nim example

lang/nim/.gitignore

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+nimcache/
+nimblecache/
+htmldocs/
+
+.DS_Store
+*.dylib
+*.so
+*.dll

lang/nim/LICENSE

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+MIT License
+
+Copyright (c) 2023 David Konsumer
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

lang/nim/README.md

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+This is an example libretro core, written in nim. This is a translation from [a basic software-rendering example](https://github.com/libretro/libretro-samples/tree/master/video/software/rendering) but you should be able to roughly translate any of the C examples into nim.
+
+Variable/type names are mostly the same as with a C core, with one exception:
+
+- Because nim disregards case in var-names, I had to rename keys like `RETROK_a` to `RETROK_LOWER_A`.
+
+For more in-depth info, check out [Pmunch's blog post](https://peterme.net/dynamic-libraries-in-nim.html) as it was very helpful in figuring out how to put it all together.
+
+## Usage
+
+Put your core-code in `src/example_libretro.nim` and you can run these:
+
+```
+# build the libretro core
+nimble core
+```
+
+You can run your core like this:
+
+```
+# mac
+/Applications/RetroArch.app/Contents/MacOS/RetroArch -L libexample_libretro.dylib
+
+# linux
+retroarch -L libexample_libretro.so
+
+# windows
+retroarch -L libexample_libretro.dll
+```

lang/nim/example_libretro.nimble

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+version       = "0.0.1"
+author        = "David Konsumer"
+description   = "Example libretro core"
+license       = "MIT"
+srcDir        = "src"
+bin           = @["example_libretro"]
+
+requires "nim >= 1.6.10"
+
+import os
+
+task core, "Build libretro core":
+  selfExec("c -d:release --app:lib --noMain --gc:orc --outDir=. src/example_libretro.nim")
+
+task clean, "Clean built files":
+  for file in listFiles("."):
+    let ext = splitFile(file).ext
+    if ext == ".dll" or ext == ".so" or ext == ".dylib":
+      echo "Deleting ", file
+      rmFile(file)

