time = Uniform "Time" :: Float

image color = FrameBuffer (DepthImage @1 1000.0, ColorImage @1 (color :: Vec 4 Float))

triangleRasterCtx = TriangleCtx CullNone PolygonFill NoOffset LastVertex
colorFragmentCtx = (DepthOp Less True, ColorOp NoBlending (V4 True True True True))

rasterizeWith = rasterizePrimitives
triangles = triangleRasterCtx

cubeVertexStream = fetch "stream4" ((Attribute "position4" :: Vec 4 Float))
mapFragments2 s fs bg = accumulate colorFragmentCtx (\((a)) -> ((fs a))) s bg

cube fv f bg = (cubeVertexStream         -- cube vertices
     &  mapPrimitives (\((v)) -> (fv v, v))
     &             rasterizeWith triangles ((Smooth))  -- rasterize
    `mapFragments2` f) bg

trMat a b = a *. b
rotate' v = (Uniform "MVP" :: Mat 4 4 Float) *. v
trX a b = V4 (a :: Float) 0 0.0 0 + b

main = ScreenOut $ 
    foldl' (\fb a -> cube (
        trMat (rotMatrixZ $ time *! a) .
        rotate' .
        (trX (0.5 *! a +! sin time *! 0.1)) . 
        (scale 0.04) . 
        trMat (rotMatrixX (time *! 2.0 *! a))
        ) id fb)
    (image navy)
    [ a | x <- [ (-0.5,True)
               , (0.0,True)
               , (0.5,True)
               , (0.3,True)
               , (0.75,True)
               ] ++ [(a,True) | a <- [(-1.0)..2.0]]
    , let (a,b) = x
    , b
    ]