diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6a329fd..e31c043 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 project("Simple Raytracer" C)
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.3)
 
 if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE "Debug")
@@ -14,6 +14,26 @@ if (CMAKE_BUILD_TYPE MATCHES Debug)
     add_link_options(--coverage)
 endif()
 
+find_package( Doxygen )
+
+if ( DOXYGEN_FOUND )
+  set( DOXYGEN_EXCLUDE_PATTERNS
+    */test/*
+    */main/*
+    */external/* )
+
+  set( DOXYGEN_OUTPUT_DIRECTORY doxygen )
+  set( DOXYGEN_EXTRACT_ALL YES )
+  set( DOXYGEN_OPTIMIZE_OUTPUT_FOR_C YES )
+
+  doxygen_add_docs( doxygen "${CMAKE_CURRENT_SOURCE_DIR}" )
+
+else()
+
+  message( "Doxygen need to be installed to generate the doxygen documentation" )
+
+endif()
+
 add_subdirectory(module_math)
 add_subdirectory(module_datastructures)
 add_subdirectory(module_shapes)
diff --git a/module_shapes/cone.h b/module_shapes/cone.h
index f3f9d97..ac3ddca 100644
--- a/module_shapes/cone.h
+++ b/module_shapes/cone.h
@@ -3,6 +3,9 @@
 
 #include "cylinder.h"
 
+/**
+ * \extends CYLINDER_Cylinder
+ */
 typedef CYLINDER_Cylinder CONE_Cone;
 
 const SHAPE_vtable CONE_vtable;
diff --git a/module_shapes/cube.h b/module_shapes/cube.h
index 8eeeb2f..729aec7 100644
--- a/module_shapes/cube.h
+++ b/module_shapes/cube.h
@@ -4,6 +4,9 @@
 #include "ray.h"
 #include "shape.h"
 
+/**
+ * \extends SHAPE_Shape
+ */
 typedef SHAPE_Shape CUBE_Cube;
 const SHAPE_vtable CUBE_vtable;
 
diff --git a/module_shapes/cylinder.h b/module_shapes/cylinder.h
index c9d7d84..917f114 100644
--- a/module_shapes/cylinder.h
+++ b/module_shapes/cylinder.h
@@ -4,6 +4,10 @@
 #include "ray.h"
 #include "shape.h"
 
+
+/**
+ * \extends SHAPE_Shape
+ */
 typedef struct CYLINDER_Cylinder {
     SHAPE_Shape shape;
     double minimum, maximum;
diff --git a/module_shapes/group.c b/module_shapes/group.c
index e9a110f..e886519 100644
--- a/module_shapes/group.c
+++ b/module_shapes/group.c
@@ -23,7 +23,7 @@ void GROUP_init(GROUP_Group* group) {
     group->list = ARRLIST_new();
 }
 
-void delete_subshape(void* void_shape, void* context) {
+static void delete_subshape(void* void_shape, void* context) {
     assert(void_shape);
     UNUSED(context);
     SHAPE_Shape* shape = (SHAPE_Shape*) void_shape;
@@ -65,7 +65,7 @@ typedef struct check_shape_context {
     RAY_Intersections* intersections;
 } check_shape_context;
 
-void check_shape(void* void_shape, void* void_context) {
+static void check_shape(void* void_shape, void* void_context) {
     check_shape_context* c = (check_shape_context*) void_context;
     SHAPE_Shape* shape = (SHAPE_Shape*) void_shape;
     SHAPE_intersect(c->intersections, shape, c->local_ray);
diff --git a/module_shapes/group.h b/module_shapes/group.h
index 060adc7..8fe60d3 100644
--- a/module_shapes/group.h
+++ b/module_shapes/group.h
@@ -18,6 +18,13 @@ void GROUP_destroy(GROUP_Group* group);
 void GROUP_delete(GROUP_Group* group);
 void GROUP_delete_shape(SHAPE_Shape* shape);
 
+/**
+ * \pure This function should never be called...it should be overridden by the members of the group.
+ * @param local_normal
+ * @param group
+ * @param local_point
+ * @param hit
+ */
 void GROUP_local_normal_at(TUPLES_Vector* local_normal, SHAPE_Shape* group, const TUPLES_Point* local_point, const RAY_Xs* hit);
 void GROUP_local_intersect(RAY_Intersections* intersections, SHAPE_Shape* group, const RAY_Ray* local_ray);
 
diff --git a/module_shapes/plane.h b/module_shapes/plane.h
index 9d7b8a3..7ef3362 100644
--- a/module_shapes/plane.h
+++ b/module_shapes/plane.h
@@ -4,7 +4,11 @@
 #include <ray.h>
 #include "shape.h"
 
+/**
+ * \extends SHAPE_Shape
+ */
 typedef SHAPE_Shape PLANE_Plane;
+
 const SHAPE_vtable PLANE_vtable;
 
 #define PLANE_new() (PLANE_Plane*)SHAPE_new(&PLANE_vtable)
diff --git a/module_shapes/sphere.h b/module_shapes/sphere.h
index c04a460..e12b700 100644
--- a/module_shapes/sphere.h
+++ b/module_shapes/sphere.h
@@ -5,7 +5,11 @@
 #include "material.h"
 #include "shape.h"
 
+/**
+ * \extends SHAPE_Shape
+ */
 typedef SHAPE_Shape SPHERE_Sphere;
+
 const SHAPE_vtable SPHERE_vtable;
 
 #define SPHERE_new() (SPHERE_Sphere*)SHAPE_new(&SPHERE_vtable)
diff --git a/module_shapes/testshape.h b/module_shapes/testshape.h
index 6d393bb..63a3af5 100644
--- a/module_shapes/testshape.h
+++ b/module_shapes/testshape.h
@@ -5,6 +5,10 @@
 #include "ray.h"
 
 const SHAPE_vtable TESTSHAPE_vtable;
+
+/**
+ * \extends SHAPE_Shape
+ */
 typedef struct TESTSHAPE_TestShape {
     SHAPE_Shape parent;  /** parent class */
     double size;
diff --git a/module_shapes/triangle.h b/module_shapes/triangle.h
index e1daf99..360d278 100644
--- a/module_shapes/triangle.h
+++ b/module_shapes/triangle.h
@@ -3,12 +3,18 @@
 
 #include "shape.h"
 
+/**
+ * \extends SHAPE_Shape
+ */
 typedef struct TRIANGLE_Triangle {
     SHAPE_Shape shape;              /* Superclass */
     TUPLES_Point p1, p2, p3;        /* Corners of the triangle */
     TUPLES_Vector e1, e2, normal;   /* Two edges and the normal vector */
 } TRIANGLE_Triangle;
 
+/**
+ * \extends TRIANGLE_Triangle
+ */
 typedef struct TRIANGLE_SmoothTriangle {
     union {
         TRIANGLE_Triangle tri;