions -fopenmp
+include_HEADERS = src/main.h src/args.h src/bmp.h src/generator.h src/rand.h src/config.h src/types.h

Makefile.dev

@@ -0,0 +1,47 @@
+TARGET ?= margen
+INSTALL_DIR ?= $(HOME)/.local/bin
+TEST_ARGS ?=
+SHELL := /bin/bash
+
+.PHONY: build
+clean:
+	@rm -rf build
+
+build:
+	@mkdir -p build
+	gcc -v -Wall -Wextra src/*.c src/*.h -lm -o build/$(TARGET)
+
+.PHONY: install
+install: build
+	cp -f build/$(TARGET) $(INSTALL_DIR)/$(TARGET)
+
+.PHONY: time
+time: build
+	time ./build/$(TARGET) $(TEST_ARGS)
+
+.PHONY: valgrind
+valgrind: build
+	valgrind --leak-check=full -s ./build/$(TARGET) $(TEST_ARGS)
+
+.PHONY: release
+release:
+	aclocal
+	autoconf
+	automake --add-missing
+	./configure
+	make distcheck
+
+.PHONY: release-arch
+release-arch: clean
+	mkdir -p build
+	cp PKGBUILD build
+	cd build && makepkg
+
+.PHONY: gif
+gif: build
+	mkdir -p tmp
+	for i in {1..50}; do \
+		./build/margen -w=1920 -h=720 --seed=$$i$$i -o=tmp/image$$i.bmp ; \
+	done
+	ffmpeg -y -f image2 -framerate 1 -i tmp/image%d.bmp -vf scale=960x360 images/sample.gif
+	rm -rf tmp

PKGBUILD

@@ -0,0 +1,20 @@
+pkgname=margen
+pkgver=1.2.4
+pkgrel=1
+pkgdesc="Generate a marble-like pattern bitmap image, blazing fast."
+arch=('i686' 'pentium4' 'x86_64' 'arm' 'armv7h' 'armv6h' 'aarch64' 'riscv64')
+url="https://github.com/klemek/margen"
+source=("${pkgname}-${pkgver}.tar.gz::https://github.com/klemek/margen/releases/download/v${pkgver}/${pkgname}-${pkgver}.tar.gz")
+sha256sums=('38fc6a66be97f6f77f9dffdbf75c214c7aa3ee8d1600b28506e943e6bfb93870')
+srcdir=build
+
+build() {
+  cd "$srcdir/$pkgname-$pkgver"
+  ./configure --prefix=/usr
+  make
+}
+
+package() {
+  cd "$srcdir/$pkgname-$pkgver"
+  sudo make DESTDIR="$pkgdir" install
+}

README.md

@@ -2,25 +2,52 @@
 
 > generate a marble-like pattern bitmap image, blazing fast.
 
-![](./images/sample1.bmp)
+<p align="center">
+  <img width="960" height="360" src="./images/sample.gif">
+</p>
 
 Written in pure C without librairies.
 
 ## Install
 
-You only need **gcc** and **make**.
+### From release
 
-```bash
+See [Releases](https://github.com/klemek/margen/releases)
+
+```sh
+tar xvzf margen-x.y.z.tar.gz
+cd margen-x.y.z
+./configure
+make
+make install
+```
+
+### From repository (PKGBUILD)
+
+```sh
 git clone https://github.com/klemek/margen
 cd margen
-make clean build install
-# margen is now installed in ~/.local/bin
+makepkg -si
+```
+
+
+### From repository (dev version)
+
+```sh
+git clone https://github.com/klemek/margen
+cd margen
+aclocal
+autoconf
+automake --add-missing
+./configure
+make
+make install
 ```
 
 ## CLI arguments
 
 ```txt
-usage: margen [--help] [-q] [-w=WIDTH] [-h=HEIGHT] [-o=PATH] [--seed=SEED][-p=PIXEL_SIZE] [-s=SLOPE] [-c=R,G,B] [-v=R,G,B] [-m]
+usage: margen [--help] [-v] [-q] [-w=WIDTH] [-h=HEIGHT] [-o=PATH] [--seed=SEED][-p=PIXEL_SIZE] [-s=SLOPE] [-c=R,G,B] [-va=R,G,B] [-vr=VAR_RANGE] [-r=ROTATION] [-m]
 
 generate a marble-like pattern bitmap image, blazing fast.
 
