From f052186c9713d288fd00c1906c25ba6ae7461c8a Mon Sep 17 00:00:00 2001
From: Nyeogmi <economicsbat@gmail.com>
Date: Sat, 31 Dec 2022 19:02:33 -0800
Subject: [PATCH] Optimize raycast in sweep

---
 chameleonic.p8 | 209 +++++++++++++++++++++++++++----------------------
 1 file changed, 115 insertions(+), 94 deletions(-)

diff --git a/chameleonic.p8 b/chameleonic.p8
index 4b28de8..e12c95c 100644
--- a/chameleonic.p8
+++ b/chameleonic.p8
@@ -102,13 +102,6 @@ function _mnmx(x,y)
  return x,y
 end
 
-function _anch_eq(a0,a1) 
- if (a0==nil) return a1==nil
- if (a1==nil) return false
- return a0.ax==a1.ax and a0.ay==a1.ay 
-end
-function _anch_unpack(a0) return a0.ax,a0.ay end
-
 
 function _rast(
  xs,ys,x0,y0,x1,y1
@@ -145,6 +138,41 @@ function _rast(
  _add()
 end
 
+-->8
+-- anchor operations (for the rope code)
+
+function _anch_eq(a0,a1) 
+ if (a0 and a1) return a0[1]==a1[1] and a0[2]==a1[2]
+ return a0==a1
+end
+--[[
+function _anch_unpack(anch)
+ assert(anch[1])
+ assert(anch[2])
+ return anch[1],anch[2]
+end
+]]--
+_anch_unpack=unpack
+
+function _anch_new(prev,next,xy)
+ local out={prev=prev,next=next,_anch_unpack(xy)}
+ if (prev) prev.next=out
+ if (next) next.prev=out
+ return out
+end
+
+function _anch_del(n1,xy)
+ local n0,n2=n1.prev,n1.next
+ if (n0) n0.next=n2
+ if (n2) n2.prev=n0
+end
+
+function _anch_update(a0,a1)
+ a0[1]=a1[1]
+ a0[2]=a1[2]
+end
+
+
 
 -->8
 -- input
@@ -380,7 +408,7 @@ function level:recollide_reanchor()
     ) then
      local key="GEOM"..mx0..","..my0..","..dx..","..dy
      anch_new[key]= {
-      ax=max(mx0,mx1),ay=max(my0,my1),adx=-dx,ady=-dy
+      max(mx0,mx1),max(my0,my1),adx=-dx,ady=-dy
      }
     end
    end
@@ -391,7 +419,7 @@ function level:recollide_reanchor()
    local mx0,my0=cr.mx,cr.my
    local mx1,my1=mx0+dx,my0+dy
    anch_new[key]={
-    ax=max(mx0,mx1),ay=max(my0,my1),adx=-dx,ady=-dy
+    max(mx0,mx1),max(my0,my1),adx=-dx,ady=-dy
    }
   end
  end
@@ -406,12 +434,14 @@ function level:recollide_reanchor()
  end
  self._anch=anch_new
  self._anch_keys={}
- for k,_ in pairs(self._anch) do
+ self._anch_by_position={}
+ for k,v in pairs(self._anch) do
   add(self._anch_keys,{key=k})
+  local pkey=_mix(_anch_unpack(v))
+  self._anch_by_position[pkey]=self._anch_by_position[pkey] or v
  end
  shellsort(self._anch_keys)
  shellsort(moves)
- --printh("!!STARTING!!")
 
  if player.rope then
   player.rope:experience_anchor_moves(moves)
@@ -436,9 +466,7 @@ function level:anchor_points()
 end
 
 function level:anchor_at(point)
- for i in self:anchor_points() do
-  if (_anch_eq(point,i)) return i
- end
+ return self._anch_by_position[_mix(_anch_unpack(point))]
 end
 
 function level:get_open_pit(mx,my)
@@ -492,10 +520,6 @@ function level:_mget(mx,my)
  )
 end
 
