pico-8 cartridge // http://www.pico-8.com
version 43
__lua__
-- global

function _init()
 frame_time = 0.01666666666
 state_menu = "menu"
 state_play = "play"
 set_state(state_menu)
end

function _update60()
 if state == state_menu then
  menu_update()
 elseif state == state_play then
  map_update()
  player_update()
  enemies_update()
  ufo_update()
 end
end

function _draw()
 cls(1)
 if state == state_menu then
  menu_draw()
 elseif state == state_play then
  map_draw()
  player_draw()
  enemies_draw()
  ufo_draw()
 end
end

function set_state(st)
 state = st
 music(-1, 100)
 if state == state_menu then
  menu_init()
 elseif state == state_play then
  map_init()
  player_init()
  enemies_init()
  ufo_init()
 end
end

function sp2m(sp)
 return (sp+4)/8
end

function is_collide(e1,e2)
 return e2.x+e2.sx > e1.x and
   e1.x+e1.sx > e2.x and
   e2.y+e2.sy > e1.y and
   e1.y+e1.sy > e2.y
end
-->8
-- player

function player_init()
 pl = {
  x = 0,
  y = 0,
  sx = 8,
  sy = 8,
  sp = 0x1,
  lives = 3,
  speed = 0,
  m_speed = 1.0,
  accel = 0.25,
  sp_speed = 0.25,
  at_tm = 0.0,
  at_delay = 0.5,
  proj_speed = 2,
  projs = {},
  score = 0,
  can_shoot = false,
 }
 pl_reset_pos()
end

function player_update()
 if btn(⬅️) then
  pl.speed -= pl.accel
  pl.sp -= pl.sp_speed
 elseif btn(➡️) then
  pl.speed += pl.accel
  pl.sp += pl.sp_speed
 else
  if pl.speed < 0 then
   pl.speed += pl.accel
  elseif pl.speed > 0 then
   pl.speed -= pl.accel
  end
 end
 
 local m_speed = btn(🅾️) and
   pl.m_speed*2 or pl.m_speed
 pl.speed = mid(-m_speed,
   pl.speed, m_speed)
 
 pl.x += pl.speed
 pl.x = mid(0, pl.x, 120)
 
 if pl.sp < 1 then
  pl.sp += 2
 elseif pl.sp >= 3.0 then
  pl.sp -= 2
 end
 
 if btn(❎) then
  if pl.can_shoot and
    pl.at_tm <= 0 then
   pl_attack()
  end
 else
  pl.can_shoot = true
 end
 
 if pl.at_tm > 0 then
  pl.at_tm -= frame_time
 end
 
 for proj in all(pl.projs) do
  pl_proj_update(proj)
 end
end

function player_draw()
 for proj in all(pl.projs) do
  spr(proj.sp, proj.x, proj.y)
 end
 spr(pl.sp, pl.x, pl.y)
 if pl.at_tm <= 0 then
  spr(0x3, pl.x, pl.y)
 end
 rectfill(0, 0, 128, 7, 6)
 for i = 1,pl.lives do
  spr(0x1, 9*i - 8, -1)
 end
 print(
   sub("000000"..pl.score, -6),
   103, 1, 13)
end

function pl_attack()
 pl.at_tm = pl.at_delay
 
 local proj = {
  sp = 0x4,
  x = flr(pl.x)+3,
  y = flr(pl.y),
  sx = 2,
  sy = 2,
 }
 add(pl.projs, proj)
 sfx(0)
end

function pl_proj_update(proj)
 proj.y -= pl.proj_speed
 if proj.y < -8 or
   map_damage(proj) or
   en_damage(proj) or
   ufo_damage(proj) then
  del(pl.projs, proj)
 end
end

function pl_damage(proj)
 if is_collide(proj, pl) then
  pl.lives -= 1
  if pl.lives > 0 then
   pl_reset_pos()
   sfx(4)
  else
   set_state(state_menu)
   sfx(5)
  end
  return true
 end
 return false
end

