GLFW.idr

module GLFW
-- https://gist.github.com/alrunner4/8a026f3bfea354b48d3294a20c9812e2

export data Monitor : Type where {}
export data Window  : Type where {}

%foreign "C:glfwInit,libglfw"
Init: PrimIO Int

%foreign "C:glfwCreateWindow,libglfw"
CreateWindow: Int -> Int -> String -> Ptr Monitor -> Ptr Window -> PrimIO( Ptr Window )

%foreign "C:glfwWindowShouldClose,libglfw"
WindowShouldClose: Ptr Window -> PrimIO Int

%foreign "C:glfwPollEvents,libglfw"
PollEvents: PrimIO ()

pollingLoop: Ptr Window -> IO ()
pollingLoop w =
  do
    wsc <- primIO (WindowShouldClose w)
    continueOrEndPolling wsc

  where
    continueOrEndPolling : Int -> IO ()
    continueOrEndPolling wsc =
      if wsc /= 0
      then pure ()
      else primIO PollEvents >> pollingLoop w

main: IO ()
main = if !( primIO Init ) /= 1
  then printLn "Init failed"
  else do
    putStrLn "Creating window..."
    w <- primIO( CreateWindow 1920 1080 "glfw"
                   ( prim__castPtr prim__getNullAnyPtr )
                   ( prim__castPtr prim__getNullAnyPtr ) )
    putStrLn "Polling events..."
    pollingLoop w
    putStrLn "Shutting down..."