Trimming

Trim up redundant nil checks, sequential assignments that could be on a shared line, and repeated references to a deeply nested variable.

chameleonic.p8

@@ -53,21 +53,18 @@ function linefill(ax,ay,bx,by,r,c)
  local dx,dy=bx-ax,by-ay
  -- avoid overflow
  -- credits: https://www.lexaloffle.com/bbs/?tid=28999
- local d=max(abs(dx),abs(dy))
- local n=min(abs(dx),abs(dy))/d
+ local n,d=_mnmx(abs(dx),abs(dy)) 
+ n/=d
  d*=sqrt(n*n+1)
  if(d<0.001) return
  local ca,sa=dx/d,-dy/d
    
  -- polygon points
- local s={
-  {0,-r},{d,-r},{d,r},{0,r}
- }
- local u,v,spans=s[4][1],s[4][2],{}
- local x0,y0=ax+u*ca+v*sa,ay-u*sa+v*ca
- for i=1,4 do
-  local u,v=s[i][1],s[i][2]
-  local x1,y1=ax+u*ca+v*sa,ay-u*sa+v*ca
+ local spans={}
+ local function calcxy(u,v) return ax+u*ca+v*sa,ay-u*sa+v*ca end
+ local x0,y0=calcxy(0,r)
+ for s in all{{0,-r},{d,-r},{d,r},{0,r}} do
+  local x1,y1=calcxy(unpack(s))
   local _x1,_y1=x1,y1
   if(y0>y1) x0,y0,x1,y1=x1,y1,x0,y0
   local dx=(x1-x0)/(y1-y0)
@@ -78,11 +75,8 @@ function linefill(ax,ay,bx,by,r,c)
   for y=y0\1+1,min(y1\1,127) do
    -- open span?
    local span=spans[y]
-   if span then
-    rectfill(x0,y,span,y)
-   else
-    spans[y]=x0
-   end
+   if (span) rectfill(x0,y,span,y)
+   spans[y]=x0
    x0+=dx
   end
   x0,y0=_x1,_y1
@@ -92,19 +86,14 @@ end
 function _apply(x,ts,a)
  local t=deli(ts,1)
  for k,v in pairs(t) do
-  if k=="update" then
-   --
-  else
-   x[k]=v
-  end
+  if (k!="update") x[k]=v 
  end
 
  if (t and t.update and not t.update(x,a)) add(ts,t,1)
 end
 
 function sgn0(x)
- if (x==0) return x
- return sgn(x)
+ return x!=0 and sgn(x) or 0
 end
 
 function _mnmx(x,y)
@@ -114,13 +103,14 @@ end
 
 
 function _rast(
- x0,y0,x1,y1
+ xs,ys,x0,y0,x1,y1
 )
- local dx=abs(x1-x0)
- local dy=abs(y1-y0)
- local x=x0
- local y=y0
+ local function _add()
+  local n=#xs
+  if (n==0 or xs[n]!=x0 or ys[n]!=y0) add(xs,x0) add(ys,y0)
+ end
 
+ local dx,dy=abs(x1-x0),abs(y1-y0)
  local sx=-1
  local sy=-1
  if (x0<x1) sx=1
@@ -129,27 +119,22 @@ function _rast(
  local done=false,err
  if dx>dy then
   err=dx/2.0
-  return function()
-   if (done) return 
-   if (x==x1) done=true return x1,y1
-   local oldx,oldy=x,y
+  while x0!=x1 do
+   _add()
    err-=dy
-   if (err<0) y+=sy err+=dx
-   x+=sx
-   return oldx,oldy
+   if (err<0) y0+=sy err+=dx
+   x0+=sx
   end
  else
   err=dy/2.0
-  return function()
-   if (done) return
-   if (y==y1) done=true return x1,y1
-   local oldx,oldy=x,y
+  while y0!=y1 do
+   _add()
    err-=dx
-   if (err<0) x+=sx err+=dy 
-   y+=sy
-   return oldx,oldy
+   if (err<0) x0+=sx err+=dy 
+   y0+=sy
   end
  end
+ _add()
 end
 
 -->8
@@ -158,74 +143,48 @@ kbd={}
 add(real_modules,kbd)
 function kbd:init()
  self.real=btn()
- self.down=0
+ self.state={btn=0}
 end
 
 function kbd:update()
  -- figure out what keys are _really_ pressed
- local now_real=btn()
- local was_real=self.real
+ local now_real,was_real=btn(),self.real
  self.real=now_real
 