@@ -30,16 +57,34 @@ options:
   -w, --width        image width (default: 1920)
   -h, --height       image height (default: 1080)
   -o, --output       output file (default: output.bmp)
-  -seed              random seed (default: time based)
+  --seed             random seed (default: time based)
   -p, --pixel        pixel size (default: random)
   -s, --slope        slope [0-255] (default: random)
   -c, --color        base color [0-255,0-255,0-255] (default: random)
-  -v, --variation    base variation [0-255,0-255,0-255] (default: random)
-  -m, --monochrome   black & white generation
+  -va, --variation   fixed variation [0-255,0-255,0-255] (default: random)
+  -vr, --var-range   random variation range [0-255] (default: 30)
+  -r, --rotation     start corner rotation [0-3] (default: random)
+  -m, --monochrome   grayscale generation
 ```
 
-## TODO
+## Release guide
 
-- monochrome
-- select corner (currently bottom left)
-- better starting parameters for convergeance
+```bash
+# get latest version
+git pull origin master
+# update configure.ac with new version
+$EDITOR configure.ac
+# make full build
+make -f Makefile.dev release
+# update PKGBUILD with new version and sha256 sum
+sha256sum margen-x.y.z.tar.gz
+$EDITOR PKGBUILD
+# push to repo
+git commit -am "margen vX.Y.Z"
+git tag vX.Y.Z
+git push origin master --tags
+# create release from tag on github
+# attach .tar.gz to the github release
+make -f Makefile.dev release-arch
+# attach .pkg.tar.zst to the github release
+```

configure.ac

@@ -0,0 +1,10 @@
+AC_INIT([margen], [1.2.4], [klemek.dev@proton.me])
+AM_INIT_AUTOMAKE
+AC_PROG_CC
+AC_CHECK_HEADERS([stdio.h])
+AC_CHECK_HEADERS([stdlib.h])
+AC_CHECK_HEADERS([stdbool.h])
+AC_CHECK_HEADERS([string.h])
+AC_CHECK_HEADERS([time.h])
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT

src/args.c

@@ -1,5 +1,5 @@
 #include "args.h"
-#include "const.h"
+#include "config.h"
 #include "rand.h"
 #include <stdio.h>
 #include <stdlib.h>
@@ -7,9 +7,9 @@
 #include <time.h>
 
 void print_help(int status_code) {
-  puts(NAME
+  puts(PACKAGE
        " " VERSION "\n\n"
-       "usage: " NAME " "
+       "usage: " PACKAGE " "
        "[--help] "
        "[-v] "
        "[-q] "
@@ -20,8 +20,11 @@ void print_help(int status_code) {
        "[-p=PIXEL_SIZE] "
        "[-s=SLOPE] "
        "[-c=R,G,B] "
-       "[--var=R,G,B] "
-       "[-m]\n\n"
+       "[-va=R,G,B] "
+       "[-vr=VAR_RANGE] "
+       "[-r=ROTATION] "
+       "[-m]"
+       "\n\n"
        "generate a marble-like pattern bitmap image, blazing fast.\n\n"
        "options:\n"
        "  --help             show this help message and exit\n"
@@ -29,13 +32,15 @@ void print_help(int status_code) {
        "  -w, --width        image width (default: 1920)\n"
        "  -h, --height       image height (default: 1080)\n"
        "  -o, --output       output file (default: output.bmp)\n"
-       "  -seed              random seed (default: time based)\n"
+       "  --seed             random seed (default: time based)\n"
        "  -p, --pixel        pixel size (default: random)\n"
        "  -s, --slope        slope [0-255] (default: random)\n"
        "  -c, --color        base color [0-255,0-255,0-255] (default: random)\n"
-       "  -v, --variation    base variation [0-255,0-255,0-255] (default: "
+       "  -va, --variation   fixed variation [0-255,0-255,0-255] (default: "
        "random)\n"
-       "  -m, --monochrome   black & white generation");
+       "  -vr, --var-range   random variation range [0-255] (default: 30)\n"
+       "  -r, --rotation    start corner rotation [0-3] (default: random)\n"
+       "  -m, --monochrome   grayscale generation\n");
   exit(status_code);
 }
 
@@ -63,7 +68,7 @@ bool is_number(char *value) {
     return false;
   }
   unsigned long value_len = strlen(value);
-  int i;
+  unsigned int i;
   for (i = 0; i < value_len; i++) {
     if (!is_digit(value[i])) {
