X-Git-Url: http://deadsoftware.ru/gitweb?a=blobdiff_plain;ds=sidebyside;f=src%2Fgame%2Fg_grid.pas;h=e45fede6f34b818d9a9f41191fc0d0c8bef8e32b;hb=747da9b7f35549ec88cec08069f6bfe725e508e2;hp=d56a24365ec397c8c071b1bfa7f648709e8ae473;hpb=2b79b90a46d647d1d5bf4205862be5ffa296add1;p=d2df-sdl.git

diff --git a/src/game/g_grid.pas b/src/game/g_grid.pas
index d56a243..e45fede 100644
--- a/src/game/g_grid.pas
+++ b/src/game/g_grid.pas
@@ -15,7 +15,6 @@
  *)
 // universal spatial grid
 {$INCLUDE ../shared/a_modes.inc}
-{$DEFINE grid_use_buckets}
 unit g_grid;
 
 interface
@@ -29,12 +28,13 @@ type
     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
 
+    const TagDisabled = $40000000;
+    const TagFullMask = $3fffffff;
+
   private
     const
       GridDefaultTileSize = 32;
-      {$IFDEF grid_use_buckets}
       GridCellBucketSize = 8; // WARNING! can't be less than 2!
-      {$ENDIF}
 
   private
     type
@@ -44,7 +44,7 @@ type
         mX, mY, mWidth, mHeight: Integer; // aabb
         mQueryMark: LongWord; // was this object visited at this query?
         mObj: ITP;
-        mTag: Integer;
+        mTag: Integer; // `TagDisabled` set: disabled ;-)
         nextLink: TBodyProxyId; // next free or nothing
 
       private
@@ -53,18 +53,17 @@ type
 
       PGridCell = ^TGridCell;
       TGridCell = record
-        {$IFDEF grid_use_buckets}
         bodies: array [0..GridCellBucketSize-1] of Integer; // -1: end of list
-        {$ELSE}
-        body: Integer;
-        {$ENDIF}
         next: Integer; // in this cell; index in mCells
       end;
 
-      TGridInternalCB = function (grida: Integer): Boolean of object; // return `true` to stop
+      TGridInternalCB = function (grida: Integer; bodyId: TBodyProxyId): Boolean of object; // return `true` to stop
+
+  private
+    //mTileSize: Integer;
+    const mTileSize = GridDefaultTileSize;
 
   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
@@ -77,10 +76,6 @@ type
     mProxyCount: Integer; // currently used
     mProxyMaxCount: Integer;
 
-    mUData: TBodyProxyId; // for inserter/remover
-    mTagMask: Integer; // for iterator
-    mItCB: TGridQueryCB; // for iterator
-
   private
     function allocCell: Integer;
     procedure freeCell (idx: Integer); // `next` is simply overwritten
@@ -88,36 +83,51 @@ type
     function allocProxy (aX, aY, aWidth, aHeight: Integer; aObj: ITP; aTag: Integer): TBodyProxyId;
     procedure freeProxy (body: TBodyProxyId);
 
-    procedure insert (body: TBodyProxyId);
-    procedure remove (body: TBodyProxyId);
+    procedure insertInternal (body: TBodyProxyId);
+    procedure removeInternal (body: TBodyProxyId);
 
-    function forGridRect (x, y, w, h: Integer; cb: TGridInternalCB): Boolean;
+    function forGridRect (x, y, w, h: Integer; cb: TGridInternalCB; bodyId: TBodyProxyId): Boolean;
 
-    function inserter (grida: Integer): Boolean;
-    function remover (grida: Integer): 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;
 
   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: ITP; ax, ay, aWidth, aHeight: Integer; aTag: Integer=0): TBodyProxyId;
+    function insertBody (aObj: ITP; ax, ay, aWidth, aHeight: Integer; aTag: Integer=-1): TBodyProxyId;
     procedure removeBody (aObj: 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);
 
-    //WARNING: can't do recursive queries
-    function forEachInAABB (x, y, w, h: Integer; cb: TGridQueryCB; tagmask: Integer=-1): Boolean;
+    function insideGrid (x, y: 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)
+    // 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: can't do recursive queries
-    function forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): 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)
+    // no callback: return `true` on the first hit
+    function forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
 
