fix remaining vulcan-family bug

last_tyrianlike.p8

@@ -1,5 +1,5 @@
 pico-8 cartridge // http://www.pico-8.com
-version 42
+version 41
 __lua__
 -- vacuum gambit
 -- by kistaro windrider
@@ -18,17 +18,12 @@ function csv(s)
  end
  return ret
 end
-function const_fxn(x)
- return function()
-  return x
- end
-end
 
 -- generate standard "overlay"
 -- constructor for type tt.
--- if tt.init is defined, generated
--- new calls tt.init(ret) after
--- ret is definitely not nil,
+-- if more is defined, generated
+-- new calls more(ret) after
+-- ret is definitely not nil
 -- before calling setmetatable.
 -- use to initialize mutables.
 --
@@ -37,8 +32,8 @@ end
 -- object *after* more, because
 -- this works better with the
 -- `more` impls i use.
-function mknew(tt)
- local mt,oldnew,more = {__index=tt},tt.new,rawget(tt, "init")
+function mknew(tt, more)
+ local mt,oldnew = {__index=tt},tt.new
  tt.new=function(ret)
   if(not ret) ret = {}
   if(more) more(ret)
@@ -46,18 +41,15 @@ function mknew(tt)
   setmetatable(ret, mt)
   return ret
  end
- return tt
 end
 
 -- intrusive singly-linked list.
 -- cannot be nested!
-linked_list = mknew{
- is_linked_list=true,
- init = function(x)
+linked_list = {is_linked_list=true}
+mknew(linked_list, function(x)
   x.next=nil
   x.tail=x
- end,
-}
+ end)
 
 function linked_list:push_back(x)
  self.tail.next = x
@@ -126,7 +118,7 @@ end
 function _init()
  init_blip_pals()
 	wipe_level()
-	primary_ship.main_gun = zap_gun_p.new()  -- redundant?
+	primary_ship.main_gun = zap_gun.new()
 	load_level(example_level_csv)
 	state = game
 	pal(2,129)
@@ -420,7 +412,7 @@ end
 
 scrollrate = 0.25 --in px/frame
 
-ship_m = mknew{
+ship_m = {
 
  -- ships have no shield by default
  shield = 0,
@@ -445,6 +437,7 @@ ship_m = mknew{
  -- ymin, ymax default to nil
  --   pship needs more constraint 
 }
+mknew(ship_m)
 
 function ship_m:die()
  self.dead = true
@@ -587,20 +580,16 @@ end
 -->8
 -- bullet and gun behaviors
 
-function player_blt_cat()
- return pbullets
-end
+bullet_base = {
+ enemyspd = 0.5
+}
+mknew(bullet_base)
 
-function enemy_blt_cat()
- return ebullets
-end
-
-bullet_base = mknew{ }
-
-gun_base = mknew{ 
+gun_base = { 
  shoot_ready = -32768,
  icon = 20
 }
+mknew(gun_base)
 
 function bullet_base:hitship(_)
  self:die()
@@ -612,10 +601,18 @@ end
 
 function bullet_base:move()
  self.x += self.dx
- self.y += self.dy
- if (self.y > 128) or (self.y < -8 * self.height) then
-  self:die()
-  return true
+ if self.enemy then
+  self.y += self.dy
+  if self.y > 128 then
+   self:die()
+   return true
+  end
+ else
+  self.y -= self.dy
+  if self.y < -8*self.height then
+   self:die()
+   return true
+  end
  end
  return false
 end
@@ -624,18 +621,17 @@ function bullet_base:draw()
  spr(self.sprite, self.x, self.y, self.width, self.height)
 end
 
--- An `actually_shoot` factory
--- for trivial guns
-function spawn_one(t)
- return function(gun, x, y)
-  t.new{}:spawn_at(x, y)
- end
-end
-
 function bullet_base:spawn_at(x, y)
- self.x = x - self.x_off
- self.y = y - self.y_off
- self.category():push_back(self)
+ self.x = x - self.center_x_off
+ if self.enemy then
+  self.dx *= self.enemyspd
+  self.dy *= self.enemyspd
+  self.y = y + self.top_y_off
+  ebullets:push_back(self)
+ else
+  self.y = y - (8 * self.height) + self.bottom_y_off
+  pbullets:push_back(self)
+ end
 end
 
 function gun_base:shoot(x, y)
@@ -649,12 +645,23 @@ function gun_base:shoot(x, y)
  return true
 end
 
