X-Git-Url: https://deadsoftware.ru/gitweb?a=blobdiff_plain;f=src%2Fgame%2Fg_grid.pas;h=87ff77ec360cd5dd32a184ff0409dc853e89fe29;hb=462c5390c88bcb0339d59e245e79fc26b8f70424;hp=3b36ba3acff15c455d8498cbae4f0afc60bd67a9;hpb=80ce0d53dfae2da0c9a3f9a82074c194b4eb2473;p=d2df-sdl.git

diff --git a/src/game/g_grid.pas b/src/game/g_grid.pas
index 3b36ba3..87ff77e 100644
--- a/src/game/g_grid.pas
+++ b/src/game/g_grid.pas
@@ -1,4 +1,4 @@
-(* Copyright (C)  DooM 2D:Forever Developers
+(* Copyright (C)  Doom 2D: Forever Developers
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -21,20 +21,37 @@
   {.$DEFINE D2F_DEBUG_MOVER}
 {$ENDIF}
 {.$DEFINE GRID_USE_ORTHO_ACCEL}
+{$DEFINE LINEAABB2}
 unit g_grid;
 
 interface
 
+uses
+  mempool;
+
+(*
+ * In order to make this usable for kind-of-recursive calls,
+ * we'll use "frame memory pool" to return results. That is,
+ * we will allocate a memory pool that will be cleared on
+ * frame start, and then used as a simple "no-free" allocator.
+ * Grid will put results into this pool, and will never bother
+ * to free it. Caller should call "release" on result, and
+ * the pool will throw away everything.
+ * No more callbacks, of course.
+ *)
+
 const
   GridTileSize = 32; // must be power of two!
 
 type
   TBodyProxyId = Integer;
 
-  generic TBodyGridBase<ITP> = class(TObject)
+  generic TBodyGridBase<ITP> = class{$IFDEF USE_MEMPOOL}(TPoolObject){$ENDIF}
   public
+    type PITP = ^ITP;
+
     type TGridQueryCB = function (obj: ITP; tag: Integer): Boolean is nested; // return `true` to stop
-    type TGridRayQueryCB = function (obj: ITP; tag: Integer; x, y, prevx, prevy: Integer): Boolean is nested; // return `true` to stop
+    //type TGridRayQueryCB = function (obj: ITP; tag: Integer; x, y, prevx, prevy: Integer): Boolean is nested; // return `true` to stop
     type TCellQueryCB = procedure (x, y: Integer) is nested; // top-left cell corner coords
 
     const TagDisabled = $40000000;
@@ -127,7 +144,7 @@ type
     mProxyFree: TBodyProxyId; // free
     mProxyCount: Integer; // currently used
     mProxyMaxCount: Integer;
-    mInQuery: Boolean;
+    //mInQuery: Boolean;
 
   public
     dbgShowTraceLog: Boolean;
@@ -142,9 +159,6 @@ type
     function allocProxy (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer): TBodyProxyId;
     procedure freeProxy (body: TBodyProxyId);
 
-    procedure insertInternal (body: TBodyProxyId);
-    procedure removeInternal (body: TBodyProxyId);
-
     function forGridRect (x, y, w, h: Integer; cb: TGridInternalCB; bodyId: TBodyProxyId): Boolean;
 
     function inserter (grida: Integer; bodyId: TBodyProxyId): Boolean;
@@ -179,12 +193,15 @@ type
     //WARNING: don't modify grid while any query is in progress (no checks are made!)
     //         you can set enabled/disabled flag, tho (but iterator can still return objects disabled inside it)
     // no callback: return `true` on the first hit
-    function forEachInAABB (x, y, w, h: Integer; cb: TGridQueryCB; tagmask: Integer=-1; allowDisabled: Boolean=false): ITP;
+    //function forEachInAABB (x, y, w, h: Integer; cb: TGridQueryCB; tagmask: Integer=-1; allowDisabled: Boolean=false): ITP;
+    // return number of ITP thingys put into frame pool
+    function forEachInAABB (x, y, w, h: Integer; tagmask: Integer=-1; allowDisabled: Boolean=false; firstHit: Boolean=false): Integer;
 
     //WARNING: don't modify grid while any query is in progress (no checks are made!)
     //         you can set enabled/disabled flag, tho (but iterator can still return objects disabled inside it)
     // no callback: return object on the first hit or nil
-    function forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1; exittag: PInteger=nil): ITP;
+    //function forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1{; exittag: PInteger=nil}): ITP;
+    function forEachAtPoint (x, y: Integer; tagmask: Integer=-1; allowDisabled: Boolean=false; firstHit: Boolean=false): Integer;
 
     function atCellInPoint (x, y: Integer): TAtPointEnumerator;
 
@@ -194,8 +211,10 @@ type
     // no callback: return object of the nearest hit or nil
     // if `inverted` is true, trace will register bodies *exluding* tagmask
     //WARNING: don't change tags in callbacks here!
+    {
     function traceRayOld (const x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP; overload;
     function traceRayOld (out ex, ey: Integer; const ax0, ay0, ax1, ay1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
+    }
 
     //WARNING: don't modify grid while any query is in progress (no checks are made!)
     //         you can set enabled/disabled flag, tho (but iterator can still return objects disabled inside it)
@@ -252,12 +271,10 @@ type
   private
     wx0, wy0, wx1, wy1: Integer; // window coordinates
     stx, sty: Integer; // "steps" for x and y axes
-    dx2, dy2: Integer; // "double lengthes" for x and y axes
+    stleft: Integer; // "steps left"
+    err, errinc, errmax: Integer;
     xd, yd: Integer; // current coord
-    e: Integer; // "error" (as in bresenham algo)
-    term: Integer; // end for xd (xd = term: done)
-    //xptr, yptr: PInteger;
-    xyswapped: Boolean; // true: xd is y
+    horiz: Boolean;
 
   public
     // call `setyp` after this
@@ -281,39 +298,15 @@ type
     // move to next tile; return `true` if the line is complete (and walker state is undefined then)
     function stepToNextTile (): Boolean; inline;
 
-    // hack for line-vs-aabb; NOT PROPERLY TESTED!
-    procedure getPrevXY (out ox, oy: Integer); inline;
-
-    // current coords
-    function x (): Integer; inline;
-    function y (): Integer; inline;
-
     procedure getXY (out ox, oy: Integer); inline;
 
-    // move directions; always [-1..1] (can be zero!)
-    function dx (): Integer; inline;
-    function dy (): Integer; inline;
+  public
+    // current coords
+    property x: Integer read xd;
+    property y: Integer read yd;
   end;
 