-function _amix(ax,ay)
- return ax..","..ay
-end
-
 function _mix(mx,my)
   return mx..","..my
 end
@@ -679,8 +703,8 @@ function player:update()
     while not level:mcoll(x,y) do x+=dx y+=dy end
 
     self.rope=rope:new(
-     {ax=x+0.5-dx*0.5,ay=y+0.5-dy*0.5},
-     {ax=self.x+0.5,ay=self.y+0.5},
+     {x+0.5-dx*0.5,y+0.5-dy*0.5},
+     {self.x+0.5,self.y+0.5},
      level:get_latch(dx,dy,x*8,y*8)
     )
     
@@ -707,10 +731,10 @@ function player:update()
    self.y=latch.rec.my+latch.dy
   end
 
-  self.rope:drag_dst(
+  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) self.orientx=tdx
@@ -858,10 +882,10 @@ function rope:update()
   if (not self.latch) wrongbleep:bleep(5) self:destroy() return
 
   if self.latch.rec then
-   self:drag_src(
+   self:drag_src{
     self.latch.rec.mx+0.5+self.latch.ax_offset,
     self.latch.rec.my+0.5+self.latch.ay_offset
-   )
+   }
 
    if self.latch.rec.dead==true then 
     self:destroy()
@@ -1035,18 +1059,18 @@ function rope:draw(artificial_px,artificial_py)
   ]]
 end
 
-function rope:drag_dst(x,y)
- self:drag(self.dst,x,y)
+function rope:drag_dst(xy)
+ self:drag(self.dst,xy)
 end
 
-function rope:drag_src(x,y)
- self:drag(self.src,x,y)
+function rope:drag_src(xy)
+ self:drag(self.src,xy)
 end
 
-function rope:drag(n1,ax_new,ay_new)
+function rope:drag(n1,axy)
  self:relax()
- self:_drag(n1,{ax=ax_new,ay=n1.ay})
- self:_drag(n1,{ax=ax_new,ay=ay_new})
+ self:_drag(n1,{axy[1],n1[2]})
+ self:_drag(n1,axy)
  self:relax()
 end
 
@@ -1057,8 +1081,7 @@ function rope:relax()
   if (not n1) break
   local n2=n1.next
   if _anch_eq(n0,n1) then
-   n0.next=n2 
-   if (n2) n2.prev=n0
+   _anch_del(n1)
   else
    n0=n0.next
   end
@@ -1072,15 +1095,10 @@ function rope:relax()
   if (not n2) return
 
   local anch=level:anchor_at(n1)
-  local wouldstick,axy_new=would_stick(anch,n0,n1,n2)
-  if not (wouldstick or _anch_eq(n1,axy_new)) then
-   self:_drag(n1,axy_new,{ax=n1.ax,ay=n1.ay})
-   n0=n1.prev
-   n2=n1.next
-   n0.next=n2
-   n2.prev=n0
-   n1.next=nil
-   n1.prev=nil
+  local wouldstick,position_new=would_stick(anch,n0,n1,n2)
+  if not (wouldstick or _anch_eq(n1,position_new)) then
+   self:_drag(n1,position_new,{_anch_unpack(n1)})
+   _anch_del(n1)
   else n0=n0.next end
  end
 end
@@ -1142,7 +1160,6 @@ function rope:_check_sane()
 
       if dmx==1 and dmy==1 and level:mcoll(mx0,my2) and level:mcoll(mx2,my0) then
       else
-       --printh("ok! "..tostring({qxs[i-2],qys[i-2]})..tostring({qxs[i],qys[i]})..tostring(m0)..tostring(m2))
        ok=true
       end
      end
@@ -1184,7 +1201,7 @@ function would_stick(anchor,xy0,xy1,xy2)
 
  return 
   anchor and anchor.adx==adx and anchor.ady==ady,
-  {ax=x1_new,ay=y1_new}
+  {x1_new,y1_new}
 end
 
 function rope:experience_anchor_moves(moves)
@@ -1197,8 +1214,8 @@ function rope:_be_dragged_by(moves)
  local n=self.src
  while n do
   for t in all(moves) do
-   local axy_old,axy_new=unpack(t)
-   if (_anch_eq(axy_old,n)) n.dest=axy_new break
+   local xy_old,xy_new=unpack(t)
+   if (_anch_eq(xy_old,n)) n.dest=xy_new break
   end
   n=n.next
  end
@@ -1232,7 +1249,6 @@ function rope:_be_pushed_by1(anch_old,anch_new)
   local nxmn,nxmx = _mnmx(nx0,nx1)
   local nymn,nymx = _mnmx(ny0,ny1)
 
