aUCBLogo Demos and Tests / test_coordinate_transform

to test_coordinate_transform
   phi=137
   w1=1
;   perspective
   clearScreen
   W=toMatrix
   (list
      (list   cos w1    -sin w1   0)
      (list   sin w1     cos w1   0)
      (list   0          0         1)
   )
   T=toMatrix
   (list
      (list   1   0          1        )
      (list   0   cos phi    -sin phi)
      (list   0   sin phi     cos phi)
   )
   T1=invertMatrix T
   mat=ModelviewMatrix
   center=FloatArray last mat
   R=toMatrix butLast mat
   repeat 360
   [   R=T1*W*T*R
      (setModelviewMatrix R center)
      setPenColor HSBA # 1 1 0.3
      repeat 4 [fd 100 rt 90]
      updateGraph
   ]
end