time = Uniform "Time" :: Float
deg45 = 0.78539816339
deg60 = 1.0471975512
deg360 = 6.28318530718

phase = fract (time *! 0.2)
smoothPhase = phase *! phase *! (3 -! 2 *! phase)

rotate' v = rotMatrixY (4.1 +! smoothPhase *! deg360) *. rotMatrixZ (deg45 *! 3) *. v

-- x = right, y = up
--leftSide :: Vec 2 Float -> Vec 4 Float
leftSide p = V4 0 1 blue (if p%y > 0.75 then 0 else 1)
  where
    blue = dot p (V2 0.5 (-0.5)) +! 0.4

-- x = up, y = left
--rightSide :: Vec 2 Float -> Vec 4 Float
rightSide p = V4 (p%x * p%x) 1 ((1 - p%x) * (1 - p%x))  (if p%y > 0.75 then 0 else 1)

-- x = left, y = down
--topSide :: Vec 2 Float -> Vec 4 Float
topSide p = V4 red 1 0  (if line > (-0.25) && line < 0 then 0 else 1)
  where
    red = dot p (V2 (-0.5) 0.5) +! 0.4
    line = dot p (V2 1 (-1))

len2 v = v%x*v%x + v%y*v%y + v%z*v%z

makeFrame (vertexstream :: PrimitiveStream Triangle ((Vec 4 Float)))

    = imageFrame (emptyDepthImage 1, emptyColorImage white)
  `overlay`
      vertexstream
    & mapPrimitives (\((x)) -> (scale (0.2 +! abs (0.5 -! smoothPhase) *! 0.6) . rotate' $ x, x))
    & rasterizePrimitives (TriangleCtx CullNone PolygonFill NoOffset LastVertex) ((Smooth))
    & mapFragments (\((pos)) -> --logo :: Vec 4 Float -> Vec 4 Float
        ((
        if abs pos%x > 0.99999 then rightSide (pos%yz *! sign pos%x *! 0.5 +! 0.5) else
        if abs pos%y > 0.99999 then topSide (pos%zx *! sign pos%y *! 0.5 +! 0.5) else
        if abs pos%z > 0.99999 then leftSide (pos%xy *! sign pos%z *! 0.5 +! 0.5) else black
        )))
    & accumulateWith (DepthOp Less True, ColorOp NoBlending (V4 True True True True))

main = renderFrame $
   makeFrame (fetch "stream4" ((Attribute "position4")))