X-Git-Url: https://deadsoftware.ru/gitweb?a=blobdiff_plain;f=src%2Fgame%2Fg_grid.pas;h=6017ad4b492dfbc436da477ccd41a685a3bca7b1;hb=295fc5575016aa0e98b95cca98618a80c6bff261;hp=579e5f8dbe90e0b2ba781707e90a54727c58555c;hpb=00d3260470d072699ceb1fe9bf655cbb4880160f;p=d2df-sdl.git

diff --git a/src/game/g_grid.pas b/src/game/g_grid.pas
index 579e5f8..6017ad4 100644
--- a/src/game/g_grid.pas
+++ b/src/game/g_grid.pas
@@ -15,6 +15,12 @@
  *)
 // universal spatial grid
 {$INCLUDE ../shared/a_modes.inc}
+{$IF DEFINED(D2F_DEBUG)}
+  {.$DEFINE D2F_DEBUG_RAYTRACE}
+  {.$DEFINE D2F_DEBUG_XXQ}
+  {.$DEFINE D2F_DEBUG_MOVER}
+{$ENDIF}
+{.$DEFINE GRID_USE_ORTHO_ACCEL}
 unit g_grid;
 
 interface
@@ -29,12 +35,14 @@ type
     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
 
+    type TCellQueryCB = procedure (x, y: Integer) is nested; // top-left cell corner coords
+
     const TagDisabled = $40000000;
     const TagFullMask = $3fffffff;
 
   private
     const
-      GridDefaultTileSize = 32;
+      GridDefaultTileSize = 32; // must be power of two!
       GridCellBucketSize = 8; // WARNING! can't be less than 2!
 
   private
@@ -64,6 +72,9 @@ type
     //mTileSize: Integer;
     const mTileSize = GridDefaultTileSize;
 
+  public
+    const tileSize = mTileSize;
+
   private
     mMinX, mMinY: Integer; // so grids can start at any origin
     mWidth, mHeight: Integer; // in tiles
@@ -79,6 +90,9 @@ type
 
   public
     dbgShowTraceLog: Boolean;
+    {$IF DEFINED(D2F_DEBUG)}
+    dbgRayTraceTileHitCB: TCellQueryCB;
+    {$ENDIF}
 
   private
     function allocCell (): Integer;
@@ -108,14 +122,16 @@ type
     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: TBodyProxyId; dx, dy: Integer);
-    procedure resizeBody (body: TBodyProxyId; sx, sy: Integer);
-    procedure moveResizeBody (body: TBodyProxyId; dx, dy, sx, sy: Integer);
+    procedure moveBody (body: TBodyProxyId; nx, ny: Integer);
+    procedure resizeBody (body: TBodyProxyId; nw, nh: Integer);
+    procedure moveResizeBody (body: TBodyProxyId; nx, ny, nw, nh: Integer);
 
     function insideGrid (x, y: Integer): Boolean; inline;
 
     // `false` if `body` is surely invalid
     function getBodyXY (body: TBodyProxyId; out rx, ry: Integer): Boolean; inline;
+    function getBodyWH (body: TBodyProxyId; out rw, rh: Integer): Boolean; inline;
+    function getBodyDims (body: TBodyProxyId; out rx, ry, rw, rh: Integer): Boolean; inline;
 
     //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)
@@ -124,21 +140,30 @@ 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 forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
+    // no callback: return object on the first hit or nil
+    function forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1; exittag: PInteger=nil): 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)
     // 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;
+    // 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 traceRay (const x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP; overload;
+    function traceRay (out ex, ey: Integer; const ax0, ay0, ax1, ay1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
+
+    //function traceOrthoRayWhileIn (const x0, y0, x1, y1: Integer; tagmask: Integer=-1): ITP; overload;
+    //function traceOrthoRayWhileIn (out ex, ey: Integer; const ax0, ay0, ax1, ay1: Integer; 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)
     // 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;
+    //WARNING: don't change tags in callbacks here!
+    function forEachAlongLine (const x0, y0, x1, y1: Integer; cb: TGridAlongQueryCB; tagmask: Integer=-1; log: Boolean=false): ITP;
 
+    // debug
+    procedure forEachBodyCell (body: TBodyProxyId; cb: TCellQueryCB);
+    function forEachInCell (x, y: Integer; cb: TGridQueryCB): ITP;
     procedure dumpStats ();
 
     //WARNING! no sanity checks!
@@ -157,9 +182,12 @@ type
 // 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;
 
-procedure swapInt (var a: Integer; var b: Integer); inline;
 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;
+
 
 implementation
 
@@ -169,6 +197,8 @@ uses
 
 // ////////////////////////////////////////////////////////////////////////// //
 procedure swapInt (var a: Integer; var b: Integer); inline; var t: Integer; begin t := a; a := b; b := t; 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;
 
@@ -187,7 +217,7 @@ var
   xd, yd: Integer; // current coord
   e: Integer; // "error" (as in bresenham algo)
   rem: Integer;
-  term: Integer;
+  //!term: Integer;
   d0, d1: PInteger;
   xfixed: Boolean;
   temp: Integer;
@@ -277,7 +307,7 @@ begin
   xd := x0;
   yd := y0;
   e := 2*dsy-dsx;
-  term := x1;
+  //!term := x1;
 
   xfixed := false;
   if (y0 < wy0) then
@@ -308,6 +338,7 @@ begin
     if (rem >= dsx) then begin Inc(yd); e -= dx2; end;
   end;
 
+  (*
   if (y1 > wy1) then
   begin
     // clip at bottom
@@ -321,10 +352,11 @@ begin
 
   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;
+  if (stx = -1) then begin xd := -xd; {!term := -term;} end;
+  //!dx2 -= dy2;
 
   inx := d0^;
   iny := d1^;
@@ -352,6 +384,9 @@ var
   idx: Integer;
 begin
   dbgShowTraceLog := false;
+  {$IF DEFINED(D2F_DEBUG)}
+  dbgRayTraceTileHitCB := nil;
+  {$ENDIF}
   {
   if aTileSize < 1 then aTileSize := 1;
   if aTileSize > 8192 then aTileSize := 8192; // arbitrary limit
@@ -371,6 +406,7 @@ begin
   for idx := 0 to High(mCells) do
   begin
     mCells[idx].bodies[0] := -1;
+    mCells[idx].bodies[GridCellBucketSize-1] := -1; // "has free room" flag
     mCells[idx].next := idx+1;
   end;
   mCells[High(mCells)].next := -1; // last cell
@@ -418,6 +454,55 @@ begin
 end;
 
