starting tesselation shader

1 files changed, 30 insertions, 0 deletions

diff --git a/Graphics/Glyph/ExtendedGL.hs b/Graphics/Glyph/ExtendedGL.hs
index d42e973..7742ba8 100644
--- a/Graphics/Glyph/ExtendedGL.hs
+++ b/Graphics/Glyph/ExtendedGL.hs
@@ -4,6 +4,14 @@ import Graphics.Rendering.OpenGL
 import Graphics.Rendering.OpenGL.Raw.Core31
 import Graphics.Rendering.OpenGL.Raw.ARB
 
+import Foreign.Marshal.Alloc
+import Foreign.Ptr
+import Foreign.Storable
+import Foreign.C.Types
+
+import System.IO.Unsafe
+import Control.Monad
+
 marshalPrimitiveMode :: PrimitiveMode -> GLenum
 marshalPrimitiveMode x = case x of
    Points -> 0x0
@@ -24,3 +32,25 @@ vertexAttributeDivisor :: AttribLocation -> SettableStateVar GLuint
 vertexAttributeDivisor (AttribLocation loc) =
     makeSettableStateVar $ \val ->
         glVertexAttribDivisor loc val
+
+patchVertices :: (Integral a) => SettableStateVar a
+patchVertices = 
+    makeSettableStateVar $ \val ->
+        glPatchParameteri gl_PATCH_VERTICES $ fromIntegral val
+
+maxPatchVertices :: IO CInt
+maxPatchVertices =
+        alloca $ \ptr -> do
+            glGetIntegerv gl_MAX_PATCH_VERTICES ptr
+            peek ptr
+
+getGLVersion :: IO String
+getGLVersion =
+    let lift2 (a,b) = do
+            x <- a ; y <- b ; return (x,y)
+             in
+    alloca $ \ptr1 -> alloca $ \ptr2 -> do
+        glGetIntegerv gl_MAJOR_VERSION ptr1
+        glGetIntegerv gl_MINOR_VERSION ptr2
+        (v1,v2) <- lift2 (peek ptr1, peek ptr2)
+        return ("OpenGL " ++ show v1 ++ "." ++ show v2)