-  -- nprinth("has: "..tostring{anch==nil,n0==nil,n1==nil})
   if
    (ax_new!=ax_old or (nxmn<ax_new and ax_new<nxmx)) and 
    (ay_new!=ay_old or (nymn<ay_new and ay_new<nymx)) and 
@@ -1250,12 +1266,8 @@ function rope:_be_pushed_by1(anch_old,anch_new)
     nx05=nx0+(ny05-ny0)/(ny1-ny0) * (nx1-nx0)
    end
 
-   local n05={ax=nx05,ay=ny05,prev=n0,next=n1}
-   n0.next=n05
-   n1.prev=n05
-   -- printh("creating: "..tostring{anch,{n0.ax,n0.ay},{n05.ax,n05.ay},{n1.ax,n1.ay}})
-   -- printh("dragging: "..tostring{anch,{n05.ax,n05.ay},{ax_new,ay_new}})
-   self:_drag(n05,{ax=ax_new,ay=ay_new})
+   local n05=_anch_new(n0,n1,{nx05,ny05})
+   self:_drag(n05,{ax_new,ay_new})
   else
    n0=n0.next
   end
@@ -1264,67 +1276,74 @@ end
 
 function rope:_drag(n1,new,removing)
  local function _sweep_radar(lhs,rhs,pivot,src,dst)
-  -- printh(tostring{{lhs.ax,lhs.ay},{rhs.ax,rhs.ay},{pivot.ax,pivot.ay},{src.ax,src.ay},{dst.ax,dst.ay}})
   if (_anch_eq(src,dst)) return
 
   local function _uncreatable(anchor)
    return _anch_eq(anchor,lhs) or _anch_eq(anchor,lhs) or _anch_eq(anchor,removing)
   end
 
-  local function _sweep(extent_old,extent_new,cb_in_bounds,cb_would_stick,cb_side)
-   for extent_new in _stepfrom(extent_old, extent_new) do
-    for anchor in level:anchor_points() do
-     if not _uncreatable(anchor) and cb_in_bounds(anchor) and 
-      cb_would_stick(anchor,extent_new) and
-      cb_side(anchor,extent_old)!=cb_side(anchor,extent_new)
-     then
-      return anchor
-     end
+  local function _sweep(extent_orig,extent_final,cb_in_bounds,cb_make_point)
+   local eligible={}
+   local point_orig=cb_make_point(extent_orig)
+   local point_final=cb_make_point(extent_final)
+
+   for anchor in level:anchor_points() do
+    -- figure out which anchors we even can stick to
+    if cb_in_bounds(anchor) and not _uncreatable(anchor) then 
+     local side_orig=_which_side(anchor,pivot,point_orig)
+     local side_final=_which_side(anchor,pivot,point_final)
+
+     if (side_orig!=side_final and would_stick(anchor,pivot,nil,point_final)) add(eligible,{anchor,side_final})
+    end
+   end
+
+   -- if no one's in the race, don't raycast
+   if (#eligible==0) return 
+   if (#eligible==1) return eligible[1][1]
+
+   -- see who wins the race
+   for extent in _stepfrom(extent_orig,extent_final) do
+    local point = cb_make_point(extent)
+    for anchor_final in all(eligible) do
+     if (_which_side(anchor_final[1],pivot,point)==anchor_final[2]) return anchor_final[1]
     end
-    extent_old=extent_new
    end
   end
 