  -- add keys that are really pressed 
  -- if they weren't really pressed before
  -- (they may have been force-
  --  released by :release())
- local real_pressed=(~was_real)&now_real
+ local real_pressed=~was_real&now_real
 
- local now_down=(self.down&now_real)|real_pressed
- local was_down=self.down
- self.down=now_down
+ local state=self.state
+ local now_down=state.btn&now_real|real_pressed
+ local was_down=state.btn
 
  -- deduce pressed/released by changes in down
- local pressed=(~was_down)&now_down
- local released=(~now_down)&was_down
-
- self.pressed=pressed
- self.released=released
+ state.btn,state.btnp,state.btnr=
+  now_down,
+  ~was_down&now_down,
+  ~now_down&was_down
 end
 
-function kbd:btn(i)
- return self.down&(1<<i)!=0
-end
-
-function kbd:btnp(i)
- return self.pressed&(1<<i)!=0
-end
-
-function kbd:btnr(i)
- return self.released&(1<<i)!=0
+for _kbdi in all(split"btn,btnp,btnr") do
+ kbd[_kbdi]=function(self,i,t) return 1<<i&self.state[_kbdi]!=0 end
 end
 
 function kbd:release(i)
- self.down&=~(1<<i)
+ self.state.btn&=~(1<<i)
 end
 
 function tostring(any)
- if type(any)=="function" then 
-     return "function" 
- end
- if any==nil then 
-     return "nil" 
- end
- if type(any)=="string" then
-     return any
- end
- if type(any)=="boolean" then
-     if any then return "true" end
-     return "false"
- end
  if type(any)=="table" then
-     local str = "{ "
-     for k,v in pairs(any) do
-         str=str..tostring(k).."->"..tostring(v).." "
-     end
-     return str.."}"
+  local str = "{ "
+  for k,v in pairs(any) do
+      str=str..tostring(k).."->"..tostring(v).." "
+  end
+  return str.."}"
  end
- if type(any)=="number" then
-     return ""..any
- end
-  return "unknown" -- should never show
+ return tostr(any)
 end
 
 -->8
@@ -233,11 +192,7 @@ end
 title={}
 add(modules,title)
 
-function title:init()
-end
-
-blinkcol = 10
-
+blinkcol=10
 function title:draw()
  cls(0)
  -- this is right for 72x32
@@ -250,29 +205,18 @@ function title:draw()
  print(lvlstr,51,90,blinkcol) 
 end
 
-start_level = 0
+start_level=0
 max_level=15
 
 function title:update()
- if time()*4\1%2==0 then
-  blinkcol=10
- else
-  blinkcol=9
- end
+ blinkcol=9
+ if (time()*4\1%2==0) blinkcol=10
  
- if btnp(0) then
-  start_level -= 1
-  if (start_level<0) start_level=max_level
- end
- if btnp(1) then
-  start_level += 1
-  if (start_level>max_level) start_level=0
- end 
- if btnp(4) or btnp(5) then
-  modules=real_modules
-  _init() 
-  music(0)
- end
+ if (btnp"0") start_level-=1
+ if (btnp"1") start_level+=1
+ start_level%=max_level
+
+ if (btnp"4" or btnp"5") modules=real_modules _init() music(0)
 end
 
 -->8
@@ -287,9 +231,7 @@ end
 function level:reinit(n)
  self.ix=n
  self.todo={}
- self.bigx=(n%8)
- self.bigy=(n\8)
- self.next_crate_id=1
+ self.bigx,self.bigy=n%8,n\8
 
  self:load_dynobjs()
  self:recollide()
@@ -358,7 +300,7 @@ function level:update()
  end
  if #remove>0 then
   self:recollide()
-  self:reanchor(true)
+  self:reanchor()
  end
 end
 
@@ -366,6 +308,7 @@ function level:load_dynobjs()
  self._crates={}
  self._pits={}
 
+ local crate_id=1
  for mx=0,15,1 do
   for my=0,15,1 do
    local mxy=_mix(mx,my)
@@ -375,22 +318,16 @@ function level:load_dynobjs()
    if def then
     self._crates[mxy]={
      s=s,def=def,
-     id=self.next_crate_id,
+     id=crate_id,
      mx=mx,my=my,
      px=px,py=py,
      todo={}
     }
-    self.next_crate_id+=1
+    crate_id+=1
    end
 
