updated Buffer base class

include/ACGL/OpenGL/Objects/Buffer.hh

@@ -31,46 +31,100 @@
 namespace ACGL{
 namespace OpenGL{
 
-class Buffer
-{
-    ACGL_NOT_COPYABLE(Buffer)
 
-    // ========================================================================================================= \/
-    // ============================================================================================ CONSTRUCTORS \/
-    // ========================================================================================================= \/
+/*
+ * A minimal(!) wrapper to allow multiple Buffer objects pointing to the same
+ * OpenGL resource (like an ArrayBuffer and a TransformFeedbackBuffer).
+ *
+ * This has to be an extra object so all Buffer types can inherit from Buffer
+ * below to allow a unified API.
+ */
+class BufferObject {
 public:
-    Buffer(void) :   mLastTarget(GL_INVALID_VALUE), mObjectName(0)
+    BufferObject()
     {
         glGenBuffers(1, &mObjectName);
+        if (openGLCriticalErrorOccured() ) {
+            ACGL::Utils::error() << "could not generate buffer!" << std::endl;
+            mObjectName = 0;
+            return;
+        }
     }
 
-    virtual ~Buffer(void)
+    ~BufferObject(void)
     {
         // buffer 0 will get ignored by OpenGL
         glDeleteBuffers(1, &mObjectName);
     }
+    GLuint mObjectName;
+};
+typedef std::tr1::shared_ptr<BufferObject> SharedBufferObject;
+
+
+/**
+ * Buffers are general OpenGL Buffer Wrapper.
+ * The OpenGL resource itself is attached via a shared pointer (GLBufferObject).
+ * This was multiple Buffers can use internaly the same OpenGL resource, this is
+ * useful if one resource should get interpreted as _different_ buffer types
+ * so in that case the same GLBufferObject will get attached to different
+ * Subclass Objects.
+ *
+ * Note: Subclasses should set the mTarget in there constructors!
+ */
+class Buffer
+{
+    // ========================================================================================================= \/
+    // ============================================================================================ CONSTRUCTORS \/
+    // ========================================================================================================= \/
+public:
+    //! Most common default: a new Buffer corresponds to a new GL resource. You might decide on a binding point
+    //! now or later.
+    Buffer( GLenum _target ) : mTarget(_target)
+    {
+        mBuffer = SharedBufferObject( new BufferObject() );
+    }
+
+    /**
+     * Init with a given, external GL resource.
+     *
+     * Calling this with:
+     * Buffer b( SharedGLBufferObject(NULL) );
+     * Is the way to _explicitly_ state that a real OpenGL resource will get added later.
+     * In this case no GL wrapper calls should ever get called until one gets set!
+     */
+    Buffer( SharedBufferObject _pBuffer, GLenum _target )
+        : mTarget(_target),
+          mBuffer( _pBuffer )
+    {}
 
     // ==================================================================================================== \/
     // ============================================================================================ GETTERS \/
     // ==================================================================================================== \/
 public:
-    inline GLuint operator()    (void) const { return mObjectName; }
-    inline GLuint getObjectName (void) const { return mObjectName; }
-    inline bool   isValid       (void) const { return glIsBuffer( mObjectName ); }
+    inline GLuint getObjectName (void) const { return mBuffer->mObjectName; }
+    inline bool   isValid       (void) const { return (mBuffer && glIsBuffer( mBuffer->mObjectName ) ); }
+    inline SharedBufferObject getBufferObject () const { return mBuffer; }
+
+    // ==================================================================================================== \/
+    // ============================================================================================ SETTERS \/
+    // ==================================================================================================== \/
+
+    //! the GL buffer can get changed at any time
+    void setBufferObject( SharedBufferObject _pBuffer ) { mBuffer = _pBuffer; }
 
 private:
     inline GLint getParameter( GLenum _parameter ) {
-        bind( mLastTarget );
+        bind( mTarget );
         GLint value;
-        glGetBufferParameteriv( mLastTarget, _parameter, &value );
+        glGetBufferParameteriv( mTarget, _parameter, &value );
         return value;
     }
 
 #if (ACGL_OPENGL_VERSION >= 32)
     inline GLint64 getParameter64( GLenum _parameter ) {
-        bind( mLastTarget );
+        bind( mTarget );
         GLint64 value;
-        glGetBufferParameteri64v( mLastTarget, _parameter, &value );
+        glGetBufferParameteri64v( mTarget, _parameter, &value );
         return value;
     }
 
