diff --git a/src/bmp.c b/src/bmp.c
index 62e7669..1b4b045 100644
--- a/src/bmp.c
+++ b/src/bmp.c
@@ -85,8 +85,9 @@ void bmp_generate(unsigned short width, unsigned short height,
   unsigned int data_length =
       ((unsigned int)width) * ((unsigned int)color_depth);
   unsigned short y;
-  unsigned char *data_buffer = malloc(data_length);
-  unsigned char *line_buffer = malloc(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));
   for (y = 0; y < height; y++) {
     generate_line(height - y - 1, data_buffer, data_length);
     bmp_data_line(line_buffer, width, color_depth, data_buffer);
diff --git a/src/generator.c b/src/generator.c
index d451776..e48b071 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -3,22 +3,18 @@
 #include "rand.h"
 #include <math.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #define COLOR_DEPTH 3
 
 parameters global_params;
 float global_fslope;
+unsigned int line_width;
+unsigned char *last_line;
+unsigned char *current_line;
 
-void generate_line(unsigned short y, unsigned char *data_buffer,
-                   unsigned int len) {
-  unsigned int i;
-  for (i = 0; i < len; i++) {
-    data_buffer[i] = rand_uchar(256);
-  }
-}
-
-unsigned char pixel_gen(unsigned char depth, unsigned char top_pixel,
-                        unsigned char left_pixel) {
+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) * global_fslope +
@@ -26,6 +22,35 @@ unsigned char pixel_gen(unsigned char depth, unsigned char top_pixel,
   return (unsigned char)v;
 }
 
+void generate_line() {
+  unsigned int i;
+  for (i = 0; i < line_width; i++) {
+    last_line[i] = current_line[i];
+  }
+  for (i = 0; i < line_width; i++) {
+    if (i < COLOR_DEPTH) {
+      current_line[i] = generate_pixel(i % COLOR_DEPTH, last_line[i],
+                                       global_params.start[i % COLOR_DEPTH]);
+    } else {
+      current_line[i] = generate_pixel(i % COLOR_DEPTH, last_line[i],
+                                       current_line[i - COLOR_DEPTH]);
+    }
+  }
+}
+
+void generate_bmp_line(unsigned short y, unsigned char *data_buffer,
+                       unsigned int len) {
+  unsigned int i;
+  unsigned int x;
+  for (i = 0; i < len; i++) {
+    if (y > 0 && y % global_params.size == 0) {
+      generate_line();
+    }
+    x = i / (COLOR_DEPTH * global_params.size);
+    data_buffer[i] = current_line[x * COLOR_DEPTH + (i % COLOR_DEPTH)];
+  }
+}
+
 void debug_parameters(parameters params) {
   if (!params.quiet) {
     printf("output  %s\n", params.file_path);
@@ -39,12 +64,29 @@ void debug_parameters(parameters params) {
   }
 }
 
-int generate(parameters params) {
+void init(parameters params) {
   global_params = params;
   global_fslope = ((float)params.slope) / 255.0;
   debug_parameters(params);
+  line_width = ((params.width / params.size) + 1) * COLOR_DEPTH;
+  last_line = (unsigned char *)malloc(line_width);
+  current_line = (unsigned char *)malloc(line_width);
+  unsigned int i = 0;
+  for (i = 0; i < line_width; i++) {
+    current_line[i] = params.start[i % COLOR_DEPTH];
+  }
   set_seed(params.seed);
+  generate_line();
+}
+
+void clean() {
+  free(last_line);
+  free(current_line);
+}
+
+void generate(parameters params) {
+  init(params);
   bmp_generate(params.width, params.height, COLOR_DEPTH, params.file_path,
-               generate_line);
-  return 0;
+               generate_bmp_line);
+  clean();
 }
\ No newline at end of file
diff --git a/src/generator.h b/src/generator.h
index 677293e..49712c2 100644
--- a/src/generator.h
+++ b/src/generator.h
@@ -3,6 +3,6 @@
 #ifndef GENERATOR_H
 #define GENERATOR_H
 
-int generate(parameters params);
+void generate(parameters params);
 
 #endif
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 5fe0fcf..f35de5c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4,5 +4,6 @@
 int main(int argc, char **argv) {
   parameters params;
   params = parse_args(argc, argv);
-  return generate(params);
+  generate(params);
+  return 0;
 }
\ No newline at end of file