X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcore%2Fbuffer.h;h=17678fd4b4008f68a7dd2f3745916fd237526a10;hb=e98188ff6c9bba9761b71f2a69f3be7eb89ba3da;hp=810bfc1a56253e181f7cc55b5d228c3441e99fee;hpb=be6ffe96ecb4707599fe1a6f620c348760213d46;p=libs%2Fgl.git

diff --git a/source/core/buffer.h b/source/core/buffer.h
index 810bfc1a..17678fd4 100644
--- a/source/core/buffer.h
+++ b/source/core/buffer.h
@@ -15,10 +15,25 @@ public:
 	virtual ~buffer_too_small() throw() { }
 };
 
+enum BufferUsage
+{
+	STATIC,
+	STREAMING
+};
+
 /**
-A buffer for storing data in GL memory.  Putting vertex and index data in
-buffers can improve rendering performance.  The VertexArray, Mesh and
-UniformBlock classes contain built-in support for buffers.
+Stores data in GPU memory.
+
+Memory must be allocated for the buffer by calling storage().  Contents can
+then be modified either synchronously with the data() and sub_data() functions,
+or asynchronously by memory-mapping the buffer.
+
+Buffers can have a static or streaming usage pattern.  Streaming buffers can be
+memory mapped for less update overhead, but memory space is more limited.  If
+the buffer is updated only rarely, static is recommended.
+
+Applications normally don't need to deal with Buffers directly.  They're
+managed by other classes such as Mesh and ProgramData.
 */
 class Buffer: public BufferBackend
 {
@@ -26,27 +41,29 @@ class Buffer: public BufferBackend
 
 private:
 	std::size_t size = 0;
+	BufferUsage usage = STATIC;
+	bool mapped = false;
 
 public:
-	/** Defines the storage size of the buffer.  Must be called before data can
-	be uploaded.  Storage cannot be changed once set. */
-	void storage(std::size_t);
+	/** Sets storage size and usage pattern and allocates memory for the buffer.
+	Size and usage cannot be changed once set. */
+	void storage(std::size_t, BufferUsage);
 
-	/** Uploads data into the buffer, completely replacing any previous
-	contents.  Storage must be defined beforehand.  The data must have size
-	matching the defined storage. */
+	/** Replaces contents of the entire buffer.  Allocated storage must exist.
+	The data must have size matching the defined storage. */
 	void data(const void *);
 
-	/** Overwrites part of the buffer data with new data.  Storage must be
-	defined beforehand. */
+	/** Replaces a range of bytes in the buffer.  Allocated storage must exist.
+	The range must be fully inside the buffer. */
 	void sub_data(std::size_t, std::size_t, const void *);
 
 	std::size_t get_size() const { return size; }
+	BufferUsage get_usage() const { return usage; }
 
 	void require_size(std::size_t) const;
 
-	using BufferBackend::map;
-	using BufferBackend::unmap;
+	void *map();
+	bool unmap();
 
 	using BufferBackend::set_debug_name;
 };