lang/nim/src/example_libretro.nim

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+import bitops
+import std/terminal
+import example_libretro/libretro
+
+const WIDTH = 320
+const HEIGHT = 240 
+const FPS = 60
+const SAMPLE_RATE = 48000
+
+var video_cb: retro_video_refresh_t
+var audio_cb: retro_audio_sample_t
+var audio_batch_cb: retro_audio_sample_batch_t
+var input_poll_cb: retro_input_poll_t
+var environ_cb: retro_environment_t
+var input_state_cb: retro_input_state_t
+
+proc NimMain() {.cdecl, importc.}
+
+# video framebuffer
+var buf:ptr UncheckedArray[cuint]
+
+# colors used for checkerboard
+const color_r:uint32 = 0xff shl 16
+const color_g:uint32 = 0xff shl 8
+
+proc log_cb(level: retro_log_level, message: string) =
+  if level == RETRO_LOG_DEBUG:
+    stdout.styledWriteLine(fgBlue, "DEBUG: ", fgDefault, message)
+  elif level == RETRO_LOG_INFO:
+    stdout.styledWriteLine(fgYellow, "INFO: ", fgDefault, message)
+  elif level == RETRO_LOG_WARN:
+    stdout.styledWriteLine(bgMagenta, "WARN: ", fgDefault, message)
+  elif level == RETRO_LOG_ERROR:
+    stdout.styledWriteLine(fgRed, "ERROR: ", fgDefault, message)
+
+proc retro_set_video_refresh*(cb: retro_video_refresh_t) {.cdecl,exportc,dynlib.} =
+  video_cb = cb
+
+proc retro_set_audio_sample*(cb: retro_audio_sample_t) {.cdecl,exportc,dynlib.} =
+  audio_cb = cb
+
+proc retro_set_audio_sample_batch*(cb: retro_audio_sample_batch_t) {.cdecl,exportc,dynlib.} =
+  audio_batch_cb = cb
+
+proc retro_set_input_poll*(cb: retro_input_poll_t) {.cdecl,exportc,dynlib.} =
+  input_poll_cb = cb
+
+proc retro_set_environment*(cb: retro_environment_t) {.cdecl,exportc,dynlib.} =
+  environ_cb = cb
+  var no_content:bool = true
+  discard cb(RETRO_ENVIRONMENT_SET_SUPPORT_NO_GAME, addr no_content)
+
+proc retro_set_input_state*(cb: retro_input_state_t) {.cdecl,exportc,dynlib.} =
+  input_state_cb = cb
+
+proc retro_init*() {.cdecl,exportc,dynlib.} =
+  NimMain() 
+  var bufPtr0 = alloc0(sizeof(cuint) * WIDTH * HEIGHT)
+  buf = cast[ptr UncheckedArray[cuint]](bufPtr0)
+  log_cb(RETRO_LOG_DEBUG, "retro_init() called.")
+
+proc retro_deinit*() {.cdecl,exportc,dynlib.} =
+  log_cb(RETRO_LOG_DEBUG, "retro_deinit() called.")
+  dealloc(buf)
+  GC_FullCollect()
+
+proc retro_api_version*(): cuint {.cdecl,exportc,dynlib.} =
+  return RETRO_API_VERSION
+
+proc retro_set_controller_port_device*(port: cuint; device: cuint) {.cdecl,exportc,dynlib.} =
+  log_cb(RETRO_LOG_DEBUG, "retro_set_controller_port_device() called.")
+  echo port, device
+
+proc retro_get_system_info*(info: ptr retro_system_info) {.cdecl,exportc,dynlib.} =
+  info.library_name = "nim_example";
+  info.library_version = "v1"
+  info.need_fullpath = false
+  info.valid_extensions = nil # we don't use any ROMs
+
+proc retro_get_system_av_info*(info: ptr retro_system_av_info) {.cdecl,exportc,dynlib.} =
+  info.timing.fps = FPS
+  info.timing.sample_rate = SAMPLE_RATE
+  info.geometry.base_width = WIDTH
+  info.geometry.base_height = HEIGHT
+  info.geometry.max_width = WIDTH
+  info.geometry.max_height = HEIGHT
+  info.geometry.aspect_ratio = WIDTH / HEIGHT
+
+proc retro_reset*() {.cdecl,exportc,dynlib.} =
+  log_cb(RETRO_LOG_DEBUG, "retro_reset() called.")
+
+proc retro_run*() {.cdecl,exportc,dynlib.} =
+  for y in 0 ..< HEIGHT:
+    let index_y = uint32 bitand((y shr 4), 1)
+    for x in 0 ..< WIDTH:
+      let b = ((y * WIDTH) + x)
+      let index_x = uint32 bitand((x shr 4), 1)
+      if bool bitxor(index_y, index_x):
+        buf[b] = color_r
+      else:
+        buf[b] = color_g
+  video_cb(buf, WIDTH, HEIGHT, (WIDTH shl 2))
+
+proc retro_load_game*(info: ptr retro_game_info): bool {.cdecl,exportc,dynlib.} =
+  var fmt = RETRO_PIXEL_FORMAT_XRGB8888
+  if not environ_cb(RETRO_ENVIRONMENT_SET_PIXEL_FORMAT, addr fmt):
+    log_cb(RETRO_LOG_INFO, "XRGB8888 is not supported.")
+    return false
+  return true
+
+proc retro_unload_game*() {.cdecl,exportc,dynlib.} =
+  log_cb(RETRO_LOG_DEBUG, "retro_unload_game() called.")
+
+proc retro_get_region*(): cuint {.cdecl,exportc,dynlib.} =
+  return 0 # NTSC
+
+proc retro_load_game_special*(`type`: cuint; info: ptr retro_game_info; num: csize_t): bool {.cdecl,exportc,dynlib.} =
+  return true
+
+proc retro_serialize_size*(): csize_t {.cdecl,exportc,dynlib.} =
+  return 0
+
+proc retro_serialize*(data: pointer; size: csize_t): bool {.cdecl,exportc,dynlib.} =
+  return true
+
+proc retro_unserialize*(data: pointer; size: csize_t): bool {.cdecl,exportc,dynlib.} =
+  return true
+
+proc retro_get_memory_data*(id: cuint): pointer {.cdecl,exportc,dynlib.} =
+  discard
+
+proc retro_get_memory_size*(id: cuint): csize_t {.cdecl,exportc,dynlib.} =
+  return 0
+
+proc retro_cheat_reset*() {.cdecl,exportc,dynlib.} =
+  discard
+
+proc retro_cheat_set*(index: cuint; enabled: bool; code: cstring) {.cdecl,exportc,dynlib.} =
+  discard