X-Git-Url: https://deadsoftware.ru/gitweb?a=blobdiff_plain;f=src%2Fgame%2Fg_grid.pas;h=c1a5f0777cd25a2416e92da03da53834e744a571;hb=f0d4e199f20938613340c53ff24e1eb7a6cc2481;hp=984d8e7e2c2b9025fe5a93c4274ad66372763d35;hpb=0d83f3f36628c487c98470a87440c87b3467f5e4;p=d2df-sdl.git

diff --git a/src/game/g_grid.pas b/src/game/g_grid.pas
index 984d8e7..c1a5f07 100644
--- a/src/game/g_grid.pas
+++ b/src/game/g_grid.pas
@@ -13,150 +13,329 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *)
-{$MODE DELPHI}
-{$modeswitch nestedprocvars}
+// universal spatial grid
+{$INCLUDE ../shared/a_modes.inc}
 unit g_grid;
 
 interface
 
-uses e_log;
-
-const
-  GridDefaultTileSize = 32;
 
 type
-  GridQueryCB = function (obj: TObject; tag: Integer): Boolean is nested; // return `true` to stop
+  TBodyProxyId = Integer;
 
-type
-  TBodyGrid = class;
+  generic TBodyGridBase<ITP> = class(TObject)
+  public
+    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 TGridAlongQueryCB = function (obj: ITP; tag: Integer): Boolean is nested; // return `true` to stop
 
-  TBodyProxy = class(TObject)
-  private
-    mX, mY, mWidth, mHeight: Integer; // aabb
-    mQueryMark: DWord; // was this object visited at this query?
-    mObj: TObject;
-    mGrid: TBodyGrid;
-    mTag: Integer;
-    prevLink: TBodyProxy; // only for used
-    nextLink: TBodyProxy; // either used or free
+    const TagDisabled = $40000000;
+    const TagFullMask = $3fffffff;
 
   private
-    procedure setup (aX, aY, aWidth, aHeight: Integer; aObj: TObject; aTag: Integer);
+    const
+      GridDefaultTileSize = 32;
+      GridCellBucketSize = 8; // WARNING! can't be less than 2!
 
-  public
-    constructor Create (aGrid: TBodyGrid; aX, aY, aWidth, aHeight: Integer; aObj: TObject; aTag: Integer);
-    destructor Destroy (); override;
+  private
+    type
+      PBodyProxyRec = ^TBodyProxyRec;
+      TBodyProxyRec = record
+      private
+        mX, mY, mWidth, mHeight: Integer; // aabb
+        mQueryMark: LongWord; // was this object visited at this query?
+        mObj: ITP;
+        mTag: Integer; // `TagDisabled` set: disabled ;-)
+        nextLink: TBodyProxyId; // next free or nothing
+
+      private
+        procedure setup (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer);
+      end;
 
-    property x: Integer read mX;
-    property y: Integer read mY;
-    property width: Integer read mWidth;
-    property height: Integer read mHeight;
-    property obj: TObject read mObj;
-    property tag: Integer read mTag;
-    property grid: TBodyGrid read mGrid;
-  end;
+      PGridCell = ^TGridCell;
+      TGridCell = record
+        bodies: array [0..GridCellBucketSize-1] of Integer; // -1: end of list
+        next: Integer; // in this cell; index in mCells
+      end;
 
-  PGridCell = ^TGridCell;
-  TGridCell = record
-    body: TBodyProxy;
-    next: Integer; // in this cell; index in mCells
-  end;
+      TGridInternalCB = function (grida: Integer; bodyId: TBodyProxyId): Boolean of object; // return `true` to stop
 
-  GridInternalCB = function (grida: Integer): Boolean is nested; // return `true` to stop
+  private
+    //mTileSize: Integer;
+    const mTileSize = GridDefaultTileSize;
 
-  TBodyGrid = class(TObject)
   private
-    mTileSize: Integer;
     mMinX, mMinY: Integer; // so grids can start at any origin
     mWidth, mHeight: Integer; // in tiles
     mGrid: array of Integer; // mWidth*mHeight, index in mCells
     mCells: array of TGridCell; // cell pool
     mFreeCell: Integer; // first free cell index or -1
-    mLastQuery: Integer;
+    mLastQuery: LongWord;
     mUsedCells: Integer;
-    mProxyFree: TBodyProxy; // free
-    mProxyList: TBodyProxy; // used
-    mProxyCount: Integer; // total allocated
+    mProxies: array of TBodyProxyRec;
+    mProxyFree: TBodyProxyId; // free
+    mProxyCount: Integer; // currently used
+    mProxyMaxCount: Integer;
+
+  public
+    dbgShowTraceLog: Boolean;
 
   private
-    function allocCell: Integer;
+    function allocCell (): Integer;
     procedure freeCell (idx: Integer); // `next` is simply overwritten
 
-    function allocProxy (aX, aY, aWidth, aHeight: Integer; aObj: TObject; aTag: Integer): TBodyProxy;
-    procedure freeProxy (body: TBodyProxy);
+    function allocProxy (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer): TBodyProxyId;
+    procedure freeProxy (body: TBodyProxyId);
 
-    procedure insert (body: TBodyProxy);
-    procedure remove (body: TBodyProxy);
+    procedure insertInternal (body: TBodyProxyId);
+    procedure removeInternal (body: TBodyProxyId);
 
-    function forGridRect (x, y, w, h: Integer; cb: GridInternalCB): Boolean;
+    function forGridRect (x, y, w, h: Integer; cb: TGridInternalCB; bodyId: TBodyProxyId): Boolean;
+
+    function inserter (grida: Integer; bodyId: TBodyProxyId): Boolean;
+    function remover (grida: Integer; bodyId: TBodyProxyId): Boolean;
+
+    function getProxyEnabled (pid: TBodyProxyId): Boolean; inline;
+    procedure setProxyEnabled (pid: TBodyProxyId; val: Boolean); inline;
+
+    function getGridWidthPx (): Integer; inline;
+    function getGridHeightPx (): Integer; inline;
 
   public
-    constructor Create (aMinPixX, aMinPixY, aPixWidth, aPixHeight: Integer; aTileSize: Integer=GridDefaultTileSize);
+    constructor Create (aMinPixX, aMinPixY, aPixWidth, aPixHeight: Integer{; aTileSize: Integer=GridDefaultTileSize});
     destructor Destroy (); override;
 
-    function insertBody (aObj: TObject; ax, ay, aWidth, aHeight: Integer; aTag: Integer=0): TBodyProxy;
-    procedure removeBody (aObj: TBodyProxy); // WARNING! this will NOT destroy proxy!
+    function insertBody (aObj: ITP; ax, ay, aWidth, aHeight: Integer; aTag: Integer=-1): TBodyProxyId;
+    procedure removeBody (body: TBodyProxyId); // WARNING! this WILL destroy proxy!
 
