Remove empty record types

CHEATSHEET.md

@@ -116,9 +116,8 @@ type
 ### Opaque Structs
 
 If you have something like ```typedef struct name name```. the concrete
-structure is opaque. See issue
-[#63](https://github.com/PascalGameDevelopment/SDL2-for-Pascal/issues/63))
-for details.
+structure is opaque, and the programmer is expected to only ever
+interact with pointers to the struct.
 
 C:
 
@@ -128,21 +127,17 @@ typedef struct SDL_Window SDL_Window;
 
 Pascal:
 
-Prefered:
 ```pascal
 type
   PPSDL_Window = ^PSDL_Window;
-  PSDL_Window = ^TSDL_Window;
-  TSDL_Window = type Pointer;
+  PSDL_Window = type Pointer;
 ```
 
-Alternativly:
-```pascal
-type
-  PPSDL_Window = ^PSDL_Window;
-  PSDL_Window = ^TSDL_Window;
-  TSDL_Window = record end;
-```
+As shown above, for opaque structs, we avoid defining the base `TType`
+and define only the pointer `PType`.
+For the rationale behind this decision, read the discussion in
+[issue #63](https://github.com/PascalGameDevelopment/SDL2-for-Pascal/issues/63).
+
 
 ## Unions
 

units/sdl2_mixer.pas

@@ -166,8 +166,7 @@   TMix_Chunk = record
 
   {* The internal format for a music chunk interpreted via mikmod *}
   PPMix_Music = ^PMix_Music;
-  PMix_Music = ^TMix_Music;
-  TMix_Music = record end;
+  PMix_Music = type Pointer;
 
   {* Open the mixer with a certain audio format *}
 function Mix_OpenAudio(frequency: cint; format: cuint16; channels: cint; chunksize: cint): cint cdecl; external MIX_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_MIX_OpenAudio' {$ENDIF} {$ENDIF};
@@ -241,7 +240,7 @@ function Mix_HasMusicDecoder(const name: PAnsiChar): TSDL_Bool cdecl;
   {* Find out the music format of a mixer music, or the currently playing
      music, if 'music' is NULL.
   *}
-function Mix_GetMusicType(music: TMix_Music): TMix_MusicType cdecl; external MIX_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_MIX_GetMusicType' {$ENDIF} {$ENDIF};
+function Mix_GetMusicType(music: PMix_Music): TMix_MusicType cdecl; external MIX_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_MIX_GetMusicType' {$ENDIF} {$ENDIF};
 
   {* Set a function that is called after all mixing is performed.
      This can be used to provide real-time visual display of the audio stream

units/sdl2_ttf.pas

@@ -175,8 +175,7 @@ procedure TTF_ByteSwappedUNICODE(swapped: TSDL_bool); cdecl;
 {* The internal structure containing font information *}
 type
   PPTTF_Font = ^PTTF_Font;
-  PTTF_Font = ^TTTF_Font;
-  TTTF_Font = record  end; //todo?
+  PTTF_Font = type Pointer;
 
 {*
  * Initialize SDL_ttf.

units/sdlaudio.inc

@@ -942,8 +942,7 @@ function SDL_ConvertAudio(cvt: PSDL_AudioCVT): cint; cdecl;
   }
 { this is opaque to the outside world.  }
 type
-  PSDL_AudioStream = ^TSDL_AudioStream;
-  TSDL_AudioStream = record end;
+  PSDL_AudioStream = type Pointer;
 
 {*
  * Create a new audio stream.

units/sdlgamecontroller.inc

@@ -15,8 +15,7 @@
 {* The gamecontroller structure used to identify an SDL game controller *}
 type
   PPSDL_GameController = ^PSDL_GameController;
-  PSDL_GameController = ^TSDL_GameController;
-  TSDL_GameController = record end;
+  PSDL_GameController = type Pointer;
 
   PPSDL_GameControllerType = ^PSDL_GameControllerType;
   PSDL_GameControllerType = ^TSDL_GameControllerType;

units/sdlhaptic.inc

@@ -93,8 +93,7 @@
    *}
 type
   PPSDL_Haptic = ^PSDL_Haptic;
-  PSDL_Haptic = ^TSDL_Haptic;
-  TSDL_Haptic = record end;
+  PSDL_Haptic = type Pointer;
 
   {**
    *   Haptic features

units/sdlhidapi.inc

@@ -42,8 +42,7 @@ type
 	(**
  	 *  \brief  A handle representing an open HID device.
  	 *)
-	PSDL_hid_device = ^TSDL_hid_device;
-	TSDL_hid_device = record end; // opaque struct
+	PSDL_hid_device = type Pointer;
 