 
-// you are not supposed to understand this
-// returns `true` if there is an intersection, and enter coords
-// enter coords will be equal to (x0, y0) if starting point is inside the box
-// if result is `false`, `inx` and `iny` are undefined
-function lineAABBIntersects (x0, y0, x1, y1: Integer; bx, by, bw, bh: Integer; out inx, iny: Integer): Boolean;
-
-// sweep two AABB's to see if and when they are overlapping
-// returns `true` if collision was detected (but boxes doesn't overlap)
-// u1 and u1 has no sense if no collision was detected
-// u0 = normalized time of first collision (i.e. collision starts at myMove*u0)
-// u1 = normalized time of second collision (i.e. collision stops after myMove*u1)
-// hitedge for `it`: 0: top; 1: right; 2: bottom; 3: left
-// enter/exit coords will form non-intersecting configuration (i.e. will be before/after the actual collision)
-function sweepAABB (mex0, mey0, mew, meh: Integer; medx, medy: Integer; itx0, ity0, itw, ith: Integer;
-                    u0: PSingle=nil; hitedge: PInteger=nil; u1: PSingle=nil): Boolean;
-
-function distanceSq (x0, y0, x1, y1: Integer): Integer; inline;
-
 procedure swapInt (var a: Integer; var b: Integer); inline;
 //function minInt (a, b: Integer): Integer; inline;
 //function maxInt (a, b: Integer): Integer; inline;
@@ -322,17 +315,15 @@ procedure swapInt (var a: Integer; var b: Integer); inline;
 implementation
 
 uses
-  SysUtils, e_log, g_console, utils;
+  SysUtils, e_log, g_console, geom, utils;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-//procedure swapInt (var a: Integer; var b: Integer); inline; var t: Integer; begin t := a; a := b; b := t; end;
-procedure swapInt (var a: Integer; var b: Integer); inline; begin a := a xor b; b := b xor a; a := a xor b; end;
+procedure swapInt (var a: Integer; var b: Integer); inline; var t: Integer; begin t := a; a := b; b := t; end;
+//procedure swapInt (var a: Integer; var b: Integer); inline; begin a := a xor b; b := b xor a; a := a xor b; end;
 //function minInt (a, b: Integer): Integer; inline; begin if (a < b) then result := a else result := b; end;
 //function maxInt (a, b: Integer): Integer; inline; begin if (a > b) then result := a else result := b; end;
 
-function distanceSq (x0, y0, x1, y1: Integer): Integer; inline; begin result := (x1-x0)*(x1-x0)+(y1-y0)*(y1-y0); end;
-
 
 // ////////////////////////////////////////////////////////////////////////// //
 constructor TLineWalker.Create (minx, miny, maxx, maxy: Integer);
@@ -349,504 +340,226 @@ begin
   wy1 := maxy;
 end;
 
-function TLineWalker.done (): Boolean; inline; begin result := (xd = term); end;
-
-function TLineWalker.step (): Boolean; inline;
-begin
-  if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
-  xd += stx;
-  result := (xd = term);
-end;
-
-function TLineWalker.stepToNextTile (): Boolean; inline;
+function TLineWalker.setup (x0, y0, x1, y1: Integer): Boolean;
 var
-  ex, ey: Integer;
-  xwalk, ywalk, wklen: Integer; // to the respective edges
-  lstx, lsty, lterm: Integer;
-  le, ldx2, ldy2: Integer;
-  lxd, lyd: Integer;
-  f: Integer;
+  sx0, sy0, sx1, sy1: Single;
 begin
-  result := false;
+  if (wx1 < wx0) or (wy1 < wy0) then begin stleft := 0; xd := x0; yd := y0; result := false; exit; end;
 
-  lstx := stx;
-  lsty := sty;
-  lterm := term;
-  lxd := xd;
-
-  // ortho?
-  if (lsty = 0) then
-  begin
-    // only xd
-    //assert(lsty <> 0);
-    if (lstx < 0) then
-    begin
-      // xd: to left edge
-      xd := (lxd and (not (TileSize-1)))-1;
-      result := (lxd <= lterm);
-      exit;
-    end
-    else
-    begin
-      // xd: to right edge
-      xd := (lxd or (TileSize-1))+1;
-      result := (lxd >= lterm);
-      exit;
-    end;
-  end;
-
-  // not ortho
-  //assert(lstx <> 0); // invariant
-
-  lyd := yd;
-  le := e;
-  ldx2 := dx2;
-  ldy2 := dy2;
-
-  // calculate xwalk
-  if (lstx < 0) then
+  if (x0 >= wx0) and (y0 >= wy0) and (x0 <= wx1) and (y0 <= wy1) and
+     (x1 >= wx0) and (y1 >= wy0) and (x1 <= wx1) and (y1 <= wy1) then
   begin
-    ex := (lxd and (not (TileSize-1)))-1;
-    xwalk := lxd-ex;
+    result := true;
   end
   else
   begin
-    ex := (lxd or (TileSize-1))+1;
-    xwalk := ex-lxd;
+    sx0 := x0; sy0 := y0;
+    sx1 := x1; sy1 := y1;
+    result := clipLine(sx0, sy0, sx1, sy1, wx0, wy0, wx1, wy1);
+    if not result then begin stleft := 0; xd := x0; yd := y0; exit; end;
+    x0 := trunc(sx0); y0 := trunc(sy0);
+    x1 := trunc(sx1); y1 := trunc(sy1);
   end;
 
-  // calculate ywalk
-  if (lsty < 0) then
+  // check for ortho lines
+  if (y0 = y1) then
   begin
-    ey := (lyd and (not (TileSize-1)))-1;
-    ywalk := lyd-ey;
+    // horizontal
+    horiz := true;
+    stleft := abs(x1-x0)+1;
+    if (x0 < x1) then stx := 1 else stx := -1;
+    sty := 0;
+    errinc := 0;
+    errmax := 10; // anything that is greater than zero
   end
-  else
+  else if (x0 = x1) then
   begin
-    ey := (lyd or (TileSize-1))+1;
-    ywalk := ey-lyd;
-  end;
-
-  while true do
+    // vertical
+    horiz := false;
+    stleft := abs(y1-y0)+1;
+    stx := 0;
+    if (y0 < y1) then sty := 1 else sty := -1;
+    errinc := 0;
+    errmax := 10; // anything that is greater than zero
+  end
+  else
   begin
-    // in which dir we want to walk?
-    if (xwalk <= ywalk) then wklen := xwalk else wklen := ywalk;
-    // walk x
-    if (lstx < 0) then
+    // diagonal
+    if (abs(x1-x0) >= abs(y1-y0)) then
     begin
-      lxd -= wklen;
-      if (lxd <= lterm) then begin xd := lxd; result := true; exit; end;
+      // horizontal
+      horiz := true;
+      stleft := abs(x1-x0)+1;
+      errinc := abs(y1-y0)+1;
     end
     else
     begin
-      lxd += wklen;
-      if (lxd >= lterm) then begin xd := lxd; result := true; exit; end;
+      // vertical
+      horiz := false;
+      stleft := abs(y1-y0)+1;
+      errinc := abs(x1-x0)+1;
     end;
-    // walk y
-    for f := 1 to wklen do if (le >= 0) then begin lyd += lsty; le -= ldx2; end else le += ldy2;
-    if (lxd = ex) or (lyd = ey) then break;
-    xwalk -= wklen; if (xwalk = 0) then xwalk := TileSize;
-    ywalk -= wklen; if (ywalk = 0) then ywalk := TileSize;
+    if (x0 < x1) then stx := 1 else stx := -1;
+    if (y0 < y1) then sty := 1 else sty := -1;
+    errmax := stleft;
   end;
-  //assert((xd div TileSize <> lxd div TileSize) or (yd div TileSize <> lyd div TileSize));
-  xd := lxd;
-  yd := lyd;
-  e := le;
+  xd := x0;
+  yd := y0;
+  err := -errmax;
 end;
 
