[reactive] windowPoint function in Reactive/GLUT/SimpleGL.hs
bugfact at gmail.com
Sat Nov 29 12:11:49 EST 2008
The windowPoint function in Reactive/GLUT/SimpleGL.hs has the following
-- | Convert a window position to a logical X,Y. Logical zero is at the
-- origin, and [size??].
-- TODO: this def is completely broken. What do I even want? Probably to
-- go backward through the viewing transform to the XY plane.
The function I made in the past for doing this is:
windowPoint :: GL.Position -> IO (Double,Double)windowPoint
pos@(GL.Position x y) =
viewport@(_,GL.Size _ height) <- get GL.viewport
modelviewMatrix <- getMatrix $ GL.Modelview 0
projectionMatrix <- getMatrix $ GL.Projection
let pos3 = GL.Vertex3 (fromIntegral x) (fromIntegral (height-y)) 0
GL.Vertex3 vx vy _ <- GLU.unProject pos3 modelviewMatrix
getMatrix :: GL.MatrixMode -> IO(GL.GLmatrix Scalar)
getMatrix mode = get $ GL.matrix $ Just mode
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