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raw | patch | inline | side by side (parent: 7dfe4bf)
| author | Ketmar Dark <ketmar@ketmar.no-ip.org> | |
| Tue, 29 Aug 2017 13:54:43 +0000 (16:54 +0300) | ||
| committer | Ketmar Dark <ketmar@ketmar.no-ip.org> | |
| Tue, 29 Aug 2017 13:55:03 +0000 (16:55 +0300) |
| src/game/g_grid.pas | patch | blob | history |
diff --git a/src/game/g_grid.pas b/src/game/g_grid.pas
index 42ce88300ab4fb896667d5c5acd4a8a18cb0a311..b4b0e32795cddfaa38864fa8154c2f260e903328 100644 (file)
--- a/src/game/g_grid.pas
+++ b/src/game/g_grid.pas
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
type TCellQueryCB = procedure (x, y: Integer) is nested; // top-left cell corner coords
// 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
//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;
+ function forEachAlongLine (ax0, ay0, ax1, ay1: Integer; cb: TGridQueryCB; tagmask: Integer=-1; log: Boolean=false): ITP;
// debug
procedure forEachBodyCell (body: TBodyProxyId; cb: TCellQueryCB);
lq: LongWord;
f, ptag, distSq: Integer;
x0, y0, x1, y1: Integer;
- swapped: Boolean = false; // true: xd is yd, and vice versa
+ //swapped: Boolean = false; // true: xd is yd, and vice versa
// horizontal walker
{$IFDEF GRID_USE_ORTHO_ACCEL}
wklen, wkstep: Integer;
if (dsx < dsy) then
begin
- swapped := true;
+ //swapped := true;
xptr := @yd;
yptr := @xd;
swapInt(x0, y0);
// DON'T DO THIS! loop will take care of that
if (xd = term) then
begin
+ //FIXME!
result := forEachAtPoint(ax0, ay0, nil, tagmask, @ptag);
if (result <> nil) then
begin
begin
if cb(px.mObj, ptag, x, y, x, y) then
begin
- result := lastObj;
+ result := px.mObj;
ex := x;
ey := y;
exit;
begin
if cb(px.mObj, ptag, x, y, prevx, prevy) then
begin
- result := lastObj;
+ result := px.mObj;
ex := prevx;
ey := prevy;
exit;
ccidx := cc.next;
end;
if wasHit and not assigned(cb) then begin result := lastObj; exit; end;
+ if assigned(cb) and cb(nil, 0, x, y, x, y) then begin result := lastObj; exit; end;
end;
// skip to next tile
if hopt then
begin
if cb(px.mObj, ptag, x, y, prevx, prevy) then
begin
- result := lastObj;
+ result := px.mObj;
ex := prevx;
ey := prevy;
exit;
end;
- (*
- {$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;
- {$ENDIF}
- *)
end
else
begin
// ////////////////////////////////////////////////////////////////////////// //
//FIXME! optimize this with real tile walking
-function TBodyGridBase.forEachAlongLine (const x0, y0, x1, y1: Integer; cb: TGridAlongQueryCB; tagmask: Integer=-1; log: Boolean=false): ITP;
+function TBodyGridBase.forEachAlongLine (ax0, ay0, ax1, ay1: Integer; cb: TGridQueryCB; tagmask: Integer=-1; log: Boolean=false): ITP;
const
tsize = mTileSize;
var
- i: Integer;
- dx, dy, d: Integer;
- xerr, yerr: Integer;
- incx, incy: Integer;
- stepx, stepy: Integer;
- x, y: Integer;
- maxx, maxy: Integer;
- gw, gh: Integer;
- ccidx: Integer;
- curci: Integer;
+ wx0, wy0, wx1, wy1: Integer; // window coordinates
+ stx, sty: Integer; // "steps" for x and y axes
+ dsx, dsy: Integer; // "lengthes" for x and y axes
+ dx2, dy2: Integer; // "double lengthes" for x and y axes
+ xd, yd: Integer; // current coord
+ e: Integer; // "error" (as in bresenham algo)
+ rem: Integer;
+ term: Integer;
+ xptr, yptr: PInteger;
+ xfixed: Boolean;
+ temp: Integer;
+ ccidx, curci: Integer;
+ lastGA: Integer = -1;
+ ga, x, y: Integer;
+ gw, gh, minx, miny, maxx, maxy: Integer;
cc: PGridCell;
px: PBodyProxyRec;
lq: LongWord;
- minx, miny: Integer;
- ptag: Integer;
- lastWasInGrid: Boolean;
- tbcross: Boolean;
- f: Integer;
- //tedist: Integer;
+ f, ptag: Integer;
+ x0, y0, x1, y1: Integer;
+ //swapped: Boolean = false; // true: xd is yd, and vice versa
+ // horizontal walker
+ {$IFDEF GRID_USE_ORTHO_ACCEL}
+ wklen, wkstep: Integer;
+ //wksign: Integer;
+ hopt: Boolean;
+ {$ENDIF}
+ // skipper
+ xdist, ydist: Integer;
begin
log := false;
result := Default(ITP);
tagmask := tagmask and TagFullMask;
if (tagmask = 0) or not assigned(cb) then exit;