-    //WARNING: can't do recursive queries
+    //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
-    function traceRay (x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): Boolean; overload;
+    // 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; x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
 
     procedure dumpStats ();
+
+    //WARNING! no sanity checks!
+    property proxyEnabled[pid: TBodyProxyId]: Boolean read getProxyEnabled write setProxyEnabled;
   end;
 
 
@@ -142,19 +152,21 @@ end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-constructor TBodyGridBase.Create (aMinPixX, aMinPixY, aPixWidth, aPixHeight: Integer; aTileSize: Integer=GridDefaultTileSize);
+constructor TBodyGridBase.Create (aMinPixX, aMinPixY, aPixWidth, aPixHeight: Integer{; aTileSize: Integer=GridDefaultTileSize});
 var
   idx: Integer;
 begin
+  {
   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);
@@ -162,11 +174,7 @@ begin
   // init free list
   for idx := 0 to High(mCells) do
   begin
-    {$IFDEF grid_use_buckets}
     mCells[idx].bodies[0] := -1;
-    {$ELSE}
-    mCells[idx].body := -1;
-    {$ENDIF}
     mCells[idx].next := idx+1;
   end;
   mCells[High(mCells)].next := -1; // last cell
@@ -180,9 +188,6 @@ begin
   mProxyFree := 0;
   mProxyCount := 0;
   mProxyMaxCount := 0;
-  mUData := 0;
-  mTagMask := -1;
-  mItCB := nil;
   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;
 
@@ -216,6 +221,37 @@ begin
 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.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 TBodyGridBase.allocCell: Integer;
 var
   idx: Integer;
@@ -227,11 +263,7 @@ begin
     SetLength(mCells, mFreeCell+32768); // arbitrary number
     for idx := mFreeCell to High(mCells) do
     begin
-      {$IFDEF grid_use_buckets}
       mCells[idx].bodies[0] := -1;
-      {$ELSE}
-      mCells[idx].body := -1;
-      {$ENDIF}
       mCells[idx].next := idx+1;
     end;
     mCells[High(mCells)].next := -1; // last cell
@@ -239,11 +271,7 @@ begin
   result := mFreeCell;
   mFreeCell := mCells[result].next;
   mCells[result].next := -1;
-  {$IFDEF grid_use_buckets}
   mCells[result].bodies[0] := -1;
-  {$ELSE}
-  mCells[result].body := -1;
-  {$ENDIF}
   Inc(mUsedCells);
   //e_WriteLog(Format('grid: allocated new cell #%d (total: %d)', [result, mUsedCells]), MSG_NOTIFY);
 end;
@@ -254,11 +282,7 @@ begin
   if (idx >= 0) and (idx < Length(mCells)) then
   begin
     //if mCells[idx].body = -1 then exit; // the thing that should not be
-    {$IFDEF grid_use_buckets}
     mCells[idx].bodies[0] := -1;
-    {$ELSE}
-    mCells[idx].body := -1;
-    {$ENDIF}
     mCells[idx].next := mFreeCell;
     mFreeCell := idx;
     Dec(mUsedCells);
@@ -304,10 +328,12 @@ begin
 end;
 
 
-function TBodyGridBase.forGridRect (x, y, w, h: Integer; cb: TGridInternalCB): Boolean;
+function TBodyGridBase.forGridRect (x, y, w, h: Integer; cb: TGridInternalCB; bodyId: TBodyProxyId): Boolean;
+const
+  tsize = mTileSize;
 var
   gx, gy: Integer;
-  gw, gh, tsize: Integer;
+  gw, gh: Integer;
 begin
   result := false;
   if (w < 1) or (h < 1) or not assigned(cb) then exit;
@@ -318,7 +344,7 @@ begin
   if (x+w <= 0) or (y+h <= 0) then exit;
   gw := mWidth;
   gh := mHeight;
-  tsize := mTileSize;
+  //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
@@ -328,26 +354,23 @@ begin
     begin
       if (gx < 0) then continue;
       if (gx >= gw) then break;
-      result := cb(gy*gw+gx);
+      result := cb(gy*gw+gx, bodyId);
       if result then exit;
     end;
   end;
 end;
 
