game: map units combat and SDL2 render slice

src/map.c

@@ -0,0 +1,19 @@
+#include "ok_map.h"
+#include <stdlib.h>
+
+void ok_map_generate(OkMap *m) {
+  for (int y = 0; y < OK_MAP_H; y++) {
+    for (int x = 0; x < OK_MAP_W; x++) {
+      m->tile[y][x] = 0;
+      if (x == 0 || y == 0 || x == OK_MAP_W - 1 || y == OK_MAP_H - 1)
+        m->tile[y][x] = 1;
+      else if ((x * 17 + y * 31) % 47 == 0)
+        m->tile[y][x] = 2; /* scrap pile */
+    }
+  }
+}
+
+bool ok_map_walkable(const OkMap *m, int x, int y) {
+  if (x < 0 || y < 0 || x >= OK_MAP_W || y >= OK_MAP_H) return false;
+  return m->tile[y][x] != 1;
+}