function pl_reset_pos()
 pl.x = 60
 pl.y = 119
end

-->8
-- map

function map_init()
 map_c = 6
 map_areas = {}
 
 foreach(get_shelter(19, 107),
   function(v)
   add(map_areas, v) end)
 
 foreach(get_shelter(49, 107),
   function(v)
   add(map_areas, v) end)
   
 foreach(get_shelter(79, 107),
   function(v)
   add(map_areas, v) end)
   
 foreach(get_shelter(109, 107),
   function(v)
   add(map_areas, v) end)
end

function map_update()

end

function map_draw()
 map()
 --rectfill(0, 104, 128, 127, 12)
 --rectfill(0, 127, 128, 128, 5)
 
 for a in all(map_areas) do
  for i = 0, 15 do
   if a.v & (1 << i) != 0 then
    local x = a.x+i%4
    local y = a.y+i\4
    pset(x, y, map_c)
   end
  end
 end
end

function map_damage(proj)
 local is_collided = false
 
 for a in all(map_areas) do
  if is_collide(a, proj) and
    a.v != 0 then
   for i = 0, 15 do
    if a.v & (1 << i) != 0 then
     local p = {
      x = a.x+i%4,
      y = a.y+i\4,
      sx = 1,
      sy = 1,
     }
     if is_collide(p,proj) then
      a.v &= ~(1 << i)
      is_collided = true
     end
    end
   end
  end
 end
 
 return is_collided
end

function get_area(ax, ay, av)
  return {
   x = ax,
   y = ay,
   sx = 4,
   sy = 4,
   v = av,
  }
end

function get_shelter(x, y)
 return {
  get_area(x-10, y,   0xec80),
  get_area(x-6,  y,   0xfffe),
  get_area(x-2,  y,   0xffff),
  get_area(x+2,  y,   0xfff7),
  get_area(x+6,  y,   0x7310),
  
  get_area(x-10, y+4, 0xffff),
  get_area(x-6,  y+4, 0xffff),
  get_area(x-2,  y+4, 0xffff),
  get_area(x+2,  y+4, 0xffff),
  get_area(x+6,  y+4, 0xffff),
  
  get_area(x-10, y+8, 0xffff),
  get_area(x-6,  y+8, 0x0013),
  get_area(x+2,  y+8, 0x008c),
  get_area(x+6,  y+8, 0xffff),
 }
end

-->8
-- enemies

function enemies_init()
 en = {
  mv_left = true,
  mv_speed = 0.025,
  mv_speed_inc = 0.01,
  mv_speed_inc_inc = 0.0005,
  descent_speed = 1.0,
  descent_speed_inc = 0.03,
  at_tm = 1.0,
  at_delay = 1.5,
  at_delay_dec = -0.01,
  proj_speed = 1,
  projs = {},
 }
 enemies = {}
 local row = 1
 for ly = 9, 60, 9 do
  local en_row = {}
  for lx = 17, 102, 8 do
   local enemy = {
    x = lx,
    y = ly,
    sx = 8,
    sx = (ly<21) and 8
      or (ly<38) and 6 or 4,
    sy = 8,
    sp = (ly<21) and 0x22
      or (ly<38) and 0x21
      or 0x20,
   }
   add(en_row, enemy)
  end
  enemies[row] = en_row
  row += 1
 end
end

function enemies_update() 
 if en.at_tm > 0 then
  en.at_tm -= frame_time
 end
 
 en_move()
 
 if en.at_tm <= 0 then
  en.at_tm = en.at_delay
  en_attack()
 end
 
 for proj in all(en.projs) do
  en_proj_update(proj)
 end
end

function enemies_draw()
 for proj in all(en.projs) do
  spr(proj.sp, proj.x, proj.y)
 end
 for row in all(enemies) do
  for e in all(row) do
   spr(e.sp, e.x, e.y)
  end
 end
end

function en_move()
 if en.mv_left then
  if en_can_mv_side(true) then
   en_mv_side(-en.mv_speed)
  else
   en_mv_down()
   en.mv_left = false
  end
 else
  if en_can_mv_side(false) then
   en_mv_side(en.mv_speed)
  else
   en_mv_down()
   en.mv_left = true
  end
 end
end