-   if s==28 then -- pit
-    self._pits[mxy]={
-      s=s,
-      mx=mx,my=my,
-      px=px,py=py,
-      contents=nil
-    }
-   end
+   -- pit
+   if (s==28) self._pits[mxy]={s=s,mx=mx,my=my,px=px,py=py}
   end
  end
 end
@@ -461,17 +398,11 @@ function level:reanchor()
  end
  shellsort(self._anch_keys)
  for point in self:anchor_points() do
-  if point.ax_old!=nil then
-   if (player.rope!=nil) player.rope:be_pushed_by(point,point.ax_old,point.ay_old)
-   point.ax_old=nil
-   point.ay_old=nil
-  end
- end
- for point in self:anchor_points() do
-  assert(not point.dropped)
+  if (point.ax_old and player.rope) player.rope:be_pushed_by(point,point.ax_old,point.ay_old)
+  point.ax_old,point.ay_old=nil,nil
  end
 
- if (player.rope!=nil) player.rope:relax()
+ if (player.rope) player.rope:relax()
 end
 
 function level:win_at(mx,my)
@@ -507,7 +438,9 @@ function level:spawn_exit()
   if (self:_mget(x,y)!=18) return
   for nx=x-1,x+1 do
    for ny=y-1,y+1 do
-    if nx<0 or ny<0 or nx>15 or ny>15 then
+    -- next check: is at least one of
+    -- nx or ny out of range [0, 15]?
+    if (nx | ny) & 0xFFF0 ~= 0 then
      self._wins[_mix(nx,ny)]=true
     end
    end
@@ -541,26 +474,24 @@ end
 
 function _amix(ax,ay)
  return ax..","..ay
- --if (ax<0 or ay<0 or ax>31 or ay>31) return nil
- --return ay*32+ax
 end
 
 function _mix(mx,my)
   return mx..","..my
- --if (mx<0 or my<0 or mx>15 or my>15) return nil
- --return my*16+mx
 end
 
+-- crate spec:
+-- "up" == 1
+-- "right" == 2
+-- "down" == 4
+-- "left" == 8
+--
+--    +1+
+--    8 2
+--    +4+
 function level:_get_cratedef(s)
- if (s<64 or s>=80) return nil
- 
- local s2=s-64
- return {
-  up=s2&1!=0,
-  right=s2&2!=0,
-  down=s2&4!=0,
-  left=s2&8!=0
- }
+ if (s<64 or s>=80) return
+ return s & 0x000F
 end
 
 function level:get_latch(dx,dy,px,py)
@@ -571,12 +502,7 @@ function level:get_latch(dx,dy,px,py)
  local dx1,dy1=-sgn0(dx),-sgn0(dy)
 
  if crate then
-  if
-   (crate.def.up and dy>0) or
-   (crate.def.down and dy<0) or 
-   (crate.def.left and dx>0) or
-   (crate.def.right and dx<0)
-  then
+  if crate.def & dy1*dy1*(2.5+1.5*dy1)+dx1*dx1*(5-3*dx1) ~= 0 then
    return {
     el="crate",
     dx=dx1,dy=dy1,
@@ -609,35 +535,23 @@ function level:can_move(
  is_player,
  mx0,my0,dmx,dmy,exclude_src,exclude_dst
 )
- if is_player and self:win_at(mx0+dmx,my0+dmy) then
-  return true 
- end
- if is_player and self:get_open_pit(mx0+dmx,my0+dmy) then
-  return wrongbleep:adequately_warned()
- end
+ local mx1,my1=mx0+dmx,my0+dmy
+ if (is_player and self:win_at(mx1,my1)) return true 
+ if (is_player and self:get_open_pit(mx1,my1)) return wrongbleep:adequately_warned()
 
- if self:mcoll(mx0+dmx,my0+dmy) then
-  return false
- end
+ if (self:mcoll(mx1,my1) or player.x==mx1 and player.y==my1) return false
 
- if player.x==mx0+dmx and player.y==my0+dmy then
-  return false
- end
- 
- -- todo: check tongue collision
  if player.rope then
   local chk=false
-  if dmx==0 and dmy==-1 then
-   chk=player.rope:collide_mrect(mx0+0.4,my0-0.8,0.2,1.6,exclude_src,exclude_dst)
-  elseif dmx==0 and dmy==1 then
-   chk=player.rope:collide_mrect(mx0+0.4,my0+0.2,0.2,1.6,exclude_src,exclude_dst)
-  elseif dmx==-1 and dmy==0 then
-   chk=player.rope:collide_mrect(mx0-0.8,my0+0.4,1.6,0.2,exclude_src,exclude_dst)
-  elseif dmx==1 and dmy==0 then
-   chk=player.rope:collide_mrect(mx0+0.2,my0+0.4,1.6,0.2,exclude_src,exclude_dst)
+  local w,h=1.6,0.2
+  if dmx==0 then 
+    w,h=0.2,1.6
+  else
+    dmy = 0
   end
+  rectx,recty=dmx*(0.4>>>dmx),dmy*(0.4>>>dmy)
 