-    procedure moveBody (body: TBodyProxy; dx, dy: Integer);
-    procedure resizeBody (body: TBodyProxy; sx, sy: Integer);
-    procedure moveResizeBody (body: TBodyProxy; dx, dy, sx, sy: Integer);
+    procedure moveBody (body: TBodyProxyId; dx, dy: Integer);
+    procedure resizeBody (body: TBodyProxyId; sx, sy: Integer);
+    procedure moveResizeBody (body: TBodyProxyId; dx, dy, sx, sy: Integer);
 
-    function forEachInAABB (x, y, w, h: Integer; cb: GridQueryCB): Boolean;
+    function insideGrid (x, y: Integer): Boolean; inline;
 
-    function getProxyForBody (aObj: TObject; x, y, w, h: Integer): TBodyProxy;
+    // `false` if `body` is surely invalid
+    function getBodyXY (body: TBodyProxyId; out rx, ry: Integer): Boolean; inline;
 
-    procedure dumpStats ();
-  end;
+    //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;
 
+    //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 forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
 
-type
-  TBinaryHeapLessFn = function (a, b: TObject): Boolean;
+    //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)
+    // cb with `(nil)` will be called before processing new tile
+    // no callback: return `true` on the nearest hit
+    function traceRay (x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP; overload;
+    function traceRay (out ex, ey: Integer; ax0, ay0, ax1, ay1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
 
-  TBinaryHeapObj = class(TObject)
-  private
-    elem: array of TObject;
-    elemUsed: Integer;
-    lessfn: TBinaryHeapLessFn;
+    //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)
+    // trace line along the grid, calling `cb` for all objects in passed cells, in no particular order
+    function forEachAlongLine (x0, y0, x1, y1: Integer; cb: TGridAlongQueryCB; tagmask: Integer=-1): ITP;
 
-  private
-    procedure heapify (root: Integer);
+    procedure dumpStats ();
 
-  public
-    constructor Create (alessfn: TBinaryHeapLessFn);
-    destructor Destroy (); override;
+    //WARNING! no sanity checks!
+    property proxyEnabled[pid: TBodyProxyId]: Boolean read getProxyEnabled write setProxyEnabled;
 
-    procedure clear ();
+    property gridX0: Integer read mMinX;
+    property gridY0: Integer read mMinY;
+    property gridWidth: Integer read getGridWidthPx; // in pixels
+    property gridHeight: Integer read getGridHeightPx; // in pixels
+  end;
 
-    procedure insert (val: TObject);
 
-    function front (): TObject;
-    procedure popFront ();
+// 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;
 
-    property count: Integer read elemUsed;
-  end;
+procedure swapInt (var a: Integer; var b: Integer); inline;
+function distanceSq (x0, y0, x1, y1: Integer): Integer; inline;
 
 
 implementation
 
 uses
-  SysUtils;
+  SysUtils, e_log;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-constructor TBodyProxy.Create (aGrid: TBodyGrid; aX, aY, aWidth, aHeight: Integer; aObj: TObject; aTag: Integer);
-begin
-  mGrid := aGrid;
-  setup(aX, aY, aWidth, aHeight, aObj, aTag);
-end;
+procedure swapInt (var a: Integer; var b: Integer); inline; var t: Integer; begin t := a; a := b; b := t; end;
 
+function distanceSq (x0, y0, x1, y1: Integer): Integer; inline; begin result := (x1-x0)*(x1-x0)+(y1-y0)*(y1-y0); end;
 
-destructor TBodyProxy.Destroy ();
+
+// ////////////////////////////////////////////////////////////////////////// //
+// 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
-  inherited;
+  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
+  begin
+    // check this point
+    result := (x0 >= bx) and (y0 >= by) and (x0 < bx+bw) and (y0 < by+bh);
+    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;
+
+  // 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
+    d0 := @yd;
+    d1 := @xd;
+    swapInt(x0, y0);
+    swapInt(x1, y1);
+    swapInt(dsx, dsy);
+    swapInt(wx0, wy0);
+    swapInt(wx1, wy1);
+    swapInt(stx, sty);
+  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;
+      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);
+  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;
 
 
-procedure TBodyProxy.setup (aX, aY, aWidth, aHeight: Integer; aObj: TObject; aTag: Integer);
+// ////////////////////////////////////////////////////////////////////////// //
+procedure TBodyGridBase.TBodyProxyRec.setup (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer);
 begin
   mX := aX;
   mY := aY;
@@ -165,72 +344,63 @@ begin
   mQueryMark := 0;
   mObj := aObj;
   mTag := aTag;
-  prevLink := nil;
-  nextLink := nil;
+  nextLink := -1;
 end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-constructor TBodyGrid.Create (aMinPixX, aMinPixY, aPixWidth, aPixHeight: Integer; aTileSize: Integer=GridDefaultTileSize);
+constructor TBodyGridBase.Create (aMinPixX, aMinPixY, aPixWidth, aPixHeight: Integer{; aTileSize: Integer=GridDefaultTileSize});
 var
   idx: Integer;
 begin
+  dbgShowTraceLog := false;
+  {
   if aTileSize < 1 then aTileSize := 1;
   if aTileSize > 8192 then aTileSize := 8192; // arbitrary limit
-  if aPixWidth < aTileSize then aPixWidth := aTileSize;
-  if aPixHeight < aTileSize then aPixHeight := aTileSize;
   mTileSize := aTileSize;
+  }
+  if (aPixWidth < mTileSize) then aPixWidth := mTileSize;
+  if (aPixHeight < mTileSize) then aPixHeight := mTileSize;
   mMinX := aMinPixX;
   mMinY := aMinPixY;
-  mWidth := (aPixWidth+aTileSize-1) div aTileSize;
-  mHeight := (aPixHeight+aTileSize-1) div aTileSize;
+  mWidth := (aPixWidth+mTileSize-1) div mTileSize;
+  mHeight := (aPixHeight+mTileSize-1) div mTileSize;
   SetLength(mGrid, mWidth*mHeight);
   SetLength(mCells, mWidth*mHeight);
+  SetLength(mProxies, 8192);
   mFreeCell := 0;
   // init free list
   for idx := 0 to High(mCells) do
   begin
-    mCells[idx].body := nil;
+    mCells[idx].bodies[0] := -1;
     mCells[idx].next := idx+1;
   end;
   mCells[High(mCells)].next := -1; // last cell
   // init grid
   for idx := 0 to High(mGrid) do mGrid[idx] := -1;
+  // init proxies
+  for idx := 0 to High(mProxies) do mProxies[idx].nextLink := idx+1;
+  mProxies[High(mProxies)].nextLink := -1;
   mLastQuery := 0;
   mUsedCells := 0;
-  mProxyFree := nil;
-  mProxyList := nil;
+  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);
 end;
 