       return false;
@@ -94,7 +99,7 @@ unsigned short parse_ushort(char *arg, char *value) {
   return (unsigned short)tmp_value;
 }
 
-unsigned short parse_ulong(char *arg, char *value) {
+unsigned long parse_ulong(char *arg, char *value) {
   if (!is_number(value)) {
     invalid_value(arg, value);
   }
@@ -121,10 +126,13 @@ parameters parse_args(int argc, char **argv) {
   params.file_path = "output.bmp";
   params.monochrome = false;
 
+  unsigned char var_range = 30;
+
   bool size_set = false;
   bool slope_set = false;
   bool start_set = false;
   bool var_set = false;
+  bool rot_set = false;
 
   int i;
   char *arg;
@@ -137,7 +145,7 @@ parameters parse_args(int argc, char **argv) {
     } else if (is_arg(arg, "-q") || is_arg(arg, "--quiet")) {
       params.quiet = true;
     } else if (is_arg(arg, "-v") || is_arg(arg, "--version")) {
-      puts(NAME " " VERSION);
+      puts(PACKAGE " " VERSION);
       exit(0);
     } else if (is_arg(arg, "-w") || is_arg(arg, "--width")) {
       params.width = parse_ushort(arg, value);
@@ -171,9 +179,14 @@ parameters parse_args(int argc, char **argv) {
     } else if (is_arg(arg, "-c") || is_arg(arg, "--color")) {
       parse_color(arg, value, params.start);
       start_set = true;
-    } else if (is_arg(arg, "-v") || is_arg(arg, "--variation")) {
+    } else if (is_arg(arg, "-va") || is_arg(arg, "--variation")) {
       parse_color(arg, value, params.var);
       var_set = true;
+    } else if (is_arg(arg, "-vr") || is_arg(arg, "--var-range")) {
+      var_range = parse_char(arg, value);
+    } else if (is_arg(arg, "-r") || is_arg(arg, "--rotation")) {
+      params.rotation = parse_char(arg, value) % 4;
+      rot_set = true;
     } else if (is_arg(arg, "-m") || is_arg(arg, "--monochrome")) {
       params.monochrome = true;
     } else {
@@ -189,7 +202,7 @@ parameters parse_args(int argc, char **argv) {
   set_seed(params.seed);
 
   if (!size_set) {
-    params.size = rand_ushort(10) + 3;
+    params.size = rand_ushort(6) + 6;
   }
 
   if (!slope_set) {
@@ -203,9 +216,13 @@ parameters parse_args(int argc, char **argv) {
   }
 
   if (!var_set) {
-    params.var[0] = rand_uchar(20);
-    params.var[1] = rand_uchar(20);
-    params.var[2] = rand_uchar(20);
+    params.var[0] = rand_uchar(var_range + 1);
+    params.var[1] = rand_uchar(var_range + 1);
+    params.var[2] = rand_uchar(var_range + 1);
+  }
+
+  if (!rot_set) {
+    params.rotation = rand_uchar(4);
   }
 
   return params;

src/bmp.c

@@ -32,23 +32,36 @@ unsigned char *bmp_header(unsigned short width, unsigned short height,
   unsigned char *output = (unsigned char *)malloc(HEADER_SIZE);
   unsigned int data_length = ((unsigned int)width) * ((unsigned int)height) *
                              ((unsigned int)color_depth);
-  write_str(output, 0x00, 0x02, (unsigned char *)"BM"); // 0x00(2) BM
-  write_num(output, 0x02, 0x04,
-            HEADER_SIZE + data_length);       // 0x02(4) file size
-  write_nul(output, 0x06, 0x04);              // 0x06(4) application reserved
-  write_num(output, 0x0A, 0x04, HEADER_SIZE); // 0x0A(4) data offset
-  write_num(output, 0x0E, 0x04, 40);          // 0x0E(4) DIB header size
-  write_num(output, 0x12, 0x04, width);       // 0x12(4) width
-  write_num(output, 0x16, 0x04, height);      // 0x16(4) height
-  write_num(output, 0x1A, 0x04, 1);           // 0x1A(2) color panes
-  write_num(output, 0x1C, 0x02, color_depth * 8); // 0x1C(2) bits per pixel
-  write_nul(output, 0x1E, 0x04); // 0x1E(4) BI_RGB, no compression
-  write_num(output, 0x22, 0x04,
-            data_length);              // 0x22(4) size of raw bitmap data
-  write_num(output, 0x26, 0x04, 2835); // 0x26(4) horizontal print resolution
-  write_num(output, 0x2A, 0x04, 2835); // 0x2A(4) vertical print resolution
-  write_nul(output, 0x2E, 0x04);       // 0x2E(4) color in palette
-  write_nul(output, 0x32, 0x04);       // 0x32(4) 0 important colors
+  // 0x00(2) BM