-  if (chk) return false
+  if (player.rope:collide_mrect(mx0+rectx,my0+recty,w,h,exclude_src,exclude_dst)) return false
  end
  
  return true
@@ -646,22 +560,21 @@ end
 function level:tug_crate(mx0,my0,dmx,dmy)
  local mxy0=_mix(mx0,my0)
  local existing=self._crates[mxy0]
- if (existing==nil) return
+ if (not existing) return
  
  self._crates[mxy0]=nil
-
  local mx1,my1=mx0+dmx,my0+dmy
- local mxy1=_mix(mx1,my1) 
+ local px1,py1=mx1*8,my1*8
  existing.todo={
-  {px=mx1*8+dmx,py=my1*8+dmy,mx=mx1,my=my1,update=function()
+  {px=px1+dmx,py=py1+dmy,mx=mx1,my=my1,update=function()
    self:recollide()
    self:reanchor()
    return true
   end},
-  {px=mx1*8,py=my1*8}
+  {px=px1,py=py1}
  }
 
- self._crates[mxy1]=existing
+ self._crates[_mix(mx1,my1)]=existing
 end
 
 -->8
@@ -670,54 +583,27 @@ player={}
 add(real_modules,player)
 
 function player:init()
- --self:reinit(8,14)
-
  -- don't change this on reinit:
  -- it stays the same when the level is changed or reloaded
  self.vanish_frame=0 
 end
 
 function player:reinit(x,y)
- self.x=x
- self.y=y
- self.px=0
- self.py=0
+ self.x,self.y=x,y
+ self.px,self.py=0,0
  self.todo={}
 
  self.fall_frame=0
- self.reset_frame=0
  
- self.orientx=-1
- self.orienty=0
- 
- self.rope=nil
-end
-
-function player:any_busy()
- if (#self.todo>0) return true
- if (level:busy()) return true
- return false
+ self.orientx,self.orienty=-1,0
 end
 
 function player:update()
- local _addall=function(t,xs)
-  for i in all(xs) do
-   add(t,i)
-  end
- end
-
- local f4 = function(xs) 
-  -- todo: other anim stuff
-  xs[#xs].px=0
-  xs[#xs].py=0
-  return xs
- end
-
  -- this is a non-gameplay action that takes precedence over 
  -- all gameplay actions
  self:_vanish_if_requested()
 
- if not self:any_busy() then
+ if not (#self.todo>0 or level:busy()) then
   if level:win_at(self.x,self.y) then
    level:advance()
    return
@@ -740,29 +626,25 @@ function player:update()
   end
 
   if kbd:btn(4) then
-   if kbd:btnp(4) and self.rope!=nil then 
+   if kbd:btnp(4) and self.rope then 
     self.rope:destroy()
     kbd:release(4)
    end
    -- wait for user to release it
   else
+   local function try_move(dx,dy,f)
+    if (level:can_move(true,self.x,self.y,dx,dy,0,2)) self.todo=f return
+    wrongbleep:bleep()
+   end
    if kbd:btn(0) then 
-    if level:can_move(true,self.x,self.y,-1,0,0,2) then
-     self.todo=f4({{orientx=-1,orienty=0,px=-2},{px=-7},{x=self.x-1}})
-    else wrongbleep:bleep() end
+    try_move(-1,0,{{orientx=-1,orienty=0,px=-2},{px=-7},{x=self.x-1,px=0}})
    elseif kbd:btn(1) then
-    if level:can_move(true,self.x,self.y,1,0,0,2) then
-     self.todo=f4({{orientx=1,orienty=0,px=2},{px=7},{x=self.x+1}})
-    else wrongbleep:bleep() end
+    try_move(1,0,{{orientx=1,orienty=0,px=2},{px=7},{x=self.x+1,px=0}})
    elseif kbd:btn(2) then
-    if level:can_move(true,self.x,self.y,0,-1,0,2) then
-     self.todo=f4({{orienty=-1,py=-2},{py=-7},{y=self.y-1}})
-    else wrongbleep:bleep() end
+    try_move(0,-1,{{orienty=-1,py=-2},{py=-7},{y=self.y-1,py=0}})
    elseif kbd:btn(3) then
-    if level:can_move(true,self.x,self.y,0,1,0,2) then
-     self.todo=f4({{orienty=1,py=2},{py=7},{y=self.y+1}})
-    else wrongbleep:bleep() end
-   elseif self.rope==nil and kbd:btnr(4) then
+    try_move(0,1,{{orienty=1,py=2},{py=7},{y=self.y+1,py=0}})
+   elseif not self.rope and kbd:btnr(4) then
     local dx,dy=self.orientx,self.orienty
     if (dy!=0) dx=0
 