 
-destructor TBodyGrid.Destroy ();
-var
-  px: TBodyProxy;
+destructor TBodyGridBase.Destroy ();
 begin
-  // free all owned proxies
-  while mProxyFree <> nil do
-  begin
-    px := mProxyFree;
-    mProxyFree := px.nextLink;
-    px.Free();
-  end;
-
-  while mProxyList <> nil do
-  begin
-    px := mProxyList;
-    mProxyList := px.nextLink;
-    px.Free();
-  end;
-
   mCells := nil;
   mGrid := nil;
+  mProxies := nil;
   inherited;
 end;
 
 
-procedure TBodyGrid.dumpStats ();
+// ////////////////////////////////////////////////////////////////////////// //
+procedure TBodyGridBase.dumpStats ();
 var
   idx, mcb, cidx, cnt: Integer;
 begin
@@ -246,11 +416,65 @@ 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; proxies allocated: %d', [mWidth, mHeight, mTileSize, mWidth*mTileSize, mHeight*mTileSize, mUsedCells, mcb, 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]), MSG_NOTIFY);
+end;
+
+
+// ////////////////////////////////////////////////////////////////////////// //
+function TBodyGridBase.getGridWidthPx (): Integer; inline; begin result := mWidth*mTileSize; end;
+function TBodyGridBase.getGridHeightPx (): Integer; inline; begin result := mHeight*mTileSize; end;
+
+
+function TBodyGridBase.insideGrid (x, y: Integer): Boolean; inline;
+begin
+  // fix coords
+  Dec(x, mMinX);
+  Dec(y, mMinY);
+  result := (x >= 0) and (y >= 0) and (x < mWidth*mTileSize) and (y < mHeight*mTileSize);
+end;
+
+
+function TBodyGridBase.getBodyXY (body: TBodyProxyId; out rx, ry: Integer): Boolean; inline;
+begin
+  if (body >= 0) and (body < Length(mProxies)) then
+  begin
+    with mProxies[body] do begin rx := mX; ry := mY; end;
+    result := true;
+  end
+  else
+  begin
+    rx := 0;
+    ry := 0;
+    result := false;
+  end;
+end;
+
+
+// ////////////////////////////////////////////////////////////////////////// //
+function TBodyGridBase.getProxyEnabled (pid: TBodyProxyId): Boolean; inline;
+begin
+  if (pid >= 0) then result := ((mProxies[pid].mTag and TagDisabled) = 0) else result := false;
+end;
+
+
+procedure TBodyGridBase.setProxyEnabled (pid: TBodyProxyId; val: Boolean); inline;
+begin
+  if (pid >= 0) then
+  begin
+    if val then
+    begin
+      mProxies[pid].mTag := mProxies[pid].mTag and not TagDisabled;
+    end
+    else
+    begin
+      mProxies[pid].mTag := mProxies[pid].mTag or TagDisabled;
+    end;
+  end;
 end;
 
 
-function TBodyGrid.allocCell: Integer;
+// ////////////////////////////////////////////////////////////////////////// //
+function TBodyGridBase.allocCell (): Integer;
 var
   idx: Integer;
 begin
@@ -261,7 +485,7 @@ begin
     SetLength(mCells, mFreeCell+32768); // arbitrary number
     for idx := mFreeCell to High(mCells) do
     begin
-      mCells[idx].body := nil;
+      mCells[idx].bodies[0] := -1;
       mCells[idx].next := idx+1;
     end;
     mCells[High(mCells)].next := -1; // last cell
@@ -269,17 +493,18 @@ begin
   result := mFreeCell;
   mFreeCell := mCells[result].next;
   mCells[result].next := -1;
+  mCells[result].bodies[0] := -1;
   Inc(mUsedCells);
   //e_WriteLog(Format('grid: allocated new cell #%d (total: %d)', [result, mUsedCells]), MSG_NOTIFY);
 end;
 
 
-procedure TBodyGrid.freeCell (idx: Integer);
+procedure TBodyGridBase.freeCell (idx: Integer);
 begin
-  if (idx >= 0) and (idx < High(mCells)) then
+  if (idx >= 0) and (idx < Length(mCells)) then
   begin
-    if mCells[idx].body = nil then exit; // the thing that should not be
-    mCells[idx].body := nil;
+    //if mCells[idx].body = -1 then exit; // the thing that should not be
+    mCells[idx].bodies[0] := -1;
     mCells[idx].next := mFreeCell;
     mFreeCell := idx;
     Dec(mUsedCells);
@@ -287,53 +512,52 @@ begin
 end;
 
 
-function TBodyGrid.allocProxy (aX, aY, aWidth, aHeight: Integer; aObj: TObject; aTag: Integer): TBodyProxy;
+// ////////////////////////////////////////////////////////////////////////// //
+function TBodyGridBase.allocProxy (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer): TBodyProxyId;
+var
+  olen, idx: Integer;
+  px: PBodyProxyRec;
 begin
-  if (mProxyFree = nil) then
-  begin
-    // no free proxies, create new
-    result := TBodyProxy.Create(self, aX, aY, aWidth, aHeight, aObj, aTag);
-    Inc(mProxyCount);
-  end
-  else
+  if (mProxyFree = -1) then
   begin
-    // get one from list
-    result := mProxyFree;
-    mProxyFree := result.nextLink;
-    result.setup(aX, aY, aWidth, aHeight, aObj, aTag);
+    // no free proxies, resize list
+    olen := Length(mProxies);
+    SetLength(mProxies, olen+8192); // arbitrary number
+    for idx := olen to High(mProxies) do mProxies[idx].nextLink := idx+1;
+    mProxies[High(mProxies)].nextLink := -1;
+    mProxyFree := olen;
   end;
+  // get one from list
+  result := mProxyFree;
+  px := @mProxies[result];
+  mProxyFree := px.nextLink;
+  px.setup(aX, aY, aWidth, aHeight, aObj, aTag);
   // add to used list
-  result.nextLink := mProxyList;
-  if (mProxyList <> nil) then mProxyList.prevLink := result;
-  mProxyList := result;
+  px.nextLink := -1;
+  // statistics
+  Inc(mProxyCount);
+  if (mProxyMaxCount < mProxyCount) then mProxyMaxCount := mProxyCount;
 end;
 