 
-function TBodyGridBase.inserter (grida: Integer): Boolean;
+function TBodyGridBase.inserter (grida: Integer; bodyId: TBodyProxyId): Boolean;
 var
   cidx: Integer;
   pc: Integer;
-  {$IFDEF grid_use_buckets}
   pi: PGridCell;
   f: Integer;
-  {$ENDIF}
 begin
   result := false; // never stop
   // add body to the given grid cell
   pc := mGrid[grida];
-  {$IFDEF grid_use_buckets}
   if (pc <> -1) then
   begin
     pi := @mCells[pc];
@@ -357,7 +380,7 @@ begin
       if (pi.bodies[f] = -1) then
       begin
         // can add here
-        pi.bodies[f] := mUData;
+        pi.bodies[f] := bodyId;
         if (f+1 < Length(TGridCell.bodies)) then pi.bodies[f+1] := -1;
         exit;
       end;
@@ -365,40 +388,28 @@ begin
   end;
   // either no room, or no cell at all
   cidx := allocCell();
-  mCells[cidx].bodies[0] := mUData;
+  mCells[cidx].bodies[0] := bodyId;
   mCells[cidx].bodies[1] := -1;
   mCells[cidx].next := pc;
   mGrid[grida] := cidx;
-  {$ELSE}
-  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 := mUData;
-  mCells[cidx].next := pc;
-  mGrid[grida] := cidx;
-  {$ENDIF}
 end;
 
-
-procedure TBodyGridBase.insert (body: TBodyProxyId);
+procedure TBodyGridBase.insertInternal (body: TBodyProxyId);
 var
   px: PBodyProxyRec;
 begin
   if (body < 0) or (body > High(mProxies)) then exit; // just in case
   px := @mProxies[body];
-  mUData := body;
-  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, inserter);
+  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, inserter, body);
 end;
 
 
-function TBodyGridBase.remover (grida: Integer): Boolean;
+// absolutely not tested
+function TBodyGridBase.remover (grida: Integer; bodyId: TBodyProxyId): Boolean;
 var
-  {$IFDEF grid_use_buckets}
   f: Integer;
-  {$ENDIF}
   pidx, idx, tmp: Integer;
-  {$IFDEF grid_use_buckets}
   pc: PGridCell;
-  {$ENDIF}
 begin
   result := false; // never stop
   // find and remove cell
@@ -407,12 +418,11 @@ begin
   while (idx >= 0) do
   begin
     tmp := mCells[idx].next;
-    {$IFDEF grid_use_buckets}
     pc := @mCells[idx];
     f := 0;
     while (f < High(TGridCell.bodies)) do
     begin
-      if (pc.bodies[f] = mUData) then
+      if (pc.bodies[f] = bodyId) then
       begin
         // i found her!
         if (f = 0) and (pc.bodies[1] = -1) then
@@ -438,43 +448,34 @@ begin
       end;
       Inc(f);
     end;
-    {$ELSE}
-    if (mCells[idx].body = mUData) then
-    begin
-      if (pidx = -1) then mGrid[grida] := tmp else mCells[pidx].next := tmp;
-      freeCell(idx);
-      exit; // assume that we cannot have one object added to bucket twice
-    end;
-    {$ENDIF}
     pidx := idx;
     idx := tmp;
   end;
 end;
 
-
 // absolutely not tested
-procedure TBodyGridBase.remove (body: TBodyProxyId);
+procedure TBodyGridBase.removeInternal (body: TBodyProxyId);
 var
   px: PBodyProxyRec;
 begin
   if (body < 0) or (body > High(mProxies)) then exit; // just in case
   px := @mProxies[body];
-  mUData := body;
-  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, remover);
+  forGridRect(px.mX, px.mY, px.mWidth, px.mHeight, remover, body);
 end;
 
 
-function TBodyGridBase.insertBody (aObj: ITP; aX, aY, aWidth, aHeight: Integer; aTag: Integer=0): TBodyProxyId;
+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;
 
 
 procedure TBodyGridBase.removeBody (aObj: TBodyProxyId);
 begin
   if (aObj < 0) or (aObj > High(mProxies)) then exit; // just in case
-  remove(aObj);
+  removeInternal(aObj);
   freeProxy(aObj);
 end;
 