-// NOT TESTED!
-procedure TLineWalker.getPrevXY (out ox, oy: Integer); inline;
+function TLineWalker.done (): Boolean; inline; begin result := (stleft <= 0); end;
+
+// true: done
+function TLineWalker.step (): Boolean; inline;
 begin
-  //writeln('e=', e, '; dx2=', dx2, '; dy2=', dy2);
-  if xyswapped then
+  if horiz then
   begin
-    if (e >= 0) then ox := yd-sty else ox := yd;
-    oy := xd-stx;
+    xd += stx;
+    err += errinc;
+    if (err >= 0) then begin err -= errmax; yd += sty; end;
   end
   else
   begin
-    if (e >= 0) then oy := yd-sty else oy := yd;
-    ox := xd-stx;
+    yd += sty;
+    err += errinc;
+    if (err >= 0) then begin err -= errmax; xd += stx; end;
   end;
+  Dec(stleft);
+  result := (stleft <= 0);
 end;
 
-function TLineWalker.x (): Integer; inline; begin if xyswapped then result := yd else result := xd; end;
-function TLineWalker.y (): Integer; inline; begin if xyswapped then result := xd else result := yd; end;
-procedure TLineWalker.getXY (out ox, oy: Integer); inline; begin if xyswapped then begin ox := yd; oy := xd; end else begin ox := xd; oy := yd; end; end;
-
-function TLineWalker.dx (): Integer; inline; begin if xyswapped then result := stx else result := sty; end;
-function TLineWalker.dy (): Integer; inline; begin if xyswapped then result := sty else result := stx; end;
-
-function TLineWalker.setup (x0, y0, x1, y1: Integer): Boolean;
-  procedure swapInt (var a: Integer; var b: Integer); inline; begin a := a xor b; b := b xor a; a := a xor b; end;
+// true: done
+function TLineWalker.stepToNextTile (): Boolean; inline;
 var
-  dsx, dsy: Integer; // "lengthes" for x and y axes
-  rem: Integer;
-  xfixed: Boolean;
-  temp: Integer;
+  ex, ey: Integer;
+  xwalk, ywalk, wklen: Integer; // to the respective edges
+  f: Integer;
 begin
   result := false;
-  xyswapped := false;
-
-  // horizontal setup
-  if (x0 < x1) then
-  begin
-    // from left to right
-    if (x0 > wx1) or (x1 < wx0) then exit; // out of screen
-    stx := 1; // going right
-  end
-  else
-  begin
-    // from right to left
-    if (x1 > wx1) or (x0 < wx0) then exit; // out of screen
-    stx := -1; // going left
-    x0 := -x0;
-    x1 := -x1;
-    wx0 := -wx0;
-    wx1 := -wx1;
-    swapInt(wx0, wx1);
-  end;
-
-  // vertical setup
-  if (y0 < y1) then
-  begin
-    // from top to bottom
-    if (y0 > wy1) or (y1 < wy0) then exit; // out of screen
-    sty := 1; // going down
-  end
-  else
-  begin
-    // from bottom to top
-    if (y1 > wy1) or (y0 < wy0) then exit; // out of screen
-    sty := -1; // going up
-    y0 := -y0;
-    y1 := -y1;
-    wy0 := -wy0;
-    wy1 := -wy1;
-    swapInt(wy0, wy1);
-  end;
-
-  dsx := x1-x0;
-  dsy := y1-y0;
-
-  if (dsx < dsy) then
-  begin
-    xyswapped := true;
-    //xptr := @yd;
-    //yptr := @xd;
-    swapInt(x0, y0);
-    swapInt(x1, y1);
-    swapInt(dsx, dsy);
-    swapInt(wx0, wy0);
-    swapInt(wx1, wy1);
-    swapInt(stx, sty);
-  end
-  else
-  begin
-    //xptr := @xd;
-    //yptr := @yd;
-  end;
 
-  dx2 := 2*dsx;
-  dy2 := 2*dsy;
-  xd := x0;
-  yd := y0;
-  e := 2*dsy-dsx;
-  term := x1;
+  if (stleft < 2) then begin result := true; exit; end; // max one pixel left, nothing to do
 
-  xfixed := false;
-  if (y0 < wy0) then
+  // strictly horizontal?
+  if (sty = 0) then
   begin
-    // clip at top
-    temp := dx2*(wy0-y0)-dsx;
-    xd += temp div dy2;
-    rem := temp mod dy2;
-    if (xd > wx1) then exit; // x is moved out of clipping rect, nothing to do
-    if (xd+1 >= wx0) then
+    // only xd
+    if (stx < 0) then
     begin
-      yd := wy0;
-      e -= rem+dsx;
-      //if (rem > 0) then begin Inc(xd); e += dy2; end; //BUGGY
-      if (xd < wx0) then begin xd += 1; e += dy2; end; //???
-      xfixed := true;
+      // xd: to left edge
+      ex := (xd and (not (TileSize-1)))-1;
+      stleft -= xd-ex;
+    end
+    else
+    begin
+      // xd: to right edge
+      ex := (xd or (TileSize-1))+1;
+      stleft -= ex-xd;
     end;
+    result := (stleft <= 0);
+    xd := ex;
+    exit;
   end;
 