-procedure TBodyGrid.freeProxy (body: TBodyProxy);
+procedure TBodyGridBase.freeProxy (body: TBodyProxyId);
 begin
-  if body = nil then exit; // just in case
-  // remove from used list
-  if (body.prevLink = nil) then
-  begin
-    // this must be head
-    if (body <> mProxyList) then raise Exception.Create('wutafuuuuu in grid?');
-    mProxyList := body.nextLink;
-  end
-  else
-  begin
-    body.prevLink.nextLink := body.nextLink;
-  end;
-  if (body.nextLink <> nil) then body.nextLink.prevLink := body.prevLink;
+  if (body < 0) or (body > High(mProxies)) then exit; // just in case
+  if (mProxyCount = 0) then raise Exception.Create('wutafuuuuu in grid (no allocated proxies, what i should free now?)');
   // add to free list
-  //body.mObj := nil; //WARNING! DON'T DO THIS! `removeBody()` depends on valid mObj
-  body.prevLink := nil;
-  body.nextLink := mProxyFree;
+  mProxies[body].mObj := nil;
+  mProxies[body].nextLink := mProxyFree;
   mProxyFree := body;
+  Dec(mProxyCount);
 end;
 
 
-function TBodyGrid.forGridRect (x, y, w, h: Integer; cb: GridInternalCB): Boolean;
+// ////////////////////////////////////////////////////////////////////////// //
+function TBodyGridBase.forGridRect (x, y, w, h: Integer; cb: TGridInternalCB; bodyId: TBodyProxyId): Boolean;
+const
+  tsize = mTileSize;
 var
   gx, gy: Integer;
+  gw, gh: Integer;
 begin
   result := false;
   if (w < 1) or (h < 1) or not assigned(cb) then exit;
@@ -342,143 +566,333 @@ begin
   Dec(y, mMinY);
   // go on
   if (x+w <= 0) or (y+h <= 0) then exit;
-  if (x >= mWidth*mTileSize) or (y >= mHeight*mTileSize) then exit;
-  for gy := y div mTileSize to (y+h-1) div mTileSize do
+  gw := mWidth;
+  gh := mHeight;
+  //tsize := mTileSize;
+  if (x >= gw*tsize) or (y >= gh*tsize) then exit;
+  for gy := y div tsize to (y+h-1) div tsize do
   begin
     if (gy < 0) then continue;
-    if (gy >= mHeight) then break;
-    for gx := x div mTileSize to (x+w-1) div mTileSize do
+    if (gy >= gh) then break;
+    for gx := x div tsize to (x+w-1) div tsize do
     begin
       if (gx < 0) then continue;
-      if (gx >= mWidth) then break;
-      if (cb(gy*mWidth+gx)) then begin result := true; exit; end;
+      if (gx >= gw) then break;
+      result := cb(gy*gw+gx, bodyId);
+      if result then exit;
     end;
   end;
 end;
 
 
-procedure TBodyGrid.insert (body: TBodyProxy);
-
-  function inserter (grida: Integer): Boolean;
-  var
-    cidx: Integer;
+// ////////////////////////////////////////////////////////////////////////// //
+function TBodyGridBase.inserter (grida: Integer; bodyId: TBodyProxyId): Boolean;
+var
+  cidx: Integer;
+  pc: Integer;
+  pi: PGridCell;
+  f: Integer;
+begin
+  result := false; // never stop
+  // add body to the given grid cell
+  pc := mGrid[grida];
+  if (pc <> -1) then
   begin
-    result := false; // never stop
-    // add body to the given grid cell
-    cidx := allocCell();
-    //e_WriteLog(Format('  01: allocated cell for grid coords (%d,%d), body coords:(%d,%d): #%d', [gx, gy, dx, dy, cidx]), MSG_NOTIFY);
-    mCells[cidx].body := body;
-    mCells[cidx].next := mGrid[grida];
-    mGrid[grida] := cidx;
+    pi := @mCells[pc];
+    f := 0;
+    for f := 0 to High(TGridCell.bodies) do
+    begin
+      if (pi.bodies[f] = -1) then
+      begin
+        // can add here
+        pi.bodies[f] := bodyId;
+        if (f+1 < Length(TGridCell.bodies)) then pi.bodies[f+1] := -1;
+        exit;
+      end;
+    end;
   end;
+  // either no room, or no cell at all
+  cidx := allocCell();
+  mCells[cidx].bodies[0] := bodyId;
+  mCells[cidx].bodies[1] := -1;
+  mCells[cidx].next := pc;
+  mGrid[grida] := cidx;
+end;
 
+procedure TBodyGridBase.insertInternal (body: TBodyProxyId);
+var
+  px: PBodyProxyRec;
 begin
-  if body = nil then exit;
-  forGridRect(body.mX, body.mY, body.mWidth, body.mHeight, inserter);
+  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;
 
 
 // absolutely not tested
-procedure TBodyGrid.remove (body: TBodyProxy);
-
-  function remover (grida: Integer): Boolean;
-  var
-    pidx, idx, tmp: Integer;
+function TBodyGridBase.remover (grida: Integer; bodyId: TBodyProxyId): Boolean;
+var
+  f: Integer;
+  pidx, idx, tmp: Integer;
+  pc: PGridCell;
+begin
+  result := false; // never stop
+  // find and remove cell
+  pidx := -1;
+  idx := mGrid[grida];
+  while (idx >= 0) do
   begin
-    result := false; // never stop
-    // find and remove cell
-    pidx := -1;
-    idx := mGrid[grida];
-    while idx >= 0 do
+    tmp := mCells[idx].next;
+    pc := @mCells[idx];
+    f := 0;
+    while (f < High(TGridCell.bodies)) do
     begin
-      tmp := mCells[idx].next;
-      if (mCells[idx].body = body) then
+      if (pc.bodies[f] = bodyId) then
       begin
-        if (pidx = -1) then mGrid[grida] := tmp else mCells[pidx].next := tmp;
-        freeCell(idx);
-        break; // assume that we cannot have one object added to bucket twice
-      end
-      else
-      begin
-        pidx := idx;
+        // i found her!
+        if (f = 0) and (pc.bodies[1] = -1) then
+        begin
+          // this cell contains no elements, remove it
+          tmp := mCells[idx].next;
+          if (pidx = -1) then mGrid[grida] := tmp else mCells[pidx].next := tmp;
+          freeCell(idx);
+        end
+        else
+        begin
+          // remove element from bucket
+          Inc(f);
+          while (f < High(TGridCell.bodies)) do
+          begin
+            pc.bodies[f-1] := pc.bodies[f];
+            if (pc.bodies[f] = -1) then break;
+            Inc(f);
+          end;
+          pc.bodies[High(TGridCell.bodies)] := -1; // just in case
+        end;
+        exit; // assume that we cannot have one object added to bucket twice
       end;
-      idx := tmp;
+      Inc(f);
     end;
+    pidx := idx;
+    idx := tmp;
   end;
+end;
 
