From 6658f71ba24de33125aaba278fd7e467ae5ac3c6 Mon Sep 17 00:00:00 2001
From: Nyeogmi <economicsbat@gmail.com>
Date: Wed, 21 Dec 2022 19:12:21 -0800
Subject: [PATCH] Correct when the rope crashes into the other side of
 something

---
 chameleonic.p8 | 110 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 87 insertions(+), 23 deletions(-)

diff --git a/chameleonic.p8 b/chameleonic.p8
index 9c28c88..8abe8a4 100644
--- a/chameleonic.p8
+++ b/chameleonic.p8
@@ -450,7 +450,7 @@ function level:reanchor()
   local old=anch_old[k]
   if old then
    anch_new[k]=old
-   old.ax,old.ay,old.adx,old.ady=new.ax,new.ay,new.adx,new.ady
+   old.ax_old,old.ay_old,old.ax,old.ay,old.adx,old.ady=old.ax,old.ay,new.ax,new.ay,new.adx,new.ady
    old.dropped=nil
   end
  end
@@ -459,6 +459,17 @@ function level:reanchor()
  for k,_ in pairs(self._anch) do
   add(self._anch_keys,{key=k})
  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)
+ end
 
  if (player.rope!=nil) player.rope:relax()
 end
@@ -617,13 +628,13 @@ function level:can_move(
  if player.rope then
   local chk=false
   if dmx==0 and dmy==-1 then
-   chk=player.rope:collide_mrect(mx0,my0-1,1,2,exclude_src,exclude_dst)
+   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,my0,1,2,exclude_src,exclude_dst)
+   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(mx0-1,my0,2,1,exclude_src,exclude_dst)
+   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,my0,2,1,exclude_src,exclude_dst)
+   chk=player.rope:collide_mrect(mx0+0.2,my0+0.4,1.6,0.2,exclude_src,exclude_dst)
   end
 
   if (chk) return false
@@ -781,7 +792,10 @@ function player:update()
 
  if self.rope then
   self.rope:update()
-  self.rope:drag_dst(self.x+self.px/8+0.5,self.y+self.py/8+0.5)
+  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)
 
   local tdx,tdy=self.rope:tug_orientxy()
   if (tdx!=0) self.orientx=tdx
@@ -1030,7 +1044,7 @@ function rope:draw(artificial_px,artificial_py)
     --assert(not (adx==0 and ady==0))
 
     local c=3
-    if (n1.associated_with.dropped) c=8
+    if (n1.associated_with.dropped) c=4
     rectfill(x+2,y+2,x+4,y+4,c)
     pset(x+adx*2,y,9)
     pset(x,y+ady*2,9)
@@ -1083,6 +1097,20 @@ function rope:relax()
   n=n.next
  end
 
+ local n0=self.src
+ while true do
+  local n1=n0.next
+  if (n1==nil) break
+  local n2=n1.next
+
+  if n0.ax==n1.ax and n0.ay==n1.ay then 
+   n0.next=n2 
+   n2.prev=n0
+  else
+   n0=n0.next
+  end
+ end
+
  local n0=self.src
  while true do
   if (n0==nil) return
@@ -1187,7 +1215,6 @@ end
 
 function would_stick(x0,y0,anchor,x2,y2)
  local x1,y1=anchor.ax,anchor.ay
- if (x0>x2) x0,y0,x2,y2=x2,y2,x0,y0
 
  local dx=x2-x0
  local dy=y2-y0
@@ -1195,6 +1222,7 @@ function would_stick(x0,y0,anchor,x2,y2)
  local adx,ady
  local x1_new,y1_new
  if abs(dx)>abs(dy) then
+  if (x0>x2) dx,x0,y0,x2,y2=-dx,x2,y2,x0,y0
   local dprop=(x1-x0)/dx
   x1_new,y1_new=x1,y0+dprop*(y2-y0)
   ady=sgn0(y1_new-y1)
@@ -1202,25 +1230,66 @@ function would_stick(x0,y0,anchor,x2,y2)
   if (y0>y2) adx=ady
   if (y0<y2) adx=-ady
  else
+  if (y0>y2) dy,x0,y0,x2,y2=-dy,x2,y2,x0,y0
   local dprop=(y1-y0)/dy
   x1_new,y1_new=x0+dprop*(x2-x0),y1
   adx=sgn0(x1_new-x1)
   ady=0
-  if (y0>y2) ady=adx
-  if (y0<y2) ady=-adx
+  if (x0>x2) ady=adx
+  if (x0<x2) ady=-adx
  end
 
