platformer_part2.nelua

require"sdl2"
require"utils"
require"os"
require"arg"
require"string"

Debug = true  -- for dprint()

local Input     = @enum{none = 0,left = 1, right = 2, jump = 3 , restart = 4, quit = 5}
local Game = @record{
    renderer: *SDL_Renderer,
    inputs : [6]boolean,
}

local WindowSize  = Vec2f{1280, 720}

-----------
-- toInput
-----------
local toInput = function (key:integer)
  local write = function(str:string)
    dwrite(str)
  end
  write("\n")
  if     key == SDL_SCANCODE_A or key == SDL_SCANCODE_H or key == SDL_SCANCODE_LEFT then write("LEFT: ") return Input.left
  elseif key == SDL_SCANCODE_D or key == SDL_SCANCODE_L or key == SDL_SCANCODE_RIGHT then write("RIGHT: ") return Input.right
  elseif key == SDL_SCANCODE_UP or key == SDL_SCANCODE_SPACE or key == SDL_SCANCODE_J or key == SDL_SCANCODE_K then write("JUMP: ") return Input.jump
  elseif key == SDL_SCANCODE_R then write("Rstart: ") return Input.restart
  elseif key == SDL_SCANCODE_Q then write("Quit: ") return Input.quit
  else write("None: ") return Input.none
  end
end

------------
--- newGame   -- Game type
------------
local newGame = function(renderer: *SDL_Renderer): Game
  return Game{
    renderer    = renderer,
    inputs      = {false,false,false, false,false,false},
  }
end

--------------------
-- Game:handleInput
--------------------
function Game:handleInput()
  local event: SDL_Event
  while SDL_PollEvent(event) ~= 0 do
    local kind = event.type
    if kind == SDL_QUIT then
      self.inputs[Input.quit] = true
    elseif kind == SDL_KEYDOWN then
      dprint("KeyDown")
      self.inputs[toInput(event.key.keysym.scancode)] = true
    elseif kind == SDL_KEYUP then
      dprint("KeyUp")
      self.inputs[toInput(event.key.keysym.scancode)] = false
    end
  end
end

----------------
--- Game:render
----------------
function Game:render()
   SDL_RenderClear(self.renderer)
   SDL_RenderPresent(self.renderer)
end

------------------
--- Main function
------------------
local main = function()
  if sdlFailIf(0 == SDL_Init(SDL_INIT_VIDEO + SDL_INIT_TIMER + SDL_INIT_EVENTS),
    "SDL2 initialization failed") then os.exit(1) end
  if sdlFailIf(SDL_TRUE == SDL_SetHint("SDL_RENDER_SCALE_QUALITY", "2"),
     "Linear texture filtering could not be enabled") then os.exit(1) end
  local window = SDL_CreateWindow(string.format("%s:  [ %s ]","Our own 2D platformer written in NeLua",getExeName(arg[0])),
      SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
      WindowSize.x, WindowSize.y, SDL_WINDOW_SHOWN)
  if sdlFailIf(0 ~= window,"Window could not be created") then os.exit(1) end

  local renderer = SDL_CreateRenderer(window,-1,
    SDL_RENDERER_ACCELERATED or SDL_RENDERER_PRESENTVSYNC)
  if sdlFailIf(0 ~= renderer,"Renderer could not be created") then os.exit(1) end

  SDL_SetRenderDrawColor(renderer,110,132,174,255)

  local game = newGame(renderer)

  --------------
  --- Main loop
  --------------
  -- Game loop, draws each frame
  while not game.inputs[Input.quit] do
    game:handleInput()
    game:render()
  end

  --------------
  --- End procs
  --------------
  SDL_DestroyRenderer(renderer)
  SDL_DestroyWindow(window)
  SDL_Quit()
end

---------
--- main
---------
main()