 
+procedure TBodyGridBase.forEachBodyCell (body: TBodyProxyId; cb: TCellQueryCB);
+var
+  g, f, cidx: Integer;
+  cc: PGridCell;
+begin
+  if (body < 0) or (body > High(mProxies)) or not assigned(cb) then exit;
+  for g := 0 to High(mGrid) do
+  begin
+    cidx := mGrid[g];
+    while (cidx <> -1) do
+    begin
+      cc := @mCells[cidx];
+      for f := 0 to GridCellBucketSize-1 do
+      begin
+        if (cc.bodies[f] = -1) then break;
+        if (cc.bodies[f] = body) then cb((g mod mWidth)*mTileSize+mMinX, (g div mWidth)*mTileSize+mMinY);
+      end;
+      // next cell
+      cidx := cc.next;
+    end;
+  end;
+end;
+
+
+function TBodyGridBase.forEachInCell (x, y: Integer; cb: TGridQueryCB): ITP;
+var
+  f, cidx: Integer;
+  cc: PGridCell;
+begin
+  result := Default(ITP);
+  if not assigned(cb) then exit;
+  Dec(x, mMinX);
+  Dec(y, mMinY);
+  if (x < 0) or (y < 0) or (x >= mWidth*mTileSize) or (y > mHeight*mTileSize) then exit;
+  cidx := mGrid[(y div mTileSize)*mWidth+(x div mTileSize)];
+  while (cidx <> -1) do
+  begin
+    cc := @mCells[cidx];
+    for f := 0 to GridCellBucketSize-1 do
+    begin
+      if (cc.bodies[f] = -1) then break;
+      if cb(mProxies[cc.bodies[f]].mObj, mProxies[cc.bodies[f]].mTag) then begin result := mProxies[cc.bodies[f]].mObj; exit; end;
+    end;
+    // next cell
+    cidx := cc.next;
+  end;
+end;
+
+
 // ////////////////////////////////////////////////////////////////////////// //
 function TBodyGridBase.getGridWidthPx (): Integer; inline; begin result := mWidth*mTileSize; end;
 function TBodyGridBase.getGridHeightPx (): Integer; inline; begin result := mHeight*mTileSize; end;
@@ -448,6 +533,41 @@ begin
 end;
 
 
+function TBodyGridBase.getBodyWH (body: TBodyProxyId; out rw, rh: Integer): Boolean; inline;
+begin
+  if (body >= 0) and (body < Length(mProxies)) then
+  begin
+    with mProxies[body] do begin rw := mWidth; rh := mHeight; end;
+    result := true;
+  end
+  else
+  begin
+    rw := 0;
+    rh := 0;
+    result := false;
+  end;
+end;
+
+
+function TBodyGridBase.getBodyDims (body: TBodyProxyId; out rx, ry, rw, rh: Integer): Boolean; inline;
+begin
+  if (body >= 0) and (body < Length(mProxies)) then
+  begin
+    with mProxies[body] do begin rx := mX; ry := mY; rw := mWidth; rh := mHeight; end;
+    result := true;
+  end
+  else
+  begin
+    rx := 0;
+    ry := 0;
+    rw := 0;
+    rh := 0;
+    result := false;
+  end;
+end;
+
+
+
 // ////////////////////////////////////////////////////////////////////////// //
 function TBodyGridBase.getProxyEnabled (pid: TBodyProxyId): Boolean; inline;
 begin
@@ -475,6 +595,7 @@ end;
 function TBodyGridBase.allocCell (): Integer;
 var
   idx: Integer;
+  pc: PGridCell;
 begin
   if (mFreeCell < 0) then
   begin
@@ -484,14 +605,15 @@ begin
     for idx := mFreeCell to High(mCells) do
     begin
       mCells[idx].bodies[0] := -1;
+      mCells[idx].bodies[GridCellBucketSize-1] := -1; // 'has free room' flag
       mCells[idx].next := idx+1;
     end;
     mCells[High(mCells)].next := -1; // last cell
   end;
   result := mFreeCell;
-  mFreeCell := mCells[result].next;
-  mCells[result].next := -1;
-  mCells[result].bodies[0] := -1;
+  pc := @mCells[result];
+  mFreeCell := pc.next;
+  pc.next := -1;
   Inc(mUsedCells);
   //e_WriteLog(Format('grid: allocated new cell #%d (total: %d)', [result, mUsedCells]), MSG_NOTIFY);
 end;
@@ -501,9 +623,12 @@ procedure TBodyGridBase.freeCell (idx: Integer);
 begin
   if (idx >= 0) and (idx < Length(mCells)) then
   begin
-    //if mCells[idx].body = -1 then exit; // the thing that should not be
-    mCells[idx].bodies[0] := -1;
-    mCells[idx].next := mFreeCell;
+    with mCells[idx] do
+    begin
+      bodies[0] := -1;
+      bodies[GridCellBucketSize-1] := -1; // 'has free room' flag
+      next := mFreeCell;
+    end;
     mFreeCell := idx;
     Dec(mUsedCells);
   end;
@@ -596,24 +721,49 @@ begin
   pc := mGrid[grida];
   if (pc <> -1) then
   begin
-    pi := @mCells[pc];
-    f := 0;
-    for f := 0 to High(TGridCell.bodies) do
+    {$IF DEFINED(D2F_DEBUG)}
+    cidx := pc;
+    while (cidx <> -1) do
     begin
-      if (pi.bodies[f] = -1) then
+      pi := @mCells[cidx];
+      for f := 0 to GridCellBucketSize-1 do
+      begin
+        if (pi.bodies[f] = -1) then break;
+        if (pi.bodies[f] = bodyId) then raise Exception.Create('trying to insert already inserted proxy');
+      end;
+      cidx := pi.next;
+    end;
+    {$ENDIF}
+    cidx := pc;
+    while (cidx <> -1) do
+    begin
+      pi := @mCells[cidx];
+      // check "has room" flag
+      if (pi.bodies[GridCellBucketSize-1] = -1) then
       begin
         // can add here
-        pi.bodies[f] := bodyId;
-        if (f+1 < Length(TGridCell.bodies)) then pi.bodies[f+1] := -1;
-        exit;
+        for f := 0 to GridCellBucketSize-1 do
+        begin
+          if (pi.bodies[f] = -1) then
+          begin
+            pi.bodies[f] := bodyId;
+            if (f+1 < GridCellBucketSize) then pi.bodies[f+1] := -1;
+            exit;
+          end;
+        end;
+        raise Exception.Create('internal error in grid inserter');
       end;
+      // no room, go to next cell in list (if there is any)
+      cidx := pi.next;
     end;
+    // no room in cells, add new cell to list
   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;
+  pi := @mCells[cidx];
+  pi.bodies[0] := bodyId;
+  pi.bodies[1] := -1;
+  pi.next := pc;
   mGrid[grida] := cidx;
 end;
 
