diff --git a/ag.cc b/ag.cc
index b2a925e..08f93b0 100644
--- a/ag.cc
+++ b/ag.cc
@@ -23,11 +23,14 @@ namespace ag
         static const luaL_Reg functions[] = {
             { "clearEventHandler", clearEventHandler },
             { "doPhysics", doPhysics },
+            { "drawLine", drawLine },
             { "drawObjects", drawObjects },
+            { "drawRect", drawRect },
             { "drawText", drawText },
             { "elapsedTime", elapsedTime },
             { "endFrame", endFrame },
             { "exit", exit },
+            { "fillRect", fillRect },
             { "getCamera", getCamera },
             { "getScreenSize", getScreenSize },
             { "getTextSize", getTextSize },
diff --git a/doc/index.html b/doc/index.html
index 154d669..1eb7394 100644
--- a/doc/index.html
+++ b/doc/index.html
@@ -64,6 +64,20 @@ mode is enabled; this mode is enabled by default.
 See <a href="#ag_setAutoPhysics">setAutoPhysics</a> for more information.
 </p>
 
+<a name="ag_drawLine" />
+<h3>drawLine</h3>
+<p><tt>ag.drawLine(r, g, b, x1, y1, x2, y2 [, width])</tt></p>
+<p>
+This function tells the engine to draw a line to the screen.
+The color of the line is given by (r, g, b).
+The start and end coordinates of the line are (x1, y1) and (x2, y2).
+<tt>width</tt> is an optional parameter and defaults to 1 if not
+specified.
+It controls the width of the line to be drawn.
+<tt>drawLine()</tt> should normally be called from the
+<tt>update_overlay</tt> event handler.
+</p>
+
 <a name="ag_drawObjects" />
 <h3>drawObjects</h3>
 <p><tt>ag.drawObjects()</tt></p>
@@ -75,6 +89,31 @@ See <a href="#ag_setAutoDrawObjects">setAutoDrawObjects</a>
 for more information.
 </p>
 
+<a name="ag_drawRect" />
+<h3>drawRect</h3>
+<p><tt>ag.drawRect(r, g, b, width, height, x, y [, rot])</tt></p>
+<p>
+This function draws a rectangle to the screen.
+The color of the rectangle is given by (r, g, b).
+The size is given by <tt>width</tt> and <tt>height</tt>.
+The center of the rectangle is given by (x, y).
+<tt>rot</tt> is an optional parameter that defaults to 0.0.
+It specifies the rotation of the rectangle.
+<tt>drawRect()</tt> should normally be called from the
+<tt>update_overlay</tt> event handler.
+</p>
+
+<a name="ag_drawText" />
+<h3>drawText</h3>
+<p><tt>ag.drawText(message, r, g, b, ptsize, x, y)</tt></p>
+<p>
+This function draws the text <tt>message</tt>, which should be
+a string, to the screen at position (x, y), with color
+specified by (r, g, b), and with font size <tt>ptsize</tt>.
+It should normally be called from the <tt>update_overlay</tt>
+event handler.
+</p>
+
 <a name="ag_elapsedTime" />
 <h3>elapsedTime</h3>
 <p><tt>elapsed_msec = ag.elapsedTime()</tt></p>
@@ -107,6 +146,20 @@ will be executed and callbacks to other events may still be called.
 The engine should exit within one update step.
 </p>
 
+<a name="ag_fillRect" />
+<h3>fillRect</h3>
+<p><tt>ag.fillRect(r, g, b, width, height, x, y [, rot])</tt></p>
+<p>
+This function draws a solid, filled rectangle to the screen.
+The color of the rectangle is given by (r, g, b).
+The size is given by <tt>width</tt> and <tt>height</tt>.
+The center of the rectangle is given by (x, y).
+<tt>rot</tt> is an optional parameter that defaults to 0.0.
+It specifies the rotation of the rectangle.
+<tt>fillRect()</tt> should normally be called from the
+<tt>update_overlay</tt> event handler.
+</p>
+
 <a name="ag_getCamera" />
 <h3>getCamera</h3>
 <p><tt>eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z = ag.getCamera()</tt></p>
@@ -116,6 +169,15 @@ focus position (center coordinates), and up vector for the current
 camera settings.
 </p>
 
+<a name="ag_getTextSize" />
+<h3>getTextSize</h3>
+<p><tt>width, height = ag.getTextSize(message, ptsize)</tt></p>
+<p>
+This function returns the width and height, in pixels, that
+the text specified by <tt>message</tt>, which should be a string,
+would take when drawn to the screen using font size <tt>ptsize</tt>.
+</p>
+
 <a name="ag_getScreenSize" />
 <h3>getScreenSize</h3>
 <p><tt>width, height = ag.getScreenSize()</tt></p>