feat: remove math (#11)

* feat: remove math

* working

* remove unused stdint

* small fix

Makefile.am

@@ -1,5 +1,4 @@
 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
-include_HEADERS = src/main.h src/args.h src/bmp.h src/generator.h src/rand.h src/config.h src/types.h
+include_HEADERS = src/main.h src/args.h src/bmp.h src/generator.h src/rand.h src/config.h src/types.h
-margen_LDADD = -lm

configure.ac

@@ -6,6 +6,5 @@ AC_CHECK_HEADERS([stdlib.h])
 AC_CHECK_HEADERS([stdbool.h])
 AC_CHECK_HEADERS([string.h])
 AC_CHECK_HEADERS([time.h])
-AC_CHECK_HEADERS([math.h])
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT

src/args.c

@@ -23,7 +23,7 @@ void print_help(int status_code) {
        "[-va=R,G,B] "
        "[-vr=VAR_RANGE] "
        "[-r=ROTATION] "
-       //  "[-m]"
+       "[-m]"
        "\n\n"
        "generate a marble-like pattern bitmap image, blazing fast.\n\n"
        "options:\n"
@@ -216,9 +216,9 @@ parameters parse_args(int argc, char **argv) {
   }
 
   if (!var_set) {
-    params.var[0] = rand_uchar(var_range);
+    params.var[0] = rand_uchar(var_range + 1);
-    params.var[1] = rand_uchar(var_range);
+    params.var[1] = rand_uchar(var_range + 1);
-    params.var[2] = rand_uchar(var_range);
+    params.var[2] = rand_uchar(var_range + 1);
   }
 
   if (!rot_set) {

src/generator.c

@@ -2,7 +2,6 @@
 #include "bmp.h"
 #include "config.h"
 #include "rand.h"
-#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
@@ -18,11 +17,10 @@ unsigned char *current_line;
 
 unsigned char generate_pixel(unsigned char depth, unsigned char top_pixel,
                              unsigned char left_pixel) {
-  float v = fminf(
+  short k = rand_uchar(global_params.var[depth] + 1);
-      255.0, fmaxf(0.0, (rand_float(2.0) - 1.0) * global_params.var[depth] +
+  short v = (rand_uchar(2) == 0 ? k : -k) + (left_pixel)*slope +
-                            ((float)left_pixel) * slope +
+            (top_pixel) * (1.0 - slope);
-                            ((float)top_pixel) * (1.0 - slope)));
+  return (unsigned char)(v < 0 ? 0 : (v > 255 ? (unsigned char)255 : v));
-  return (unsigned char)v;
 }
 
 void generate_line() {
@@ -62,6 +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]);

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); }
+  mcg_state = x * multiplier;
-
+  x ^= x >> 22;
-float rand(float seed) {
+  return (unsigned long)(x >> (22 + count));
-  float v = powf(seed, 6. / 7.);
-  v *= sinf(v) + 1.;
-  return v - floorf(v);
 }
 
-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);
+void set_seed(unsigned long long seed);
-float rand_float(const float max);
 unsigned char rand_uchar(unsigned int max);
 unsigned short rand_ushort(unsigned int max);