twn_input: add twn_scancode.h as port of SDL_scancode.h, remove SDL2/SDL.h header usage sa for plans on having clean public headers

include/twn_input.h

@@ -4,12 +4,11 @@
 #include "twn_config.h"
 #include "twn_vec.h"
 #include "twn_engine_api.h"
-
-#include <SDL2/SDL.h>
+#include "twn_scancode.h"
 
 #include <stdint.h>
 #include <stdbool.h>
-
+#include <stddef.h>
 
 typedef enum ButtonSource {
     BUTTON_SOURCE_NOT_SET,
@@ -20,20 +19,8 @@ typedef enum ButtonSource {
 } ButtonSource;
 
 
-union ButtonCode {
-    SDL_Scancode scancode;
-    SDL_Keycode keycode;
-    SDL_GameControllerButton gamepad_button;
-    uint8_t mouse_button;   /* SDL_BUTTON_ enum */
-};
-
-
-/* an input to which an action is bound */
-/* it is not limited to literal buttons */
-typedef struct Button {
-    enum ButtonSource source;
-    union ButtonCode code;
-} Button;
+/* internal */
+typedef struct Button Button;
 
 
 /* represents the collective state of a group of buttons */
@@ -58,13 +45,15 @@ typedef struct ActionHashItem {
 
 
 typedef struct InputState {
-    ActionHashItem *action_hash;
     const uint8_t *keyboard_state; /* array of booleans indexed by scancode */
     uint32_t mouse_state;          /* SDL mouse button bitmask */
     Vec2i mouse_window_position;
     Vec2i mouse_relative_position;
     ButtonSource last_active_source;
     bool is_anything_just_pressed;
+
+    /* engine state */
+    ActionHashItem *action_hash;
 } InputState;
 
 
@@ -74,10 +63,10 @@ TWN_API void input_state_update(InputState *input);
 
 TWN_API void input_bind_action_scancode(InputState *input,
                                 char *action_name,
-                                SDL_Scancode scancode);
+                                Scancode scancode);
 TWN_API void input_unbind_action_scancode(InputState *input,
                                   char *action_name,
-                                  SDL_Scancode scancode);
+                                  Scancode scancode);
 TWN_API void input_bind_action_mouse(InputState *input,
                              char *action_name,
                              uint8_t mouse_button);