@@ -485,13 +486,13 @@ var
 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;
-  remove(body);
+  removeInternal(body);
   px := @mProxies[body];
   Inc(px.mX, dx);
   Inc(px.mY, dy);
   Inc(px.mWidth, sx);
   Inc(px.mHeight, sy);
-  insert(body);
+  insertInternal(body);
 end;
 
 procedure TBodyGridBase.moveBody (body: TBodyProxyId; dx, dy: Integer);
@@ -506,18 +507,19 @@ end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-function TBodyGridBase.forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): Boolean;
+// no callback: return `true` on the first hit
+function TBodyGridBase.forEachAtPoint (x, y: Integer; cb: TGridQueryCB; tagmask: Integer=-1): ITP;
 var
-  {$IFDEF grid_use_buckets}
   f: Integer;
-  {$ENDIF}
   idx, curci: Integer;
   cc: PGridCell = nil;
   px: PBodyProxyRec;
   lq: LongWord;
+  ptag: Integer;
 begin
-  result := false;
-  if not assigned(cb) or (tagmask = 0) then exit;
+  result := Default(ITP);
+  tagmask := tagmask and TagFullMask;
+  if (tagmask = 0) then exit;
 
   // make coords (0,0)-based
   Dec(x, mMinX);
@@ -542,57 +544,53 @@ begin
   while (curci <> -1) do
   begin
     cc := @mCells[curci];
-    {$IFDEF grid_use_buckets}
     for f := 0 to High(TGridCell.bodies) do
     begin
       if (cc.bodies[f] = -1) then break;
       px := @mProxies[cc.bodies[f]];
-      if (px.mQueryMark <> lq) and ((px.mTag and tagmask) <> 0) then
+      ptag := px.mTag;
+      if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
       begin
         if (x >= px.mX) and (y >= px.mY) and (x < px.mX+px.mWidth) and (y < px.mY+px.mHeight) then
         begin
           px.mQueryMark := lq;
-          result := cb(px.mObj, px.mTag);
-          if result then exit;
-        end;
-      end;
-    end;
-    {$ELSE}
-    if (cc.body <> -1) then
-    begin
-      px := @mProxies[cc.body];
-      if (px.mQueryMark <> lq) and ((px.mTag and tagmask) <> 0) then
-      begin
-        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;
-          result := cb(px.mObj, px.mTag);
-          if result then exit;
+          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;
     end;
-    {$ENDIF}
     curci := cc.next;
   end;
 end;
 
 
-function TBodyGridBase.forEachInAABB (x, y, w, h: Integer; cb: TGridQueryCB; tagmask: Integer=-1): Boolean;
+// 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;
-  {$IFDEF grid_use_buckets}
   f: Integer;
-  {$ENDIF}
   cc: PGridCell = nil;
   px: PBodyProxyRec;
   lq: LongWord;
-  tsize, gw: Integer;
+  gw: Integer;
   x0, y0: Integer;
+  ptag: Integer;
 begin
-  result := false;
-  if (w < 1) or (h < 1) or 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;
@@ -602,7 +600,7 @@ begin
   Dec(y, mMinY);
 
   gw := mWidth;
-  tsize := mTileSize;
+  //tsize := mTileSize;
 
