Re: [Haskell-cafe] OpenGL: No instance for Random GLfloat
Hi,
GLfloat haskell is instance of several number related typeclasses. A
function like 'fromRational' could be used to create a GLfloat from another
number that has a random instance.
L
On May 3, 2012 4:39 AM, Mark Spezzano mark.spezz...@chariot.net.au
wrote:
Hi,
I tried this but now I get another error:
The data constructors of `GLfloat' are not all in scope
so you cannot derive an instance for it
In the stand-alone deriving instance for `Random GLfloat'
Mark
On 03/05/2012, at 10:39 AM, Patrick Palka wrote:
Because GLfloat is simply a newtype wrapper for CFloat, which has a Random
instance, I would do:
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
deriving instance Random GLFloat
On Wed, May 2, 2012 at 6:29 PM, Mark Spezzano
mark.spezz...@chariot.net.au wrote:
Hi Haskellers,
I'm trying to generate a random vertex in OpenGL as follows.
genPosition :: IO (Vertex3 GLfloat)
genPosition = do x - getStdRandom $ randomR (-1.6,1.6)
y - getStdRandom $ randomR (-1.0,1.0)
return (Vertex3 x y (-1))
Unfortunately the compiler complains about me having to implement an
instance of Random for GLfloat.
How do I do this (or avoid having to do this)?
Cheers,
Mark
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[Haskell-cafe] OpenGL: No instance for Random GLfloat
Hi Haskellers, I'm trying to generate a random vertex in OpenGL as follows. genPosition :: IO (Vertex3 GLfloat) genPosition = do x - getStdRandom $ randomR (-1.6,1.6) y - getStdRandom $ randomR (-1.0,1.0) return (Vertex3 x y (-1)) Unfortunately the compiler complains about me having to implement an instance of Random for GLfloat. How do I do this (or avoid having to do this)? Cheers, Mark ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] OpenGL: No instance for Random GLfloat
Because GLfloat is simply a newtype wrapper for CFloat, which has a Random
instance, I would do:
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
deriving instance Random GLFloat
On Wed, May 2, 2012 at 6:29 PM, Mark Spezzano
mark.spezz...@chariot.net.auwrote:
Hi Haskellers,
I'm trying to generate a random vertex in OpenGL as follows.
genPosition :: IO (Vertex3 GLfloat)
genPosition = do x - getStdRandom $ randomR (-1.6,1.6)
y - getStdRandom $ randomR (-1.0,1.0)
return (Vertex3 x y (-1))
Unfortunately the compiler complains about me having to implement an
instance of Random for GLfloat.
How do I do this (or avoid having to do this)?
Cheers,
Mark
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Re: [Haskell-cafe] OpenGL: No instance for Random GLfloat
Hi,
I tried this but now I get another error:
The data constructors of `GLfloat' are not all in scope
so you cannot derive an instance for it
In the stand-alone deriving instance for `Random GLfloat'
Mark
On 03/05/2012, at 10:39 AM, Patrick Palka wrote:
Because GLfloat is simply a newtype wrapper for CFloat, which has a Random
instance, I would do:
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
deriving instance Random GLFloat
On Wed, May 2, 2012 at 6:29 PM, Mark Spezzano mark.spezz...@chariot.net.au
wrote:
Hi Haskellers,
I'm trying to generate a random vertex in OpenGL as follows.
genPosition :: IO (Vertex3 GLfloat)
genPosition = do x - getStdRandom $ randomR (-1.6,1.6)
y - getStdRandom $ randomR (-1.0,1.0)
return (Vertex3 x y (-1))
Unfortunately the compiler complains about me having to implement an instance
of Random for GLfloat.
How do I do this (or avoid having to do this)?
Cheers,
Mark
___
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