cal3d-opengl-0.1: Graphics/Animation/Cal3D/OpenGL.hs

{-# LANGUAGE ForeignFunctionInterface #-}
{-# INCLUDE "cal3d_c.h" #-}

module Graphics.Animation.Cal3D.OpenGL
    ( getAmbientColor
    , getDiffuseColor
    , getSpecularColor
    )

where

import Foreign

import Graphics.Rendering.OpenGL
import Graphics.Animation.Cal3D

getAmbientColor :: Renderer -> IO (Color4 GLfloat)
getAmbientColor = withAmbientColorPtr toColor

getDiffuseColor :: Renderer -> IO (Color4 GLfloat)
getDiffuseColor = withDiffuseColorPtr toColor

getSpecularColor :: Renderer -> IO (Color4 GLfloat)
getSpecularColor = withSpecularColorPtr toColor

-- toColor takes a pointer to 4 bytes of 8-bit color component
-- and returns a nice OpenGL Color4 GLfloat.
toColor :: Ptr Word8 -> IO (Color4 GLfloat)
toColor ptr = do 
  {
    r <- peekElemOff ptr 0
  ; g <- peekElemOff ptr 1
  ; b <- peekElemOff ptr 2
  ; a <- peekElemOff ptr 3
  ; return $ Color4 (float r) (float g) (float b) (float a)
  }

-- Helper function for calColor
float :: Word8 -> GLfloat
float w = (fromIntegral w) / 255.0