@@ -777,41 +659,35 @@ function player:update()
     
     self.todo={{
      update=function()
-      return self.rope==nil or self.rope:latched()
+      return not self.rope or self.rope:latched()
      end
     }}
    elseif kbd:btnp(5) then
-    if self.rope!=nil then
-     if (not self.rope:tug()) wrongbleep:bleep(9)
-    end
+    if (self.rope and not self.rope:tug()) wrongbleep:bleep(9)
    end
   end
  end
 
- if self.rope then
-  self.rope:update()
- end
  _apply(self,self.todo)
 
  if self.rope then
   self.rope:update()
   if self.rope:done_reeling() then 
-   self.x=self.rope.latch.rec.mx+self.rope.latch.dx
-   self.y=self.rope.latch.rec.my+self.rope.latch.dy
+   local latch=self.rope.latch
+   self.x=latch.rec.mx+latch.dx
+   self.y=latch.rec.my+latch.dy
   end
 
-  local rx=self.x+self.px/8+0.5
-  local ry=self.y+self.py/8+0.5
-  -- do the hokey pokey to work out kinks in the rope
-  self.rope:drag_dst(rx,ry)
+  self.rope:drag_dst(
+   self.x+self.px/8+0.5,
+   self.y+self.py/8+0.5
+  )
 
   local tdx,tdy=self.rope:tug_orientxy()
-  if (tdx!=0) self.orientx=tdx
-  if (tdy!=0) self.orienty=tdy
+  if (tdx) self.orientx=tdx
+  if (tdy) self.orienty=tdy
 
-  if self.rope:done() then
-   self.rope=nil
-  end
+  if (self.rope:done()) self.rope=nil
  end
 end
 
@@ -840,23 +716,27 @@ function player:draw()
  local px=self.x*8+self.px+wrongbleep:vibrate()
  local py=self.y*8+self.py+wrongbleep:vibrate()
 
-
  local head=1-self.orienty
 
  local vanish_level=max((self.vanish_frame-4)/16,0)
  local invis_level=max(self.fall_frame/10,4*(vanish_level-0.75))
  if (invis_level>=1.0) return
 
- --px+=sin(vanish_level*16)*max(vanish_level-0.1,0)*1
+ --[[
  local HEAD=14--3
  local BODY=12--12
  local TAIL=14--14
  local IRIS=7--9
  local PUPIL=0--0
+ ]]
 
- local setpal=function()
-  -- base colors
-  pal{
+  -- in order: head,body,iris,pupil,body again,tail
+ local palette=split"-1,14,14,12,12,-1,-1,-1,7,0,-1,12,14,14,14"
+ local function setpal()
+  --[[
+   -- head
+   nil,14,14,
+   --body
    [2]=HEAD,
    [3]=HEAD,
    [4]=BODY,
@@ -867,7 +747,8 @@ function player:draw()
    [13]=TAIL,
    [14]=TAIL,
    [15]=TAIL,
-  }
+  ]]
+  pal(palette)
 
   -- vanish colors
   local vanish=split"13,15,14,5,4,12,2,3,9,10"
@@ -875,11 +756,7 @@ function player:draw()
    if (vanish_level>i/#vanish) pal(ilc,1)
   end
 
-  if self.fall_frame>3 then
-   local zc=@0x5f00&0xf0
-   for i=0x5f00,0x5f0c,4 do poke4(i,0x0101.0101) end
-   poke(0x5f00,zc|0x01)
-  end
+  if (self.fall_frame>3) local zc=@0x5f00&0xf0 for i=0x5f00,0x5f0c,4 do poke4(i,0x0101.0101) end poke(0x5f00,zc|0x01)
  end
 
  local rx,ry=self.x*8+self.px+1,self.y*8+self.py+2
@@ -887,7 +764,7 @@ function player:draw()
 
  if self.rope then
   local rx_adj,ry_adj=self.rope:affected_src_xy(rx,ry)
-  if rx_adj!=nil then
+  if rx_adj then
    local drx,dry=rx_adj-rx,ry_adj-ry
    rx,ry=rx+drx,ry+dry
    px,py=px+drx,py+dry
@@ -921,8 +798,8 @@ function rope:new(
  local r={
   id=0,
   anchors={
-   {ax=src_ax,ay=src_ay,prev=nil,next=nil},
-   {ax=dst_ax,ay=dst_ay,prev=nil,next=nil}
+   {ax=src_ax,ay=src_ay},
+   {ax=dst_ax,ay=dst_ay}
   },
   state={name="cast",frame=0},
   latch=latch,
@@ -955,10 +832,7 @@ function rope:update()
  elseif self.state.name=="latched" then
   if (self.latch==nil) wrongbleep:bleep(5) self:destroy() return
 
