fix remaining vulcan-family bug

next step is to pick a real direction -- MMBN-like (+STS-like) or
Survivors-like -- and adapt to match. I am likely to completely remove
the energy system and use permanent autofire, freeing both fire buttons
for more interesting tasks. It loses the opportunity to create a dynamic
around baiting an enemy to keep shooting so its shields don't recover,
but I don't think it loses a lot else.

Either energy management needs to become really important and the game
becomes strategic and tactical, or it needs to be a non-issue and it is
an arcade game. Tyrian itself did not make the energy system interesting
and it was just a tax, so making it interesting would be doing something
new. But I think it's a kind of "interesting" that almost nobody would
adopt unless I go _very hard_ into creating a tactical/strategic shmup.
A shmup that is actually a strange kind of RTS sounds... really cool,
actually, but I'm not at all confident I could design it.

Removing energy entirely gives us a button _and_ a meter back, which
can be used for XP (Survivors-like) or rearm time (MMBN-like).

vacuum_gambit.p8

@@ -1,5 +1,5 @@
 pico-8 cartridge // http://www.pico-8.com
-version 41
+version 42
 __lua__
 -- vacuum gambit
 -- by kistaro windrider
@@ -18,6 +18,11 @@ function csv(s)
  end
  return ret
 end
+function const_fxn(x)
+ return function()
+  return x
+ end
+end
 
 -- generate standard "overlay"
 -- constructor for type tt.
@@ -118,7 +123,7 @@ end
 function _init()
  init_blip_pals()
 	wipe_level()
-	primary_ship.main_gun = zap_gun.new()
+	primary_ship.main_gun = zap_gun_p.new()  -- redundant?
 	load_level(example_level_csv)
 	state = game
 	pal(2,129)
@@ -320,6 +325,7 @@ function drawgame()
 end
 
 powcols=split"170,154,153,148,68"
+shlcols = split"204,220,221"
 function drawhud()
  -- 112-and-right is hud zone
  rectfill(112, 0, 127, 127,0x56)
@@ -337,12 +343,16 @@ function drawhud()
 
  inset(120,66,125,125)
  -- 57 px vertically
- local mxs, mxh = primary_ship.maxshield, primary_ship.maxhp
- if mxs + mxh > 1 then
-  local split = 57 * (mxs / (mxs + mxh-1)) \ 1 + 66
+ local mxs, cs, mxh, ch = primary_ship.maxshield, primary_ship.shield, primary_ship.maxhp, primary_ship.hp
+ if (mxs > 0) and (mxh > 0) then
+  local split = 57 * (mxs / (mxs + mxh)) \ 1 + 66
   line(121, split, 124, split, 0xba)
-  vertmeter(121,67,124,split-1,primary_ship.shield, mxs,{204,220,221})
-  vertmeter(121,split+1,124,124,primary_ship.hp-1, mxh-1, hpcols)
+  vertmeter(121,67,124,split-1,cs, mxs,shlcols)
+  vertmeter(121,split+1,124,124,ch, mxh, hpcols)
+ elseif mxs > 0 then
+  vertmeter(121,67,124,124,cs,mxs,shlcols)
+ elseif mxh > 0 then
+  vertmeter(121,67,124,124,ch,mxh,hpcols)
  else
   print("!", 122, 94, 9)
   print("!", 121, 93, 8)
@@ -436,7 +446,7 @@ mknew(ship_m)
 
 function ship_m:die()
  self.dead = true
- if (self.hp <= 0) boom(self.x+self.size*4, self.y+self.size*4,12*self.size, self.boss)
+ if (self.hp < 0) boom(self.x+self.size*4, self.y+self.size*4,12*self.size, self.boss)
 end
 
 function ship_m:calc_velocity(v0, t)
@@ -546,7 +556,7 @@ function ship_m:hitsomething(dmg)
  dmg -= self.shield
  self.shield = 0
  self.hp -= dmg
- if self.hp <= 0 then
+ if self.hp < 0 then
   self:die()
   return true
  end
@@ -575,9 +585,15 @@ end
 -->8
 -- bullet and gun behaviors
 