-  if (not xfixed) and (x0 < wx0) then
-  begin
-    // clip at left
-    temp := dy2*(wx0-x0);
-    yd += temp div dx2;
-    rem := temp mod dx2;
-    if (yd > wy1) or (yd = wy1) and (rem >= dsx) then exit;
-    xd := wx0;
-    e += rem;
-    if (rem >= dsx) then begin Inc(yd); e -= dx2; end;
-  end;
-
-  if (y1 > wy1) then
-  begin
-    // clip at bottom
-    temp := dx2*(wy1-y0)+dsx;
-    term := x0+temp div dy2;
-    rem := temp mod dy2;
-    if (rem = 0) then Dec(term);
-  end;
-
-  if (term > wx1) then term := wx1; // clip at right
-
-  Inc(term); // draw last point (it is ok to inc here, as `term` sign will be changed later
-  //if (term = xd) then exit; // this is the only point, get out of here
-
-  if (sty = -1) then yd := -yd;
-  if (stx = -1) then begin xd := -xd; term := -term; end;
-  dx2 -= dy2;
-
-  result := true;
-end;
-
-
-// ////////////////////////////////////////////////////////////////////////// //
-// you are not supposed to understand this
-// returns `true` if there is an intersection, and enter coords
-// enter coords will be equal to (x0, y0) if starting point is inside the box
-// if result is `false`, `inx` and `iny` are undefined
-function lineAABBIntersects (x0, y0, x1, y1: Integer; bx, by, bw, bh: Integer; out inx, iny: Integer): Boolean;
-var
-  wx0, wy0, wx1, wy1: Integer; // window coordinates
-  stx, sty: Integer; // "steps" for x and y axes
-  dsx, dsy: Integer; // "lengthes" for x and y axes
-  dx2, dy2: Integer; // "double lengthes" for x and y axes
-  xd, yd: Integer; // current coord
-  e: Integer; // "error" (as in bresenham algo)
-  rem: Integer;
-  //!term: Integer;
-  d0, d1: PInteger;
-  xfixed: Boolean;
-  temp: Integer;
-begin
-  result := false;
-  // why not
-  inx := x0;
-  iny := y0;
-  if (bw < 1) or (bh < 1) then exit; // impossible box
-
-  if (x0 = x1) and (y0 = y1) then
+  // strictly vertical?
+  if (stx = 0) then
   begin
-    // check this point
-    result := (x0 >= bx) and (y0 >= by) and (x0 < bx+bw) and (y0 < by+bh);
+    // only xd
+    if (sty < 0) then
+    begin
+      // yd: to top edge
+      ey := (yd and (not (TileSize-1)))-1;
+      stleft -= yd-ey;
+    end
+    else
+    begin
+      // yd: to bottom edge
+      ey := (yd or (TileSize-1))+1;
+      stleft -= ey-yd;
+    end;
+    result := (stleft <= 0);
+    yd := ey;
     exit;
   end;
 
-  // check if staring point is inside the box
-  if (x0 >= bx) and (y0 >= by) and (x0 < bx+bw) and (y0 < by+bh) then begin result := true; exit; end;
-
-  // clip rectange
-  wx0 := bx;
-  wy0 := by;
-  wx1 := bx+bw-1;
-  wy1 := by+bh-1;
-
-  // horizontal setup
-  if (x0 < x1) then
-  begin
-    // from left to right
-    if (x0 > wx1) or (x1 < wx0) then exit; // out of screen
-    stx := 1; // going right
-  end
-  else
-  begin
-    // from right to left
-    if (x1 > wx1) or (x0 < wx0) then exit; // out of screen
-    stx := -1; // going left
-    x0 := -x0;
-    x1 := -x1;
-    wx0 := -wx0;
-    wx1 := -wx1;
-    swapInt(wx0, wx1);
-  end;
+  // diagonal
 
-  // vertical setup
-  if (y0 < y1) then
+  // calculate xwalk
+  if (stx < 0) then
   begin
-    // from top to bottom
-    if (y0 > wy1) or (y1 < wy0) then exit; // out of screen
-    sty := 1; // going down
+    ex := (xd and (not (TileSize-1)))-1;
+    xwalk := xd-ex;
   end
   else
   begin
-    // from bottom to top
-    if (y1 > wy1) or (y0 < wy0) then exit; // out of screen
-    sty := -1; // going up
-    y0 := -y0;
-    y1 := -y1;
-    wy0 := -wy0;
-    wy1 := -wy1;
-    swapInt(wy0, wy1);
+    ex := (xd or (TileSize-1))+1;
+    xwalk := ex-xd;
   end;
 
-  dsx := x1-x0;
-  dsy := y1-y0;
-
-  if (dsx < dsy) then
+  // calculate ywalk
+  if (sty < 0) then
   begin
-    d0 := @yd;
-    d1 := @xd;
-    swapInt(x0, y0);
-    swapInt(x1, y1);
-    swapInt(dsx, dsy);
-    swapInt(wx0, wy0);
-    swapInt(wx1, wy1);
-    swapInt(stx, sty);
+    ey := (yd and (not (TileSize-1)))-1;
+    ywalk := yd-ey;
   end
   else
   begin
-    d0 := @xd;
-    d1 := @yd;
-  end;
-
-  dx2 := 2*dsx;
-  dy2 := 2*dsy;
-  xd := x0;
-  yd := y0;
-  e := 2*dsy-dsx;
-  //!term := x1;
-
-  xfixed := false;
-  if (y0 < wy0) then
-  begin
-    // clip at top
-    temp := dx2*(wy0-y0)-dsx;
-    xd += temp div dy2;
-    rem := temp mod dy2;
-    if (xd > wx1) then exit; // x is moved out of clipping rect, nothing to do
-    if (xd+1 >= wx0) then
-    begin
-      yd := wy0;
-      e -= rem+dsx;
-      //if (rem > 0) then begin Inc(xd); e += dy2; end; //BUGGY
-      if (xd < wx0) then begin xd += 1; e += dy2; end; //???
-      xfixed := true;
-    end;
-  end;
-
-  if (not xfixed) and (x0 < wx0) then
-  begin
-    // clip at left
-    temp := dy2*(wx0-x0);
-    yd += temp div dx2;
-    rem := temp mod dx2;
-    if (yd > wy1) or (yd = wy1) and (rem >= dsx) then exit;
-    xd := wx0;
-    e += rem;
-    if (rem >= dsx) then begin Inc(yd); e -= dx2; end;
-  end;
-
-  (*
-  if (y1 > wy1) then
-  begin
-    // clip at bottom
-    temp := dx2*(wy1-y0)+dsx;
-    term := x0+temp div dy2;
-    rem := temp mod dy2;
-    if (rem = 0) then Dec(term);
+    ey := (yd or (TileSize-1))+1;
+    ywalk := ey-yd;
   end;
 
