Xor 2 Fans

The _MapTriangle subst code works here but QBJS still needs Xor:
_Title "Xor 2 fans" 'b+ 2022-09-10 just saw at JB
' hmm... how to do this in QB64?
Screen _NewImage(800, 600, 32)
Dim As Long f1, f2
f1 = _NewImage(800, 600, 32)
f2 = _NewImage(800, 600, 32)
Color , &HFF990000
Do
   Cls
   ao1 = ao1 + .012: ao2 = ao2 - .012
   _Dest f1
   Line (0, 0)-(799, 599), _RGB32(0, 0, 0), BF
   drawFan 300, 300, 295, 32, &HFFFFFFFF, ao1

   _Dest f2
   Line (0, 0)-(799, 599), _RGB32(0, 0, 0), BF
   drawFan 500, 300, 295, 32, &HFFFFFFFF, ao2

   _Dest 0
   For y = 0 To 599
       For x = 0 To 799
           _Source f1
           If Point(x, y) = _RGB32(0, 0, 0) Then p1 = 0 Else p1 = -1
           _Source f2
           If Point(x, y) = _RGB32(0, 0, 0) Then p2 = 0 Else p2 = -1
           If p1 Xor p2 Then PSet (x, y), &HFFAAAAAA ' tone it down a bit
       Next
   Next
   _Display
   _Limit 60 'Draw as fast as you can!
Loop

Sub drawFan (x, y, r, nBlades, colr As _Unsigned Long, ao)
   angle = _Pi(1 / nBlades)
   For i = 0 To 2 * nBlades - 1 Step 2
       x1 = x + r * Cos(i * angle + ao)
       y1 = y + r * Sin(i * angle + ao)
       x2 = x + r * Cos((i + 1) * angle + ao)
       y2 = y + r * Sin((i + 1) * angle + ao)
       filltri x, y, x1, y1, x2, y2, colr
   Next
End Sub

'Sub ftri (x1, y1, x2, y2, x3, y3, K As _Unsigned Long)
'    Dim D As Long
'    Static a&
'    D = _Dest
'    If a& = 0 Then a& = _NewImage(1, 1, 32)
'    _Dest a&
'    _DontBlend a& '  '<<<< new 2019-12-16 fix
'    PSet (0, 0), K
'    _Blend a& '<<<< new 2019-12-16 fix
'    _Dest D
'    _MapTriangle _Seamless(0, 0)-(0, 0)-(0, 0), a& To(x1, y1)-(x2, y2)-(x3, y3)
'End Sub

'Andy Amaya's triangle fill modified for QB64, use if color already set
Sub filltri (xx1, yy1, xx2, yy2, xx3, yy3, K As _Unsigned Long)
   Dim x1 As Single, y1 As Single, x2 As Single, y2 As Single, x3 As Single, y3 As Single
   Dim slope1 As Single, slope2 As Single, length As Single, x As Single, lastx%, y As Single
   Dim slope3 As Single
   'make copies before swapping
   x1 = xx1: y1 = yy1: x2 = xx2: y2 = yy2: x3 = xx3: y3 = yy3

   'triangle coordinates must be ordered: where x1 < x2 < x3
   If x2 < x1 Then Swap x1, x2: Swap y1, y2
   If x3 < x1 Then Swap x1, x3: Swap y1, y3
   If x3 < x2 Then Swap x2, x3: Swap y2, y3
   If x1 <> x3 Then slope1 = (y3 - y1) / (x3 - x1)

   'draw the first half of the triangle
   length = x2 - x1
   If length <> 0 Then
       slope2 = (y2 - y1) / length
       For x = 0 To length
           Line (Int(x + x1), Int(x * slope1 + y1))-(Int(x + x1), Int(x * slope2 + y1))
           lastx% = Int(x + x1)
       Next
   End If

   'draw the second half of the triangle
   y = length * slope1 + y1: length = x3 - x2
   If length <> 0 Then
       slope3 = (y3 - y2) / length
       For x = 0 To length
           If Int(x + x2) <> lastx% Then
               Line (Int(x + x2), Int(x * slope1 + y))-(Int(x + x2), Int(x * slope3 + y2))
           End If
       Next
   End If
End Sub