+function gun_base:actually_shoot(x, y)
+ local typ = self.t
+ local b = typ.new{
+  enemy = self.enemy,
+  sprite = self.enemy and typ.esprite or typ.psprite,
+ }
+ b:spawn_at(x, y)
+ return true
+end
+
 -->8
 -- bullets and guns
 
-zap_e = mknew(bullet_base.new{
+zap = bullet_base.new{
  --shape
- sprite = 9, --index of enemy ammo sprite
+ psprite = 8, --index of player ammo sprite
+ esprite = 9, -- index of enemy ammo sprite
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -663,39 +670,33 @@ zap_e = mknew(bullet_base.new{
   width = 2,
   height = 8
  },
- x_off = 1, -- how to position by ship
- y_off = 8,
+ center_x_off = 1, -- how to position by ship
+ bottom_y_off = 0,
+ top_y_off = 0,
  
  damage = 1,
  dx = 0,  -- px/frame
- dy = 4,
+ dy = 8,
 
- hitship = const_fxn(true),
+ hitship = function(_, _)
+  return true
+ end
+}
+mknew(zap)
 
- category = enemy_blt_cat,
-})
-
-zap_p = mknew(zap_e.new{
- sprite = 8,
- dy = -8,
- y_off = 0,
- category = player_blt_cat,
-})
-
-zap_gun_e = mknew(gun_base.new{
+zap_gun = gun_base.new{
+ enemy = false,
  power = 20, -- power consumed per shot
  cooldown = 0x0.000a, -- frames between shots
  ammo = nil, -- unlimited ammo - main gun
- actually_shoot = spawn_one(zap_e),
-})
+ t = zap -- metatable of bullet to fire
+}
+mknew(zap_gun)
 
-zap_gun_p = mknew(zap_gun_e.new{
- actually_shoot = spawn_one(zap_p),
-})
-
-blast = mknew(bullet_base.new{
+blast = bullet_base.new{
  --shape
- sprite = 12, --index of player ammo sprite
+ psprite = 12, --index of player ammo sprite
+ esprite = 3, -- index of enemy ammo sprite
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -704,12 +705,13 @@ blast = mknew(bullet_base.new{
   width = 6,
   height = 6
  },
- x_off = 4, -- how to position by ship
- y_off = 0,
+ center_x_off = 4, -- how to position by ship
+ bottom_y_off = 0,
+ top_y_off = 0,
  
  damage = 4,
  dx = 0,  -- px/frame
- dy = -2,
+ dy = 2,
  awaitcancel = false,
 
  -- disable damage for 2 frames
@@ -734,22 +736,25 @@ blast = mknew(bullet_base.new{
     self.awaitcancel = false
    end)
   end
- end,
- category=player_blt_cat
-})
+ end
+}
+mknew(blast)
 
-blast_gun = mknew(gun_base.new{
+blast_gun = gun_base.new{
  icon = 13,
- power = 0, -- only cost is ammo
+ enemy = false,
+ power = 0, -- ammo, not power
  cooldown = 0x0.0020, -- frames between shots
  ammo = 5,
  maxammo = 5,
- actually_shoot = spawn_one(blast),
-})
+ t = blast -- type of bullet to fire
+}
+mknew(blast_gun)
 
-protron_e = mknew(bullet_base.new{
+protron = bullet_base.new{
  --shape
- sprite = 24,
+ psprite = 23, --index of player ammo sprite
+ esprite = 24, -- index of enemy ammo sprite
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -758,59 +763,56 @@ protron_e = mknew(bullet_base.new{
   width = 2,
   height = 2
  },
- x_off = 1, -- how to position by ship
- y_off = 4,
+ center_x_off = 1, -- how to position by ship
+ bottom_y_off = 4,
+ top_y_off = 0,
  
  damage = 1,
- dym = 0.5, -- gun sets dy;
-             -- this is mult
- category = enemy_blt_cat,
-})
+ dx = 0,  -- px/frame
+ dy = 3,
+}
+mknew(protron)
 
