Fix cmake files and add input file

engine/input.cpp

@@ -0,0 +1,35 @@
+
+#include "input.h"
+
+void process_input(SDL_Keysym keysym) {
+
+
+
+
+
+
+
+    // Call engine.keypressed(key)
+    lua_getglobal(luaState, "engine");
+    if (lua_istable(luaState, -1)) {
+        lua_getfield(luaState, -1, "KeyPressed");
+        if (lua_isfunction(luaState, -1)) {
+            lua_pushinteger(luaState, keysym.scancode);
+
+            if (lua_pcall(luaState, 1, 0, 0) != LUA_OK) {
+                const char* error = lua_tostring(luaState, -1);
+                std::cerr << "Lua error in engine.keypressed: " << error << std::endl;
+            }
+        }
+    }
+
+    switch (keysym.scancode) {
+    case SDL_SCANCODE_ESCAPE:
+        isRunning = false;
+
+        std::cout << "Closing game\n";
+        break;
+    default:
+        break;
+    }
+}