@@ -627,23 +777,21 @@ begin
 end;
 
 
-// absolutely not tested
+// assume that we cannot have one object added to bucket twice
 function TBodyGridBase.remover (grida: Integer; bodyId: TBodyProxyId): Boolean;
 var
-  f: Integer;
-  pidx, idx, tmp: Integer;
+  f, c: Integer;
+  pidx, cidx: Integer;
   pc: PGridCell;
 begin
   result := false; // never stop
   // find and remove cell
-  pidx := -1;
-  idx := mGrid[grida];
-  while (idx >= 0) do
+  pidx := -1; // previous cell index
+  cidx := mGrid[grida]; // current cell index
+  while (cidx <> -1) do
   begin
-    tmp := mCells[idx].next;
-    pc := @mCells[idx];
-    f := 0;
-    while (f < High(TGridCell.bodies)) do
+    pc := @mCells[cidx];
+    for f := 0 to GridCellBucketSize-1 do
     begin
       if (pc.bodies[f] = bodyId) then
       begin
@@ -651,32 +799,25 @@ begin
         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
+          if (pidx = -1) then mGrid[grida] := pc.next else mCells[pidx].next := pc.next;
+          freeCell(cidx);
+          exit;
+        end;
+        // remove element from bucket
+        for c := f to GridCellBucketSize-2 do
         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
+          pc.bodies[c] := pc.bodies[c+1];
+          if (pc.bodies[c] = -1) then break;
         end;
-        exit; // assume that we cannot have one object added to bucket twice
+        pc.bodies[GridCellBucketSize-1] := -1; // "has free room" flag
+        exit;
       end;
-      Inc(f);
     end;
-    pidx := idx;
-    idx := tmp;
+    pidx := cidx;
+    cidx := pc.next;
   end;
 end;
 
-// absolutely not tested
 procedure TBodyGridBase.removeInternal (body: TBodyProxyId);
 var
   px: PBodyProxyRec;
@@ -705,83 +846,210 @@ end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-procedure TBodyGridBase.moveResizeBody (body: TBodyProxyId; dx, dy, sx, sy: Integer);
+procedure TBodyGridBase.moveResizeBody (body: TBodyProxyId; nx, ny, nw, nh: Integer);
 var
   px: PBodyProxyRec;
   x0, y0, w, h: Integer;
 begin
   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;
+  {$IF DEFINED(D2F_DEBUG_MOVER)}
+  e_WriteLog(Format('proxy #%d: MOVERESIZE: xg=%d;yg=%d;w=%d;h=%d;nx=%d;ny=%d;nw=%d;nh=%d', [body, x0-mMinX, y0-mMinY, w, h, nx-mMinX, ny-mMinY, nw, nh]), MSG_NOTIFY);
+  {$ENDIF}
+  if (nx = x0) and (ny = y0) and (nw = w) and (nh = h) then exit;
+  // map -> grid
+  Dec(x0, mMinX);
+  Dec(y0, mMinY);
+  Dec(nx, mMinX);
+  Dec(ny, mMinY);
   // 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
+  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
   begin
     removeInternal(body);
-    Inc(px.mX, dx);
-    Inc(px.mY, dy);
-    Inc(px.mWidth, sx);
-    Inc(px.mHeight, sy);
+    px.mX := nx+mMinX;
+    px.mY := ny+mMinY;
+    px.mWidth := nw;
+    px.mHeight := nh;
     insertInternal(body);
   end
   else
   begin
-    Inc(px.mX, dx);
-    Inc(px.mY, dy);
-    Inc(px.mWidth, sx);
-    Inc(px.mHeight, sy);
+    px.mX := nx+mMinX;
+    px.mY := ny+mMinY;
+    px.mWidth := nw;
+    px.mHeight := nh;
   end;
 end;
 
