Update sdlrender.inc to 2.0.22

[suve]

This patch adds missing type and function definitions, updating sdlrenderer.inc to SDL 2.0.22. Solves issue #47.

This patch omits the SDL_RenderGetMetalLayer() and SDL_RenderGetMetalCommandEncoder() functions. FPC doesn't have units for working with Metal, so these will be of very limited use to anyone. We may still do it for completeness sake, though.

[Free-Pascal-meets-SDL-Website]

Thanks for this work!

This patch omits the SDL_RenderGetMetalLayer() and SDL_RenderGetMetalCommandEncoder() functions. FPC doesn't have units for working with Metal, so these will be of very limited use to anyone. We may still do it for completeness sake, though.

I agree we shouldn't omit these, we don't know if in the future there will be support or someone may need these for whatever reason we can't think of. This can be a task for a later update. Maybe we create an issue about this.

Some ideas to the PR:

1. We should rename the file to sdlrender.inc (as the C-include is SDL_render.h).
2. The enums should be adapted accord. to our code style guidelines (see example below).
3. Comments should be retained.

Line 39+

  PSDL_ScaleMode = ^TSDL_ScaleMode;
  TSDL_ScaleMode = (
    SDL_ScaleModeNearest,
    SDL_ScaleModeLinear,
    SDL_ScaleModeBest
  ); 

According to out style guide it should be like:

C:

typedef enum
{
   SDL_JOYSTICK_POWER_UNKNOWN = -1,
   SDL_JOYSTICK_POWER_EMPTY,   /* <= 5% */
   SDL_JOYSTICK_POWER_LOW,     /* <= 20% */
   SDL_JOYSTICK_POWER_MEDIUM,  /* <= 70% */
   SDL_JOYSTICK_POWER_FULL,    /* <= 100% */
   SDL_JOYSTICK_POWER_WIRED,
   SDL_JOYSTICK_POWER_MAX
} SDL_JoystickPowerLevel;

Pascal:

type
  TSDL_JoystickPowerLevel = type Integer;

const
  SDL_JOYSTICK_POWER_UNKNOWN = TSDL_JoystickPowerLevel(-1);
  SDL_JOYSTICK_POWER_EMPTY   = TSDL_JoystickPowerLevel(0);  {* <= 5% *}
  SDL_JOYSTICK_POWER_LOW     = TSDL_JoystickPowerLevel(1);  {* <= 20% *}
  SDL_JOYSTICK_POWER_MEDIUM  = TSDL_JoystickPowerLevel(2);  {* <= 70% *}
  SDL_JOYSTICK_POWER_FULL    = TSDL_JoystickPowerLevel(3);  {* <= 100% *}
  SDL_JOYSTICK_POWER_WIRED   = TSDL_JoystickPowerLevel(4);
  SDL_JOYSTICK_POWER_MAX     = TSDL_JoystickPowerLevel(5);

Hint 1: C enums start at 0 if no explicit value is set.

What do you think? Best regards

[suve]

Changed enumeration types to type aliases and added the Metal functions.

[Free-Pascal-meets-SDL-Website]

Thanks, excellent work!