Re: [Haskell-beginners] Performance problem with Haskell/OpenGL/GLFW

I'm building glfw now on 10.7.5 and I'll try your test code. I've been learning haskell (still very much a beginner) but I know OpenGL, so I'm very interested in how this turns out. -Hollister On Mar 10, 2013, at 4:38 AM, Jesper Särnesjö wrote:

On Sun, Mar 10, 2013 at 4:46 PM, Jesper Särnesjö wrote:

...

I've figured out what the problem is: the Haskell program is using a software implementation of OpenGL, so rendering *does* in fact happen on the CPU.

It would appear that there is in fact some relevant difference between the Haskell and C versions of my program, or possibly some way in which the bindings from the GLFW-b package are different from the C library.

To remove any possibility of the problem being in GLFW-b or OpenGLRaw, I created two new programs, one in Haskell [1] and one in C [2], that don't import or include anything related to OpenGL, and that simply create a context, check if it is hardware accelerated, and then exit. That is all. And still, the Haskell program receives a software renderer, while the C program receives a hardware one:

$ ghc -O2 Test2.hs -lglfw -framework OpenGL -fforce-recomp && ./Test2 [1 of 1] Compiling Main ( Test2.hs, Test2.o ) Linking Test2 ... software (2,7,7) (3,2,0) $ gcc -O2 test2.c -lglfw -framework OpenGL && ./a.out hardware 2.7.7 3.2.0

I haven't had the chance to run these programs on any OS other than Mac OS X 10.8.2, so I don't know if this problem is Mac-specific. Still, it's really weird that the system would differentiate between Haskell and C programs in this way.

If anyone has any ideas about what's going on here, I'd very much like to hear them.

-- Jesper Särnesjö http://jesper.sarnesjo.org/

[1] https://gist.github.com/sarnesjo/5116084#file-test2-hs [2] https://gist.github.com/sarnesjo/5116084#file-test2-c

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