-protron_p = mknew(protron_e.new{
- sprite=23,
- dym = -1,
- y_off = 0,
- category=player_blt_cat,
-})
-
-protron_gun_e = mknew(gun_base.new{
+protron_gun = gun_base.new{
  icon = 25,
+ enemy = false,
  power = 60,
  cooldown = 0x0.000f, -- frames between shots
  ammo = nil,
  maxammo = nil,
- munition = protron_e
-})
-
-function protron_gun_e:actually_shoot(x, y)
- local m = self.munition.dym
- for i=1,3 do
-  local b = self.munition.new{
-   dx = i*m,
-   dy = (4-i)*m,
+ actually_shoot = function(self, x, y)
+  local sprite = protron.psprite
+  if (self.enemy) sprite=protron.esprite
+  for i=1,3 do
+   local b = protron.new{
+    enemy=self.enemy,
+    sprite=sprite,
+    dx = i,
+    dy = 4-i
+   }
+   b:spawn_at(x,y)
+   local b2 = protron.new{
+    enemy=self.enemy,
+    sprite=sprite,
+    dx = -i,
+    dy = 4-i
+   }
+   b2:spawn_at(x,y)
+  end
+  local bup = protron.new{
+   enemy=self.enemy,
+   sprite=sprite,
+   dy=4
   }
-  b:spawn_at(x,y)
-  local b2 = self.munition.new{
-   dx = -i*m,
-   dy = (4-i)*m,
-  }
-  b2:spawn_at(x,y)
+  bup:spawn_at(x,y)
  end
- local bup = self.munition.new{
-  dx=0,
-  dy=4*m,
- }
- bup:spawn_at(x,y)
-end
+}
+mknew(protron_gun)
 
-protron_gun_p = mknew(protron_gun_e.new{
- munition = protron_p,
-})
-
-vulcan_e = mknew(bullet_base.new{
+vulcan = bullet_base.new{
  --shape
- sprite = 21,
+ psprite = 22, --index of player ammo sprite
+ esprite = 21, -- index of enemy ammo sprite
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -819,46 +821,39 @@ vulcan_e = mknew(bullet_base.new{
   width = 1,
   height = 4
  },
- x_off = 0.5, -- how to position by ship
- y_off = 0,
+ center_x_off = 0.5, -- how to position by ship
+ bottom_y_off = 4,
+ top_y_off = 0,
  
  damage = 0.5,
- -- dx from gun
- dy = 2,
- category=enemy_blt_cat
-})
+ dx = 0,  -- px/frame
+ dy = 4,
+}
+mknew(vulcan)
 
-vulcan_p = mknew(vulcan_e.new{
- sprite=22,
- y_off = 4,
- dy = -4,
- category=player_blt_cat
-})
-
-vulcan_gun_e = mknew(gun_base.new{
+vulcan_gun = gun_base.new{
  icon = 37,
  enemy = false,
  power = 8,
  cooldown = 0x0.0002, -- frames between shots
  ammo = nil,
  maxammo = nil,
- munition=vulcan_e,
  dxs = {0.35, -0.35, -0.7, 0.7, 0.35, -0.35},
  xoffs = {1, 0, -1, 1, 0, -1},
  dxidx = 1,
  actually_shoot = function(self, x, y)
-  local b = self.munition.new{
+  local sprite = self.enemy and vulcan.esprite or vulcan.psprite
+  local b = vulcan.new{
+   enemy=self.enemy,
+   sprite=sprite,
    dx = self.dxs[self.dxidx],
   }
   b:spawn_at(self.xoffs[self.dxidx]+x,y)
   self.dxidx += 1
   if (self.dxidx > #self.dxs) self.dxidx = 1
  end
-})
-
-vulcan_gun_p = mknew(vulcan_gun_e.new{
- munition=vulcan_p,
-})
+}
+mknew(vulcan_gun)
 