-procedure TBodyGridBase.moveBody (body: TBodyProxyId; dx, dy: Integer);
+//TODO: optimize for horizontal/vertical moves
+procedure TBodyGridBase.moveBody (body: TBodyProxyId; nx, ny: Integer);
 var
   px: PBodyProxyRec;
-  nx, ny: Integer;
+  x0, y0: Integer;
+  ogx0, ogx1, ogy0, ogy1: Integer; // old grid rect
+  ngx0, ngx1, ngy0, ngy1: Integer; // new grid rect
+  gx, gy: Integer;
+  gw, gh: Integer;
+  pw, ph: Integer;
 begin
   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
+  x0 := px.mX;
+  y0 := px.mY;
+  if (nx = x0) and (ny = y0) then exit;
+  // map -> grid
+  Dec(x0, mMinX);
+  Dec(y0, mMinY);
+  Dec(nx, mMinX);
+  Dec(ny, mMinY);
+  // check for heavy work
+  pw := px.mWidth;
+  ph := px.mHeight;
+  ogx0 := x0 div mTileSize;
+  ogy0 := y0 div mTileSize;
+  ngx0 := nx div mTileSize;
+  ngy0 := ny div mTileSize;
+  ogx1 := (x0+pw-1) div mTileSize;
+  ogy1 := (y0+ph-1) div mTileSize;
+  ngx1 := (nx+pw-1) div mTileSize;
+  ngy1 := (ny+ph-1) div mTileSize;
+  {$IF DEFINED(D2F_DEBUG_MOVER)}
+  e_WriteLog(Format('proxy #%d: checkmove: xg=%d;yg=%d;w=%d;h=%d;nx=%d;ny=%d og:(%d,%d)-(%d,%d); ng:(%d,%d)-(%d,%d)', [body, x0, y0, pw, ph, nx, ny, ogx0, ogy0, ogx1, ogy1, ngx0, ngy0, ngx1, ngy1]), MSG_NOTIFY);
+  {$ENDIF}
+  if (ogx0 <> ngx0) or (ogy0 <> ngy0) or (ogx1 <> ngx1) or (ogy1 <> ngy1) then
   begin
     // crossed tile boundary, do heavy work
-    moveResizeBody(body, dx, dy, 0, 0);
+    gw := mWidth;
+    gh := mHeight;
+    // cycle with old rect, remove body where it is necessary
+    // optimized for horizontal moves
+    {$IF DEFINED(D2F_DEBUG_MOVER)}
+    e_WriteLog(Format('proxy #%d: xg=%d;yg=%d;w=%d;h=%d;nx=%d;ny=%d og:(%d,%d)-(%d,%d); ng:(%d,%d)-(%d,%d)', [body, x0, y0, pw, ph, nx, ny, ogx0, ogy0, ogx1, ogy1, ngx0, ngy0, ngx1, ngy1]), MSG_NOTIFY);
+    {$ENDIF}
+    // remove stale marks
+    if not ((ogy0 >= gh) or (ogy1 < 0)) and
+       not ((ogx0 >= gw) or (ogx1 < 0)) then
+    begin
+      if (ogx0 < 0) then ogx0 := 0;
+      if (ogy0 < 0) then ogy0 := 0;
+      if (ogx1 > gw-1) then ogx1 := gw-1;
+      if (ogy1 > gh-1) then ogy1 := gh-1;
+      {$IF DEFINED(D2F_DEBUG_MOVER)}
+      e_WriteLog(Format(' norm og:(%d,%d)-(%d,%d)', [ogx0, ogy0, ogx1, ogy1]), MSG_NOTIFY);
+      {$ENDIF}
+      for gx := ogx0 to ogx1 do
+      begin
+        if (gx < ngx0) or (gx > ngx1) then
+        begin
+          // this column is completely outside of new rect
+          for gy := ogy0 to ogy1 do
+          begin
+            {$IF DEFINED(D2F_DEBUG_MOVER)}
+            e_WriteLog(Format('  remove0:(%d,%d)', [gx, gy]), MSG_NOTIFY);
+            {$ENDIF}
+            remover(gy*gw+gx, body);
+          end;
+        end
+        else
+        begin
+          // heavy checks
+          for gy := ogy0 to ogy1 do
+          begin
+            if (gy < ngy0) or (gy > ngy1) then
+            begin
+              {$IF DEFINED(D2F_DEBUG_MOVER)}
+              e_WriteLog(Format('  remove1:(%d,%d)', [gx, gy]), MSG_NOTIFY);
+              {$ENDIF}
+              remover(gy*gw+gx, body);
+            end;
+          end;
+        end;
+      end;
+    end;
+    // cycle with new rect, add body where it is necessary
+    if not ((ngy0 >= gh) or (ngy1 < 0)) and
+       not ((ngx0 >= gw) or (ngx1 < 0)) then
+    begin
+      if (ngx0 < 0) then ngx0 := 0;
+      if (ngy0 < 0) then ngy0 := 0;
+      if (ngx1 > gw-1) then ngx1 := gw-1;
+      if (ngy1 > gh-1) then ngy1 := gh-1;
+      {$IF DEFINED(D2F_DEBUG_MOVER)}
+      e_WriteLog(Format(' norm ng:(%d,%d)-(%d,%d)', [ngx0, ngy0, ngx1, ngy1]), MSG_NOTIFY);
+      {$ENDIF}
+      for gx := ngx0 to ngx1 do
+      begin
+        if (gx < ogx0) or (gx > ogx1) then
+        begin
+          // this column is completely outside of old rect
+          for gy := ngy0 to ngy1 do
+          begin
+            {$IF DEFINED(D2F_DEBUG_MOVER)}
+            e_WriteLog(Format('  insert0:(%d,%d)', [gx, gy]), MSG_NOTIFY);
+            {$ENDIF}
+            inserter(gy*gw+gx, body);
+          end;
+        end
+        else
+        begin
+          // heavy checks
+          for gy := ngy0 to ngy1 do
+          begin
+            if (gy < ogy0) or (gy > ogy1) then
+            begin
+              {$IF DEFINED(D2F_DEBUG_MOVER)}
+              e_WriteLog(Format('  insert1:(%d,%d)', [gx, gy]), MSG_NOTIFY);
+              {$ENDIF}
+              inserter(gy*gw+gx, body);
+            end;
+          end;
+        end;
+      end;
+    end;
+    // done
   end
   else
   begin
-    // nothing to do with the grid, just fix coordinates
-    px.mX := nx;
-    px.mY := ny;
+    {$IF DEFINED(D2F_DEBUG_MOVER)}
+    e_WriteLog(Format('proxy #%d: GRID OK: xg=%d;yg=%d;w=%d;h=%d;nx=%d;ny=%d og:(%d,%d)-(%d,%d); ng:(%d,%d)-(%d,%d)', [body, x0, y0, pw, ph, nx, ny, ogx0, ogy0, ogx1, ogy1, ngx0, ngy0, ngx1, ngy1]), MSG_NOTIFY);
+    {$ENDIF}
   end;
+  // update coordinates
+  px.mX := nx+mMinX;
+  px.mY := ny+mMinY;
 end;
 
-procedure TBodyGridBase.resizeBody (body: TBodyProxyId; sx, sy: Integer);
+procedure TBodyGridBase.resizeBody (body: TBodyProxyId; nw, nh: Integer);
 var
   px: PBodyProxyRec;
-  x0, y0: Integer;
-  nw, nh: Integer;
+  x0, y0, w, h: Integer;
 begin
   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
+  x0 := px.mX-mMinX;
+  y0 := px.mY-mMinY;
+  w := px.mWidth;
+  h := px.mHeight;
+  {$IF DEFINED(D2F_DEBUG_MOVER)}
+  e_WriteLog(Format('proxy #%d: RESIZE: xg=%d;yg=%d;w=%d;h=%d;nw=%d;nh=%d', [body, x0, y0, w, h, nw, nh]), MSG_NOTIFY);
+  {$ENDIF}
+  if ((x0+w) div mTileSize <> (x0+nw) div mTileSize) or
+     ((y0+h) div mTileSize <> (y0+nh) div mTileSize) then
   begin
     // crossed tile boundary, do heavy work
-    moveResizeBody(body, 0, 0, sx, sy);
+    removeInternal(body);
+    px.mWidth := nw;
+    px.mHeight := nh;
+    insertInternal(body);
   end
   else
   begin
@@ -794,7 +1062,7 @@ end;
 