+// absolutely not tested
+procedure TBodyGridBase.removeInternal (body: TBodyProxyId);
+var
+  px: PBodyProxyRec;
 begin
-  if body = nil then exit;
-  forGridRect(body.mX, body.mY, body.mWidth, body.mHeight, remover);
+  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 TBodyGrid.insertBody (aObj: TObject; aX, aY, aWidth, aHeight: Integer; aTag: Integer=0): TBodyProxy;
+// ////////////////////////////////////////////////////////////////////////// //
+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);
-  insert(result);
+  insertInternal(result);
 end;
 
 
-// WARNING! this will NOT destroy proxy!
-procedure TBodyGrid.removeBody (aObj: TBodyProxy);
+procedure TBodyGridBase.removeBody (body: TBodyProxyId);
 begin
-  if aObj = nil then exit;
-  if (aObj.mGrid <> self) then raise Exception.Create('trying to remove alien proxy from grid');
-  removeBody(aObj);
-  //HACK!
-  freeProxy(aObj);
-  if (mProxyFree <> aObj) then raise Exception.Create('grid deletion invariant fucked');
-  mProxyFree := aObj.nextLink;
-  aObj.nextLink := nil;
+  if (body < 0) or (body > High(mProxies)) then exit; // just in case
+  removeInternal(body);
+  freeProxy(body);
 end;
 
 
-procedure TBodyGrid.moveResizeBody (body: TBodyProxy; dx, dy, sx, sy: Integer);
+// ////////////////////////////////////////////////////////////////////////// //
+procedure TBodyGridBase.moveResizeBody (body: TBodyProxyId; dx, dy, sx, sy: Integer);
+var
+  px: PBodyProxyRec;
+  x0, y0, w, h: Integer;
 begin
-  if (body = nil) or ((dx = 0) and (dy = 0) and (sx = 0) and (sy = 0)) then exit;
-  remove(body);
-  Inc(body.mX, dx);
-  Inc(body.mY, dy);
-  Inc(body.mWidth, sx);
-  Inc(body.mHeight, sy);
-  insert(body);
+  if (body < 0) or (body > High(mProxies)) then exit; // just in case
+  if (dx = 0) and (dy = 0) and (sx = 0) and (sy = 0) then exit;
+  px := @mProxies[body];
+  x0 := px.mX;
+  y0 := px.mY;
+  w := px.mWidth;
+  h := px.mHeight;
+  // did any corner crossed tile boundary?
+  if (x0 div mTileSize <> (x0+dx) div mTileSize) or
+     (y0 div mTileSize <> (y0+dx) div mTileSize) or
+     ((x0+w) div mTileSize <> (x0+w+sx) div mTileSize) or
+     ((y0+h) div mTileSize <> (y0+h+sy) div mTileSize) then
+  begin
+    removeInternal(body);
+    Inc(px.mX, dx);
+    Inc(px.mY, dy);
+    Inc(px.mWidth, sx);
+    Inc(px.mHeight, sy);
+    insertInternal(body);
+  end
+  else
+  begin
+    Inc(px.mX, dx);
+    Inc(px.mY, dy);
+    Inc(px.mWidth, sx);
+    Inc(px.mHeight, sy);
+  end;
 end;
 
-procedure TBodyGrid.moveBody (body: TBodyProxy; dx, dy: Integer);
+procedure TBodyGridBase.moveBody (body: TBodyProxyId; dx, dy: Integer);
+var
+  px: PBodyProxyRec;
+  nx, ny: Integer;
 begin
-  moveResizeBody(body, dx, dy, 0, 0);
+  if (body < 0) or (body > High(mProxies)) then exit; // just in case
+  if (dx = 0) and (dy = 0) then exit;
+  // check if tile coords was changed
+  px := @mProxies[body];
+  nx := px.mX+dx;
+  ny := px.mY+dy;
+  if (nx div mTileSize <> px.mX div mTileSize) or (ny div mTileSize <> px.mY div mTileSize) then
+  begin
+    // crossed tile boundary, do heavy work
+    moveResizeBody(body, dx, dy, 0, 0);
+  end
+  else
+  begin
+    // nothing to do with the grid, just fix coordinates
+    px.mX := nx;
+    px.mY := ny;
+  end;
 end;
 
-procedure TBodyGrid.resizeBody (body: TBodyProxy; sx, sy: Integer);
+procedure TBodyGridBase.resizeBody (body: TBodyProxyId; sx, sy: Integer);
+var
+  px: PBodyProxyRec;
+  x0, y0: Integer;
+  nw, nh: Integer;
 begin
-  moveResizeBody(body, 0, 0, sx, sy);
+  if (body < 0) or (body > High(mProxies)) then exit; // just in case
+  if (sx = 0) and (sy = 0) then exit;
+  // check if tile coords was changed
+  px := @mProxies[body];
+  x0 := px.mX;
+  y0 := px.mY;
+  nw := px.mWidth+sx;
+  nh := px.mHeight+sy;
+  if ((x0+px.mWidth) div mTileSize <> (x0+nw) div mTileSize) or
+     ((y0+px.mHeight) div mTileSize <> (y0+nh) div mTileSize) then
+  begin
+    // crossed tile boundary, do heavy work
+    moveResizeBody(body, 0, 0, sx, sy);
+  end
+  else
+  begin
+    // nothing to do with the grid, just fix size
+    px.mWidth := nw;
+    px.mHeight := nh;
+  end;
 end;
 