 -->8
 --ships, including player
@@ -866,7 +861,7 @@ vulcan_gun_p = mknew(vulcan_gun_e.new{
 firespark = split"9, 8, 2, 5, 1"
 smokespark = split"13, 13, 5, 5"
 
-player = mknew(ship_m.new{
+player = ship_m.new{
  --shape
  sprite = 1, --index of ship sprite
  size = 1, --all ships are square; how many 8x8 sprites?
@@ -916,20 +911,21 @@ player = mknew(ship_m.new{
   end
   --dx, dy, shoot_spec, shoot_main
   return (((b&0x2)>>1) - (b&0x1)) * th, (((b&0x8)>>3) - ((b&0x4)>>2)) * th, (b&0x10) > 0, (b&0x20) > 0
- end,
-
- init = function(p)
-  p.main_gun = zap_gun_p.new()
+ end
+}
+mknew(player,
+ function(p)
+  p.main_gun = zap_gun.new()
   -- ONE HIT MODE
   --
   -- p.hp = 0
   -- p.maxhp = 0
   -- p.shield = 0
   -- p.maxshield = 0
- end,
-})
+ end
+)
 
-frownie = mknew(ship_m.new{
+frownie = ship_m.new{
  --shape
  sprite = 3, --index of ship sprite
  size = 1, --all ships are square; how many 8x8 sprites?
@@ -960,9 +956,10 @@ frownie = mknew(ship_m.new{
   if (tstate>=4) dx=self.thrust
   return dx,0,false,false
  end,
-})
+}
+mknew(frownie)
 
-blocky = mknew(frownie.new{
+blocky = frownie.new{
  sprite = 10,
  hp = 1.5,
  hurt = {
@@ -980,9 +977,10 @@ blocky = mknew(frownie.new{
   end
   ship_m.ow(self)
  end
-})
+}
+mknew(blocky)
 
-spewy = mknew(frownie.new{
+spewy = frownie.new{
  sprite=26,
  power=-20,
  hurt = {
@@ -999,13 +997,13 @@ spewy = mknew(frownie.new{
  act=function(self)
   local dx,dy,shoot_spec=frownie.act(self)
   return dx, dy, shoot_spec, true
- end,
- init = function(ship)
-  ship.main_gun=ship.main_gun or protron_gun_e.new{}
  end
-})
+}
+mknew(spewy, function(ship)
+ ship.main_gun=ship.main_gun or protron_gun.new{enemy=true}
+end)
 
-chasey = mknew(ship_m.new{
+chasey = ship_m.new{
  sprite = 5,
  size = 1,
  hurt = {
@@ -1028,11 +1026,10 @@ chasey = mknew(ship_m.new{
  thrust = 0.2,
  drag = 0.075,
  slip = true,
-
- init = function(ship)
-  ship.main_gun=ship.main_gun or zap_gun_e.new{}
- end
-})
+}
+mknew(chasey, function(ship)
+ ship.main_gun=ship.main_gun or zap_gun.new{enemy=true}
+end)
 
 function chasey:act()
  self.xmin = max(primary_ship.x-8, 0)
@@ -1040,7 +1037,7 @@ function chasey:act()
  return 0, 0, false, self.x - 16 < primary_ship.x and self.x + 16 > primary_ship.x
 end
 
-xl_chasey=mknew(chasey.new{
+xl_chasey=chasey.new{
  size=2,
  maxspd=1.25,
  hurt = {
@@ -1049,8 +1046,6 @@ xl_chasey=mknew(chasey.new{
   width = 12,
   height = 10
  },
- fire_off_x = 8,
- fire_off_y = 15,
  hp = 19.5,
  shield = 5,
  boss = true,
@@ -1065,11 +1060,10 @@ xl_chasey=mknew(chasey.new{
   sspr(40, 0, 8, 8, self.x, self.y, 16, 16)
   pal()
  end,
- init = function(ship)
-  ship.main_gun=ship.main_gun or zap_gun_e.new{}
- end,
-})
-
+}
+mknew(xl_chasey, function(ship)
+ ship.main_gun=ship.main_gun or zap_gun.new{enemy=true}
+end)
 -->8
 -- collisions
 