   if (x+w <= 0) or (y+h <= 0) then exit;
   if (x >= gw*tsize) or (y >= mHeight*tsize) then exit;
@@ -632,39 +630,30 @@ begin
       while (curci <> -1) do
       begin
         cc := @mCells[curci];
-        {$IFDEF grid_use_buckets}
         for f := 0 to High(TGridCell.bodies) do
         begin
           if (cc.bodies[f] = -1) then break;
           px := @mProxies[cc.bodies[f]];
-          if (px.mQueryMark <> lq) and ((px.mTag and tagmask) <> 0) then
+          ptag := px.mTag;
+          if (not allowDisabled) and ((ptag and TagDisabled) <> 0) then continue;
+          if ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          //if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
+          //if ( ((ptag and TagDisabled) = 0) = ignoreDisabled) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
           begin
             if (x0 >= px.mX+px.mWidth) or (y0 >= px.mY+px.mHeight) then continue;
             if (x0+w <= px.mX) or (y0+h <= px.mY) then continue;
             px.mQueryMark := lq;
-            result := cb(px.mObj, px.mTag);
-            if result then exit;
-          end;
-        end;
-        {$ELSE}
-        if (cc.body <> 1) then
-        begin
-          px := @mProxies[cc.body];
-          if (px.mQueryMark <> lq) and ((px.mTag and tagmask) <> 0) then
-          begin
-            if (x0 >= px.mX+px.mWidth) or (y0 >= px.mY+px.mHeight) or (x0+w <= px.mX) or (y0+h <= px.mY) then
+            if assigned(cb) then
             begin
-              // no intersection
+              if cb(px.mObj, ptag) then begin result := px.mObj; exit; end;
             end
             else
             begin
-              px.mQueryMark := lq;
-              result := cb(px.mObj, px.mTag);
-              if result then exit;
+              result := px.mObj;
+              exit;
             end;
           end;
         end;
-        {$ENDIF}
         curci := cc.next;
       end;
     end;
@@ -673,41 +662,51 @@ end;
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-function TBodyGridBase.traceRay (x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): Boolean;
+// 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
+  result := traceRay(ex, ey, x0, y0, x1, y1, cb, tagmask);
+end;
+
+
+// no callback: return `true` on the nearest hit
+function TBodyGridBase.traceRay (out ex, ey: Integer; x0, y0, x1, y1: Integer; cb: TGridRayQueryCB; tagmask: Integer=-1): ITP;
+const
+  tsize = mTileSize;
 var
   i: Integer;
-  dx, dy: Integer;
-  xerr: Integer = 0;
-  yerr: Integer = 0;
-  d: Integer;
+  dx, dy, d: Integer;
+  xerr, yerr: Integer;
   incx, incy: Integer;
+  stepx, stepy: Integer;
   x, y: Integer;
   maxx, maxy: Integer;
-  tsize: Integer; // tile size
   gw, gh: Integer;
-  lastGA: Integer = -1;
-  ga: Integer = -1; // last used grid address
-  ccidx: Integer = -1;
-  curci: Integer = -1;
-  cc: PGridCell = nil;
+  ccidx: Integer;
+  curci: Integer;
+  cc: PGridCell;
   hasUntried: Boolean;
-  f: Integer;
   px: PBodyProxyRec;
   lq: LongWord;
   prevX, prevY: Integer;
   minx, miny: Integer;
+  ptag: Integer;
+  lastDistSq, distSq: Integer;
+  wasHit: Boolean = false;
+  lastObj: ITP;
+  lastWasInGrid: Boolean;
+  tbcross: Boolean;
+  f: Integer;
 begin
-  result := false;
+  result := Default(ITP);
+  lastObj := Default(ITP);
+  tagmask := tagmask and TagFullMask;
+  if (tagmask = 0) then begin ex := x0; ey := y0; exit; end;
 
-  if (tagmask = 0) then exit;
-
-  // make coords (0,0)-based
   minx := mMinX;
   miny := mMinY;
-  Dec(x0, minx);
-  Dec(y0, miny);
-  Dec(x1, minx);
-  Dec(y1, miny);
 
   dx := x1-x0;
   dy := y1-y0;
@@ -720,8 +719,9 @@ begin
 
   if (dx > dy) then d := dx else d := dy;
 
-  x := x0;
-  y := y0;
+  // `x` and `y` will be in grid coords
+  x := x0-minx;
+  y := y0-miny;
 
   // increase query counter
   Inc(mLastQuery);
@@ -733,102 +733,167 @@ begin
   end;
   lq := mLastQuery;
 
-  tsize := mTileSize;
+  // cache various things
+  //tsize := mTileSize;
   gw := mWidth;
   gh := mHeight;
   maxx := gw*tsize-1;
   maxy := gh*tsize-1;
 