 
-function TBodyGrid.forEachInAABB (x, y, w, h: Integer; cb: GridQueryCB): Boolean;
-  function iterator (grida: Integer): Boolean;
-  var
-    idx: Integer;
+// ////////////////////////////////////////////////////////////////////////// //
+// no callback: return `true` on the first hit
+function TBodyGridBase.forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
+var
+  f: Integer;
+  idx, curci: Integer;
+  cc: PGridCell = nil;
+  px: PBodyProxyRec;
+  lq: LongWord;
+  ptag: Integer;
+begin
+  result := Default(ITP);
+  tagmask := tagmask and TagFullMask;
+  if (tagmask = 0) then exit;
+
+  // make coords (0,0)-based
+  Dec(x, mMinX);
+  Dec(y, mMinY);
+  if (x < 0) or (y < 0) or (x >= mWidth*mTileSize) or (y >= mHeight*mTileSize) then exit;
+
+  curci := mGrid[(y div mTileSize)*mWidth+(x div mTileSize)];
+  // restore coords
+  Inc(x, mMinX);
+  Inc(y, mMinY);
+
+  // increase query counter
+  Inc(mLastQuery);
+  if (mLastQuery = 0) then
   begin
-    result := false;
-    idx := mGrid[grida];
-    while idx >= 0 do
+    // just in case of overflow
+    mLastQuery := 1;
+    for idx := 0 to High(mProxies) do mProxies[idx].mQueryMark := 0;
+  end;
+  lq := mLastQuery;
+
+  while (curci <> -1) do
+  begin
+    cc := @mCells[curci];
+    for f := 0 to High(TGridCell.bodies) do
     begin
-      if (mCells[idx].body <> nil) and (mCells[idx].body.mQueryMark <> mLastQuery) then
+      if (cc.bodies[f] = -1) then break;
+      px := @mProxies[cc.bodies[f]];
+      ptag := px.mTag;
+      if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
       begin
-        //e_WriteLog(Format('  query #%d body hit: (%d,%d)-(%dx%d) tag:%d', [mLastQuery, mCells[idx].body.mX, mCells[idx].body.mY, mCells[idx].body.mWidth, mCells[idx].body.mHeight, mCells[idx].body.mTag]), MSG_NOTIFY);
-        mCells[idx].body.mQueryMark := mLastQuery;
-        if (cb(mCells[idx].body.mObj, mCells[idx].body.mTag)) then begin result := true; exit; end;
+        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;
+          if assigned(cb) then
+          begin
+            if cb(px.mObj, ptag) then begin result := px.mObj; exit; end;
+          end
+          else
+          begin
+            result := px.mObj;
+            exit;
+          end;
+        end;
       end;
-      idx := mCells[idx].next;
     end;
+    curci := cc.next;
   end;
+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;
+const
+  tsize = mTileSize;
 var
   idx: Integer;
+  gx, gy: Integer;
+  curci: Integer;
+  f: Integer;
+  cc: PGridCell = nil;
+  px: PBodyProxyRec;
+  lq: LongWord;
+  gw: Integer;
+  x0, y0: Integer;
+  ptag: Integer;
 begin
-  result := false;
-  if not assigned(cb) then exit;
+  result := Default(ITP);
+  if (w < 1) or (h < 1) then exit;
+  tagmask := tagmask and TagFullMask;
+  if (tagmask = 0) then exit;
+
+  x0 := x;
+  y0 := y;
+
+  // fix coords
+  Dec(x, mMinX);
+  Dec(y, mMinY);
+
+  gw := mWidth;
+  //tsize := mTileSize;
+
+  if (x+w <= 0) or (y+h <= 0) then exit;
+  if (x >= gw*tsize) or (y >= mHeight*tsize) then exit;
 
   // increase query counter
   Inc(mLastQuery);
@@ -486,119 +900,537 @@ begin
   begin
     // just in case of overflow
     mLastQuery := 1;
-    for idx := 0 to High(mCells) do if (mCells[idx].body <> nil) then mCells[idx].body.mQueryMark := 0;
+    for idx := 0 to High(mProxies) do mProxies[idx].mQueryMark := 0;
   end;
   //e_WriteLog(Format('grid: query #%d: (%d,%d)-(%dx%d)', [mLastQuery, minx, miny, maxx, maxy]), MSG_NOTIFY);
+  lq := mLastQuery;
 
-  result := forGridRect(x, y, w, h, iterator);
-end;
-
-
-function TBodyGrid.getProxyForBody (aObj: TObject; x, y, w, h: Integer): TBodyProxy;
-var
-  res: TBodyProxy = nil;
-
-  function iterator (grida: Integer): Boolean;
-  var
-    idx: Integer;
+  // go on
+  for gy := y div tsize to (y+h-1) div tsize do
   begin
-    result := false;
-    idx := mGrid[grida];
-    while idx >= 0 do
+    if (gy < 0) then continue;
+    if (gy >= mHeight) then break;
+    for gx := x div tsize to (x+w-1) div tsize do
     begin
-      if (mCells[idx].body <> nil) and (mCells[idx].body = aObj) then
+      if (gx < 0) then continue;
+      if (gx >= gw) then break;
+      // process cells
+      curci := mGrid[gy*gw+gx];
+      while (curci <> -1) do
       begin
-        result := true;
-        res := mCells[idx].body;
-        exit;
+        cc := @mCells[curci];
+        for f := 0 to High(TGridCell.bodies) do
+        begin
+          if (cc.bodies[f] = -1) then break;
+          px := @mProxies[cc.bodies[f]];
+          ptag := px.mTag;
+          if (not allowDisabled) and ((ptag and TagDisabled) <> 0) then continue;
+          if ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          //if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          //if ( ((ptag and TagDisabled) = 0) = ignoreDisabled) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          begin
+            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;
+            px.mQueryMark := lq;
+            if assigned(cb) then
+            begin
+              if cb(px.mObj, ptag) then begin result := px.mObj; exit; end;
+            end
+            else
+            begin
+              result := px.mObj;
+              exit;
+            end;
+          end;
+        end;
+        curci := cc.next;
       end;
-      idx := mCells[idx].next;
     end;
   end;
-
-begin
-  result := nil;
-  if (aObj = nil) then exit;
-  forGridRect(x, y, w, h, iterator);
-  result := res;
 end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-constructor TBinaryHeapObj.Create (alessfn: TBinaryHeapLessFn);
+// no callback: return `true` on the nearest hit
+function TBodyGridBase.traceRay (x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
+var
+  ex, ey: Integer;
 begin
-  if not assigned(alessfn) then raise Exception.Create('wutafuck?!');
-  lessfn := alessfn;
-  SetLength(elem, 8192); // 'cause why not?
-  elemUsed := 0;
+  result := traceRay(ex, ey, x0, y0, x1, y1, cb, tagmask);
 end;
 