-  if 
-   self.latch!=nil and
-   self.latch.rec!=nil 
-  then
+  if self.latch and self.latch.rec then
    self:drag_src(
     self.latch.rec.mx+0.5+self.latch.ax_offset,
     self.latch.rec.my+0.5+self.latch.ay_offset
@@ -1020,11 +894,10 @@ end
 
 function rope:draw(artificial_px,artificial_py)
  local points,highlight=self:_tug(true)
- if (self.state.name=="done") return
- local perc_to_show=1.0
- local from_end=false
- if (self.state.name=="cast") perc_to_show=self.state.frame/2
- if (self.state.name=="destroy") perc_to_show=(1.0-self.state.frame/8)^2
+ local n,perc_to_show,from_end = self.state.name,1.0,false
+ if (n=="done") return
+ if (n=="cast") perc_to_show=self.state.frame/2
+ if (n=="destroy") perc_to_show=(1.0-self.state.frame/8)^2
  if (self.state.reelin) from_end=true
 
  points[#points]={x=artificial_px,y=artificial_py}
@@ -1134,7 +1007,7 @@ function rope:draw(artificial_px,artificial_py)
 	 pset(x+p.adx,y,11)
 	 pset(x,y+p.ady,11)
 	end
- ]]
+ ]]--
 end
 
 function rope:drag_dst(x,y)
@@ -1153,18 +1026,6 @@ function rope:drag(n1,ax_new,ay_new)
 end
 
 function rope:relax()
- local n=self.src
-
- while true do
-  if (n==nil) break
-
-  if (n.associated_with) then 
-   self:_drag(n,n.associated_with.ax,n.associated_with.ay)
-  end
-
-  n=n.next
- end
-
  local n0=self.src
  while true do
   local n1=n0.next
@@ -1173,7 +1034,7 @@ function rope:relax()
 
   if n0.ax==n1.ax and n0.ay==n1.ay then 
    n0.next=n2 
-   n2.prev=n0
+   if (n2!=nil) n2.prev=n0
   else
    n0=n0.next
   end
@@ -1193,9 +1054,14 @@ function rope:relax()
    local x1,y1=n1.ax,n1.ay
    local x2,y2=n2.ax,n2.ay
 
+   if x1!=n1.associated_with.ax or y1!=n1.associated_with.ay then
+    -- printh("dragging home: "..tostring{n1.ax,n1.ay}.."->"..tostring(n1.associated_with))
+    self:_drag(n1,n1.associated_with.ax,n1.associated_with.ay)
+   end
+
    local would,x1_new,y1_new=would_stick(x0,y0,n1.associated_with,x2,y2)
    if not would and not (n1.ax==x1_new and n1.ay==y1_new) then
-    --printh("relaxing: "..tostring(n0.associated_with).."->"..tostring(n1.associated_with).."->"..tostring(n2.associated_with))
+    -- printh("relaxing: "..tostring(n0.associated_with).."->"..tostring(n1.associated_with).."->"..tostring(n2.associated_with))
     self:_drag(n1,x1_new,y1_new)
     n0=n1.prev
     n2=n1.next
@@ -1219,12 +1085,7 @@ function rope:_check_sane()
   local n1=n0.next
   if (n1==nil) break 
 
-  for qx,qy in _rast(flr(n0.ax*2),flr(n0.ay*2),flr(n1.ax*2),flr(n1.ay*2)) do
-   if not (qx==qxs[#qxs] and qy==qys[#qys]) then
-    add(qxs,qx)
-    add(qys,qy)
-   end
-  end
+  _rast(qxs,qys,flr(n0.ax*2),flr(n0.ay*2),flr(n1.ax*2),flr(n1.ay*2)) 
   n0=n1
  end
 
@@ -1287,6 +1148,14 @@ function would_stick(x0,y0,anchor,x2,y2)
  local dx=x2-x0
  local dy=y2-y0
 