+ if (ax0 = ax1) and (ay0 = ay1) then
+ begin
+ result := forEachAtPoint(ax0, ay0, cb, tagmask, @ptag);
+ exit;
+ end;
+
+ gw := mWidth;
+ gh := mHeight;
minx := mMinX;
miny := mMinY;
+ maxx := gw*tsize-1;
+ maxy := gh*tsize-1;
- dx := x1-x0;
- dy := y1-y0;
+ x0 := ax0;
+ y0 := ay0;
+ x1 := ax1;
+ y1 := ay1;
- 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;
+ // offset query coords to (0,0)-based
+ Dec(x0, minx);
+ Dec(y0, miny);
+ Dec(x1, minx);
+ Dec(y1, miny);
- if (incx = 0) and (incy = 0) then exit; // just incase
+ // clip rectange
+ wx0 := 0;
+ wy0 := 0;
+ wx1 := maxx;
+ wy1 := maxy;
- dx := abs(dx);
- dy := abs(dy);
+ // 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
+ //swapped := true;
+ xptr := @yd;
+ yptr := @xd;
+ swapInt(x0, y0);
+ swapInt(x1, y1);
+ swapInt(dsx, dsy);
+ swapInt(wx0, wy0);
+ swapInt(wx1, wy1);
+ swapInt(stx, sty);
+ end
+ else
+ begin
+ xptr := @xd;
+ yptr := @yd;
+ end;
+
+ dx2 := 2*dsx;
+ dy2 := 2*dsy;
+ xd := x0;
+ yd := y0;
+ e := 2*dsy-dsx;
+ term := x1;
+
+ 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
+ // DON'T DO THIS! loop will take care of that
+ if (xd = term) then
+ begin
+ result := forEachAtPoint(ax0, ay0, cb, tagmask, @ptag);
+ exit;
+ end;
- if (dx > dy) then d := dx else d := dy;
+ (*
+ // move coords
+ if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
+ xd += stx;
+ // done?
+ if (xd = term) then exit;
+ *)
- // `x` and `y` will be in grid coords
- x := x0-minx;
- y := y0-miny;
+ {$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)');
+ {$ENDIF}
+ // DON'T DO THIS! loop will take care of that
+ //lastGA := (yptr^ div tsize)*gw+(xptr^ div tsize);
+ //ccidx := mGrid[lastGA];
// increase query counter
Inc(mLastQuery);
begin
// just in case of overflow
mLastQuery := 1;
- for i := 0 to High(mProxies) do mProxies[i].mQueryMark := 0;
+ for f := 0 to High(mProxies) do mProxies[f].mQueryMark := 0;
end;
lq := mLastQuery;
- // cache various things
- //tsize := mTileSize;
- gw := mWidth;
- gh := mHeight;
- maxx := gw*tsize-1;
- maxy := gh*tsize-1;
-
- // setup distance and flags
- lastWasInGrid := (x >= 0) and (y >= 0) and (x <= maxx) and (y <= maxy);
-
- // setup starting tile ('cause we'll adjust tile vars only on tile edge crossing)
- if lastWasInGrid then ccidx := mGrid[(y div tsize)*gw+(x div tsize)] else ccidx := -1;
-
- // it is slightly faster this way
- xerr := -d;
- yerr := -d;
-
- if (log) then e_WriteLog(Format('tracing: (%d,%d)-(%d,%d)', [x, y, x1-minx, y1-miny]), MSG_NOTIFY);
-
- // now trace
- i := 0;
- while (i < d) do
+ {$IFDEF GRID_USE_ORTHO_ACCEL}
+ // if this is strict horizontal/vertical trace, use optimized codepath
+ if (ax0 = ax1) or (ay0 = ay1) then
begin
- Inc(i);
- // do one step
- xerr += dx;
- yerr += dy;
- // invariant: one of those always changed
+ // 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 begin {wksign := -1;} wklen := -(term-xd); end else begin {wksign := 1;} wklen := term-xd; end;
{$IF DEFINED(D2F_DEBUG)}
- if (xerr < 0) and (yerr < 0) then raise Exception.Create('internal bug in grid raycaster (0)');
+ if dbgShowTraceLog then e_LogWritefln('optimized htrace; wklen=%d', [wklen]);
{$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
+ ga := (yptr^ div tsize)*gw+(xptr^ div tsize);
+ // one of those will never change
+ x := xptr^+minx;
+ y := yptr^+miny;
{$IF DEFINED(D2F_DEBUG)}
- if ((stepx or stepy) = 0) then raise Exception.Create('internal bug in grid raycaster (1)');
+ if hopt then
+ begin
+ if (y <> ay0) then raise Exception.Create('htrace fatal internal error');
+ end
+ else
+ begin
+ if (x <> ax0) then raise Exception.Create('vtrace fatal internal error');
+ end;
{$ENDIF}
+ while (wklen > 0) do
begin
- // check for crossing tile/grid boundary
- if (x >= 0) and (y >= 0) and (x <= maxx) and (y <= maxy) then
+ {$IF DEFINED(D2F_DEBUG)}
+ if dbgShowTraceLog then e_LogWritefln(' htrace; ga=%d; x=%d, y=%d; y=%d; y=%d', [ga, xptr^+minx, yptr^+miny, y, ay0]);
+ {$ENDIF}
+ // new tile?