@@ -1083,11 +1077,12 @@ function collides(box1, box2)
 	  or box1.y+box1.height<box2.y)
 end
 
-collider = mknew{
- init = function(x)
+collider = { }
+mknew(collider,
+ function(x)
   x.suppress = {}
- end,
-}
+ end
+)
 
 function collider_indexes(box)
  local ret = {}
@@ -1276,9 +1271,9 @@ end
 
 function spawn_bonus_vulcan_chasey()
  local c = spawn_chasey()
- c.main_gun=vulcan_gun_e.new{enemy=true}
+ c.main_gun=vulcan_gun.new{enemy=true}
  c.die = function(self)
-  spawn_main_gun_at(self.x-1, self.y-1, vulcan_gun_p)
+  spawn_main_gun_at(self.x-1, self.y-1, vulcan_gun)
   chasey.die(self)
  end
  c.sprite=4
@@ -1381,7 +1376,7 @@ example_level_csv=[[1,spawn_frownie
 310,spawn_blocking_blocky
 310,spawn_blocking_blocky
 311,spawn_frownie
-350,spawn_main_gun_at,70,-11,protron_gun_p
+350,spawn_main_gun_at,70,-11,protron_gun
 401,spawn_frownie
 420,spawn_blocking_frownie
 430,spawn_bonus_vulcan_chasey
@@ -1491,9 +1486,8 @@ bullets
   shots much easier to dodge
 * damage - damage per hit;
   used by ships
-* sprite - sprite index.
-* x_off, y_off - renamed for
-  the next two vars. may revert
+* psprite, esprite - index of
+  player or enemy sprite.
 * center_off_x - the horizontal
   centerpoint of the bullet,
   for positioning when firing.
@@ -1782,7 +1776,7 @@ true, they are dropped.
 -->8
 -- standard events
 
-blip_fx = mknew{
+blip_fx = {
  cancel=false
 }
 
@@ -1800,6 +1794,8 @@ function blip_fx:abort()
  self.cancel=true
 end
 
+mknew(blip_fx)
+
 blip_pals = {}
 function init_blip_pals()
  for i=0,15 do
@@ -1834,7 +1830,8 @@ function boom(x,y,boominess,is_boss)
  return
 end
 
-spark_particle=mknew{}
+spark_particle={}
+mknew(spark_particle)
 
 function spark_particle:move()
  if (rnd(4) < 1) self.sidx += 1
@@ -1863,7 +1860,7 @@ end
 -->8
 -- powerups
 
-powerup = mknew(bullet_base.new{
+powerup = bullet_base.new{
  -- animated sprite array: "sprites"
  -- to draw under or over anim,
  -- override draw, draw the
@@ -1879,12 +1876,13 @@ powerup = mknew(bullet_base.new{
  -- easy to pick up
  dx = 0,
  dy = 1.5, -- 0.75 after enemyspd
- category = enemy_blt_cat, -- collides with player ship
+ enemy = true, -- collides with player ship
  damage = 0,
  
  anim_speed = 2,
  loop_pause = 30 -- affected by animspeed
-})
+}
+mknew(powerup)
 
 -- sprite indexes for "sheen" animation
 sheen8x8 = split"2,54,55,56,57,58,59,60,61"
@@ -1904,15 +1902,16 @@ function powerup:draw()
      self.width, self.height) 
 end
 