@@ -89,8 +143,6 @@ private:
     inline GLint     getAccessFlags() { return (GLint)     getParameter  ( GL_BUFFER_ACCESS_FLAGS ); }
     inline GLboolean isMapped()       { return (GLboolean) getParameter  ( GL_BUFFER_MAPPED       ); }
 
-
-
     // ===================================================================================================== \/
     // ============================================================================================ WRAPPERS \/
     // ===================================================================================================== \/
@@ -98,15 +150,14 @@ public:
     //! Bind this buffer
     inline void bind( GLenum _target )
     {
-        glBindBuffer( _target, mObjectName );
+        glBindBuffer( _target, mBuffer->mObjectName );
         openGLRareError();
-        mLastTarget = _target;
     }
 
-    //! Bind this buffer to its last target
+    //! Bind this buffer to its target
     inline void bind()
     {
-        glBindBuffer( mLastTarget, mObjectName );
+        glBindBuffer( mTarget, mBuffer->mObjectName );
         openGLRareError();
     }
 
@@ -120,7 +171,7 @@ public:
 
     //! Set data for this buffer at the last used target. Use only to init the buffer!
     inline void setData( GLsizeiptr _size, const GLvoid *_pData = NULL, GLenum _usage = GL_STATIC_DRAW ) {
-        setData( mLastTarget, _size, _pData, _usage );
+        setData( mTarget, _size, _pData, _usage );
     }
 
     //! Use this to modify the buffer
@@ -133,7 +184,7 @@ public:
 
     //! Use this to modify the buffer
     inline void setSubData( GLintptr _offset, GLsizeiptr _size, const GLvoid *_pData ) {
-        setSubData( mLastTarget, _offset, _size, _pData );
+        setSubData( mTarget, _offset, _size, _pData );
     }
 
 
@@ -154,7 +205,7 @@ public:
     }
 
     inline GLvoid *mapRange( GLintptr _offset, GLsizeiptr _length, GLbitfield _access ) {
-        return mapRange( mLastTarget, _offset, _length, _access );
+        return mapRange( mTarget, _offset, _length, _access );
     }
 
     /**
@@ -173,7 +224,7 @@ public:
     }
 
     inline void flushMappedRange( GLintptr _offset, GLsizeiptr _length ) {
-        flushMappedRange( mLastTarget, _offset, _length );
+        flushMappedRange( mTarget, _offset, _length );
     }
 
     // TODO: bindBufferRange
@@ -189,7 +240,7 @@ public:
         return ret;
     }
     inline GLvoid *map( GLenum _access ) {
-        return map( mLastTarget, _access );
+        return map( mTarget, _access );
     }
 
     GLboolean unmap( GLenum _target ) {
@@ -200,7 +251,7 @@ public:
     }
 
     inline GLboolean unmap() {
-        return unmap( mLastTarget );
+        return unmap( mTarget );
     }
 
     // TODO: CopyBufferSubData
@@ -218,19 +269,30 @@ public:
         GL_TEXTURE_BUFFER
         GL_TRANSFORM_FEEDBACK_BUFFER
         GL_UNIFORM_BUFFER
-     * Can be changed at any time. Will get changed if a _target gets specified at any call.
+     * Can be changed at any time.
+     *
+     * Subclasses should overload this with a non-working function (+ a warning)
+     * because an X-Buffer should not be attached _per default_ to Y!
+     * Subclass buffers can however always use the method calls / binds with an
+     * _explicit_ target (that doesn't match there one ones):
+     *
+     * XBuffer x;
+     * x.bind( Y ); // ok, hope the programmer knowns what s/he does
+     *
+     * x.setTarget( Y ); // this is just calling for unintended side-effects!
+     * x.bind();
      */
-    inline void setTarget( GLenum _target ) { mLastTarget = _target; }
+    virtual inline void setTarget( GLenum _target ) { mTarget = _target; }
 
     // =================================================================================================== \/
     // ============================================================================================ FIELDS \/
     // =================================================================================================== \/
 protected:
-    GLenum       mLastTarget;
-    GLuint       mObjectName;
+    GLenum             mTarget;
+    SharedBufferObject mBuffer;
 };
 
-ACGL_SHARED_TYPEDEF(ArrayBuffer)
+ACGL_SHARED_TYPEDEF(Buffer)
 
 } // OpenGL
 } // ACGL