+  // setup distance and flags
+  lastDistSq := (x1-x0)*(x1-x0)+(y1-y0)*(y1-y0)+1;
+  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
+    // prevs are always in map coords
     prevX := x+minx;
     prevY := y+miny;
-    Inc(xerr, dx); if (xerr >= d) then begin Dec(xerr, d); Inc(x, incx); end;
-    Inc(yerr, dy); if (yerr >= d) then begin Dec(yerr, d); Inc(y, incy); end;
-
-    if (x >= 0) and (y >= 0) and (x <= maxx) and (y <= maxy) then
+    // do one step
+    xerr += dx;
+    yerr += dy;
+    // invariant: one of those always changed
+    if (xerr < 0) and (yerr < 0) then raise Exception.Create('internal bug in grid raycaster (0)');
+    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 ((stepx or stepy) = 0) then raise Exception.Create('internal bug in grid raycaster (1)');
     begin
-      ga := (y div tsize)*gw+(x div tsize);
-      if (lastGA <> ga) then
+      // check for crossing tile/grid boundary
+      if (x >= 0) and (y >= 0) and (x <= maxx) and (y <= maxy) then
       begin
-        // new cell
-        lastGA := ga;
-        ccidx := mGrid[lastGA];
-        {
-        if (ccidx <> -1) then
+        // 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
-          result := cb(nil, 0, x+minx, y+miny, prevX, prevY);
-          if result then exit;
+          // had something in the cell we're leaving?
+          if (ccidx <> -1) then
+          begin
+            // yes, signal cell completion
+            if assigned(cb) then
+            begin
+              if cb(nil, 0, x+minx, y+miny, prevX, prevY) then begin result := lastObj; exit; end;
+            end
+            else if wasHit then
+            begin
+              result := lastObj;
+              exit;
+            end;
+          end;
+          // setup new cell index
+          ccidx := mGrid[(y div tsize)*gw+(x div tsize)];
         end;
-        }
-      end;
-    end
-    else
-    begin
-      if (ccidx <> -1) then
+      end
+      else
       begin
-        ccidx := -1;
-        result := cb(nil, 0, x+minx, y+miny, prevX, prevY);
-        if result then exit;
+        // out of grid, had something in the last processed cell?
+        if (ccidx <> -1) then
+        begin
+          // yes, signal cell completion
+          ccidx := -1;
+          if assigned(cb) then
+          begin
+            if cb(nil, 0, x+minx, y+miny, prevX, prevY) then begin result := lastObj; exit; end;
+          end
+          else if wasHit then
+          begin
+            result := lastObj;
+            exit;
+          end;
+        end;
+        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;
-      hasUntried := false;
+      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)
       Inc(x, minx);
       Inc(y, miny);
+      // process cell list
       while (curci <> -1) do
       begin
         cc := @mCells[curci];
-        {$IFDEF grid_use_buckets}
         for f := 0 to High(TGridCell.bodies) do
         begin
           if (cc.bodies[f] = -1) then break;
           px := @mProxies[cc.bodies[f]];
-          if (px.mQueryMark <> lq) and ((px.mTag and tagmask) <> 0) then
+          ptag := px.mTag;
+          if ((ptag and TagDisabled) = 0) and ((ptag and tagmask) <> 0) and (px.mQueryMark <> lq) then
           begin
+            // can we process this proxy?
             if (x >= px.mX) and (y >= px.mY) and (x < px.mX+px.mWidth) and (y < px.mY+px.mHeight) then
             begin
-              px.mQueryMark := lq;
-              result := cb(px.mObj, px.mTag, x, y, prevX, prevY);
-              if result then exit;
+              px.mQueryMark := lq; // mark as processed
+              if assigned(cb) then
+              begin
+                if cb(px.mObj, ptag, x, y, prevX, prevY) then
+                begin
+                  result := lastObj;
+                  ex := prevX;
+                  ey := prevY;
+                  exit;
+                end;
+              end
+              else
+              begin
+                // remember this hitpoint if it is nearer than an old one
+                distSq := (prevX-x0)*(prevX-x0)+(prevY-y0)*(prevY-y0);
+                if (distSq < lastDistSq) then
+                begin
+                  wasHit := true;
+                  lastDistSq := distSq;
+                  ex := prevX;
+                  ey := prevY;
+                  lastObj := px.mObj;
+                end;
+              end;
             end
             else
             begin
+              // this is possibly interesting proxy, set "has more to check" flag
               hasUntried := true;
             end;
           end;
         end;
-        {$ELSE}
-        if (cc.body <> -1) then
-        begin
-          px := @mProxies[cc.body];
-          if (px.mQueryMark <> lq) and ((px.mTag and tagmask) <> 0) then
-          begin
-            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;
-              result := cb(px.mObj, px.mTag, x, y, prevX, prevY);
-              if result then exit;
-            end
-            else
-            begin
-              hasUntried := true;
-            end;
-          end;
-        end;
-        {$ENDIF}
+        // next cell
         curci := cc.next;
       end;
+      // still has something interesting in this cell?
       if not hasUntried then
       begin
-        // don't process this cell anymore
+        // nope, don't process this cell anymore; signal cell completion
         ccidx := -1;
-        result := cb(nil, 0, x, y, prevX, prevY);
-        if result then exit;
+        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;
+      // convert coords to grid
       Dec(x, minx);
       Dec(y, miny);
     end;