 // ////////////////////////////////////////////////////////////////////////// //
 // no callback: return `true` on the first hit
-function TBodyGridBase.forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
+function TBodyGridBase.forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1; exittag: PInteger=nil): ITP;
 var
   f: Integer;
   idx, curci: Integer;
@@ -804,15 +1072,25 @@ var
   ptag: Integer;
 begin
   result := Default(ITP);
+  if (exittag <> nil) then exittag^ := 0;
   tagmask := tagmask and TagFullMask;
   if (tagmask = 0) then exit;
 
+  {$IF DEFINED(D2F_DEBUG_XXQ)}
+  if (assigned(cb)) then e_WriteLog(Format('0: grid pointquery: (%d,%d)', [x, y]), MSG_NOTIFY);
+  {$ENDIF}
+
   // 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)];
+
+  {$IF DEFINED(D2F_DEBUG_XXQ)}
+  if (assigned(cb)) then e_WriteLog(Format('1: grid pointquery: (%d,%d) (%d,%d) %d', [x, y, (x div mTileSize), (y div mTileSize), curci]), MSG_NOTIFY);
+  {$ENDIF}
+
   // restore coords
   Inc(x, mMinX);
   Inc(y, mMinY);
@@ -827,26 +1105,44 @@ begin
   end;
   lq := mLastQuery;
 
+  {$IF DEFINED(D2F_DEBUG_XXQ)}
+  if (assigned(cb)) then e_WriteLog(Format('2: grid pointquery: (%d,%d); lq=%u', [x, y, lq]), MSG_NOTIFY);
+  {$ENDIF}
+
   while (curci <> -1) do
   begin
+    {$IF DEFINED(D2F_DEBUG_XXQ)}
+    if (assigned(cb)) then e_WriteLog(Format(' cell #%d', [curci]), MSG_NOTIFY);
+    {$ENDIF}
     cc := @mCells[curci];
-    for f := 0 to High(TGridCell.bodies) do
+    for f := 0 to GridCellBucketSize-1 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
+      {$IF DEFINED(D2F_DEBUG_XXQ)}
+      if (assigned(cb)) then e_WriteLog(Format('  proxy #%d; qm:%u; tag:%08x; tagflag:%d  %u', [cc.bodies[f], px.mQueryMark, px.mTag, (px.mTag and tagmask), LongWord(px.mObj)]), MSG_NOTIFY);
+      {$ENDIF}
+      // shit. has to do it this way, so i can change tag in callback
+      if (px.mQueryMark <> lq) then
       begin
-        if (x >= px.mX) and (y >= px.mY) and (x < px.mX+px.mWidth) and (y < px.mY+px.mHeight) then
+        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
-          px.mQueryMark := lq;
           if assigned(cb) then
           begin
-            if cb(px.mObj, ptag) then begin result := px.mObj; exit; end;
+            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;
@@ -917,28 +1213,26 @@ begin
       while (curci <> -1) do
       begin
         cc := @mCells[curci];
-        for f := 0 to High(TGridCell.bodies) do
+        for f := 0 to GridCellBucketSize-1 do
         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
+          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) 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
+          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;
+          if assigned(cb) 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;
+            if cb(px.mObj, ptag) then begin result := px.mObj; exit; end;
+          end
+          else
+          begin
+            result := px.mObj;
+            exit;
           end;
         end;
         curci := cc.next;
@@ -950,7 +1244,7 @@ end;
 
 // ////////////////////////////////////////////////////////////////////////// //
 // no callback: return `true` on the nearest hit
-function TBodyGridBase.traceRay (x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
+function TBodyGridBase.traceRay (const x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
 var
   ex, ey: Integer;
 begin
@@ -960,7 +1254,7 @@ end;
 
 // 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;
+function TBodyGridBase.traceRay (out ex, ey: Integer; const ax0, ay0, ax1, ay1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
 const
   tsize = mTileSize;
 var
@@ -989,6 +1283,11 @@ var
   lq: LongWord;
   f, ptag, distSq: Integer;
   x0, y0, x1, y1: Integer;
+  // horizontal walker
+  {$IFDEF GRID_USE_ORTHO_ACCEL}
+  wklen, wkstep: Integer;
+  hopt: Boolean;
+  {$ENDIF}
 begin
   result := Default(ITP);
   lastObj := Default(ITP);
@@ -997,7 +1296,15 @@ begin
   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
+  if (ax0 = ax1) and (ay0 = ay1) then
+  begin
+    result := forEachAtPoint(ax0, ay0, nil, tagmask, @ptag);
+    if (result <> nil) then
+    begin
+      if assigned(cb) and not cb(result, ptag, ax0, ay0, ax0, ay0) then result := Default(ITP);
+    end;
+    exit;
+  end;
 
   lastDistSq := distanceSq(ax0, ay0, ax1, ay1)+1;
 
@@ -1008,6 +1315,10 @@ begin
   maxx := gw*tsize-1;
   maxy := gh*tsize-1;
 
+  {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+  if assigned(dbgRayTraceTileHitCB) then e_WriteLog(Format('TRACING: (%d,%d)-(%d,%d) [(%d,%d)-(%d,%d)]; maxdistsq=%d', [ax0, ay0, ax1, ay1, minx, miny, maxx, maxy, lastDistSq]), MSG_NOTIFY);
+  {$ENDIF}
+
   x0 := ax0;
   y0 := ay0;
   x1 := ax1;
@@ -1138,24 +1449,55 @@ begin
   dx2 -= dy2;
 
   // first move, to skip starting point
-  if (xd = term) then exit;
+  // DON'T DO THIS! loop will take care of that
+  if (xd = term) then
+  begin
+    result := forEachAtPoint(ax0, ay0, nil, tagmask, @ptag);
+    if (result <> nil) then
+    begin
+      if assigned(cb) then
+      begin
+        if cb(result, ptag, ax0, ay0, ax0, ay0) then
+        begin
+          ex := ax0;
+          ey := ay0;
+        end
+        else
+        begin
+          result := nil;
+        end;
+      end
+      else
+      begin
+        ex := ax0;
+        ey := ay0;
+      end;
+    end;
+    exit;
+  end;
+
   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 (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ > mHeight*tsize) then raise Exception.Create('raycaster internal error (0)');
+  {$IF DEFINED(D2F_DEBUG)}
+  if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ >= gh*tsize) then raise Exception.Create('raycaster internal error (0)');
+  {$ENDIF}
+  // DON'T DO THIS! loop will take care of that
+  //lastGA := (yptr^ div tsize)*gw+(xptr^ div tsize);
+  //ccidx := mGrid[lastGA];
 
