module GLHelp (mglCreate,mglDelete,checkGLError,glCreate) where

import Foreign.Marshal
import Foreign.Ptr
import Foreign.Storable
import Graphics.GL.Core45

mglCreate :: (GLsizei -> Ptr GLuint -> IO ()) -> IO GLuint
mglCreate f = alloca $ \ptr -> f 1 ptr >> peek ptr

glCreate :: (GLsizei -> Ptr GLuint -> IO ()) -> Int -> IO [GLuint]
glCreate f n = alloca $ \ptr -> f (fromIntegral n) ptr >> peekArray n ptr

mglDelete :: (GLsizei -> Ptr GLuint -> IO ()) -> GLuint -> IO ()
mglDelete f i = with i $ f 1

checkGLError :: String -> IO ()
checkGLError s = do
    err <- glGetError
    case err of
        0 -> return ()
        i -> error $ "OpenGL error: " ++ show i ++ " - " ++ s