function InTriangle(const Pt, v1, v2, v3:TPoint): Boolean;
var
  b1,b2,b3: Boolean;
  p1,p2,p3: TPoint;
begin
  p1:=v1; p2:=v2; p3:=v3;
  if p3.y < p1.y then tSwap(p1,p3);
  if p1.x < p2.x then tSwap(p1,p2);
  b1 := (pt.x - p2.x) * (p1.y - p2.y) - (p1.x - p2.x) * (pt.y - p2.y) < 0;
  b2 := (pt.x - p3.x) * (p2.y - p3.y) - (p2.x - p3.x) * (pt.y - p3.y) < 0;
  if (b1 <> b2) then Exit;
  b3 := (pt.x - p1.x) * (p3.y - p1.y) - (p3.x - p1.x) * (pt.y - p1.y) < 0;
  if (b2 <> b3) then Exit;
  Result := True;
end;

function TPAFromTriangle(P1, P2, P3: TPoint): TPointArray;
var
  x, y, r: Integer;
  b: TBox;
  p: TPoint;
begin
  b := IntToBox(Min(Min(P1.X, P2.X), P3.X), Min(Min(P1.Y, P2.Y), P3.Y), Max(Max(P1.X, P2.X), P3.X), Max(Max(P1.Y, P2.Y), P3.Y));
  SetLength(Result, (((b.X2 - b.X1) + 1) * ((b.Y2 - b.Y1) + 1)));
  r := 0;
  for y := b.Y1 to b.Y2 do
    for x := b.X1 to b.X2 do
    begin
      p.X := x;
      p.Y := y;
      if InTriangle(p, P1, P2, P3) then
      begin
        Result[r] := p;
        r := (r + 1);
      end;
    end;
  SetLength(Result, r);
end;

procedure DebugBitmap(bmp: Integer);
var
  w, h: Integer;
begin
  GetBitmapSize(bmp, w, h);
  DisplayDebugImgWindow(w, h);
  DrawBitmapDebugImg(bmp);
end;

var
  triangle: array[0..2] of TPoint;
  x, y, i: Integer;
  bmp: Integer;
  t: TPointArray;
  s: Integer;

begin
  for i := 0 to 2 do
  begin
    triangle[i].X := (50 + Random(700));
    triangle[i].Y := (50 + Random(500));
  end;
  s := GetSystemTime;
  t := TPAFromTriangle(triangle[0], triangle[1], triangle[2]);
  WriteLn(IntToStr(GetSystemTime - s) + ' ms.');
  bmp := CreateBitmap(900, 600);
  DrawTPABitmap(bmp, t, 255);
  FastSetPixel(bmp, triangle[0].X, triangle[0].Y, 16777215);
  FastSetPixel(bmp, triangle[1].X, triangle[1].Y, 16024898);
  FastSetPixel(bmp, triangle[2].X, triangle[2].Y, 32768);
  DebugBitmap(bmp);
end.