Example of setting up OpenCL to use an OpenGL context. Uses the CLUtil library.

CLGLInterop.hs

{-# LANGUAGE ForeignFunctionInterface #-}
module Renderer.CLGLInterop (initFromGL) where
import Control.Parallel.CLUtil
import Foreign.Ptr (nullPtr, Ptr)

foreign import ccall "CGLGetCurrentContext"
  cGLGetCurrentContext :: IO (Ptr ())

foreign import ccall "CGLGetShareGroup"
  cGLGetShareGroup :: Ptr () -> IO (Ptr ())

initFromGL :: CLDeviceType -> IO OpenCLState
initFromGL devType = 
  do (dev:_) <- clGetDeviceIDs nullPtr devType
     shareGroup <- cGLGetCurrentContext >>= cGLGetShareGroup
     context <- clCreateContext [CL_CGL_SHAREGROUP_KHR shareGroup]
                                [dev]
                                putStrLn
     q <- clCreateCommandQueue context dev []
     return $ OpenCLState dev context q