+write to image support

Writes output to "data.png"

main.c

@@ -13,6 +13,8 @@
 #include <raylib.h>
 #include <raymath.h>
 
+#include <stb/stb_image_write.h>
+
 #include "./lib.h"
 
 void step(state_t *state)
@@ -101,11 +103,11 @@ int main(void)
         if (sandpile == 0)
           c = BLACK;
         else if (sandpile == 1)
-          c = GREEN;
+          c = MAGENTA;
         else if (sandpile == 2)
-          c = PURPLE;
+          c = RED;
         else if (sandpile == 3)
-          c = YELLOW;
+          c = BLUE;
 
         DrawRectangle(i * state.multiplier, j * state.multiplier,
                       state.multiplier, state.multiplier, c);
@@ -121,6 +123,33 @@ int main(void)
   }
 
   CloseWindow();
+  unsigned char *image_data =
+      calloc(3 * state.dwidth * state.dwidth, sizeof(*image_data));
+
+  size_t image_ptr = 0;
+
+  for (size_t i = 0; i < state.dwidth; ++i)
+    for (size_t j = 0; j < state.dwidth; ++j, image_ptr += 3)
+    {
+      Color c           = {0};
+      uint64_t sandpile = state.data[(i * state.dwidth) + j];
+      if (sandpile == 0)
+        c = BLACK;
+      else if (sandpile == 1)
+        c = MAGENTA;
+      else if (sandpile == 2)
+        c = RED;
+      else if (sandpile == 3)
+        c = BLUE;
+
+      image_data[image_ptr]     = c.r;
+      image_data[image_ptr + 1] = c.g;
+      image_data[image_ptr + 2] = c.b;
+    }
+
+  stbi_write_png("data.png", state.dwidth, state.dwidth, 3, image_data,
+                 3 * state.dwidth);
+  free(image_data);
   free(state.data);
   return 0;
 }