--
-- |
-- Module      : Logo
-- Authors     : Sean Seefried (http://www.cse.unsw.edu.au/~sseefried)
-- Copyright   : (c) 2006
-- License     : BSD3
-- Created     : 12 Jan 2006
--
module Logo
where

import Pan

effect :: UI DisplayFun
effect = do
           side       <- makeSlider "side" (1,100) 5
           numSquares <- makeISlider "number of squares" (1,60) 14
           sep        <- makeSlider "separation" (10,50) 20
           numCircles <- makeISlider "number of circles" (1,9) 3
           startRad   <- makeSlider "start radius" (10,100) 30
           swirlFactor <- makeSlider "swirl Factor" (100,10000) 500
           imageToDisplayFun $ swirl swirlFactor $ 
             manyCirclesOfSquares numCircles startRad sep numSquares side blue

----

manyCirclesOfSquares numCircles startRad separation numSquares side col =
  let n = fromIntegral numCircles
      rads = [startRad, startRad + separation .. startRad + (n-1) * separation]
  in  foldr over emptyI 
           (map (\r -> circleOfSquares numSquares r side col) rads)


circleOfSquares n rad side col = 
  let angles = [2*pi/(fromIntegral n),4*pi/(fromIntegral n) .. 2*pi]
      placeSquare ang= squareAtPosWithRotation 
                         (fromPolar (Pol rad ang)) ang side col
  in foldr over emptyI (map placeSquare angles)


squareAtPosWithRotation :: Point -> Frac -> Frac -> Colour -> ImageC
squareAtPosWithRotation (Pt x y) ang side col =
  let square = condR (squareReg side) (lift0 col) emptyI
  in translate (Vec x y) (rotate ang square)


squareReg :: Frac -> Region
squareReg s (Pt x y) = -s <= x && x <= s && -s <= y && y <= s