 
-destructor TBinaryHeapObj.Destroy ();
+// no callback: return `true` on the nearest hit
+// you are not supposed to understand this
+function TBodyGridBase.traceRay (out ex, ey: Integer; ax0, ay0, ax1, ay1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
+const
+  tsize = mTileSize;
+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;
+  xptr, yptr: PInteger;
+  xfixed: Boolean;
+  temp: Integer;
+  prevx, prevy: Integer;
+  lastDistSq: Integer;
+  ccidx, curci: Integer;
+  hasUntried: Boolean;
+  lastGA: Integer = -1;
+  ga, x, y: Integer;
+  lastObj: ITP;
+  wasHit: Boolean = false;
+  gw, gh, minx, miny, maxx, maxy: Integer;
+  cc: PGridCell;
+  px: PBodyProxyRec;
+  lq: LongWord;
+  f, ptag, distSq: Integer;
+  x0, y0, x1, y1: Integer;
 begin
-  inherited;
-end;
+  result := Default(ITP);
+  lastObj := Default(ITP);
+  tagmask := tagmask and TagFullMask;
+  ex := ax1; // why not?
+  ey := ay1; // why not?
+  if (tagmask = 0) then exit;
+
+  if (ax0 = ax1) and (ay0 = ay1) then exit; // as the first point is ignored, just get outta here
+
+  lastDistSq := distanceSq(ax0, ay0, ax1, ay1)+1;
+
+  gw := mWidth;
+  gh := mHeight;
+  minx := mMinX;
+  miny := mMinY;
+  maxx := gw*tsize-1;
+  maxy := gh*tsize-1;
+
+  x0 := ax0;
+  y0 := ay0;
+  x1 := ax1;
+  y1 := ay1;
+
+  // offset query coords to (0,0)-based
+  Dec(x0, minx);
+  Dec(y0, miny);
+  Dec(x1, minx);
+  Dec(y1, miny);
+
+  // clip rectange
+  wx0 := 0;
+  wy0 := 0;
+  wx1 := maxx;
+  wy1 := maxy;
+
+  // 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;
 
-procedure TBinaryHeapObj.clear ();
-begin
-  elemUsed := 0;
-end;
+  dsx := x1-x0;
+  dsy := y1-y0;
+
+  if (dsx < dsy) then
+  begin
+    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;
 
-procedure TBinaryHeapObj.heapify (root: Integer);
-var
-  smallest, right: Integer;
-  tmp: TObject;
-begin
-  while true do
-  begin
-    smallest := 2*root+1; // left child
-    if (smallest >= elemUsed) then break; // anyway
-    right := smallest+1; // right child
-    if not lessfn(elem[smallest], elem[root]) then smallest := root;
-    if (right < elemUsed) and (lessfn(elem[right], elem[smallest])) then smallest := right;
-    if (smallest = root) then break;
-    // swap
-    tmp := elem[root];
-    elem[root] := elem[smallest];
-    elem[smallest] := tmp;
-    root := smallest;
+  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;
+      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);
+  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;
+
+  // first move, to skip starting point
+  if (xd = term) then exit;
+  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;
+
+  {$IF DEFINED(D2F_DEBUG)}
+  if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ > mHeight*tsize) then raise Exception.Create('raycaster internal error (0)');
+  {$ENDIF}
+
+  //if (dbgShowTraceLog) then e_WriteLog(Format('raycast start: (%d,%d)-(%d,%d); xptr^=%d; yptr^=%d', [ax0, ay0, ax1, ay1, xptr^, yptr^]), MSG_NOTIFY);
+
+  // restore query coords
+  Inc(ax0, minx);
+  Inc(ay0, miny);
+  //Inc(ax1, minx);
+  //Inc(ay1, miny);
+
+  // increase query counter
+  Inc(mLastQuery);
+  if (mLastQuery = 0) then
+  begin
+    // just in case of overflow
+    mLastQuery := 1;
+    for f := 0 to High(mProxies) do mProxies[f].mQueryMark := 0;
+  end;
+  lq := mLastQuery;
+
+  ccidx := -1;
+  // draw it; can omit checks
+  while (xd <> term) do
+  begin
+    // check cell(s)
+    {$IF DEFINED(D2F_DEBUG)}
+    if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ > mHeight*tsize) then raise Exception.Create('raycaster internal error (0)');
+    {$ENDIF}
+    // new tile?
+    ga := (yptr^ div tsize)*gw+(xptr^ div tsize);
+    if (ga <> lastGA) then
+    begin
+      // yes
+      if (ccidx <> -1) then
+      begin
+        // signal cell completion
+        if assigned(cb) then
+        begin
+          if cb(nil, 0, xptr^+minx, yptr^+miny, prevx, prevy) then begin result := lastObj; exit; end;
+        end
+        else if wasHit then
+        begin
+          result := lastObj;
+          exit;
+        end;
+      end;
+      lastGA := ga;
+      ccidx := mGrid[lastGA];
+    end;
+    // has something to process in this tile?
+    if (ccidx <> -1) then
+    begin
+      // process cell
+      curci := ccidx;
+      hasUntried := false; // this will be set to `true` if we have some proxies we still want to process at the next step
+      // convert coords to map (to avoid ajdusting coords inside the loop)
+      x := xptr^+minx;
+      y := yptr^+miny;
+      // process cell list
+      while (curci <> -1) do
+      begin
+        cc := @mCells[curci];
+        for f := 0 to High(TGridCell.bodies) do
+        begin
+          if (cc.bodies[f] = -1) then break;
+          px := @mProxies[cc.bodies[f]];
+          ptag := px.mTag;
+          if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          begin
+            // can we process this proxy?
+            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; // mark as processed
+              if assigned(cb) then
+              begin
+                if cb(px.mObj, ptag, x, y, prevx, prevy) then
+                begin
+                  result := lastObj;
+                  ex := prevx;
+                  ey := prevy;
+                  exit;
+                end;
+              end
+              else
+              begin
+                // remember this hitpoint if it is nearer than an old one
+                distSq := distanceSq(ax0, ay0, prevx, prevy);
+                if (distSq < lastDistSq) then
+                begin
+                  wasHit := true;
+                  lastDistSq := distSq;
+                  ex := prevx;
+                  ey := prevy;
+                  lastObj := px.mObj;
+                end;
+              end;
+            end
+            else
+            begin
+              // this is possibly interesting proxy, set "has more to check" flag
+              hasUntried := true;
+            end;
+          end;
+        end;
+        // next cell
+        curci := cc.next;
+      end;
+      // still has something interesting in this cell?
+      if not hasUntried then
+      begin
+        // nope, don't process this cell anymore; signal cell completion
+        ccidx := -1;
+        if assigned(cb) then
+        begin
+          if cb(nil, 0, x, y, prevx, prevy) then begin result := lastObj; exit; end;
+        end
+        else if wasHit then
+        begin
+          result := lastObj;
+          exit;
+        end;
+      end;
+    end;
+    //putPixel(xptr^, yptr^);
+    // move coords
+    prevx := xptr^+minx;
+    prevy := yptr^+miny;
+    if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
+    xd += stx;
   end;
 end;
 
