Add new file - state.h

include/state.h

+#include <stdio.h>
+#include <stdlib.h>
+#include "sdl_wrapper.h"
+#include "polygon.h"
+#include <math.h>
+
+/**
+ * Stores the demo state
+ * Use this to store any variable needed every 'tick' of your demo
+ */ 
+typedef struct state state_t;
+
+/**
+ * Initializes sdl as well as the variables needed
+ * Creates and stores all necessary variables for the demo in a created state variable
+ * Returns the pointer to this state
+ * (This is the state emscripten_main and emscripten_free work with)
+ */
+state_t *emscripten_init();
+
+/**
+ * Called on each tick of the program
+ * Updates the state variables and display as necessary, depending on the time that has passed
+ */ 
+void emscripten_main(state_t *state);
+
+/**
+ * Frees anything allocated in the demo
+ * Should free everything in state as well as state itself. 
+ */ 
+void emscripten_free(state_t *state);