-  //if (dbgShowTraceLog) then e_WriteLog(Format('raycast start: (%d,%d)-(%d,%d); xptr^=%d; yptr^=%d', [ax0, ay0, ax1, ay1, xptr^, yptr^]), MSG_NOTIFY);
+  {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+  //if assigned(dbgRayTraceTileHitCB) then e_WriteLog('1:TRACING!', MSG_NOTIFY);
+  {$ENDIF}
 
-  // restore query coords
-  Inc(ax0, minx);
-  Inc(ay0, miny);
-  //Inc(ax1, minx);
-  //Inc(ay1, miny);
+  //if (dbgShowTraceLog) then e_WriteLog(Format('raycast start: (%d,%d)-(%d,%d); xptr^=%d; yptr^=%d', [ax0, ay0, ax1, ay1, xptr^, yptr^]), MSG_NOTIFY);
 
   // increase query counter
   Inc(mLastQuery);
@@ -1167,17 +1509,247 @@ begin
   end;
   lq := mLastQuery;
 
+  {$IFDEF GRID_USE_ORTHO_ACCEL}
+  // if this is strict horizontal trace, use optimized codepath
+  if (ax0 = ax1) or (ay0 = ay1) then
+  begin
+    // horizontal trace: walk the whole tiles, calculating mindist once for each proxy in cell
+    //   stx < 0: going left, otherwise `stx` is > 0, and we're going right
+    // vertical trace: walk the whole tiles, calculating mindist once for each proxy in cell
+    // stx < 0: going up, otherwise `stx` is > 0, and we're going down
+    hopt := (ay0 = ay1); // horizontal?
+    if (stx < 0) then wklen := -(term-xd) else wklen := term-xd;
+    {$IF DEFINED(D2F_DEBUG)}
+    if dbgShowTraceLog then e_LogWritefln('optimized htrace; wklen=%d', [wklen]);
+    {$ENDIF}
+    ga := (yptr^ div tsize)*gw+(xptr^ div tsize);
+    // one of those will never change
+    x := xptr^+minx;
+    y := yptr^+miny;
+    {$IF DEFINED(D2F_DEBUG)}
+    if hopt then
+    begin
+      if (y <> ay0) then raise Exception.Create('htrace fatal internal error');
+    end
+    else
+    begin
+      if (x <> ax0) then raise Exception.Create('vtrace fatal internal error');
+    end;
+    {$ENDIF}
+    while (wklen > 0) do
+    begin
+      {$IF DEFINED(D2F_DEBUG)}
+      if dbgShowTraceLog then e_LogWritefln('  htrace; ga=%d; x=%d, y=%d; y=%d; y=%d', [ga, xptr^+minx, yptr^+miny, y, ay0]);
+      {$ENDIF}
+      // new tile?
+      if (ga <> lastGA) then
+      begin
+        lastGA := ga;
+        ccidx := mGrid[lastGA];
+        // convert coords to map (to avoid ajdusting coords inside the loop)
+        if hopt then x := xptr^+minx else y := yptr^+miny;
+        while (ccidx <> -1) do
+        begin
+          cc := @mCells[ccidx];
+          for f := 0 to GridCellBucketSize-1 do
+          begin
+            if (cc.bodies[f] = -1) then break;
+            px := @mProxies[cc.bodies[f]];
+            ptag := px.mTag;
+            if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) and
+               // constant coord should be inside
+               ((hopt and (y >= px.mY) and (y < px.mY+px.mHeight)) or
+                ((not hopt) and (x >= px.mX) and (x < px.mX+px.mWidth))) then
+            begin
+              px.mQueryMark := lq; // mark as processed
+              // inside the proxy?
+              if (hopt and (x > px.mX) and (x < px.mX+px.mWidth-1)) or
+                 ((not hopt) and (y > px.mY) and (y < px.mY+px.mHeight-1)) then
+              begin
+                if assigned(cb) then
+                begin
+                  if cb(px.mObj, ptag, x, y, x, y) then
+                  begin
+                    result := lastObj;
+                    ex := prevx;
+                    ey := prevy;
+                    exit;
+                  end;
+                  x := xptr^+minx;
+                end
+                else
+                begin
+                  distSq := distanceSq(ax0, ay0, x, y);
+                  {$IF DEFINED(D2F_DEBUG)}
+                  if dbgShowTraceLog then e_LogWritefln('  EMBEDDED hhit(%d): a=(%d,%d), h=(%d,%d), distsq=%d; lastsq=%d', [cc.bodies[f], ax0, ay0, x, y, distSq, lastDistSq]);
+                  {$ENDIF}
+                  if (distSq < lastDistSq) then
+                  begin
+                    ex := x;
+                    ey := y;
+                    result := px.mObj;
+                    exit;
+                  end;
+                end;
+                continue;
+              end;
+              // remember this hitpoint if it is nearer than an old one
+              if hopt then
+              begin
+                prevy := y;
+                if (stx < 0) then
+                begin
+                  // going left
+                  if (x < px.mX) then continue;
+                  prevx := px.mX+px.mWidth;
+                end
+                else
+                begin
+                  // going right
+                  if (x > px.mX{+px.mWidth}) then continue;
+                  prevx := px.mX-1;
+                end;
+              end
+              else
+              begin
+                prevx := x;
+                if (stx < 0) then
+                begin
+                  // going up
+                  if (y < px.mY) then continue;
+                  prevy := px.mY+px.mHeight;
+                end
+                else
+                begin
+                  // going down
+                  if (y > px.mY{+px.mHeight}) then continue;
+                  prevy := px.mY-1;
+                end;
+              end;
+              if assigned(cb) then
+              begin
+                if (stx < 0) then
+                begin
+                  if hopt then x := prevx-1 else y := prevy-1;
+                end
+                else
+                begin
+                  if hopt then x := prevx+1 else y := prevy+1;
+                end;
+                if cb(px.mObj, ptag, x, y, prevx, prevy) then
+                begin
+                  result := lastObj;
+                  ex := prevx;
+                  ey := prevy;
+                  exit;
+                end;
+                x := xptr^+minx;
+                y := yptr^+miny;
+              end
+              else
+              begin
+                distSq := distanceSq(ax0, ay0, prevx, prevy);
+                {$IF DEFINED(D2F_DEBUG)}
+                if dbgShowTraceLog then e_LogWritefln('  hhit(%d): a=(%d,%d), h=(%d,%d), p=(%d,%d), distsq=%d; lastsq=%d', [cc.bodies[f], ax0, ay0, x, y, prevx, prevy, distSq, lastDistSq]);
+                {$ENDIF}
+                if (distSq < lastDistSq) then
+                begin
+                  wasHit := true;
