Preset path wildcard replacement

[chyyran]

Implement path wildcard replacement from https://github.com/libretro/RetroArch/pull/15023

It remains to be seen whether or not presets will use these wildcards but librashader should eventually add support for them via a context object if they see common use.

Some wildcards can be inferred from when loading from path.

• $VID-DRV-SHADER-EXT$ is always .slang for librashader.
• $VID-DRV-PRESET-EXT$ is always .slangp for librashader.
• $PRESET_DIR$ can be inferred at load time.
• $PRESET$ can be inferred at load time.

The remaining wildcards can be represented with structs; this gives a the context object that can be #[repr(C)].

• $VID_DRIV$ is a static enum

  #[repr(C)]
  pub enum GraphicsRuntime {
      OpenGL = 0,
      Vulkan = 1,
      Direct3D11 = 2,
      Direct3D12 = 3
  } 

• $CORE-REQ-ROT$, $VID-USER-ROT$, $SCREEN-ORIENT$ can be represented by an integer mod 4 as quarter-rotations on the unit circle (i.e. 0 = 0, 1 = 90deg, 2 = 180deg, 3 = 270deg).
• $VID-FINAL-ROT$ is calculated as the sum of $CORE-REQ-ROT$ and $VID-USER-ROT$.
• $VIEW-ASPECT-ORIENT$, $CORE-ASPECT-ORIENT$ , $VID-ALLOW-CORE-ROT$ will be encoded as booleans.
• $CORE$ , $GAME$, and $CONTENT-DIR$ will have to be parsed from C strings owned by the caller.

Example C struct definition:

struct libra_context_t {
  LIBRA_RUNTIME runtime;
  uint8_t core_rotation;
  uint8_t user_rotation;
  bool core_aspect_vertical;
  bool view_aspect_vertical;
  bool allow_core_rotation;
  char* core_name;
  char* game_name;
  char* context_directory;
}

Because paths are canonicalized, this information needs to be available at preset parse time.

[HyperspaceMadness]

This sounds really great!!! I'm curious if you have support for the reference chaining and params files what I put into Retroarch. feel free to contact me on the libretro forum, or at HyperspaceMadness@outlook.com I have some ideas I'd like to discuss with you if you are interested :)

[chyyran]

Reference chains and params files should already work with similar resolution logic as RetroArch.

On Thu, May 25, 2023 at 11:38 AM HyperspaceMadness @.***> wrote:

This sounds really great!!! I'm curious if you have support for the reference chaining and params files what I put into Retroarch. feel free to contact me on the libretro forum, or at @.*** I have some ideas I'd like to discuss with you if you are interested :)

— Reply to this email directly, view it on GitHub https://github.com/SnowflakePowered/librashader/issues/16#issuecomment-1562175161, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAHUIN3XMMYMULJXBVBIIUTXH3A2DANCNFSM6AAAAAAVZ5ZB54 . You are receiving this because you authored the thread.Message ID: @.***>