 
-procedure TBinaryHeapObj.insert (val: TObject);
+// ////////////////////////////////////////////////////////////////////////// //
+//FIXME! optimize this with real tile walking
+function TBodyGridBase.forEachAlongLine (x0, y0, x1, y1: Integer; cb: TGridAlongQueryCB; tagmask: Integer=-1): ITP;
+const
+  tsize = mTileSize;
 var
-  i, par: Integer;
+  i: Integer;
+  dx, dy, d: Integer;
+  xerr, yerr: Integer;
+  incx, incy: Integer;
+  stepx, stepy: Integer;
+  x, y: Integer;
+  maxx, maxy: Integer;
+  gw, gh: Integer;
+  ccidx: Integer;
+  curci: Integer;
+  cc: PGridCell;
+  px: PBodyProxyRec;
+  lq: LongWord;
+  minx, miny: Integer;
+  ptag: Integer;
+  lastWasInGrid: Boolean;
+  tbcross: Boolean;
+  f: Integer;
 begin
-  if (val = nil) then exit;
-  i := elemUsed;
-  if (i = Length(elem)) then SetLength(elem, Length(elem)+16384); // arbitrary number
-  Inc(elemUsed);
-  while (i <> 0) do
-  begin
-    par := (i-1) div 2; // parent
-    if not lessfn(val, elem[par]) then break;
-    elem[i] := elem[par];
-    i := par;
-  end;
-  elem[i] := val;
-end;
+  result := Default(ITP);
+  tagmask := tagmask and TagFullMask;
+  if (tagmask = 0) then exit;
 
-function TBinaryHeapObj.front (): TObject;
-begin
-  if elemUsed > 0 then result := elem[0] else result := nil;
-end;
+  minx := mMinX;
+  miny := mMinY;
 
+  dx := x1-x0;
+  dy := y1-y0;
 
-procedure TBinaryHeapObj.popFront ();
-begin
-  if (elemUsed > 0) then
+  if (dx > 0) then incx := 1 else if (dx < 0) then incx := -1 else incx := 0;
+  if (dy > 0) then incy := 1 else if (dy < 0) then incy := -1 else incy := 0;
+
+  dx := abs(dx);
+  dy := abs(dy);
+
+  if (dx > dy) then d := dx else d := dy;
+
+  // `x` and `y` will be in grid coords
+  x := x0-minx;
+  y := y0-miny;
+
+  // increase query counter
+  Inc(mLastQuery);
+  if (mLastQuery = 0) then
   begin
-    Dec(elemUsed);
-    elem[0] := elem[elemUsed];
-    heapify(0);
+    // just in case of overflow
+    mLastQuery := 1;
+    for i := 0 to High(mProxies) do mProxies[i].mQueryMark := 0;
+  end;
+  lq := mLastQuery;
+
+  // cache various things
+  //tsize := mTileSize;
+  gw := mWidth;
+  gh := mHeight;
+  maxx := gw*tsize-1;
+  maxy := gh*tsize-1;
+
+  // setup distance and flags
+  lastWasInGrid := (x >= 0) and (y >= 0) and (x <= maxx) and (y <= maxy);
+
+  // setup starting tile ('cause we'll adjust tile vars only on tile edge crossing)
+  if lastWasInGrid then ccidx := mGrid[(y div tsize)*gw+(x div tsize)] else ccidx := -1;
+
+  // it is slightly faster this way
+  xerr := -d;
+  yerr := -d;
+
+  // now trace
+  for i := 1 to d do
+  begin
+    // do one step
+    xerr += dx;
+    yerr += dy;
+    // invariant: one of those always changed
+    {$IF DEFINED(D2F_DEBUG)}
+    if (xerr < 0) and (yerr < 0) then raise Exception.Create('internal bug in grid raycaster (0)');
+    {$ENDIF}
+    if (xerr >= 0) then begin xerr -= d; x += incx; stepx := incx; end else stepx := 0;
+    if (yerr >= 0) then begin yerr -= d; y += incy; stepy := incy; end else stepy := 0;
+    // invariant: we always doing a step
+    {$IF DEFINED(D2F_DEBUG)}
+    if ((stepx or stepy) = 0) then raise Exception.Create('internal bug in grid raycaster (1)');
+    {$ENDIF}
+    begin
+      // check for crossing tile/grid boundary
+      if (x >= 0) and (y >= 0) and (x <= maxx) and (y <= maxy) then
+      begin
+        // we're still in grid
+        lastWasInGrid := true;
+        // check for tile edge crossing
+             if (stepx < 0) and ((x mod tsize) = tsize-1) then tbcross := true
+        else if (stepx > 0) and ((x mod tsize) = 0) then tbcross := true
+        else if (stepy < 0) and ((y mod tsize) = tsize-1) then tbcross := true
+        else if (stepy > 0) and ((y mod tsize) = 0) then tbcross := true
+        else tbcross := false;
+        // crossed tile edge?
+        if tbcross then
+        begin
+          // setup new cell index
+          ccidx := mGrid[(y div tsize)*gw+(x div tsize)];
+        end;
+      end
+      else
+      begin
+        // out of grid
+        if lastWasInGrid then exit; // oops, stepped out of the grid -- there is no way to return
+      end;
+    end;
+
+    // has something to process in the current cell?
+    if (ccidx <> -1) then
+    begin
+      // process cell
+      curci := ccidx;
+      // convert coords to map (to avoid ajdusting coords inside the loop)
+      Inc(x, minx);
+      Inc(y, miny);
+      // process cell list
+      while (curci <> -1) do
+      begin
+        cc := @mCells[curci];
+        for f := 0 to High(TGridCell.bodies) do
+        begin
+          if (cc.bodies[f] = -1) then break;
+          px := @mProxies[cc.bodies[f]];
+          ptag := px.mTag;
+          if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          begin
+            px.mQueryMark := lq; // mark as processed
+            if cb(px.mObj, ptag) then begin result := px.mObj; exit; end;
+          end;
+        end;
+        // next cell
+        curci := cc.next;
+      end;
+      ccidx := -1; // don't process this anymore
+      // convert coords to grid
+      Dec(x, minx);
+      Dec(y, miny);
+    end;
   end;
 end;