+ if (ga <> lastGA) then
begin
- // 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)];
- 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
+ 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
- // 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
+ cc := @mCells[ccidx];
+ for f := 0 to GridCellBucketSize-1 do
begin
- // horizontal line
- if (incx < 0) then tedist := x-(x and (not tsize)) else tedist := (x or (tsize-1))-x;
- if (tedist > 1) 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
- 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);
+ px.mQueryMark := lq; // mark as processed
+ 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;
- *)
- (*
- 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;
+ // next cell
+ ccidx := cc.next;
+ 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^;
{$IF DEFINED(D2F_DEBUG)}
- if (tedist < 0) then raise Exception.Create('internal bug in grid raycaster (2.x)');
+ if dbgShowTraceLog then e_LogWritefln(' right step: wklen=%d; wkstep=%d', [wklen, wkstep]);
{$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 (wkstep >= wklen) then break;
+ Inc(xptr^, wkstep);
+ Inc(ga);
+ end
+ else
+ begin
+ // to the left
+ wkstep := xptr^-((xptr^ and (not (mTileSize-1)))-1);
{$IF DEFINED(D2F_DEBUG)}
- if (f < 0) then raise Exception.Create('internal bug in grid raycaster (2.y)');
+ if dbgShowTraceLog then e_LogWritefln(' left step: wklen=%d; wkstep=%d', [wklen, wkstep]);
{$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;
- *)
+ if (wkstep >= wklen) then break;
+ Dec(xptr^, wkstep);
+ Dec(ga);
end;
end
else
begin
- // out of grid
- if lastWasInGrid then exit; // oops, stepped out of the grid -- there is no way to return
+ 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;
+ exit;
+ end;
+ {$ENDIF}
+
+ {$IF DEFINED(D2F_DEBUG_RAYTRACE)}
+ if assigned(dbgRayTraceTileHitCB) then dbgRayTraceTileHitCB((xptr^ div tsize*tsize)+minx, (yptr^ div tsize*tsize)+miny);
+ {$ENDIF}
- // has something to process in the current cell?
+ ccidx := -1;
+ // can omit checks
+ while (xd <> term) do
+ begin
+ // check cell(s)
+ {$IF DEFINED(D2F_DEBUG)}
+ if (xptr^ < 0) or (yptr^ < 0) or (xptr^ >= gw*tsize) and (yptr^ >= 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}
+ lastGA := ga;
+ ccidx := mGrid[lastGA];
+ end;
+ // has something to process in this tile?
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);
+ x := xptr^+minx;
+ y := yptr^+miny;
// process cell list
while (curci <> -1) do
begin
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;
+ 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;
// next cell
curci := cc.next;
end;
- ccidx := -1; // don't process this anymore
- // convert coords to grid
- //Dec(x, minx);
- //Dec(y, miny);
+ // nothing more interesting in this cell
+ ccidx := -1;
+ end;
+ // move to cell edge, as we have nothing to trace here anymore
+ if (stx < 0) then xdist := xd and (not (mTileSize-1)) else xdist := xd or (mTileSize-1);
+ if (sty < 0) then ydist := yd and (not (mTileSize-1)) else ydist := yd or (mTileSize-1);
+ //e_LogWritefln('0: swapped=%d; xd=%d; yd=%d; stx=%d; sty=%d; e=%d; dx2=%d; dy2=%d; term=%d; xdist=%d; ydist=%d', [swapped, xd, yd, stx, sty, e, dx2, dy2, term, xdist, ydist]);
+ while (xd <> xdist) and (yd <> ydist) do
+ begin
+ // step
+ xd += stx;
+ if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
+ //e_LogWritefln(' xd=%d; yd=%d', [xd, yd]);
+ if (xd = term) then break;
end;
+ //e_LogWritefln('1: swapped=%d; xd=%d; yd=%d; stx=%d; sty=%d; e=%d; dx2=%d; dy2=%d; term=%d; xdist=%d; ydist=%d', [swapped, xd, yd, stx, sty, e, dx2, dy2, term, xdist, ydist]);
+ if (xd = term) then break;
+ //putPixel(xptr^, yptr^);
+ // move coords
+ if (e >= 0) then begin yd += sty; e -= dx2; end else e += dy2;
+ xd += stx;
end;
end;