-bullet_base = {
- enemyspd = 0.5
-}
+function player_blt_cat()
+ return pbullets
+end
+
+function enemy_blt_cat()
+ return ebullets
+end
+
+bullet_base = { }
 mknew(bullet_base)
 
 gun_base = { 
@@ -596,18 +612,10 @@ end
 
 function bullet_base:move()
  self.x += self.dx
- 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
+ self.y += self.dy
+ if (self.y > 128) or (self.y < -8 * self.height) then
+  self:die()
+  return true
  end
  return false
 end
@@ -616,19 +624,20 @@ function bullet_base:draw()
  spr(self.sprite, self.x, self.y, self.width, self.height)
 end
 
-function bullet_base:spawn_at(x, y)
- 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)
+-- 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)
+end
+
 function gun_base:shoot(x, y)
  if (lframe < self.shoot_ready) return false
  if self.ammo then
@@ -640,23 +649,12 @@ 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 = bullet_base.new{
+zap_e = bullet_base.new{
  --shape
- psprite = 8, --index of player ammo sprite
- esprite = 9, -- index of enemy ammo sprite
+ sprite = 9, --index of enemy ammo sprite
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -665,33 +663,43 @@ zap = bullet_base.new{
   width = 2,
   height = 8
  },
- center_x_off = 1, -- how to position by ship
- bottom_y_off = 0,
- top_y_off = 0,
+ x_off = 1, -- how to position by ship
+ y_off = 8,
  
  damage = 1,
  dx = 0,  -- px/frame
- dy = 8,
+ dy = 4,
 
- hitship = function(_, _)
-  return true
- end
+ hitship = const_fxn(true),
+
+ category = enemy_blt_cat,
 }
-mknew(zap)
+mknew(zap_e)
 
-zap_gun = gun_base.new{
- enemy = false,
+zap_p = zap_e.new{
+ sprite = 8,
+ dy = -8,
+ y_off = 0,
+ category = player_blt_cat,
+}
+mknew(zap_p)
+
+zap_gun_e = gun_base.new{
  power = 20, -- power consumed per shot
  cooldown = 0x0.000a, -- frames between shots
  ammo = nil, -- unlimited ammo - main gun
- t = zap -- metatable of bullet to fire
+ actually_shoot = spawn_one(zap_e),
 }
-mknew(zap_gun)
+mknew(zap_gun_e)
+
+zap_gun_p = zap_gun_e.new{
+ actually_shoot = spawn_one(zap_p),
+}
+mknew(zap_gun_p)
 
 blast = bullet_base.new{
  --shape
- psprite = 12, --index of player ammo sprite
- esprite = 3, -- index of enemy ammo sprite
+ sprite = 12, --index of player ammo sprite
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -700,13 +708,12 @@ blast = bullet_base.new{
   width = 6,
   height = 6
  },
- center_x_off = 4, -- how to position by ship
- bottom_y_off = 0,
- top_y_off = 0,
+ x_off = 4, -- how to position by ship
+ y_off = 0,
  
  damage = 4,
  dx = 0,  -- px/frame
- dy = 2,
+ dy = -2,
  awaitcancel = false,
 
  -- disable damage for 2 frames
@@ -731,25 +738,24 @@ blast = bullet_base.new{
     self.awaitcancel = false
    end)
   end
- end
+ end,
+ category=player_blt_cat
 }
 mknew(blast)
 
 blast_gun = gun_base.new{
  icon = 13,
- enemy = false,
- power = 0, -- ammo, not power
+ power = 0, -- only cost is ammo
  cooldown = 0x0.0020, -- frames between shots
  ammo = 5,
  maxammo = 5,
- t = blast -- type of bullet to fire
+ actually_shoot = spawn_one(blast),
 }
 mknew(blast_gun)
 
-protron = bullet_base.new{
+protron_e = bullet_base.new{
  --shape
- psprite = 23, --index of player ammo sprite
- esprite = 24, -- index of enemy ammo sprite
+ sprite = 24,
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -758,56 +764,63 @@ protron = bullet_base.new{
   width = 2,
   height = 2
  },
- center_x_off = 1, -- how to position by ship
- bottom_y_off = 4,
- top_y_off = 0,
+ x_off = 1, -- how to position by ship
+ y_off = 4,
  
  damage = 1,
- dx = 0,  -- px/frame
- dy = 3,
+ dym = 0.5, -- gun sets dy;
+             -- this is mult
+ category = enemy_blt_cat,
 }
-mknew(protron)
+mknew(protron_e)
 