+  write_str(output, 0x00, 0x02, (unsigned char *)"BM");
+  // 0x02(4) file size
+  write_num(output, 0x02, 0x04, HEADER_SIZE + data_length);
+  // 0x06(4) application reserved
+  write_nul(output, 0x06, 0x04);
+  // 0x0A(4) data offset
+  write_num(output, 0x0A, 0x04, HEADER_SIZE);
+  // 0x0E(4) DIB header size
+  write_num(output, 0x0E, 0x04, 40);
+  // 0x12(4) width
+  write_num(output, 0x12, 0x04, width);
+  // 0x16(4) height
+  write_num(output, 0x16, 0x04, height);
+  // 0x1A(2) color panes
+  write_num(output, 0x1A, 0x04, 1);
+  // 0x1C(2) bits per pixel
+  write_num(output, 0x1C, 0x02, color_depth * 8);
+  // 0x1E(4) BI_RGB, no compression
+  write_nul(output, 0x1E, 0x04);
+  // 0x22(4) size of raw bitmap data
+  write_num(output, 0x22, 0x04, data_length);
+  // 0x26(4) horizontal print resolution
+  write_num(output, 0x26, 0x04, 2835);
+  // 0x2A(4) vertical print resolution
+  write_num(output, 0x2A, 0x04, 2835);
+  // 0x2E(4) color in palette (0)
+  write_nul(output, 0x2E, 0x04);
+  // 0x32(4) important colors (0)
+  write_nul(output, 0x32, 0x04);
 
   return output;
 }
@@ -75,7 +88,7 @@ void bmp_data_line(unsigned char *buffer, unsigned short width,
 }
 
 void bmp_generate(unsigned short width, unsigned short height,
-                  unsigned char color_depth, char *file_path,
+                  unsigned char color_depth, bool descending, char *file_path,
                   line_fn generate_line) {
   FILE *fptr;
   fptr = fopen(file_path, "w");
@@ -84,14 +97,17 @@ void bmp_generate(unsigned short width, unsigned short height,
   free(header);
   unsigned int data_length =
       ((unsigned int)width) * ((unsigned int)color_depth);
-  unsigned short y;
+  unsigned int line_length = bmp_data_line_length(width, color_depth);
   unsigned char *data_buffer = (unsigned char *)malloc(data_length);
-  unsigned char *line_buffer =
-      (unsigned char *)malloc(bmp_data_line_length(width, color_depth));
+  unsigned char *line_buffer = (unsigned char *)malloc(line_length);
+  unsigned short y;
   for (y = 0; y < height; y++) {
-    generate_line(height - y - 1, data_buffer, data_length);
+    generate_line(y, data_buffer, data_length);
     bmp_data_line(line_buffer, width, color_depth, data_buffer);
-    fwrite(line_buffer, bmp_data_line_length(width, color_depth), 1, fptr);
+    if (descending) {
+      fseek(fptr, HEADER_SIZE + (height - y - 1) * line_length, SEEK_SET);
+    }
+    fwrite(line_buffer, line_length, 1, fptr);
   }
   free(line_buffer);
   free(data_buffer);

src/bmp.h

@@ -4,7 +4,7 @@
 #define BMP_H
 
 void bmp_generate(unsigned short width, unsigned short height,
-                  unsigned char color_depth, char *file_path,
+                  unsigned char color_depth, bool descending, char *file_path,
                   line_fn generate_line);
 
 #endif

src/config.h

@@ -0,0 +1,12 @@
+#ifndef CONFIG_H
+#define CONFIG_H
+
+#ifndef PACKAGE
+#define PACKAGE "margen"
+#endif
+
+#ifndef VERSION
+#define VERSION "(dev)"
+#endif
+
+#endif

src/const.h

@@ -1,7 +0,0 @@
-#ifndef CONST_H
-#define CONST_H
-
-#define NAME "margen"
-#define VERSION "v1.0.1"
-
-#endif

src/generator.c

@@ -1,10 +1,12 @@
 #include "args.h"
 #include "bmp.h"
-#include "const.h"
+#include "config.h"
 #include "rand.h"
-#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <time.h>
+
+#define BMP_COLOR_DEPTH 3
 
 parameters global_params;
 float slope;
@@ -15,11 +17,10 @@ unsigned char *current_line;
 
 unsigned char generate_pixel(unsigned char depth, unsigned char top_pixel,
                              unsigned char left_pixel) {
-  float v = fminf(
-      255.0, fmaxf(0.0, (rand_float(2.0) - 1.0) * global_params.var[depth] +
-                            ((float)left_pixel) * slope +
-                            ((float)top_pixel) * (1.0 - slope)));
-  return (unsigned char)v;
+  short k = rand_uchar(global_params.var[depth] + 1);