+ -- there is no reason for an acute angle to stick around in this world
+ --[[
+ local ang0=atan2(x2-x1,y2-y1)
+ local ang2=atan2(x0-x1,y0-y1)
+ local diff=abs((ang0-ang2 + 0.5)%1-0.5)
+ if (diff<0.25) return false,x0,y0,0,0
+ ]]--
+
  local adx,ady
  local x1_new,y1_new
  if abs(dx)>abs(dy) then
@@ -1317,14 +1186,17 @@ function rope:be_pushed_by(anchor,ax_old,ay_old)
  local ax_new,ay_new=anchor.ax,anchor.ay
  while true do
   n1=n0.next
-  if (n1==nil) return
+  if (not n1) return
 
   local nx0,ny0=n0.ax,n0.ay
   local nx1,ny1=n1.ax,n1.ay
 
   if
+   (ax_new==ax_old and nx0<=anchor.ax and anchor.ax<=nx1) and 
+   (ay_new==ay_old and ny0<=anchor.ay and anchor.ay<=ny1) and 
    not (anchor.ax==nx0 and anchor.ay==ny0) and
    not (anchor.ax==nx1 and anchor.ay==ny1) and
+
    (_which_side(ax_old,ay_old,nx0,ny0,nx1,ny1)!= 
     _which_side(ax_new,ay_new,nx0,ny0,nx1,ny1) 
    ) and would_stick(nx0,ny0,anchor,nx1,ny1)
@@ -1368,7 +1240,7 @@ function rope:_drag(n1,ax1_new,ay1_new)
     for anchor in level:anchor_points() do
      if 
       not (anchor.ax==ax_pivot and anchor.ay==ay_pivot) and
-      not (anchor.ax==ax_far0 and anchor.ay==ay_far0) and
+      -- not (anchor.ax==ax_far0 and anchor.ay==ay_far0) and
       not (anchor.ax==ax_far1 and anchor.ay==ay_far1) and
       (ax0<=anchor.ax and anchor.ax<=ax1) and 
       would_stick(ax_pivot,ay_pivot,anchor,ax_far,ay_far_new) and
@@ -1391,7 +1263,7 @@ function rope:_drag(n1,ax1_new,ay1_new)
     for anchor in level:anchor_points() do
      if 
       not (anchor.ax==ax_pivot and anchor.ay==ay_pivot) and
-      not (anchor.ax==ax_far0 and anchor.ay==ay_far0) and
+      -- not (anchor.ax==ax_far0 and anchor.ay==ay_far0) and
       not (anchor.ax==ax_far1 and anchor.ay==ay_far1) and
       would_stick(ax_pivot,ay_pivot,anchor,ax_far_new,ay_far) and
       (ay0<=anchor.ay and anchor.ay<=ay1) and 
@@ -1418,7 +1290,7 @@ function rope:_drag(n1,ax1_new,ay1_new)
   local anch=_sweep_radar(n0.ax,n0.ay,ax1_old,ay1_old,ax1_new,ay1_new)
   if (anch==nil) break
   local n05={ax=anch.ax,ay=anch.ay,associated_with=anch,prev=n0,next=n1}
-  --printh("creating post: "..tostring(n0.associated_with).."->"..tostring(n05.associated_with).."->"..tostring(n1.associated_with))
+  -- printh("creating pre: "..tostring(n0.associated_with).."->"..tostring(n05.associated_with).."->"..tostring(n1.associated_with))
   n0.next=n05
   n1.prev=n05
   n0=n05
@@ -1430,7 +1302,7 @@ function rope:_drag(n1,ax1_new,ay1_new)
   local anch=_sweep_radar(n2.ax,n2.ay,ax1_old,ay1_old,ax1_new,ay1_new)
   if (anch==nil) break
   local n15={ax=anch.ax,ay=anch.ay,associated_with=anch,prev=n1,next=n2}
-  --printh("creating post: "..tostring(n1.associated_with).."->"..tostring(n15.associated_with).."->"..tostring(n2.associated_with))
+  -- printh("creating post: "..tostring(n1.associated_with).."->"..tostring(n15.associated_with).."->"..tostring(n2.associated_with))
   n1.next=n15
   n2.prev=n15
   n2=n15
@@ -1441,7 +1313,7 @@ function _stepfrom(x0,x1)
  local done=false
  if x0==x1 then
   return function() 
-   if (done) return nil
+   if (done) return
    done=true return x0
   end
  end
@@ -1492,31 +1364,30 @@ function rope:collide_mrect(mx0,my0,mw,mh,exclude_src,exclude_dst)
    if (nd==nil) return false
   end
 