-repair = mknew(powerup.new{
+repair = powerup.new{
  hurt = {
   x_off = -2,
   y_off = -2,
   width = 12,
   height = 12
  },
- x_off = 4,
- y_off = 0,
+ center_x_off = 4,
+ top_y_off = 0,
+ bottom_y_off = 0,
  sprites = sheen8x8,
  hitship = function(self, ship)
   if (ship ~= primary_ship) return false
@@ -1923,13 +1922,14 @@ repair = mknew(powerup.new{
   spr(53, self.x, self.y, self.width, self.height)
   powerup.draw(self)
  end  
-})
+}
+mknew(repair)
 
 function spawn_repair_at(x, y)
  repair.new():spawn_at(x, y)
 end
 
-gun_swap = mknew(powerup.new{
+gun_swap = powerup.new{
  hurt = {
   x_off = -2,
   y_off = -2,
@@ -1937,8 +1937,9 @@ gun_swap = mknew(powerup.new{
   height = 16
  },
  -- gun = gun_type.new{}
- x_off = 6,
- y_off = 0,
+ center_x_off = 6,
+ top_y_off = 0,
+ bottom_y_off = 4,
  width = 2,
  height = 2,
  sprites = {64, 66, 68, 70, 72, 74, 76, 78},
@@ -1951,7 +1952,8 @@ gun_swap = mknew(powerup.new{
   powerup.draw(self)
   spr(self.gun.icon, self.x+2, self.y+2, 1, 1)
  end
-})
+}
+mknew(gun_swap)
 
 function spawn_main_gun_at(x, y, gunt)
  if (type(gunt)=="string") gunt=_ENV[gunt]

