Add attributes and begin to GL.

These provide a context manager for managing
glPushAttrib, glPopAttrib, glBegin and glEnd.

Author: adamlwgriffiths

pygly/gl.py

@@ -4,6 +4,8 @@
 .. moduleauthor:: Adam Griffiths <[email protected]>
 '''
 
+from contextlib import contextmanager
+
 from pyglet.gl import *
 
 from pyrr import rectangle
@@ -12,6 +14,10 @@
 def set_viewport( rect ):
     """Calls glViewport with the dimensions of
     the rectangle
+
+    This call can be undone by first calling
+    glPushAttrib( GL_VIEWPORT_BIT )
+    and later calling glPopAttrib().
     """
     glViewport(
         int(rect[ 0 ][ 0 ]),
@@ -30,6 +36,10 @@ def set_scissor( rect ):
     .. seealso::
         Module :py:mod:`pygly.window`
           Documentation of the :py:mod:`pygly.window` module.
+
+    This call can be undone by first calling
+    glPushAttrib( GL_SCISSOR_BIT )
+    and later calling glPopAttrib().
     """
     glScissor(
         int(rect[ (0,0) ]),
@@ -38,3 +48,34 @@ def set_scissor( rect ):
         int(rect[ (1,1) ])
         )
 
+@contextmanager
+def attributes( attributes ):
+    """Wraps glPushAttrib and glPopAttrib
+    in a context manager, providing the 'with'
+    keyword.
+
+    For example:
+    with gl.attributes( GL_VIEWPORT_BIT ):
+        glViewport( 0, 0, 100, 100 )
+    """
+    glPushAttrib( attributes )
+    yield
+    glPopAttrib()
+
+@contextmanager
+def begin( mode ):
+    """Wraps glBegin and glEnd in a
+    context manager, providing the 'with'
+    keyword.
+
+    For example:
+    with gl.begin( GL_TRIANGLES ):
+        glVertex2f( 0.0, 0.0 )
+        glVertex2f( 0.5, 1.0 )
+        glVertex2f( 1.0, 0.0 )
+    """
+    glBegin( mode )
+    yield
+    glEnd()
+
+