added some comments, clean up, less redundant code

include/ACGL/OpenGL/Objects/ArrayBuffer.hh

@@ -6,6 +6,24 @@
 #ifndef ACGL_OPENGL_OBJECTS_ARRAYBUFFER_HH
 #define ACGL_OPENGL_OBJECTS_ARRAYBUFFER_HH
 
+/*
+ * An ArrayBuffer holds an array of per-vertex data. In its simplest form an
+ * array of one attribute, for example the vertex position or texture-coordinate.
+ * An ArrayBuffer however can also hold multiple attributes in an interleaved
+ * way.
+ *
+ * An ArrayBuffer can be drawn directly or indexed in combination with an
+ * ElementArrayBuffer.
+ *
+ * The combination of (multiple) attributes of (multiple) ArrayBuffers
+ * and one (optional) ElementArrayBuffer is a VertexBufferObject or VertexArrayObject.
+ *
+ * Note: In some documents ArrayBuffers (and sometimes ElementArrayBuffers) are
+ *       called VertexBufferObjects, VBOs. The original extension that introduced
+ *       these two new buffer types was called ARB_vertex_buffer_object but the buffers
+ *       itself are called ArrayBuffer and ElementArrayBuffer.
+ */
+
 #include <ACGL/ACGL.hh>
 
 #include <ACGL/Base/Macros.hh>
@@ -153,44 +171,33 @@ public:
 
         setAttributePointer(index, _indexInShader);
         return true;
-    }
+    }    
 
-    //! Set data for this buffer
-    //! Note: The function is not const, because it changes the corresponding GPU data
-    inline void setData(const GLvoid* _pData)
+    //! Set data for this buffer and change its size, usage and mode
+    inline void setData(
+        const GLvoid* _pData,
+        GLsizei       _elements,
+        GLenum        _usage,
+        GLenum        _mode)
     {
-        glBindBuffer(GL_ARRAY_BUFFER, mContext);
-        glBufferData(
-            GL_ARRAY_BUFFER,
-            mStride * mElements,
-            _pData,
-            mUsage);
+        mUsage = _usage;
+        mMode  = _mode;
+        setData( _pData, _elements );
     }
 
     //! Set data for this buffer and change its size
     inline void setData(
         const GLvoid* _pData,
-        GLsizei _elements)
+        GLsizei       _elements)
     {
         mElements = _elements;
-        glBindBuffer(GL_ARRAY_BUFFER, mContext);
-        glBufferData(
-            GL_ARRAY_BUFFER,
-            mStride * mElements,
-            _pData,
-            mUsage);
+        setData( _pData );
     }
 
-    //! Set data for this buffer and change its size
-    inline void setData(
-        const GLvoid* _pData,
-        GLsizei _elements,
-        GLenum _usage,
-        GLenum _mode)
+    //! Set data for this buffer
+    //! Note: The function is not const, because it changes the corresponding GPU data
+    inline void setData(const GLvoid* _pData)
     {
-        mElements = _elements;
-        mUsage = _usage;
-        mMode = _mode;
         glBindBuffer(GL_ARRAY_BUFFER, mContext);
         glBufferData(
             GL_ARRAY_BUFFER,

include/ACGL/OpenGL/Objects/ElementArrayBuffer.hh

@@ -6,6 +6,20 @@
 #ifndef ACGL_OPENGL_OBJECTS_ELEMENTBUFFERDATA_HH
 #define ACGL_OPENGL_OBJECTS_ELEMENTBUFFERDATA_HH
 
+/*
+ * An ElementArrayBuffer is an index into ArrayBuffers and defines which
+ * elements of that array should be drawn in which order.
+ *
+ * The combination of (multiple) attributes of (multiple) ArrayBuffers
+ * and one (optional) ElementArrayBuffer is a VertexBufferObject or VertexArrayObject.
+ *
+ * Note: In some documents ElementArrayBuffer are called VertexBufferObjects, VBOs
+ *       or IndexBufferObjects (IBOs). But ArrayBuffers can also be called VBOs...
+ *       The original extension that introduced these two new buffer types was called
+ *       ARB_vertex_buffer_object but the buffers itself are called ArrayBuffer and
+ *       ElementArrayBuffer.
+ */
+
 #include <ACGL/ACGL.hh>
 
 #include <ACGL/Base/Macros.hh>
@@ -27,8 +41,8 @@ class ElementArrayBuffer
 public:
     ElementArrayBuffer(
         GLenum _usage = GL_STATIC_DRAW,
-        GLenum _mode = GL_TRIANGLES,
-        GLenum _type = GL_UNSIGNED_INT)
+        GLenum _mode  = GL_TRIANGLES,
+        GLenum _type  = GL_UNSIGNED_INT)
     :   mContext(0),
         mUsage(_usage),
         mMode(_mode),
@@ -96,30 +110,26 @@ public:
     }
 
     //! Set data for this buffer
-    //! Note: The function is not const, because it changes the corresponding GPU data
     inline void setData(
-        const GLvoid* _pData)
+        const GLvoid* _pData,
+        GLsizei _elements)
     {
-        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mContext);
-        glBufferData(
-            GL_ELEMENT_ARRAY_BUFFER,
-            mElements * mSizeOfType,
-            _pData,
-            mUsage);
+        mElements = _elements;
+        setData( _pData );
     }
 
     //! Set data for this buffer
+    //! Note: The function is not const, because it changes the corresponding GPU data
     inline void setData(
-        const GLvoid* _pData,
-        GLsizei _elements)
+        const GLvoid* _pData)
     {
-        mElements = _elements;
         glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mContext);
         glBufferData(
             GL_ELEMENT_ARRAY_BUFFER,
             mElements * mSizeOfType,
             _pData,
             mUsage);
+        openGLRareError();
     }
 
     // =================================================================================================== \/

include/ACGL/OpenGL/Objects/VertexBufferObject.hh

@@ -6,6 +6,14 @@
 #ifndef ACGL_OPENGL_OBJECTS_VERTEXBUFFEROBJECT_HH
 #define ACGL_OPENGL_OBJECTS_VERTEXBUFFEROBJECT_HH
 
+/*
+ * A VertexBufferObject combines the two tightly related buffers from the
+ * ARB_vertex_buffer_object extension.
+ *
+ * M Attributes from N ArrayBuffer and one (optional) ElementArrayBuffer form
+ * one VertexBufferObject.
+ */
+
 #include <ACGL/ACGL.hh>
 
 #include <ACGL/Base/Macros.hh>
@@ -124,7 +132,7 @@ public:
         enable();
         draw();
         disable();
-    };
+    }
 
     void drawElements(void) const
     {
@@ -160,5 +168,4 @@ ACGL_SHARED_TYPEDEF(VertexBufferObject)
 
 } // OpenGL
 } // ACGL
-
 #endif // ACGL_OPENGL_OBJECTS_VERTEXBUFFEROBJECT_HH