+  short v = (rand_uchar(2) == 0 ? k : -k) + (left_pixel)*slope +
+            (top_pixel) * (1.0 - slope);
+  return (unsigned char)(v < 0 ? 0 : (v > 255 ? (unsigned char)255 : v));
 }
 
 void generate_line() {
@@ -42,12 +43,13 @@ void generate_bmp_line(unsigned short y, unsigned char *data_buffer,
                        unsigned int len) {
   unsigned int i;
   unsigned int x;
-  if (y > 0 && (y % global_params.size) == 0) {
+  if (y % global_params.size == 0) {
     generate_line();
   }
   for (i = 0; i < len; i++) {
-    x = i / (color_depth * global_params.size);
-    data_buffer[i] = current_line[x * color_depth + (i % color_depth)];
+    x = i / (BMP_COLOR_DEPTH * global_params.size);
+    data_buffer[(global_params.rotation / 2) == 1 ? i : (len - i - 1)] =
+        current_line[x * color_depth + (i % color_depth)];
   }
 }
 
@@ -58,6 +60,7 @@ void debug_parameters(parameters params) {
     printf("  width   %d\n", params.width);
     printf("  height  %d\n", params.height);
     printf("  pixel   %d\n", params.size);
+    printf("  slope   %d\n", params.slope);
     if (params.monochrome) {
       printf("  color   %u\n", params.start[0]);
       printf("  var.    %u\n", params.var[0]);
@@ -67,6 +70,7 @@ void debug_parameters(parameters params) {
       printf("  var.    %u,%u,%u\n", params.var[0], params.var[1],
              params.var[2]);
     }
+    printf("  rot.    %d\n", params.rotation);
   }
 }
 
@@ -83,7 +87,6 @@ void init(parameters params) {
     current_line[i] = params.start[i % color_depth];
   }
   set_seed(params.seed);
-  generate_line();
 }
 
 void clean() {
@@ -91,12 +94,21 @@ void clean() {
   free(current_line);
 }
 
+void print_time(parameters params, clock_t start) {
+  if (!params.quiet) {
+    clock_t now = clock();
+    printf("time: %.3fs\n", (float)(now - start) / CLOCKS_PER_SEC);
+  }
+}
+
 void generate(parameters params) {
   if (!params.quiet) {
-    puts(NAME " " VERSION);
+    puts(PACKAGE " " VERSION);
   }
+  clock_t start = clock();
   init(params);
-  bmp_generate(params.width, params.height, color_depth, params.file_path,
-               generate_bmp_line);
+  bmp_generate(params.width, params.height, BMP_COLOR_DEPTH,
+               params.rotation % 2 == 1, params.file_path, generate_bmp_line);
   clean();
+  print_time(params, start);
 }

src/rand.c

@@ -1,21 +1,25 @@
-#include <math.h>
+static unsigned long long mcg_state = 0xcafef00dd15ea5e5u; // Must be odd
+static unsigned long long const multiplier = 6364136223846793005u;
 
-float seed;
+// https://en.wikipedia.org/wiki/Permuted_congruential_generator
+unsigned long rand(void) {
+  unsigned long long x = mcg_state;
+  unsigned count = (unsigned)(x >> 61);
 
-void set_seed(unsigned long new_seed) { seed = (float)(new_seed % 1000000); }
-
-float rand(float seed) {
-  float v = powf(seed, 6. / 7.);
-  v *= sinf(v) + 1.;
-  return v - floorf(v);
+  mcg_state = x * multiplier;
+  x ^= x >> 22;
+  return (unsigned long)(x >> (22 + count));
 }
 
-float rand_float(const float max) { return rand(seed++) * max; }
+void set_seed(unsigned long long seed) {
+  mcg_state = 2 * seed + 1;
+  (void)rand();
+}
 
 unsigned char rand_uchar(const unsigned int max) {
-  return (unsigned char)(rand(seed++) * max);
+  return max == 0 ? 0 : (unsigned char)(rand() % max);
 }
 
 unsigned short rand_ushort(const unsigned int max) {
-  return (unsigned short)(rand(seed++) * max);
+  return max == 0 ? 0 : (unsigned short)(rand() % max);
 }

src/rand.h

@@ -1,8 +1,7 @@
 #ifndef RAND_H
 #define RAND_H
 
-void set_seed(unsigned long new_seed);
-float rand_float(const float max);
+void set_seed(unsigned long long seed);
 unsigned char rand_uchar(unsigned int max);
 unsigned short rand_ushort(unsigned int max);
 

src/types.h

@@ -14,6 +14,7 @@ struct Parameters {
   unsigned char slope;
   unsigned char start[3];
   unsigned char var[3];
+  unsigned char rotation;
 };
 
 typedef struct Parameters parameters;