-  if src.ax==dst.ax then
-   local ax_pivot,ax_dst=pivot.ax,dst.ax
+  local ax_pivot,ay_pivot=_anch_unpack(pivot)
+  local ax_src,ay_src=_anch_unpack(src)
+  local ax_dst,ay_dst=_anch_unpack(dst)
+
+  if ax_src==ax_dst then
    return _sweep(
-    src.ay,dst.ay,
-    function(anchor) return mid(ax_pivot,anchor.ax,ax_dst)==anchor.ax end,
-    function(anchor,ay) return would_stick(anchor,pivot,nil,{ax=ax_dst,ay=ay}) end,
-    function(anchor,ay) return _which_side(anchor,pivot,{ax=ax_dst,ay=ay}) end
+    ay_src,ay_dst,
+    function(anchor) return mid(ax_pivot,anchor[1],ax_dst)==anchor[1] end,
+    function(ay) return {ax_dst,ay} end
    )
   else
-   local ay_pivot,ay_dst=pivot.ay,dst.ay
    return _sweep(
-    src.ax,dst.ax,
-    function(anchor) return mid(ay_pivot,anchor.ay,ay_dst)==anchor.ay end,
-    function(anchor,ax) return would_stick(anchor,pivot,nil,{ax=ax,ay=ay_dst}) end,
-    function(anchor,ax) return _which_side(anchor,pivot,{ax=ax,ay=ay_dst}) end
+    ax_src,ax_dst,
+    function(anchor) return mid(ay_pivot,anchor[2],ay_dst)==anchor[2] end,
+    function(ax) return {ax,ay_dst} end
    )
   end
  end
 
- local old={ax=n1.ax,ay=n1.ay}
- n1.ax,n1.ay=new.ax,new.ay
+ local old={_anch_unpack(n1)}
+ _anch_update(n1,new)
 
  local n0=n1.prev
  while n0 do
   local anch=_sweep_radar(n0,n1,n0,old,new)
   if (not anch) break
-  local n05={ax=anch.ax,ay=anch.ay,prev=n0,next=n1}
-  n0.next=n05
-  n1.prev=n05
-  n0=n05
+  n0=_anch_new(n0,n1,anch)
  end
 
  local n2=n1.next
  while n2 do
   local anch=_sweep_radar(n1,n2,n2,old,new)
   if (not anch) break
-  local n15={ax=anch.ax,ay=anch.ay,prev=n1,next=n2}
-  n1.next=n15
-  n2.prev=n15
-  n2=n15
+  n2=_anch_new(n1,n2,anch)
  end
 end
 
@@ -1337,9 +1356,7 @@ function _stepfrom(x0,x1)
   end
  end
 
- local mul=0.5
- x0*=2
- x1*=2
+ local mul=1
  if (x0>x1) x0,x1,mul=-x0,-x1,-mul
  local i=flr(x0)
  local top=flr(x1)
@@ -1359,7 +1376,6 @@ function _which_side(xy,x0y0,x1y1)
  local x,y=_anch_unpack(xy)
  local x0,y0=_anch_unpack(x0y0)
  local x1,y1=_anch_unpack(x1y1)
- -- printh("anchors: "..tostring{x,y,x0,y0,x1,y1})
 
  return sgn0((x1-x0)*(y-y0) - (y1-y0)*(x-x0))
 end
@@ -1388,7 +1404,8 @@ function rope:collide_mrect(mx0,my0,mw,mh,exclude_src,exclude_dst)
    if (not nd) return
   end
 
-  local x1,y1,x2,y2=n0.ax,n0.ay,n1.ax,n1.ay
+  local x1,y1=_anch_unpack(n0)
+  local x2,y2=_anch_unpack(n1)
   local function _line_line(x3,y3,x4,y4)
    local denom=(y4-y3)*(x2-x1)-(x4-x3)*(y2-y1)
 
@@ -1418,12 +1435,15 @@ end
 function rope:tug_orientxy()
  local a1=self.dst
  local a0=self.dst.prev
- local dx=a0.ax-a1.ax
+ local ax0,ay0=_anch_unpack(a0)
+ local ax1,ay1=_anch_unpack(a1)
+
+ local dx=ax0-ax1
  local tdx
  if (dx>3/8) tdx=1
  if (dx<-3/8) tdx=-1
 
- local dy=a0.ay-a1.ay
+ local dy=ay0-ay1
  local tdy
  if abs(dy)>abs(dx)/2 then 
   if (dy>3/8) tdy=1
@@ -1608,9 +1628,10 @@ function rope:_anchors_simplified()
  end
  a=self.src
  while a do
+  local ax,ay=_anch_unpack(a)
   local point={
-   x=flr(a.ax*8+0.5),y=flr(a.ay*8+0.5),
-   ax=a.ax,ay=a.ay
+   ax,ay,
+   x=flr(ax*8+0.5),y=flr(ay*8+0.5),
   }
   local aw=level:anchor_at(a)
   local l=self.latch