- local wouldnt=anchor.dropped or (anchor.adx==-adx or anchor.ady==-ady)
+ local wouldnt=anchor.dropped or (anchor.adx!=adx or anchor.ady!=ady)
 
  return not wouldnt,x1_new,y1_new,adx,ady
 end
 
+function rope:be_pushed_by(anchor,ax_old,ay_old)
+ local n0=self.src
+ local ax_new,ay_new=anchor.ax,anchor.ay
+ while true do
+  n1=n0.next
+  if (n1==nil) return
+
+  local nx0,ny0=n0.ax,n0.ay
+  local nx1,ny1=n1.ax,n1.ay
+
+  if
+   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)
+  then
+   local nx05,ny05
+   if ax_new==ax_old then
+    nx05=anchor.ax
+    ny05=ny0+(nx05-nx0)/(nx1-nx0) * (ny1-ny0)
+    --printh("found (x): "..tostring({nx05,ny05}))
+   elseif ay_new==ay_old then
+    ny05=anchor.ay
+    nx05=nx0+(ny05-ny0)/(ny1-ny0) * (nx1-nx0)
+    --printh("found (y): "..tostring({nx05,ny05}))
+   else
+    assert(false,"wtf?")
+   end
+
+   local n05={ax=nx05,ay=ny05,associated_with=anchor,prev=n0,next=n1}
+   --printh("adding: "..tostring({nx05,ny05,anchor}))
+   n0.next=n05
+   n1.prev=n05
+   self:_drag(n05,anchor.ax,anchor.ay)
+   -- printh("dragged: "..tostring({n05.ax,n05.ay,anchor}))
+   -- printh("local: "..tostring(n0.associated_with).."->"..tostring(n05.associated_with).."->"..tostring(n1.associated_with))
+  else
+   n0=n0.next
+  end
+ end
+end
+
 function rope:_drag(n1,ax1_new,ay1_new)
  local function _sweep_radar(ax_pivot,ay_pivot,ax_far0,ay_far0,ax_far1,ay_far1)
   if (ax_far0==ax_far1 and ay_far0==ay_far1) return nil
-  local function crossed(x,y)
-   return x!=y
-  end
 
   if ax_far0==ax_far1 then
    local ax_far=ax_far0
@@ -1235,8 +1304,8 @@ function rope:_drag(n1,ax1_new,ay1_new)
       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
-      crossed(
-        _which_side(anchor.ax,anchor.ay,ax_pivot,ay_pivot,ax_far,ay_far_old),
+      (
+        _which_side(anchor.ax,anchor.ay,ax_pivot,ay_pivot,ax_far,ay_far_old) !=
         _which_side(anchor.ax,anchor.ay,ax_pivot,ay_pivot,ax_far,ay_far_new)
       )
      then
@@ -1258,8 +1327,8 @@ function rope:_drag(n1,ax1_new,ay1_new)
       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 
-      crossed(
-        _which_side(anchor.ax,anchor.ay,ax_pivot,ay_pivot,ax_far_old,ay_far),
+      (
+        _which_side(anchor.ax,anchor.ay,ax_pivot,ay_pivot,ax_far_old,ay_far) !=
         _which_side(anchor.ax,anchor.ay,ax_pivot,ay_pivot,ax_far_new,ay_far)
       )
      then
@@ -1345,11 +1414,6 @@ function rope:collide_mrect(mx0,my0,mw,mh,exclude_src,exclude_dst)
  local mx1,my1=mx0+mw,my0+mh
  local n0=self.src
 
- mx0+=0.4
- my0+=0.4
- mx1-=0.4
- my1-=0.4
-
  while true do
   local n1=n0.next
   if (n1==nil) return false