-  if (term > wx1) then term := wx1; // clip at right
-
-  Inc(term); // draw last point
-  //if (term = xd) then exit; // this is the only point, get out of here
-  *)
-
-  if (sty = -1) then yd := -yd;
-  if (stx = -1) then begin xd := -xd; {!term := -term;} end;
-  //!dx2 -= dy2;
-
-  inx := d0^;
-  iny := d1^;
-  result := true;
-end;
-
-
-// ////////////////////////////////////////////////////////////////////////// //
-function sweepAABB (mex0, mey0, mew, meh: Integer; medx, medy: Integer; itx0, ity0, itw, ith: Integer;
-                    u0: PSingle=nil; hitedge: PInteger=nil; u1: PSingle=nil): Boolean;
-var
-  tin, tout: Single;
-
-  function axisOverlap (me0, me1, it0, it1, d, he0, he1: Integer): Boolean; inline;
-  var
-    t: Single;
+  {
+  while (xd <> ex) and (yd <> ey) do
   begin
-    result := false;
-
-    if (me1 < it0) then
+    if horiz then
     begin
-      if (d >= 0) then exit; // oops, no hit
-      t := (me1-it0+1)/d;
-      if (t > tin) then begin tin := t; hitedge^ := he1; end;
+      xd += stx;
+      err += errinc;
+      if (err >= 0) then begin err -= errmax; yd += sty; end;
     end
-    else if (it1 < me0) then
+    else
     begin
-      if (d <= 0) then exit; // oops, no hit
-      t := (me0-it1-1)/d;
-      if (t > tin) then begin tin := t; hitedge^ := he0; end;
+      yd += sty;
+      err += errinc;
+      if (err >= 0) then begin err -= errmax; xd += stx; end;
     end;
+    Dec(stleft);
+    if (stleft < 1) then begin result := true; exit; end;
+  end;
+  }
 
-    if (d < 0) and (it1 > me0) then
+  if (xwalk <= ywalk) then wklen := xwalk else wklen := ywalk;
+  while true do
+  begin
+    // in which dir we want to walk?
+    stleft -= wklen;
+    if (stleft <= 0) then begin result := true; exit; end;
+    if horiz then
     begin
-      t := (me0-it1-1)/d;
-      if (t < tout) then tout := t;
+      xd += wklen*stx;
+      for f := 1 to wklen do
+      begin
+        err += errinc;
+        if (err >= 0) then begin err -= errmax; yd += sty; end;
+      end;
     end
-    else if (d > 0) and (me1 > it0) then
+    else
     begin
-      t := (me1-it0+1)/d;
-      if (t < tout) then tout := t;
+      yd += wklen*sty;
+      for f := 1 to wklen do
+      begin
+        err += errinc;
+        if (err >= 0) then begin err -= errmax; xd += stx; end;
+      end;
     end;
-
-    result := true;
-  end;
-
-var
-  mex1, mey1, itx1, ity1, vx, vy: Integer;
-  htt: Integer = -1;
-begin
-  result := false;
-  if (u0 <> nil) then u0^ := -1.0;
-  if (u1 <> nil) then u1^ := -1.0;
-  if (hitedge = nil) then hitedge := @htt else hitedge^ := -1;
-
-  if (mew < 1) or (meh < 1) or (itw < 1) or (ith < 1) then exit;
-
-  mex1 := mex0+mew-1;
-  mey1 := mey0+meh-1;
-  itx1 := itx0+itw-1;
-  ity1 := ity0+ith-1;
-
-  // check if they are overlapping right now (SAT)
-  //if (mex1 >= itx0) and (mex0 <= itx1) and (mey1 >= ity0) and (mey0 <= ity1) then begin result := true; exit; end;
-
-  if (medx = 0) and (medy = 0) then exit; // both boxes are sationary
-
-  // treat b as stationary, so invert v to get relative velocity
-  vx := -medx;
-  vy := -medy;
-
-  tin := -100000000.0;
-  tout := 100000000.0;
-
-  if not axisOverlap(mex0, mex1, itx0, itx1, vx, 1, 3) then exit;
-  if not axisOverlap(mey0, mey1, ity0, ity1, vy, 2, 0) then exit;
-
-  if (u0 <> nil) then u0^ := tin;
-  if (u1 <> nil) then u1^ := tout;
-
-  if (tin <= tout) and (tin >= 0.0) and (tin <= 1.0) then
-  begin
-    result := true;
+    // check for walk completion
+    if (xd = ex) or (yd = ey) then exit;
+    wklen := 1;
   end;
 end;
 
+procedure TLineWalker.getXY (out ox, oy: Integer); inline; begin ox := xd; oy := yd; end;
+
 
 // ////////////////////////////////////////////////////////////////////////// //
 procedure TBodyGridBase.TBodyProxyRec.setup (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer);
@@ -969,7 +682,7 @@ begin
   mProxyFree := 0;
   mProxyCount := 0;
   mProxyMaxCount := 0;
-  e_WriteLog(Format('created grid with size: %dx%d (tile size: %d); pix: %dx%d', [mWidth, mHeight, mTileSize, mWidth*mTileSize, mHeight*mTileSize]), MSG_NOTIFY);
+  e_WriteLog(Format('created grid with size: %dx%d (tile size: %d); pix: %dx%d', [mWidth, mHeight, mTileSize, mWidth*mTileSize, mHeight*mTileSize]), TMsgType.Notify);
 end;
 
 
@@ -999,7 +712,7 @@ begin
     end;
     if (mcb < cnt) then mcb := cnt;
   end;
-  e_WriteLog(Format('grid size: %dx%d (tile size: %d); pix: %dx%d; used cells: %d; max bodies in cell: %d; max proxies allocated: %d; proxies used: %d', [mWidth, mHeight, mTileSize, mWidth*mTileSize, mHeight*mTileSize, mUsedCells, mcb, mProxyMaxCount, mProxyCount]), MSG_NOTIFY);
+  e_WriteLog(Format('grid size: %dx%d (tile size: %d); pix: %dx%d; used cells: %d; max bodies in cell: %d; max proxies allocated: %d; proxies used: %d', [mWidth, mHeight, mTileSize, mWidth*mTileSize, mHeight*mTileSize, mUsedCells, mcb, mProxyMaxCount, mProxyCount]), TMsgType.Notify);
 end;
 
 
@@ -1232,8 +945,9 @@ end;
 // ////////////////////////////////////////////////////////////////////////// //
 function TBodyGridBase.forGridRect (x, y, w, h: Integer; cb: TGridInternalCB; bodyId: TBodyProxyId): Boolean;
 var
-  gx, gy: Integer;
   gw, gh: Integer;
+  ex, ey: Integer;
+  gx, gy: Integer;
 begin
   result := false;
   if (w < 1) or (h < 1) or not assigned(cb) then exit;
@@ -1244,16 +958,22 @@ begin
   if (x+w <= 0) or (y+h <= 0) then exit;
   gw := mWidth;
   gh := mHeight;
-  //tsize := mTileSize;
   if (x >= gw*mTileSize) or (y >= gh*mTileSize) then exit;
-  for gy := y div mTileSize to (y+h-1) div mTileSize do
-  begin
-    if (gy < 0) then continue;
-    if (gy >= gh) then break;
-    for gx := x div mTileSize to (x+w-1) div mTileSize do
+  ex := (x+w-1) div mTileSize;
+  ey := (y+h-1) div mTileSize;
+  x := x div mTileSize;
+  y := y div mTileSize;
+  // clip rect
+  if (x < 0) then x := 0 else if (x >= gw) then x := gw-1;
+  if (y < 0) then y := 0 else if (y >= gh) then y := gh-1;
+  if (ex < 0) then ex := 0 else if (ex >= gw) then ex := gw-1;
+  if (ey < 0) then ey := 0 else if (ey >= gh) then ey := gh-1;
+  if (x > ex) or (y > ey) then exit; // just in case
+  // do the work
+  for gy := y to ey do
+  begin
+    for gx := x to ex do
     begin
-      if (gx < 0) then continue;
-      if (gx >= gw) then break;
       result := cb(gy*gw+gx, bodyId);
       if result then exit;
     end;
@@ -1320,15 +1040,6 @@ begin
   mGrid[grida] := ccidx;
 end;
 
