Type TMatrix
  Field aa#, ab#, ac#
  Field ba#, bb#, bc#
  Field ca#, cb#, cc#
End Type

Type TPoint
   Field X#, Y#
End Type

Function CreateMatrix.TMatrix()
   m.TMatrix = New TMatrix
   MatrixIdentity(m)
   Return m
End Function

Function MatrixIdentity(m.TMatrix)
   m\aa# = 1: m\ab# = 0: m\ac# = 0
   m\ba# = 0: m\bb# = 1: m\bc# = 0
   m\ca# = 0: m\cb# = 0: m\cc# = 1
End Function

Function MatrixRotate(m.TMatrix, a#)
   m\aa# =  Cos(a#): m\ab# = Sin(a#): m\ac# = 0
   m\ba# = -Sin(a#): m\bb# = Cos(a#): m\bc# = 0
   m\ca# =  0:       m\cb# = 0:       m\cc# = 1
End Function

Function MatrixTranslate(m.TMatrix, x#, y#)
   m\aa# =  1: m\ab# =  0: m\ac# = 0
   m\ba# =  0: m\bb# =  1: m\bc# = 0
   m\ca# = x#: m\cb# = y#: m\cc# = 1
End Function

Function PointMultMatrix(p.TPoint, m.TMatrix, r.TPoint)
   r\X# = p\X#*m\aa# + p\Y#*m\ba# + m\ca#
   r\Y# = p\X#*m\ab# + p\Y#*m\bb# + m\cb#
End Function

Global Rotate.TMatrix, Translate.TMatrix
Global Point1.TPoint, Point2.TPoint
Global Angle#, X#, Y#
Global Temp1.TPoint, Temp2.TPoint

Graphics(640, 480, 0, 2)
SetBuffer(BackBuffer())

Rotate    = New TMatrix
Translate = New TMatrix

Point1 = New TPoint
Point1\X# = -25.0 : Point1\Y# = 0.0

Point2 = New TPoint
Point2\X# = +25.0 : Point2\Y# = 0.0

X# = 320.0 : Y# = 240.0
Temp1 = New TPoint : Temp2 = New TPoint

While Not KeyDown(1)
   Cls()

   If KeyDown(30) Then Angle# = Angle#-1.0
   If KeyDown(44) Then Angle# = Angle#+1.0
   
   If KeyDown(200) Then Y# = Y#-1.0
   If KeyDown(208) Then Y# = Y#+1.0
   If KeyDown(203) Then X# = X#-1.0
   If KeyDown(205) Then X# = X#+1.0

   MatrixRotate(Rotate, Angle#)
   MatrixTranslate(Translate, X#, Y#)

   PointMultMatrix(Point1, Rotate, Temp1)
   PointMultMatrix(Temp1, Translate, Temp1)

   PointMultMatrix(Point2, Rotate, Temp2)
   PointMultMatrix(Temp2, Translate, Temp2)
   
   Line(Temp1\X#, Temp1\Y#, Temp2\X#, Temp2\Y#)
   Flip()
Wend

End