From efb13bfd786b58179713e81f70497e0c01a498e1 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 9 Nov 2015 22:16:21 -0500
Subject: Update documentation a bit.

---
 doc/api/rendering.texi | 57 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 44 insertions(+), 13 deletions(-)

(limited to 'doc/api/rendering.texi')

diff --git a/doc/api/rendering.texi b/doc/api/rendering.texi
index 364d09c..236863d 100644
--- a/doc/api/rendering.texi
+++ b/doc/api/rendering.texi
@@ -1,8 +1,14 @@
 @node Rendering
 @section Rendering
 
+Keeping with the theme of declarative and functional code, Sly's
+rendering module provide a purely functional interface to the
+imperative world of OpenGL.  An abstraction on top of OpenGL known as
+``render combinators'' provide a convenient way to describe and
+compose rendering pipelines.
+
 @menu
-* Scene Graph::                 Declarative rendering.
+* Render Combinators::          Purely functional rendering API.
 * Sprites::                     2D textured rectangles.
 * Textures::                    Pixel arrays.
 * Fonts::                       Font loading and text rendering.
@@ -10,25 +16,47 @@
 * Cameras::                     Defining a viewpoint.
 * Colors::                      Pretty colors.
 * Framebuffers::                Offscreen rendering.
+* Shaders::                     Programs that run on the GPU.
 @end menu
 
-@node Scene Graph
-@subsection Scene Graph
-
-@menu
-* Models::                      Renderable objects.
-* Groups::                      Transformation hierarchy.
-@end menu
-
-@node Models
-@subsubsection Models
+@node Render Combinators
+@subsection Render Combinators
 
-@node Groups
-@subsubsection Groups
+Render combinators provide a purely functional interface to the OpenGL
+state machine.
 
 @node Sprites
 @subsection Sprites
 
+@deffn {Scheme Procedure} make-sprite @var{texture} [#:anchor]
+Create a sprite that displays the image in @var{texture}.  The size of
+the mesh is the size of @var{texture} in pixels.  @var{anchor} defines
+the origin of the sprite.  By default, the anchor is @code{center},
+which puts the origin in the middle of the sprite.  See
+'anchor-texture' for more anchoring options.
+@end deffn
+
+@deffn {Scheme Procedure} load-sprite @var{file} [#:anchor]
+Create a sprite from the texture in @var{file} whose origin is defined
+by @var{anchor}.  The default anchor is @code{center}.
+@end deffn
+
+@deffn {Scheme Syntax} sprite? @var{obj}
+Return @code{#t} if @var{obj} is a sprite.
+@end deffn
+
+@deffn {Scheme Syntax} sprite-texture @var{sprite}
+Return the texture for @var{sprite}.
+@end deffn
+
+@deffn {Scheme Syntax} sprite-mesh @var{mesh}
+Return the mesh for @var{sprite}.
+@end deffn
+
+@deffn {Scheme Procedure} render-sprite @var{sprite}
+Create a renderer for @var{sprite}.
+@end deffn
+
 @node Textures
 @subsection Textures
 
@@ -46,3 +74,6 @@
 
 @node Framebuffers
 @subsection Framebuffers
+
+@node Shaders
+@subsection Shaders
-- 
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