Talk:OpenGLTutorial2

Excellent article and it got me going with OpenGL and Haskell but there is a small mistake that prevents the successful compilation at the point "3.1 Animation" in the revised Display.hs, function 'idle' ...

idle angle = do
  a <- get angle
  angle $=! a+0.1
  postRedisplay Nothing

To get it to work on Ubuntu with ghc 6.12.3 I had to change it by enclosing the update in parentheses like so,

idle angle = do
  a <- get angle
  angle $=! (a+0.1)
  postRedisplay Nothing

Hope that helps somebody else! EmacsTheViking