 	PSDL_hid_device_info = ^TSDL_hid_device_info;
 

units/sdljoystick.inc

@@ -30,8 +30,7 @@
 type
   {* The joystick structure used to identify an SDL joystick *}
   PPSDL_Joystick = ^PSDL_Joystick;
-  PSDL_Joystick = ^TSDL_Joystick;
-  TSDL_Joystick = record end;
+  PSDL_Joystick = type Pointer;
 
   {* A structure that encodes the stable unique id for a joystick device *}
   PPSDL_JoystickGUID = ^PSDL_JoystickGUID;

units/sdlrenderer.inc

@@ -91,17 +91,13 @@ type
    *}
 
   PPSDL_Renderer = ^PSDL_Renderer;
-  PSDL_Renderer = ^TSDL_Renderer;
-  TSDL_Renderer = record
-    end;
+  PSDL_Renderer = type Pointer;
 
   {**
    *  An efficient driver-specific representation of pixel data
    *}
   PPSDL_Texture = ^PSDL_Texture;
-  PSDL_Texture = ^TSDL_Texture;
-  TSDL_Texture = record
-    end;
+  PSDL_Texture = type Pointer;
 
   {* Function prototypes *}
 

units/sdlsensor.inc

@@ -10,8 +10,7 @@
  *}
 type
 	PPSDL_Sensor = ^PSDL_Sensor;
-	PSDL_Sensor = ^TSDL_Sensor;
-	TSDL_Sensor = record end;
+	PSDL_Sensor = type Pointer;
 
 {**
  * This is a unique ID for a sensor for the time it is connected to the system,

units/sdlstdinc.inc

@@ -685,8 +685,7 @@ const
   SDL_ICONV_EINVAL = csize_t(-4);
 
 type
-  TSDL_iconv = record end;
-  PSDL_iconv = ^TSDL_iconv;
+  PSDL_iconv = type Pointer;
 
 function SDL_iconv_open(Const tocode, fromcode: PAnsiChar): PSDL_iconv; cdecl;
   external SDL_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_SDL_iconv_open' {$ENDIF} {$ENDIF};

units/sdlsurface.inc

@@ -23,10 +23,7 @@ type
    *  which, if not NULL, contains the raw pixel data for the surface.
    *}
   PPSDL_BlitMap = ^PSDL_BlitMap;
-  PSDL_BlitMap = ^TSDL_BlitMap;
-  TSDL_BlitMap = record
-    map: Pointer;
-  end;
+  PSDL_BlitMap = type Pointer;
 
   PPSDL_Surface = ^PSDL_Surface;
   PSDL_Surface = ^TSDL_Surface;
@@ -51,7 +48,7 @@ type
     clip_rect: TSDL_Rect;        {**< Read-only *}
 
     {** info for fast blit mapping to other surfaces *}
-    map: Pointer;                {**< Private *} // TODO: Check: Why Pointer and not PSDL_BlitMap used here?
+    map: PSDL_BlitMap;           {**< Private *}
 
     {** Reference count -- used when freeing surface *}
     refcount: cint;              {**< Read-mostly *}

units/sdlthread.inc

@@ -8,8 +8,7 @@
 
 {* The SDL thread structure, defined in SDL_thread.c *}
 type
-  PSDL_Thread = ^TSDL_Thread;
-  TSDL_Thread = record end;
+  PSDL_Thread = type Pointer;
 
   {* The SDL thread ID *}
   PPSDL_threadID = ^PSDL_threadID;
@@ -340,7 +339,7 @@ procedure SDL_WaitThread(thread: PSDL_Thread; status: pcint); cdecl;
  * \sa SDL_CreateThread
  * \sa SDL_WaitThread
  *}
-procedure SDL_DetachThread(thread:TSDL_Thread); cdecl;
+procedure SDL_DetachThread(thread:PSDL_Thread); cdecl;
   external SDL_LibName {$IFDEF DELPHI} {$IFDEF MACOS} name '_SDL_DetachThread' {$ENDIF}{$ENDIF};
 
   {**

units/sdlvideo.inc

@@ -3,8 +3,7 @@
 
 type
   PPSDL_Window = ^PSDL_Window;
-  PSDL_Window = ^TSDL_Window;
-  TSDL_Window = record end;
+  PSDL_Window = type Pointer;
 
   {**
    *  The structure that defines a display mode