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

@@ -1,223 +0,0 @@
-pico-8 cartridge // http://www.pico-8.com
-version 42
-__lua__
--- vacuum gambit
--- by kistaro windrider
-
--- stdlib
-
--- generate standard "overlay"
--- constructor for type tt.
--- if tt.init is defined, generated
--- new calls tt.init(ret) after
--- ret is definitely not nil,
--- before calling setmetatable.
--- use to initialize mutables.
---
--- if there was a previous new,
--- it is invoked on the new
--- 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")
- tt.new=function(ret)
-  if(not ret) ret = {}
-  if(more) more(ret)
-  if(oldnew) oldnew(ret)
-  setmetatable(ret, mt)
-  return ret
- end
- return tt
-end
-
-function easeoutbounce(t)
-	local n1=7.5625
-	local d1=2.75
-
-	if (t<1/d1) then
-		return n1*t*t;
-	elseif(t<2/d1) then
-		t-=1.5/d1
-		return n1*t*t+.75;
-	elseif(t<2.5/d1) then
-		t-=2.25/d1
-		return n1*t*t+.9375;
-	else
-		t-=2.625/d1
-		return n1*t*t+.984375;
-	end
-end
-
--->8
--- entry points
-function _draw()
- cls()
- draw_hud_placeholder()
- left_pane:draw()
- right_pane:draw()
- rearm_pane_instance:draw()
-end
-
-function _init()
- item=1
- bfm=1
- crt_frm = 1
- left_pane = weapon_pane.new{}
- right_pane = weapon_pane.new{
-  is_left=false,
-  s = 2,
-  hdr = "vulc",
-  body = "   rate\n\n  faster\n  firing\n   rate",
-  hot = function() return item == 2 end}
- rearm_pane_instance = rearm_pane.new{hot=function() return item < 0 end}
-end
-
-function _update60()
- crt_frm += 0.25
- if (crt_frm >= 9) crt_frm = 1
- 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
-
- if btnp(4) then
-  left_pane.pos = -1
-  right_pane.pos = -1
-  rearm_pane_instance.pos = -1
- end
-
- if btnp(5) then 
-  left_pane.pos = 1
-  right_pane.pos = 1
-  rearm_pane_instance.pos = 1
- end
-
- left_pane:update()
- right_pane:update()
- rearm_pane_instance:update()
-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
-
--->8
--- rearm pane drawing
-
-crt={-91,-166,-2641,-1441,-23041,23295,-20491,24570}
-
-function glow_box(x0, y0, x1, y1, c, cf)
- for i,v in ipairs{c[1],c[2],c[1],0} do
-  i -= 1
-  rect(x0+i,y0+i,x1-i,y1-i,v)
- end
- fillp(crt[crt_frm&0xff])
- rectfill(x0+4, y0+4, x1-4, y1-4, cf)
- fillp()
-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
-
--->8
--- rearm pane objects
-easing_pane = mknew{
- -- to enter: pos = -1; to exit: pos = 1
- -- runs for 32 frames in, 16 frames out
-}
-
-function easing_pane:frac()
- local pos = self.pos
- if (not pos) return
- if (pos < 0) return 1-easeoutbounce(1+pos)
- if (pos > 0) return (1-pos)*(1-pos)
- return 0
-end
-
-function easing_pane:update()
- local pos = self.pos
- if (not pos or pos == 0) return
- if (pos < 0) pos = min(pos + 0x0.05, 0)
- if pos > 0 then
-  pos -= 0x0.1
-  if (pos <= 0) pos = nil
- end
- self.pos = pos
-end
-
-weapon_pane = mknew(easing_pane.new{
- is_left = true,
- s = 1,
- hdr = "hull",
- body = "\n    +1\n   max\n  health",
- hot = function() return item == 1 end,
-})
-
-function weapon_pane:draw()
- local frac, is_left = self:frac(), self.is_left
- if (not frac) return
- camera(
-  frac * (is_left and 55 or -128) + (1-frac) * (is_left and 0 or -56),
-  0)
- glow_box(0,0,55,100,frame_col(self:hot()),1)
- spr(self.s,5, 5)
- print(self.hdr, 13, 8, 7)
- print(self.body, 5, 15, 6)
- camera()
-end
-
-rearm_pane = mknew(easing_pane.new{})
-
-function rearm_pane:draw()
- local frac = self:frac()
- if (not frac) return
- camera(0, -28 * frac)
- glow_box(0,101,111,127,frame_col(self:hot()),1)
- spr(5,15,107,4,2)
- print("full ammo\nfull shield\n+50% health",54, 106, 6)
- camera()
-end
-
-__gfx__
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