Update documentation a bit.

5 files changed, 61 insertions, 28 deletions

diff --git a/doc/api/init.texi b/doc/api/init.texi
index 14eff4b..7060d1d 100644
--- a/doc/api/init.texi
+++ b/doc/api/init.texi
@@ -15,6 +15,7 @@
 
 Sly uses the windowing features of SDL 1.2 under the hood, which
 currently restricts Sly applications to using only a single window.
+SDL2 support will come in a future release.
 
 The window data structure:
 
diff --git a/doc/api/input.texi b/doc/api/input.texi
index 3a4e6a3..02a42d0 100644
--- a/doc/api/input.texi
+++ b/doc/api/input.texi
@@ -8,7 +8,7 @@ events (@pxref{Signals}).
 @menu
 * Keyboard::                    Clack clack.
 * Mouse::                       Exercise the rodent.
-* Joystick::                    Wee!
+* Joystick::                    Arcade-style fun.
 @end menu
 
 @node Keyboard
diff --git a/doc/api/math.texi b/doc/api/math.texi
index 8102e04..9582ea7 100644
--- a/doc/api/math.texi
+++ b/doc/api/math.texi
@@ -159,23 +159,23 @@ dimensions (@var{width}, @var{height}).
 Rectangle with @code{x}, @code{y}, @code{width}, and @code{height} of 0.
 @end defvr
 
-@deffn {Scheme Macro} rect? @var{obj}
+@deffn {Scheme Syntax} rect? @var{obj}
 Return @code{#t} if @var{obj} is a rectangle.
 @end deffn
 
-@deffn {Scheme Macro} rect-x @var{rect}
+@deffn {Scheme Syntax} rect-x @var{rect}
 Return the x coordinate of @var{rect}.
 @end deffn
 
-@deffn {Scheme Macro} rect-y @var{rect}
+@deffn {Scheme Syntax} rect-y @var{rect}
 Return the x coordinate of @var{rect}.
 @end deffn
 
-@deffn {Scheme Macro} rect-width @var{rect}
+@deffn {Scheme Syntax} rect-width @var{rect}
 Return the width of @var{rect}.
 @end deffn
 
-@deffn {Scheme Macro} rect-height @var{rect}
+@deffn {Scheme Syntax} rect-height @var{rect}
 Return the height of @var{rect}.
 @end deffn
 
@@ -311,11 +311,11 @@ A transform composed entirely of zeroes.
 The multiplicative identity transform.
 @end defvr
 
-@deffn {Scheme Macro} transform? @var{obj}
+@deffn {Scheme Syntax} transform? @var{obj}
 Return @code{#t} if @var{obj} is a transform.
 @end deffn
 
-@deffn {Scheme Macro} transform-matrix @var{transform}
+@deffn {Scheme Syntax} transform-matrix @var{transform}
 Return the underlying 4x4 floating point array for @var{transform}.
 @end deffn
 
@@ -527,23 +527,23 @@ an angle @var{theta}) or from individual coordinates @var{w}, @var{x},
 Alternate spelling of @code{make-quaternion}.
 @end deffn
 
-@deffn {Scheme Macro} quaternion? @var{obj}
+@deffn {Scheme Syntax} quaternion? @var{obj}
 Return @code{#t} if @var{obj} is a quaternion.
 @end deffn
 
-@deffn {Scheme Macro} quaternion-w @var{q}
+@deffn {Scheme Syntax} quaternion-w @var{q}
 Return the w coordinate of the quaternion @var{q}.
 @end deffn
 
-@deffn {Scheme Macro} quaternion-x @var{q}
+@deffn {Scheme Syntax} quaternion-x @var{q}
 Return the x coordinate of the quaternion @var{q}.
 @end deffn
 
-@deffn {Scheme Macro} quaternion-y @var{q}
+@deffn {Scheme Syntax} quaternion-y @var{q}
 Return the y coordinate of the quaternion @var{q}.
 @end deffn
 
-@deffn {Scheme Macro} quaternion-z @var{q}
+@deffn {Scheme Syntax} quaternion-z @var{q}
 Return the z coordinate of the quaternion @var{q}.
 @end deffn
 
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
diff --git a/doc/api/signals.texi b/doc/api/signals.texi
index 9f674e1..0d8c589 100644
--- a/doc/api/signals.texi
+++ b/doc/api/signals.texi
@@ -8,7 +8,7 @@ number of callback procedures are registered to respond to events
 which mutate the relevant data structures.  However, this approach,
 while simple and effective, comes at the price of readability,
 reproducibility, and expression.  Instead of explicitly mutating data
-and entering ``callback hell'', Sly abstracts and formalizes the
+and entering ``callback hell,'' Sly abstracts and formalizes the
 process using a functional reactive programming style.
 
 In Sly, time-varying values are called ``signals'', and they are
@@ -34,7 +34,8 @@ player move faster.  Finally, the scaled vector is added to the
 previous player position via @code{signal-fold}.  The player's
 position is at (320, 240) initially.  As you can see, there are no
 callbacks and explicit mutation needed, and the position seems to
-magically change with the passage of time.
+magically change with the passage of time and pushing of the arrow
+keys.
 
 @deffn {Scheme Procedure} signal? @var{obj}
 Return @code{#t} if @var{obj} is a signal.