main = let
  emptyFB           = FrameBuffer (colorImage1 (V4 0.0 0.0 0.4 1.0))
  rasterCtx         = TriangleCtx CullNone PolygonFill NoOffset LastVertex
  fragmentCtx       = accumulationContext (ColorOp NoBlending (V4 True True True True))
  vertexShader v    = (v, v)
  vertexStream      = fetch "stream4" Triangle (Attribute "position4" :: Vec 4 Float)
  primitiveStream   = mapPrimitives vertexShader vertexStream
  fragmentStream    = rasterizePrimitives rasterCtx Smooth primitiveStream
  fragmentShader    = \v -> v --(V4F 1.0 0.0 0.0 1.0)
  frame             = accumulate fragmentCtx fragmentShader fragmentStream emptyFB
 in ScreenOut frame