Pixel Displacement Map - use GDI+ or Direct2D or ..... ?

[SeabrookStan]

Is it possible to create a "Displacement Bitmap" or "Pixel Displacement Map" to achieve the effects in my image, by pre-calculating pixel displacements, storing the displacement vectors in an array, and offloading the heavy lifting to the GPU? My Googling leads me to suspect GDI+ and Direct2D can do it, but I can't find any examples I can learn from.

The furthest I've gotten is these two links:
https://docs.microsoft.com/en-us/win...splacement-map
https://innerdrivestudios.com/home/d...t-maps-basics/

Can anyone help me figure out how to do this through VB6?

Option Explicit               'SeabrookStan 12/2021
Dim hW As Long, hH As Long
Const Pi = 3.14159265
Const HalfPi = 3.14159265 / 2


Private Sub Form_Load()
  hW = PBo.ScaleWidth / 2   'halfWidth    (PBo contains the original image)
  hH = PBo.ScaleHeight / 2  'halfHeight
  Show
  PB1.Picture = PBo.Picture
  PB2.Picture = PBo.Picture
  PB3.Picture = PBo.Picture
  PB4.Picture = PBo.Picture
  DisplacePixels
End Sub


Private Sub DisplacePixels()
  Dim DisplacementRadius As Single
  Dim x As Long, y As Long
  Dim dX As Single, dY As Single
  Dim D As Single, P As Single, A As Single
  
  DisplacementRadius = hH * 0.94 'arbitrary radius size of circular distortion
  
  For x = 0 To PBo.ScaleWidth
    For y = 0 To PBo.ScaleHeight
      dX = (x - hW): dY = (y - hH)    'Horizontal and Vertical distances from center of distortion
      D = Sqr(dX * dX + dY * dY)      'Distance of Destination Pixel from Distortion Center (vector length)
      If D > DisplacementRadius Then
      
      Else
      
        'Magnify -> PB1
        P = D / DisplacementRadius
        PB1.PSet (x, y), PBo.Point(hW + dX * P, hH + dY * P)
        
        'Shrink -> PB2
        P = 2 - (D / DisplacementRadius)
        PB2.PSet (x, y), PBo.Point(hW + dX * P, hH + dY * P)
        
        'Rotate -> PB3
        'A = ArcTanRadians(dX, dY) 'Current angle
        'PB3.PSet (x, y), PBo.Point(hW + D * Sin(A + 10), hH + D * Cos(A + 10))
        
        'Ripple -> PB3
        A = ArcTanRadians(dX, dY) 'Current angle
        PB3.PSet (x, y), PBo.Point(hW + (D + Cos(D * 0.1) * 8) * Sin(A), hH + (D + Cos(D * 0.1) * 8) * Cos(A))
        
        'Spiral -> PB4
        P = (DisplacementRadius - D) / (D + 0.0001) '   0.0001 to avoid division by zero error
        A = A + P * HalfPi * 0.25 'Current angle, plus additional varying angle
        PB4.PSet (x, y), PBo.Point(hW + D * Sin(A), hH + D * Cos(A))
         
      End If
      
      'Waves -> PB5
      PB5.PSet (x, y), PBo.Point(x, y + Cos(x * 0.02) * 20)
        
    Next y
    Refresh
  Next x
  
End Sub


Public Function ArcTanRadians(y As Single, x As Single) As Single
  If x > 0 Then
    ArcTanRadians = Atn(y / x)
  ElseIf x < 0 Then
    ArcTanRadians = Sgn(y) * (Pi - Atn(Abs(y / x)))
  ElseIf y = 0 Then
    ArcTanRadians = 0
  Else
    ArcTanRadians = Sgn(y) * HalfPi
  End If
End Function