[Haskell-cafe] Help with optimization
mmitar at gmail.com
Sun Jul 20 08:13:16 EDT 2008
Profiling says that my program spends 18.4 % of time (that is around
three seconds) and 18.3 % of allocations in this function which is
saving the rendered image to a PPM file:
saveImageList :: String -> Int -> Int -> [ViewportDotColor] -> IO ()
saveImageList filename width height image = do
B.writeFile filename file
where file = B.append header bytes
header = C.pack $ "P6\n" ++ show width ++ " " ++ show height
bytes = B.pack $ concatMap (color . dealpha .
(\(ViewportDotColor _ c) -> c)) image
where color (VoxelColor red green blue _) = [floor $ red *
255, floor $ green * 255, floor $ blue * 255]
dealpha c = addColor c (VoxelColor 1.0 1.0 1.0 1.0)
-- white background
For a 921615 bytes large file to save this is too much in my opinion.
And I think that it consumes to much allocations. Probably it should
not store intermediate lists?
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