-protron_gun = gun_base.new{
+protron_p = protron_e.new{
+ sprite=23,
+ dym = -1,
+ y_off = 0,
+ category=player_blt_cat,
+}
+mknew(protron_p)
+
+protron_gun_e = gun_base.new{
  icon = 25,
- enemy = false,
  power = 60,
  cooldown = 0x0.000f, -- frames between shots
  ammo = nil,
  maxammo = nil,
- 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
-  }
-  bup:spawn_at(x,y)
- end
+ munition = protron_e
 }
-mknew(protron_gun)
+mknew(protron_gun_e)
 
-vulcan = bullet_base.new{
+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,
+  }
+  b:spawn_at(x,y)
+  local b2 = self.munition.new{
+   dx = -i*m,
+   dy = (4-i)*m,
+  }
+  b2:spawn_at(x,y)
+ end
+ local bup = self.munition.new{
+  dx=0,
+  dy=4*m,
+ }
+ bup:spawn_at(x,y)
+end
+
+protron_gun_p = protron_gun_e.new{
+ munition = protron_p,
+}
+mknew(protron_gun_p)
+
+vulcan_e = bullet_base.new{
  --shape
- psprite = 22, --index of player ammo sprite
- esprite = 21, -- index of enemy ammo sprite
+ sprite = 21,
  width = 1, --in 8x8 blocks
  height = 1,
  hurt = { -- hurtbox - where this ship can be hit
@@ -816,31 +829,37 @@ vulcan = bullet_base.new{
   width = 1,
   height = 4
  },
- center_x_off = 0.5, -- how to position by ship
- bottom_y_off = 4,
- top_y_off = 0,
+ x_off = 0.5, -- how to position by ship
+ y_off = 0,
  
  damage = 0.5,
- dx = 0,  -- px/frame
- dy = 4,
+ -- dx from gun
+ dy = 2,
+ category=enemy_blt_cat
 }
-mknew(vulcan)
+mknew(vulcan_e)
 
-vulcan_gun = gun_base.new{
+vulcan_p = vulcan_e.new{
+ sprite=22,
+ y_off = 4,
+ dy = -4,
+ category=player_blt_cat
+}
+mknew(vulcan_p)
+
+vulcan_gun_e = 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 sprite = self.enemy and vulcan.esprite or vulcan.psprite
-  local b = vulcan.new{
-   enemy=self.enemy,
-   sprite=sprite,
+  local b = self.munition.new{
    dx = self.dxs[self.dxidx],
   }
   b:spawn_at(self.xoffs[self.dxidx]+x,y)
@@ -848,7 +867,12 @@ vulcan_gun = gun_base.new{
   if (self.dxidx > #self.dxs) self.dxidx = 1
  end
 }
-mknew(vulcan_gun)
+mknew(vulcan_gun_e)
+
+vulcan_gun_p = vulcan_gun_e.new{
+ munition=vulcan_p,
+}
+mknew(vulcan_gun_p)
 
 -->8
 --ships, including player
@@ -910,12 +934,11 @@ player = ship_m.new{
 }
 mknew(player,
  function(p)
-  p.main_gun = zap_gun.new()
-  -- ONE HIT MODE: max hp is
-  -- minimum nonzero value.
+  p.main_gun = zap_gun_p.new()
+  -- ONE HIT MODE
   --
-  -- p.hp = 0x0.0001
-  -- p.maxhp = 0x0.0001
+  -- p.hp = 0
+  -- p.maxhp = 0
   -- p.shield = 0
   -- p.maxshield = 0
  end
@@ -935,7 +958,7 @@ frownie = ship_m.new{
  sparkodds = 8,
  
  -- health and power
- hp = 1, -- enemy ships need no max hp
+ hp = 0.5, -- enemy ships need no max hp
 