-procedure TBodyGridBase.insertInternal (body: TBodyProxyId);
-var
-  px: PBodyProxyRec;
-begin
-  if (body < 0) or (body > High(mProxies)) then exit; // just in case
-  px := @mProxies[body];
-  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, inserter, body);
-end;
-
 
 // assume that we cannot have one object added to bucket twice
 function TBodyGridBase.remover (grida: Integer; bodyId: TBodyProxyId): Boolean;
@@ -1371,29 +1082,25 @@ begin
   end;
 end;
 
-procedure TBodyGridBase.removeInternal (body: TBodyProxyId);
-var
-  px: PBodyProxyRec;
-begin
-  if (body < 0) or (body > High(mProxies)) then exit; // just in case
-  px := @mProxies[body];
-  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, remover, body);
-end;
-
 
 // ////////////////////////////////////////////////////////////////////////// //
 function TBodyGridBase.insertBody (aObj: ITP; aX, aY, aWidth, aHeight: Integer; aTag: Integer=-1): TBodyProxyId;
 begin
   aTag := aTag and TagFullMask;
   result := allocProxy(aX, aY, aWidth, aHeight, aObj, aTag);
-  insertInternal(result);
+  //insertInternal(result);
+  forGridRect(aX, aY, aWidth, aHeight, inserter, result);
 end;
 
 
 procedure TBodyGridBase.removeBody (body: TBodyProxyId);
+var
+  px: PBodyProxyRec;
 begin
   if (body < 0) or (body > High(mProxies)) then exit; // just in case
-  removeInternal(body);
+  px := @mProxies[body];
+  //removeInternal(body);
+  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, remover, body);
   freeProxy(body);
 end;
 
@@ -1422,15 +1129,18 @@ begin
   // did any corner crossed tile boundary?
   if (x0 div mTileSize <> nx div mTileSize) or
      (y0 div mTileSize <> ny div mTileSize) or
-     ((x0+w) div mTileSize <> (nx+nw) div mTileSize) or
-     ((y0+h) div mTileSize <> (ny+nh) div mTileSize) then
+     ((x0+w-1) div mTileSize <> (nx+nw-1) div mTileSize) or
+     ((y0+h-1) div mTileSize <> (ny+nh-1) div mTileSize) then
   begin
-    removeInternal(body);
+    //writeln('moveResizeBody: cell occupation changed! old=(', x0, ',', y0, ')-(', x0+w-1, ',', y0+h-1, '); new=(', nx, ',', ny, ')-(', nx+nw-1, ',', ny+nh-1, ')');
+    //removeInternal(body);
+    forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, remover, body);
     px.mX := nx+mMinX;
     px.mY := ny+mMinY;
     px.mWidth := nw;
     px.mHeight := nh;
-    insertInternal(body);
+    //insertInternal(body);
+    forGridRect(px.mX, px.mY, nw, nh, inserter, body);
   end
   else
   begin
@@ -1441,6 +1151,7 @@ begin
   end;
 end;
 
+
 //TODO: optimize for horizontal/vertical moves
 procedure TBodyGridBase.moveBody (body: TBodyProxyId; nx, ny: Integer);
 var
@@ -1580,6 +1291,7 @@ begin
   px.mY := ny+mMinY;
 end;
 
+
 procedure TBodyGridBase.resizeBody (body: TBodyProxyId; nw, nh: Integer);
 var
   px: PBodyProxyRec;
@@ -1595,14 +1307,16 @@ begin
   {$IF DEFINED(D2F_DEBUG_MOVER)}
   e_WriteLog(Format('proxy #%d: RESIZE: xg=%d;yg=%d;w=%d;h=%d;nw=%d;nh=%d', [body, x0, y0, w, h, nw, nh]), MSG_NOTIFY);
   {$ENDIF}
-  if ((x0+w) div mTileSize <> (x0+nw) div mTileSize) or
-     ((y0+h) div mTileSize <> (y0+nh) div mTileSize) then
+  if ((x0+w-1) div mTileSize <> (x0+nw-1) div mTileSize) or
+     ((y0+h-1) div mTileSize <> (y0+nh-1) div mTileSize) then
   begin
     // crossed tile boundary, do heavy work
-    removeInternal(body);
+    //removeInternal(body);
+    forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, remover, body);
     px.mWidth := nw;
     px.mHeight := nh;
-    insertInternal(body);
+    //insertInternal(body);
+    forGridRect(px.mX, px.mY, nw, nh, inserter, body);
   end
   else
   begin
@@ -1627,7 +1341,7 @@ end;
 
 // ////////////////////////////////////////////////////////////////////////// //
 // no callback: return `true` on the first hit
-function TBodyGridBase.forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1; exittag: PInteger=nil): ITP;
+function TBodyGridBase.forEachAtPoint (x, y: Integer; tagmask: Integer=-1; allowDisabled: Boolean=false; firstHit: Boolean=false): Integer;
 var
   f: Integer;
   idx, curci: Integer;
@@ -1635,9 +1349,9 @@ var
   px: PBodyProxyRec;
   lq: LongWord;
   ptag: Integer;
+  presobj: PITP;
 begin
-  result := Default(ITP);
-  if (exittag <> nil) then exittag^ := 0;
+  result := 0;
   tagmask := tagmask and TagFullMask;
   if (tagmask = 0) then exit;
 