+                  lastDistSq := distSq;
+                  ex := prevx;
+                  ey := prevy;
+                  lastObj := px.mObj;
+                end;
+              end;
+            end;
+          end;
+          // next cell
+          ccidx := cc.next;
+        end;
+        if wasHit and not assigned(cb) then begin result := lastObj; exit; end;
+      end;
+      // skip to next tile
+      if hopt then
+      begin
+        if (stx > 0) then
+        begin
+          // to the right
+          wkstep := ((xptr^ or (mTileSize-1))+1)-xptr^;
+          {$IF DEFINED(D2F_DEBUG)}
+          if dbgShowTraceLog then e_LogWritefln('  right step: wklen=%d; wkstep=%d', [wklen, wkstep]);
+          {$ENDIF}
+          if (wkstep >= wklen) then break;
+          Inc(xptr^, wkstep);
+          Inc(ga);
+        end
+        else
+        begin
+          // to the left
+          wkstep := xptr^-((xptr^ and (not (mTileSize-1)))-1);
+          {$IF DEFINED(D2F_DEBUG)}
+          if dbgShowTraceLog then e_LogWritefln('  left step: wklen=%d; wkstep=%d', [wklen, wkstep]);
+          {$ENDIF}
+          if (wkstep >= wklen) then break;
+          Dec(xptr^, wkstep);
+          Dec(ga);
+        end;
+      end
+      else
+      begin
+        if (stx > 0) then
+        begin
+          // to the down
+          wkstep := ((yptr^ or (mTileSize-1))+1)-yptr^;
+          {$IF DEFINED(D2F_DEBUG)}
+          if dbgShowTraceLog then e_LogWritefln('  down step: wklen=%d; wkstep=%d', [wklen, wkstep]);
+          {$ENDIF}
+          if (wkstep >= wklen) then break;
+          Inc(yptr^, wkstep);
+          Inc(ga, mHeight);
+        end
+        else
+        begin
+          // to the up
+          wkstep := yptr^-((yptr^ and (not (mTileSize-1)))-1);
+          {$IF DEFINED(D2F_DEBUG)}
+          if dbgShowTraceLog then e_LogWritefln('  up step: wklen=%d; wkstep=%d', [wklen, wkstep]);
+          {$ENDIF}
+          if (wkstep >= wklen) then break;
+          Dec(yptr^, wkstep);
+          Dec(ga, mHeight);
+        end;
+      end;
+      Dec(wklen, wkstep);
+    end;
+    // we can travel less than one cell
+    if wasHit and not assigned(cb) then result := lastObj else begin ex := ax1; ey := ay1; end;
+    exit;
+  end;
+  {$ENDIF}
+
+  {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+  if assigned(dbgRayTraceTileHitCB) then dbgRayTraceTileHitCB((xptr^ div tsize*tsize)+minx, (yptr^ div tsize*tsize)+miny);
+  {$ENDIF}
+
   ccidx := -1;
-  // draw it; can omit checks
+  //  can omit checks
   while (xd <> term) do
   begin
     // check cell(s)
-    if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ > mHeight*tsize) then raise Exception.Create('raycaster internal error (0)');
+    {$IF DEFINED(D2F_DEBUG)}
+    if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ >= gh*tsize) then raise Exception.Create('raycaster internal error (0)');
+    {$ENDIF}
     // new tile?
     ga := (yptr^ div tsize)*gw+(xptr^ div tsize);
+    {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+    if assigned(dbgRayTraceTileHitCB) then e_WriteLog(Format(' xd=%d; term=%d; gx=%d; gy=%d; ga=%d; lastga=%d', [xd, term, xptr^, yptr^, ga, lastGA]), MSG_NOTIFY);
+    {$ENDIF}
     if (ga <> lastGA) then
     begin
       // yes
+      {$IF DEFINED(D2F_DEBUG)}
+      if assigned(dbgRayTraceTileHitCB) then dbgRayTraceTileHitCB((xptr^ div tsize*tsize)+minx, (yptr^ div tsize*tsize)+miny);
+      {$ENDIF}
       if (ccidx <> -1) then
       begin
         // signal cell completion
@@ -1207,7 +1779,7 @@ begin
       while (curci <> -1) do
       begin
         cc := @mCells[curci];
-        for f := 0 to High(TGridCell.bodies) do
+        for f := 0 to GridCellBucketSize-1 do
         begin
           if (cc.bodies[f] = -1) then break;
           px := @mProxies[cc.bodies[f]];
@@ -1227,11 +1799,28 @@ begin
                   ey := prevy;
                   exit;
                 end;
+                (*
+                  {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+                  distSq := distanceSq(ax0, ay0, prevx, prevy);
+                  if assigned(dbgRayTraceTileHitCB) then e_WriteLog(Format('  hit(%d): a=(%d,%d), h=(%d,%d), p=(%d,%d); distsq=%d; lastsq=%d', [cc.bodies[f], ax0, ay0, x, y, prevx, prevy, distSq, lastDistSq]), MSG_NOTIFY);
+                  if (distSq < lastDistSq) then
+                  begin
+                    wasHit := true;
+                    lastDistSq := distSq;
+                    ex := prevx;
+                    ey := prevy;
+                    lastObj := px.mObj;
+                  end;
+                  {$ENDIF}
+                *)
               end
               else
               begin
                 // remember this hitpoint if it is nearer than an old one
                 distSq := distanceSq(ax0, ay0, prevx, prevy);
+                {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+                if assigned(dbgRayTraceTileHitCB) then e_WriteLog(Format('  hit(%d): a=(%d,%d), h=(%d,%d), p=(%d,%d); distsq=%d; lastsq=%d', [cc.bodies[f], ax0, ay0, x, y, prevx, prevy, distSq, lastDistSq]), MSG_NOTIFY);
+                {$ENDIF}
                 if (distSq < lastDistSq) then
                 begin
                   wasHit := true;
@@ -1275,12 +1864,22 @@ begin
     if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
     xd += stx;
   end;
+  // we can travel less than one cell
+  if wasHit and not assigned(cb) then
+  begin
+    result := lastObj;
+  end
+  else
+  begin
+    ex := ax1; // why not?
+    ey := ay1; // why not?
+  end;
 end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
 //FIXME! optimize this with real tile walking
-function TBodyGridBase.forEachAlongLine (x0, y0, x1, y1: Integer; cb: TGridAlongQueryCB; tagmask: Integer=-1): ITP;
+function TBodyGridBase.forEachAlongLine (const x0, y0, x1, y1: Integer; cb: TGridAlongQueryCB; tagmask: Integer=-1; log: Boolean=false): ITP;
 const
   tsize = mTileSize;
 var
@@ -1302,10 +1901,12 @@ var
   lastWasInGrid: Boolean;
   tbcross: Boolean;
   f: Integer;
+  //tedist: Integer;
 begin
+  log := false;
   result := Default(ITP);
   tagmask := tagmask and TagFullMask;
-  if (tagmask = 0) then exit;
+  if (tagmask = 0) or not assigned(cb) then exit;
 