function en_attack()
 local e = en_random()
 if e == nil then
  sfx(6)
  set_state(state_menu)
  return
 end
 
 sfx(2)
 
 local proj = {
  sp = 0x24,
  x = flr(e.x)+3,
  y = flr(e.y),
  sx = 2,
  sy = 2,
 }
 add(en.projs, proj)
end

function en_mv_side(speed)
 for i = 1,#enemies do
  for e in all(enemies[i]) do
   e.x += speed
  end
 end
end

function en_mv_down()
 sfx(3)
 for i = 1,#enemies do
  for e in all(enemies[i]) do
   e.y += flr(en.descent_speed)
   if e.y > 101 then
    sfx(8)
    set_state(state_menu)
   elseif e.y > 96 then
    sfx(9)
   end
  end
 end
end

function en_can_mv_side(left)
 for row in all(enemies) do
  if #row != 0 then
   if (left and
     row[1].x <= 0) or
     (not left and
     row[#row].x >= 120) then
    return false
   end
  end
 end
 return true 
end

function en_proj_update(proj)
 proj.y += en.proj_speed
 if proj.y > 128 or
   map_damage(proj) or
   pl_damage(proj) then
  del(en.projs, proj)
 end
end

function en_random()
 local rows = {}
 for row in all(enemies) do
  if #row != 0 then
   add(rows, row)
  end
 end
 if #rows == 0 then
   return nil
 end
 return rnd(rnd(rows))
end

function en_damage(proj)
 for row in all(enemies) do
  for e in all(row) do
   if is_collide(proj, e) then
    en.mv_speed +=
      en.mv_speed_inc
    en.mv_speed_inc +=
      en.mv_speed_inc_inc
    en.at_delay +=
      en.at_delay_dec
    en.descent_speed +=
      en.descent_speed_inc
    pl.score +=
      e.sp==0x20 and 25 or
      e.sp==0x21 and 100 or 250
    del(row, e)
    sfx(1)
    return true
   end
  end
 end
 return false
end

-->8
-- menu

function menu_init()
 menu_text = "press ❎ to play"
 can_select = false
end

function menu_update()
 if btn(❎) then
  if can_select then
   set_state(state_play)
  end
 else
  can_select = true
 end
end

function menu_draw()
 print(menu_text, 32, 60, 6)
end

-->8
-- ufo

function ufo_init()
 ufo = {
  exists = false,
  x = 60,
  y = 7,
  sx = 8,
  sy = 4,
  dir = 1,
  speed = 0.25,
  speed_inc = 0.1,
  tm = 15.0,
  delay = 10.0,
  delay_dec = -1.0,
  score = 2500,
  score_inc = 1000,
 }
end

function ufo_update()
 if ufo.exists then
  ufo.x += ufo.speed * ufo.dir
  if ufo.x < -16 or
    ufo.x > 136 then
   uf_remove()
  end
 elseif ufo.tm > 0 then
  ufo.tm -= frame_time
  if ufo.tm <= 0 then
   ufo.tm = ufo.delay
   ufo.delay += ufo.delay_dec
   uf_spawn()
  end
 end
end

function ufo_draw()
 if ufo.exists then
  spr(0x1f, ufo.x, ufo.y)
 end
end

function uf_spawn()
 ufo.exists = true
 if rnd(1) < 0.5 then
  ufo.x = -16
  ufo.dir = 1
 else
  ufo.x = 136
  ufo.dir = -1
 end
 music(0)
end

function ufo_damage(proj)
 if ufo.exists and
   is_collide(proj, ufo) then
  uf_remove()
  pl.score += ufo.score
  ufo.speed += ufo.speed_inc
  ufo.score += ufo.score_inc
  sfx(7)
  return true
 end
 return false
end

function uf_remove()
 ufo.exists = false
 music(-1, 100)
end

__gfx__
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__gff__
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__map__
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__sfx__
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__music__
03 0a424344