@@ -1677,7 +1391,7 @@ begin
   while (curci <> -1) do
   begin
     {$IF DEFINED(D2F_DEBUG_XXQ)}
-    if (assigned(cb)) then e_WriteLog(Format(' cell #%d', [curci]), MSG_NOTIFY);
+    //if (assigned(cb)) then e_WriteLog(Format(' cell #%d', [curci]), MSG_NOTIFY);
     {$ENDIF}
     cc := @mCells[curci];
     for f := 0 to GridCellBucketSize-1 do
@@ -1685,32 +1399,19 @@ begin
       if (cc.bodies[f] = -1) then break;
       px := @mProxies[cc.bodies[f]];
       {$IF DEFINED(D2F_DEBUG_XXQ)}
-      if (assigned(cb)) then e_WriteLog(Format('  proxy #%d; qm:%u; tag:%08x; tagflag:%d  %u', [cc.bodies[f], px.mQueryMark, px.mTag, (px.mTag and tagmask), LongWord(px.mObj)]), MSG_NOTIFY);
+      //if (assigned(cb)) then e_WriteLog(Format('  proxy #%d; qm:%u; tag:%08x; tagflag:%d  %u', [cc.bodies[f], px.mQueryMark, px.mTag, (px.mTag and tagmask), LongWord(px.mObj)]), MSG_NOTIFY);
       {$ENDIF}
-      // shit. has to do it this way, so i can change tag in callback
-      if (px.mQueryMark <> lq) then
+      if (px.mQueryMark = lq) then continue;
+      px.mQueryMark := lq;
+      ptag := px.mTag;
+      if (not allowDisabled) and ((ptag and TagDisabled) <> 0) then continue;
+      if ((ptag and tagmask) = 0) then continue;
+      if (x >= px.mX) and (y >= px.mY) and (x < px.mX+px.mWidth) and (y < px.mY+px.mHeight) then
       begin
-        px.mQueryMark := lq;
-        ptag := px.mTag;
-        if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and
-           (x >= px.mX) and (y >= px.mY) and (x < px.mX+px.mWidth) and (y < px.mY+px.mHeight) then
-        begin
-          if assigned(cb) then
-          begin
-            if cb(px.mObj, ptag) then
-            begin
-              result := px.mObj;
-              if (exittag <> nil) then exittag^ := ptag;
-              exit;
-            end;
-          end
-          else
-          begin
-            result := px.mObj;
-            if (exittag <> nil) then exittag^ := ptag;
-            exit;
-          end;
-        end;
+        presobj := PITP(framePool.alloc(sizeof(ITP)));
+        Move(px.mObj, presobj^, sizeof(ITP));
+        Inc(result);
+        if (firstHit) then begin {mInQuery := false;} exit; end;
       end;
     end;
     curci := cc.next;
@@ -1720,21 +1421,31 @@ end;
 
 // ////////////////////////////////////////////////////////////////////////// //
 // no callback: return `true` on the first hit
-function TBodyGridBase.forEachInAABB (x, y, w, h: Integer; cb: TGridQueryCB; tagmask: Integer=-1; allowDisabled: Boolean=false): ITP;
+// return number of ITP thingys put into frame pool
+function TBodyGridBase.forEachInAABB (x, y, w, h: Integer; tagmask: Integer=-1; allowDisabled: Boolean=false; firstHit: Boolean=false): Integer;
 var
   idx: Integer;
   gx, gy: Integer;
+  sx, sy, ex, ey: Integer;
   curci: Integer;
   f: Integer;
   cc: PGridCell = nil;
   px: PBodyProxyRec;
   lq: LongWord;
-  gw: Integer;
+  gw, gh: Integer;
   x0, y0: Integer;
   ptag: Integer;
+  presobj: PITP;
 begin
-  result := Default(ITP);
+  result := 0;
   if (w < 1) or (h < 1) then exit;
+
+  if (w = 1) and (h = 1) then
+  begin
+    result := forEachAtPoint(x, y, tagmask, allowDisabled, firstHit);
+    exit;
+  end;
+
   tagmask := tagmask and TagFullMask;
   if (tagmask = 0) then exit;
 
@@ -1746,13 +1457,26 @@ begin
   Dec(y, mMinY);
 
   gw := mWidth;
-  //tsize := mTileSize;
+  gh := mHeight;
 
   if (x+w <= 0) or (y+h <= 0) then exit;
-  if (x >= gw*mTileSize) or (y >= mHeight*mTileSize) then exit;
+  if (x >= gw*mTileSize) or (y >= gh*mTileSize) then exit;
 
-  if mInQuery then raise Exception.Create('recursive queries aren''t supported');
-  mInQuery := true;
+  sx := x div mTileSize;
+  sy := y div mTileSize;
+  ex := (x+w-1) div mTileSize;
+  ey := (y+h-1) div mTileSize;
+
+  // clip rect
+  if (sx < 0) then sx := 0 else if (sx >= gw) then sx := gw-1;
+  if (sy < 0) then sy := 0 else if (sy >= gh) then sy := gh-1;
+  if (ex < 0) then ex := 0 else if (ex >= gw) then ex := gw-1;
+  if (ey < 0) then ey := 0 else if (ey >= gh) then ey := gh-1;
+  if (sx > ex) or (sy > ey) then exit; // just in case
+
+  // has something to do
+  //if mInQuery then raise Exception.Create('recursive queries aren''t supported');
+  //mInQuery := true;
 
   // increase query counter
   Inc(mLastQuery);
@@ -1766,14 +1490,10 @@ begin
   lq := mLastQuery;
 
   // go on
-  for gy := y div mTileSize to (y+h-1) div mTileSize do
+  for gy := sy to ey do
   begin
-    if (gy < 0) then continue;
-    if (gy >= mHeight) then break;
-    for gx := x div mTileSize to (x+w-1) div mTileSize do
+    for gx := sx to ex do
     begin
-      if (gx < 0) then continue;
-      if (gx >= gw) then break;
       // process cells
       curci := mGrid[gy*gw+gx];
       while (curci <> -1) do
@@ -1783,7 +1503,7 @@ begin
         begin
           if (cc.bodies[f] = -1) then break;
           px := @mProxies[cc.bodies[f]];
-          // shit. has to do it this way, so i can change tag in callback
+          // shit! has to do it this way, so i can change tag in callback
           if (px.mQueryMark = lq) then continue;
           px.mQueryMark := lq;
           ptag := px.mTag;
@@ -1791,6 +1511,11 @@ begin
           if ((ptag and tagmask) = 0) then continue;
           if (x0 >= px.mX+px.mWidth) or (y0 >= px.mY+px.mHeight) then continue;
           if (x0+w <= px.mX) or (y0+h <= px.mY) then continue;
+          presobj := PITP(framePool.alloc(sizeof(ITP)));
+          Move(px.mObj, presobj^, sizeof(ITP));
+          Inc(result);
+          if (firstHit) then begin {mInQuery := false;} exit; end;
+          (*
           if assigned(cb) then
           begin
             if cb(px.mObj, ptag) then begin result := px.mObj; mInQuery := false; exit; end;
@@ -1801,13 +1526,14 @@ begin
             mInQuery := false;
             exit;
           end;
+          *)
         end;
         curci := cc.next;
       end;
     end;
   end;
 
-  mInQuery := false;
+  //mInQuery := false;
 end;
 
 
@@ -1845,8 +1571,8 @@ begin
   lw := TLineWalker.Create(0, 0, gw*mTileSize-1, gh*mTileSize-1);
   if not lw.setup(x0, y0, x1, y1) then exit; // out of screen
 
-  if mInQuery then raise Exception.Create('recursive queries aren''t supported');
-  mInQuery := true;
+  //if mInQuery then raise Exception.Create('recursive queries aren''t supported');
+  //mInQuery := true;
 