   minx := mMinX;
   miny := mMinY;
@@ -1316,6 +1917,8 @@ begin
   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;
 
+  if (incx = 0) and (incy = 0) then exit; // just incase
+
   dx := abs(dx);
   dy := abs(dy);
 
@@ -1352,18 +1955,26 @@ begin
   xerr := -d;
   yerr := -d;
 
+  if (log) then e_WriteLog(Format('tracing: (%d,%d)-(%d,%d)', [x, y, x1-minx, y1-miny]), MSG_NOTIFY);
+
   // now trace
-  for i := 1 to d do
+  i := 0;
+  while (i < d) do
   begin
+    Inc(i);
     // 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
@@ -1381,6 +1992,62 @@ begin
         begin
           // setup new cell index
           ccidx := mGrid[(y div tsize)*gw+(x div tsize)];
+          if (log) then e_WriteLog(Format(' stepped to new tile (%d,%d) -- (%d,%d)', [(x div tsize), (y div tsize), x, y]), MSG_NOTIFY);
+        end
+        else
+        if (ccidx = -1) then
+        begin
+          // we have nothing interesting here anymore, jump directly to tile edge
+          (*
+          if (incx = 0) then
+          begin
+            // vertical line
+            if (incy < 0) then tedist := y-(y and (not tsize)) else tedist := (y or (tsize-1))-y;
+            if (tedist > 1) then
+            begin
+              if (log) then e_WriteLog(Format('  doing vertical jump from tile (%d,%d) - (%d,%d) by %d steps', [(x div tsize), (y div tsize), x, y, tedist]), MSG_NOTIFY);
+              y += incy*tedist;
+              Inc(i, tedist);
+              if (log) then e_WriteLog(Format('   jumped to tile (%d,%d) - (%d,%d) by %d steps', [(x div tsize), (y div tsize), x, y, tedist]), MSG_NOTIFY);
+            end;
+          end
+          else if (incy = 0) then
+          begin
+            // horizontal line
+            if (incx < 0) then tedist := x-(x and (not tsize)) else tedist := (x or (tsize-1))-x;
+            if (tedist > 1) then
+            begin
+              if (log) then e_WriteLog(Format('  doing horizontal jump from tile (%d,%d) - (%d,%d) by %d steps', [(x div tsize), (y div tsize), x, y, tedist]), MSG_NOTIFY);
+              x += incx*tedist;
+              Inc(i, tedist);
+              if (log) then e_WriteLog(Format('   jumped to tile (%d,%d) - (%d,%d) by %d steps', [(x div tsize), (y div tsize), x, y, tedist]), MSG_NOTIFY);
+            end;
+          end;
+          *)
+          (*
+           else if (
+          // get minimal distance to tile edges
+          if (incx < 0) then tedist := x-(x and (not tsize)) else if (incx > 0) then tedist := (x or (tsize+1))-x else tedist := 0;
+          {$IF DEFINED(D2F_DEBUG)}
+          if (tedist < 0) then raise Exception.Create('internal bug in grid raycaster (2.x)');
+          {$ENDIF}
+          if (incy < 0) then f := y-(y and (not tsize)) else if (incy > 0) then f := (y or (tsize+1))-y else f := 0;
+          {$IF DEFINED(D2F_DEBUG)}
+          if (f < 0) then raise Exception.Create('internal bug in grid raycaster (2.y)');
+          {$ENDIF}
+          if (tedist = 0) then tedist := f else if (f <> 0) then tedist := minInt(tedist, f);
+          // do jump
+          if (tedist > 1) then
+          begin
+            if (log) then e_WriteLog(Format('  doing jump from tile (%d,%d) - (%d,%d) by %d steps', [(x div tsize), (y div tsize), x, y, tedist]), MSG_NOTIFY);
+            xerr += dx*tedist;
+            yerr += dy*tedist;
+            if (xerr >= 0) then begin x += incx*((xerr div d)+1); xerr := (xerr mod d)-d; end;
+            if (yerr >= 0) then begin y += incy*((yerr div d)+1); yerr := (yerr mod d)-d; end;
+            Inc(i, tedist);
+            if (log) then e_WriteLog(Format('   jumped to tile (%d,%d) - (%d,%d) by %d steps', [(x div tsize), (y div tsize), x, y, tedist]), MSG_NOTIFY);
+          end;
+          *)
         end;
       end
       else
@@ -1396,13 +2063,13 @@ begin
       // process cell
       curci := ccidx;
       // convert coords to map (to avoid ajdusting coords inside the loop)
-      Inc(x, minx);
-      Inc(y, miny);
+      //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
+        for f := 0 to GridCellBucketSize-1 do
         begin
           if (cc.bodies[f] = -1) then break;
           px := @mProxies[cc.bodies[f]];
@@ -1418,8 +2085,8 @@ begin
       end;
       ccidx := -1; // don't process this anymore
       // convert coords to grid
-      Dec(x, minx);
-      Dec(y, miny);
+      //Dec(x, minx);
+      //Dec(y, miny);
     end;
   end;
 end;