  -- position
  x=60, -- x and y are for upper left corner
@@ -957,7 +980,7 @@ mknew(frownie)
 
 blocky = frownie.new{
  sprite = 10,
- hp = 2,
+ hp = 1.5,
  hurt = {
   x_off = 0,
   y_off = 0,
@@ -966,7 +989,7 @@ blocky = frownie.new{
  },
  
  ow = function(self)
-  if self.hp <= 1 then
+  if self.hp < 1 then
    self.sprite = 11
   else
    self.sprite = 10
@@ -985,7 +1008,7 @@ spewy = frownie.new{
   width=8,
   height=5
  },
- hp=1,
+ hp=0.5,
  maxpower=70,
  generator=0.5,
  fire_off_x=4,
@@ -996,7 +1019,7 @@ spewy = frownie.new{
  end
 }
 mknew(spewy, function(ship)
- ship.main_gun=ship.main_gun or protron_gun.new{enemy=true}
+ ship.main_gun=ship.main_gun or protron_gun_e.new{enemy=true}
 end)
 
 chasey = ship_m.new{
@@ -1010,7 +1033,7 @@ chasey = ship_m.new{
  },
  sparks = smokespark,
  sparkodds = 8,
- hp = 2,
+ hp = 1.5,
  shield = 1,
  maxshield = 1,
  shieldcost = 180,
@@ -1024,7 +1047,7 @@ chasey = ship_m.new{
  slip = true,
 }
 mknew(chasey, function(ship)
- ship.main_gun=ship.main_gun or zap_gun.new{enemy=true}
+ ship.main_gun=ship.main_gun or zap_gun_e.new{}
 end)
 
 function chasey:act()
@@ -1042,7 +1065,9 @@ xl_chasey=chasey.new{
   width = 12,
   height = 10
  },
- hp = 20,
+ fire_off_x = 8,
+ fire_off_y = 15,
+ hp = 19.5,
  shield = 5,
  boss = true,
  slip = false,
@@ -1058,7 +1083,7 @@ xl_chasey=chasey.new{
  end,
 }
 mknew(xl_chasey, function(ship)
- ship.main_gun=ship.main_gun or zap_gun.new{enemy=true}
+ ship.main_gun=ship.main_gun or zap_gun_e.new{}
 end)
 -->8
 -- collisions
@@ -1267,9 +1292,9 @@ end
 
 function spawn_bonus_vulcan_chasey()
  local c = spawn_chasey()
- c.main_gun=vulcan_gun.new{enemy=true}
+ c.main_gun=vulcan_gun_e.new{enemy=true}
  c.die = function(self)
-  spawn_main_gun_at(self.x-1, self.y-1, vulcan_gun)
+  spawn_main_gun_at(self.x-1, self.y-1, vulcan_gun_p)
   chasey.die(self)
  end
  c.sprite=4
@@ -1372,7 +1397,7 @@ 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
+350,spawn_main_gun_at,70,-11,protron_gun_p
 401,spawn_frownie
 420,spawn_blocking_frownie
 430,spawn_bonus_vulcan_chasey
@@ -1482,8 +1507,9 @@ bullets
   shots much easier to dodge
 * damage - damage per hit;
   used by ships
-* psprite, esprite - index of
-  player or enemy sprite.
+* 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.
@@ -1872,7 +1898,7 @@ powerup = bullet_base.new{
  -- easy to pick up
  dx = 0,
  dy = 1.5, -- 0.75 after enemyspd
- enemy = true, -- collides with player ship
+ category = enemy_blt_cat, -- collides with player ship
  damage = 0,
  
  anim_speed = 2,
@@ -1905,9 +1931,8 @@ repair = powerup.new{
   width = 12,
   height = 12
  },
- center_x_off = 4,
- top_y_off = 0,
- bottom_y_off = 0,
+ x_off = 4,
+ y_off = 0,
  sprites = sheen8x8,
  hitship = function(self, ship)
   if (ship ~= primary_ship) return false
@@ -1933,9 +1958,8 @@ gun_swap = powerup.new{
   height = 16
  },
  -- gun = gun_type.new{}
- center_x_off = 6,
- top_y_off = 0,
- bottom_y_off = 4,
+ x_off = 6,
+ y_off = 0,
  width = 2,
  height = 2,
  sprites = {64, 66, 68, 70, 72, 74, 76, 78},