+  local x1,y1,x2,y2=n0.ax,n0.ay,n1.ax,n1.ay
+  local function _line_line(x3,y3,x4,y4)
+   local denom=((y4-y3)*(x2-x1)-(x4-x3)*(y2-y1))
+
+   local ua=
+    ((x4-x3)*(y1-y3)-(y4-y3)*(x1-x3))/denom
+   if (ua<0 or ua>1) return false
+
+   local ub=
+    ((x2-x1)*(y1-y3)-(y2-y1)*(x1-x3))/denom
+   if (ub<0 or ub>1) return false
+
+   return true
+  end
+
+
   if exclude_src<=0 then
-   if (_line_line(n0.ax,n0.ay,n1.ax,n1.ay,mx0,my0,mx1,my0)) return true
-   if (_line_line(n0.ax,n0.ay,n1.ax,n1.ay,mx0,my0,mx0,my1)) return true
-   if (_line_line(n0.ax,n0.ay,n1.ax,n1.ay,mx0,my1,mx1,my1)) return true
-   if (_line_line(n0.ax,n0.ay,n1.ax,n1.ay,mx1,my0,mx1,my1)) return true
+   if (_line_line(mx0,my0,mx1,my0) or _line_line(mx0,my0,mx0,my1) or _line_line(mx0,my1,mx1,my1) or _line_line(mx1,my0,mx1,my1)) return true
   end
   exclude_src-=1
   n0=n1
  end
 end
 
-function _line_line(x1,y1,x2,y2,x3,y3,x4,y4)
- local denom=((y4-y3)*(x2-x1)-(x4-x3)*(y2-y1))
-
- local ua=
-  ((x4-x3)*(y1-y3)-(y4-y3)*(x1-x3))/denom
- if (ua<0 or ua>1) return false
-
- local ub=
-  ((x2-x1)*(y1-y3)-(y2-y1)*(x1-x3))/denom
- if (ub<0 or ub>1) return false
-
- return true
-end
-
 -->8
 -- moved here because it's complicated
 
@@ -1524,12 +1395,12 @@ function rope:tug_orientxy()
  local a1=self.dst
  local a0=self.dst.prev
  local dx=a0.ax-a1.ax
- local tdx=0
+ local tdx=nil
  if (dx>3/8) tdx=1
  if (dx<-3/8) tdx=-1
 
  local dy=a0.ay-a1.ay
- local tdy=0
+ local tdy=nil
  if abs(dy)>abs(dx)/2 then 
   if (dy>3/8) tdy=1
   if (dy<-3/8) tdy=-1
@@ -1717,20 +1588,20 @@ function rope:_anchors_simplified()
    x=flr(a.ax*8+0.5),y=flr(a.ay*8+0.5),
    ax=a.ax,ay=a.ay
   }
-  if a.associated_with then
-   if (a.associated_with.adx==1) point.x-=1
-   if (a.associated_with.ady==1) point.y-=1
-  elseif a.prev==nil and self.latch then
-   if (self.latch.ax_offset<0) point.x-=1
-   if (self.latch.ay_offset<0) point.y-=1
+  local aw=a.associated_with
+  local l=self.latch
+  if aw then
+   if (aw.adx==1) point.x-=1
+   if (aw.ady==1) point.y-=1
+  elseif a.prev==nil and l then
+   if (l.ax_offset<0) point.x-=1
+   if (l.ay_offset<0) point.y-=1
   end
 
-  if #points<=1 then 
+  local p0,p1=points[#points-1],points[#points]
+  if p0==nil then
    add(points,point)
-  elseif abs(
-   _slope(points[#points-1],points[#points])-
-   _slope(points[#points],point)
-  )==0 then  -- epsilon?
+  elseif _slope(p0,p1)==_slope(p1,point) then  -- epsilon?
    points[#points]=point
   else
    add(points,point)
@@ -1778,14 +1649,14 @@ function level_text:init()
  for i=0,32 do level_text.by_lvl[i]={} end
 	for row in all(level_text_raw) do
   if row then
-   lvl,x,y,s=unpack(split(row,"`"))
-   add(level_text.by_lvl[lvl],{x,y,s})
+   lvlxys=split(row,"`")
+   add(level_text.by_lvl[lvlxys[1]],lvlxys)
   end
 	end
 end
 function level_text:draw()
  for xys in all(level_text.by_lvl[level.ix]) do
-  print(xys[3],xys[1],xys[2],6)
+  print(xys[4],xys[2],xys[3],6)
  end
 end
 __gfx__
@@ -1963,22 +1834,22 @@ __gff__
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 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
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