-- ANIM — the animation helpers. A frame range + a speed becomes "which frame
-- now", timed automatically. Three critters run the SAME 4-frame sheet at
-- different speeds and modes so the helpers are easy to compare:
--   left   : anim()          — looping cycle, fast
--   middle : anim_pingpong() — bounces 0->3->0
--   right  : anim_once()     — plays once on A, holds on the last frame
--
-- build: gbalua build --target gba examples/anim/main.lua \
--          --sheet examples/anim/critter.png --map examples/anim/bg.png

function _init()
  map_show(0)   -- a tile background (so we're in tile mode: clean sprite-HUD text)
end

function _update()
  -- re-arm the one-shot critter when A is pressed
  if btnp(4) then anim_reset(2) end
end

function _draw()
  -- (no cls — the tile background is drawn by hardware)
  print("anim helpers", 8, 6, 7)
  print("loop", 40, 40, 6)
  print("pong", 108, 40, 6)
  print("once", 176, 40, 6)
  print("press a", 84, 130, 5)

  -- slot 0: a fast looping cycle over cells 0..3 at 10 fps
  spr(anim(0, 0, 3, 10), 40, 60, 2, 2)

  -- slot 1: ping-pong 0..3..0 at 8 fps
  spr(anim_pingpong(1, 0, 3, 8), 108, 60, 2, 2)

  -- slot 2: play once at 6 fps, hold on the last frame; show DONE when finished
  spr(anim_once(2, 0, 3, 6), 176, 60, 2, 2)
  if anim_done(2) != 0 then print("done", 176, 90, 11) end
end