old_readme.md

@@ -1,356 +0,0 @@
-This file contains text that used to be in the cartridge itself, but
-I'm getting increasingly anxious about cartridge space so I'm moving
-it out ot a separate file.
-
----
-
-main loop sequence
-==================
-1. level_frame
-2. events
-3. merge new_events into events
-4. update bg intangibles
-5. move ships (player first)
-6. move bullets (player first)
-7. calculate collisions
- 1. pship on eship
- 2. ebullet on pship
- 3. pbullet on eship
-8. update fg intangibles
-9. check for end of level
-
-draw order
-----------
-bottom to top:
-1. intangibles_bg
-2. player bullets
-3. player ships
-4. enemy ships
-5. enemy bullets
-6. intangibles_fg
-
-notes
------
-intangibles_fg move()s after
-all collisions and other moves
-are processed. if an intangible
-is added to the list as a result
-of a collision or move, it will
-itself be move()d before it is
-drawn.
-
-data-driven items
-=================
-guns and bullets both allow the
-most common behaviors to be
-expressed with data alone.
-ships only need a movement
-algorithm expressed.
-
-guns
-----
-* t - metatable for bullet type.
-  fired once in the bullet's
-  default direction per shot.
-* enemy - if true, fired bullets
-  are flagged as enemy bullets.
-* icon - sprite index of an
-  8x8 sprite to display in the
-  hud when the player has this
-  gun. default is 20, a generic
-  crosshair bullseye thing.
-* cooldown - min frames between
-  shots.
-* ammo, maxammo - permitted
-  number of shots. 0 is empty
-  and unfireable. maxammo = 0
-  will cause a divide by zero
-  so don't do that. if nil,
-  ammo is infinite.
-
-default guns manage ammo and
-cooldown in shoot, then call
-actually_shoot to create the
-projectile. override only
-actually_shoot to change
-projectile logic while keeping
-cooldown and ammo logic.
-
-bullets
--------
-* dx, dy - movement per frame.
-  player bullets use -dy
-  instead.
-* enemyspd - multiplier for dx
-  and dy on enemy bullets.
-  default is 0.5, making enemy
-  shots much easier to dodge
-* damage - damage per hit;
-  used by ships
-* sprite - sprite index.
-* x_off, y_off - renamed for
-  the next two vars. may revert
-* center_off_x - the horizontal
-  centerpoint of the bullet,
-  for positioning when firing.
-  assume a pixel's coordinates
-  refer to the upper left corner
-  of the pixel; the center of
-  a 2-width bullet with an
-  upper left corner at 0 is 1,
-  not 0.5.
-* top_off_y, bottom_off_y -
-  also for positioning when
-  firing. positive distance from
-  top or bottom edge to image.
-  top_off_y will usually be 0,
-  bottom_off_y will not be when
-  bullets are smaller than
-  the sprite box.
-* width, height - measured in
-  full sprites (8x8 boxes), not
-  pixels. used for drawing.
-
-bullets despawn when above or
-below the screen (player or
-enemy bullets, respectively).
-
-by default, bullets despawn
-when they hit something.
-override hitship to change this.
-
-ships
-____
-
-ships move by calculating
-momentum, then offsetting their
-position by that momentum, then
-clamping their position to the
-screen (horizontally only for
-ships that autoscroll). ships
-that autoscroll (slip==true)
-then slide down by scrollspeed.
-fractional coordinates are ok.
-after movement, ships lose
-momentum (ship.drag along each
-axis). abs(momentum) can't
-exceed ship.maxspeed.
-
-ships gain momentum by acting
-like a player pushing buttons.
-the player ship actually reads
-buttons for this.
-
-act -- returns new acceleration:
-dx, dy, shoot_spec, shoot_main.
-dx and dy are change in momentum
-in px/frame. this is controls
-only -- friction is handled in
-ship:move (`drag` value).
-
-ships hitting another ship take
-1 damage per frame of overlap.
-ships hitting a bullet check
-bullet.damage to find out how
-much damage they take. damage
-is applied to shields, then hp.
-damaged ships flash briefly -
-blue (12) if all damage was
-shielded, white (7) if hp was
-damaged. a ship that then has 0
-or less hp calls self:die() and
-tells the main game loop to
-remove it.
-
-shieldcooldown is the interval
-between restoring shield points.
-shieldpenalty is the delay
-before restoring points after
-any damage, reset to this value
-on every damaging hit (whether
-it is absorbed by the shield or
-not) -- shield behaves like
-halo and other shooters in its
-heritage, where it recovers if
-you avoid damage for a while.
-not that there is any safe cover
-in this kind of game.
-
-ships do not repair hp on their
-own. negative-damage bullets
-are treated as 0, but a bullet
-can choose to repair the ship
-it hits in its own hitship
-method, or otherwise edit it
-(changing weapons, refilling
-weapon ammo). powerups are
-therefore a kind of bullet.
-
-levels
-======
-
-a level is a table mapping
-effective frame number to
-functions. when a level starts,
-it sets lframe ("level frame")
-and distance to 0.
-
-every frame, level_frame
-increments lframe by 0x0.0001.
-then if the level is not frozen,
-it increments distance by 1.0
-and runs the function in the
-level table for exactly that
-frame number (if any). distance
-is therefore "nonfrozen frames",
-and is used to trigger level
-progress. lframe always
-increments. ships are encouraged
-to use lframe to control
-animation and movement, and may
-use distance to react to level
-progress separately from overall
-time. remember to multiply
-lframe-related stuff by 0x0001.
-
-a special sentinel value, eol,
-marks the end of the level.
-(the level engine doesn't know
-when it's out of events, so
-without eol, the level will
-simply have no events forever.)
-when it finds eol, level_frame
-throws away the current level
-and tells the main loop that it
-might be done. the main loop
-agrees the level is over and the
-player has won when the level
-has reached eol and there are
-no more enemy ships, enemy
-bullets, or background events
-remaining. player ships, player
-bullets, and intangibles are
-not counted.
-
-level freezing
---------------
-the level is frozen when the
-global value freeze > 0.
-generally, something intending
-to block level progress (a
-miniboss, a minigame, etc.)
-increments freeze and prepares
-some means of decrementing it
-when it no longer wants to block
-level progress.
-
-most commonly, we want to block
-until some specific ship or
-group of ships has died. for
-these ships, override ship:die
-to decrement freeze. make sure
-to set ship.dead in any new
-ship:die method so anything else
-looking at it can recognize
-the ship as dead.
-
-for anything else, you probably
-want an event to figure out when
-to unfreeze.
-
-levels start at 1
------------------
-
-distance is initialized to 0
-but gets incremented before the
-first time the engine looks for
-events. therefore, the first
-frame of the level executes
-level[1]. since levelframe
-executes before anything else,
-level[1] sets up the first frame
-drawn in the level. the player
-does not see a blank world
-before level[1] runs.
-level[1] can therefore be used
-to reconfigure the player ship,
-set up backgrounds, start music,
-kick off some kind of fade-in
-animation, etc.
-
-
-events
-======
-the global list "events" stores
-0-argument functions which are
-called every frame. if they
-return true, they are removed
-from the list and not run again;
-if they return false, they stay
-and will be called in later
-frames. the level does not end
-while the events table is
-nonempty.
-
-events are most commonly used
-to set up something for later
-(for example, blip uses an event
-to remove the fx_pallete from
-the flashing ship when the blip
-expires), but can also be used
-to implement a "level within a
-level" that does something
-complicated until it's done. if
-you froze the level when
-creating the event, remember
-to thaw it (freeze -= 1) on all
-paths that return true.
-
-to do complex stuff in events,
-use a closure or a metatable
-that specifies __call.
-
-to avoid editing the events
-list while it is being iterated,
-events that create new events
-must add those events to
-new_events rather than events.
-new_events is only valid during
-the "event execution" stage, so
-events created at any other time
-must go directly on events
-without using new_events.
-
-intangibles
-===========
-
-the intangibles_fg and
-intangibles_bg lists contain
-items with :move and :draw.
-like ships and bullets, they
-move during _update60 and
-draw during _draw. they are
-not checked for collisions.
-
-intangibles_bg moves/draws
-before anything else moves or
-draws. intangibles_fg
-moves/draws last. this controls
-whether your intangible object
-draws in front of or behind
-other stuff. you probably want
-intangibles_bg for decorative
-elements and intangibles_fg
-for explosions, score popups,
-etc.
-
-there's no scrolling background
-engine but intangibles_bg could
-be used to create one, including
-using the map (otherwise unused
-in this engine) for the purpose.
-
-intangibles do not prevent the
-level from ending. like bullets
-and ships, if :move returns
-true, they are dropped.