   // increase query counter
   Inc(mLastQuery);
@@ -1877,7 +1603,7 @@ begin
           if cb(px.mObj, ptag) then
           begin
             result := px.mObj;
-            mInQuery := false;
+            //mInQuery := false;
             exit;
           end;
         end;
@@ -1888,7 +1614,7 @@ begin
     // done processing cells, move to next tile
   until lw.stepToNextTile();
 
-  mInQuery := false;
+  //mInQuery := false;
 end;
 
 
@@ -1930,8 +1656,8 @@ begin
   // just in case
   if (cx0 > cx1) or (cy0 > cy1) then exit;
 
-  if mInQuery then raise Exception.Create('recursive queries aren''t supported');
-  mInQuery := true;
+  //if mInQuery then raise Exception.Create('recursive queries aren''t supported');
+  //mInQuery := true;
 
   // increase query counter
   Inc(mLastQuery);
@@ -1973,7 +1699,7 @@ begin
               begin
                 ex := ax0;
                 ey := ay0;
-                mInQuery := false;
+                //mInQuery := false;
                 exit;
               end;
             end;
@@ -1997,7 +1723,7 @@ begin
     end;
   end;
 
-  mInQuery := false;
+  //mInQuery := false;
 end;
 
 
@@ -2018,6 +1744,7 @@ var
   {$IF DEFINED(D2F_DEBUG_OTR)}
   s: AnsiString = '';
   {$ENDIF}
+  pmark: PoolMark;
 begin
   result := false;
   ex := ax1;
@@ -2027,7 +1754,9 @@ begin
   tagmask := tagmask and TagFullMask;
   if (tagmask = 0) then exit;
 
-  if (forEachAtPoint(ax0, ay0, nil, tagmask) = nil) then exit;
+  pmark := framePool.mark();
+  if (forEachAtPoint(ax0, ay0, tagmask, false, true) = 0) then exit;
+  framePool.release(pmark);
 
   minx := mMinX;
   miny := mMinY;
@@ -2146,7 +1875,7 @@ end;
 // you are not supposed to understand this
 function TBodyGridBase.traceRay (out ex, ey: Integer; const ax0, ay0, ax1, ay1: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
 var
-  lw, sweepw: TLineWalker;
+  lw: TLineWalker;
   ccidx: Integer;
   cc: PGridCell;
   px: PBodyProxyRec;
@@ -2179,12 +1908,14 @@ begin
   lw := TLineWalker.Create(0, 0, gw*mTileSize-1, gh*mTileSize-1);
   if not lw.setup(x0, y0, x1, y1) then exit; // out of screen
 
-  sweepw := TLineWalker.Create(0, 0, 1, 1); // doesn't matter, just shut ups the compiler
-
   lastDistSq := distanceSq(ax0, ay0, ax1, ay1)+1;
 
-  if mInQuery then raise Exception.Create('recursive queries aren''t supported');
-  mInQuery := true;
+  {$IF DEFINED(D2F_DEBUG)}
+  //if assigned(dbgRayTraceTileHitCB) then e_LogWritefln('*** traceRay: (%s,%s)-(%s,%s)', [x0, y0, x1, y1]);
+  {$ENDIF}
+
+  //if mInQuery then raise Exception.Create('recursive queries aren''t supported');
+  //mInQuery := true;
 
   // increase query counter
   Inc(mLastQuery);
@@ -2198,6 +1929,9 @@ begin
 
   repeat
     lw.getXY(cx, cy);
+    {$IF DEFINED(D2F_DEBUG)}
+    if assigned(dbgRayTraceTileHitCB) then dbgRayTraceTileHitCB(cx+mMinX, cy+mMinY);
+    {$ENDIF}
     // check tile
     ccidx := mGrid[(cy div mTileSize)*gw+(cx div mTileSize)];
     // process cells
@@ -2222,6 +1956,9 @@ begin
           py0 := px.mY-miny;
           px1 := px0+px.mWidth-1;
           py1 := py0+px.mHeight-1;
+          {$IF DEFINED(D2F_DEBUG)}
+          //if assigned(dbgRayTraceTileHitCB) then e_LogWritefln(' cxy=(%s,%s); pan=(%s,%s)-(%s,%s)', [cx, cy, px0, py0, px1, py1]);
+          {$ENDIF}
           // inside?
           if firstCell and (x0 >= px0) and (y0 >= py0) and (x0 <= px1) and (y0 <= py1) then
           begin
@@ -2229,24 +1966,26 @@ begin
             ex := ax0;
             ey := ay0;
             result := px.mObj;
-            mInQuery := false;
+            //mInQuery := false;
+            {$IF DEFINED(D2F_DEBUG)}
+            if assigned(dbgRayTraceTileHitCB) then e_LogWriteln('  INSIDE!');
+            {$ENDIF}
             exit;
           end;
           // do line-vs-aabb test
-          sweepw.setClip(px0, py0, px1, py1);
-          if sweepw.setup(x0, y0, x1, y1) then
+          if lineAABBIntersects(x0, y0, x1, y1, px0, py0, px1-px0+1, py1-py0+1, hx, hy) then
           begin
             // hit detected
-            sweepw.getPrevXY(hx, hy);
             distSq := distanceSq(x0, y0, hx, hy);
+            {$IF DEFINED(D2F_DEBUG)}
+            //if assigned(dbgRayTraceTileHitCB) then e_LogWritefln('  hit=(%s,%s); distSq=%s; lastDistSq=%s', [hx, hy, distSq, lastDistSq]);
+            {$ENDIF}
             if (distSq < lastDistSq) then
             begin
               lastDistSq := distSq;
               ex := hx+minx;
               ey := hy+miny;
               result := px.mObj;
-              // if this is not a first cell, get outta here
-              if not firstCell then begin mInQuery := false; exit; end;
               wasHit := true;
             end;
           end;
@@ -2257,17 +1996,18 @@ begin
     end;
     // done processing cells; exit if we registered a hit
     // next cells can't have better candidates, obviously
-    if wasHit then begin mInQuery := false; exit; end;
+    if wasHit then begin {mInQuery := false;} exit; end;
     firstCell := false;
     // move to next tile
   until lw.stepToNextTile();
 
-  mInQuery := false;
+  //mInQuery := false;
 end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
 // no callback: return `true` on the nearest hit
+(*
 function TBodyGridBase.traceRayOld (const x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
 var
   ex, ey: Integer;
@@ -2507,13 +2247,13 @@ begin
 
   prevx := xptr^+minx;
   prevy := yptr^+miny;
-  (*
+  ( *
   // move coords
   if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
   xd += stx;
   // done?
   if (xd = term) then exit;
-  *)
+  * )
 
   {$IF DEFINED(D2F_DEBUG)}
   if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*mTileSize) and (yptr^ >= gh*mTileSize) then raise Exception.Create('raycaster internal error (0)');
@@ -2910,6 +2650,7 @@ begin
 
   mInQuery := false;
 end;
+*)
 
 
 end.