rearm_prototype.p8

@@ -1,87 +0,0 @@
-pico-8 cartridge // http://www.pico-8.com
-version 42
-__lua__
--- vacuum gambit
--- by kistaro windrider
-
-function _draw()
- cls()
- draw_hud_placeholder()
- draw_weap_opt(0,0,frame_col(item==1),1,"hull","\n  +1\n max\nhealth")
- draw_weap_opt(56,0,frame_col(item==2),2,"vulc","  rate\n\n faster\n firing\n  rate")
- draw_rearm(frame_col(item<0))
-end
-
-function _init()
- item=1
- bfm=1
-end
-
-function _update()
- if (btn(3) and item > 0 or btn(2) and item < 0) item = -item
- if (btn(0)) item = 1
- if (btn(1)) item = 2
- if (btn() & 0xF ~= 0) and bfm >= 10 or bfm >= 30 then
-  bfm = 1
- else
-  bfm += 1
- end
-end
-
-function draw_hud_placeholder()
- rectfill(112, 0, 127, 127,0x56)
- rect(112,0,127,127,7)
- line(127,1,127,127,5)
- line(113,127)
-end
-
-function glow_box(x0, y0, x1, y1, c, cf)
- rect(x0, y0, x1, y1, c[1])
- rect(x0+1, y0+1, x1-1, y1-1, c[2])
- rect(x0+2, y0+2, x1-2, y1-2, c[1])
- if cf then
-  -- todo: animate "dot crawl" background
- 	fillp(…)
-  rectfill(x0+3, y0+3, x1-3, y1-3, cf)
-  fillp()
- end
-end
-
-function frame_col(hot)
- if (not hot) return {4,10}
- if (bfm<=16) return {14,7}
- return {2,8}
-end
-
-function draw_weap_opt(x, y, c, s, hdr, body)
- camera(-x,-y)
- glow_box(0,0,55,100,c,1)
- spr(s,5, 5)
- print(hdr, 13, 8, 7)
- print(body, 5, 15, 6)
- camera()
-end
-
-function draw_rearm(c)
- glow_box(0,101,111,127,c,1)
- spr(5,15,107,4,2)
- print("full ammo\nfull shield\n+50% health",54, 106, 6)
-end
-
-__gfx__
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