X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fcore%2Fbuffer.h;h=66eb8d41fc44e76c91eddc4865b2a2f1dcb43c9d;hb=c356a20547afae97b412da36e0b0a7d51e879401;hp=b642738e0e96ef370a5e748701be071998e2de54;hpb=190a7e11237351f6b730c28f7b16f183e8adc69c;p=libs%2Fgl.git

diff --git a/source/core/buffer.h b/source/core/buffer.h
index b642738e..66eb8d41 100644
--- a/source/core/buffer.h
+++ b/source/core/buffer.h
@@ -15,6 +15,12 @@ public:
 	virtual ~buffer_too_small() throw() { }
 };
 
+enum BufferUsage
+{
+	STATIC,
+	STREAMING
+};
+
 /**
 Stores data in GPU memory.
 
@@ -22,6 +28,10 @@ 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.
 */
@@ -29,13 +39,45 @@ class Buffer: public BufferBackend
 {
 	friend BufferBackend;
 
+public:
+	/**
+	An RAII handle for asynchronously writing data into a buffer.
+	*/
+	class AsyncTransfer: public NonCopyable
+	{
+		friend BufferBackend;
+		friend class Buffer;
+
+	private:
+		Buffer &buffer;
+		std::size_t offset = 0;
+		std::size_t size = 0;
+		void *dest_addr = 0;
+
+		AsyncTransfer(Buffer &, std::size_t, std::size_t);
+	public:
+		AsyncTransfer(AsyncTransfer &&);
+		~AsyncTransfer();
+
+	private:
+		void allocate();
+		void finalize();
+
+	public:
+		/** Returns an address for writing the data.  It should not be used
+		beyond the lifetime of the object. */
+		void *get_address() { return dest_addr; }
+	};
+
 private:
 	std::size_t size = 0;
+	BufferUsage usage = STATIC;
+	bool mapped = false;
 
 public:
-	/** Sets the storage size and allocates memory for the buffer.  Size 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);
 
 	/** Replaces contents of the entire buffer.  Allocated storage must exist.
 	The data must have size matching the defined storage. */
@@ -45,12 +87,24 @@ public:
 	The range must be fully inside the buffer. */
 	void sub_data(std::size_t, std::size_t, const void *);
 
+	/** Creates an asynchronous transfer for writing data to a range of bytes in
+	the buffer.  While the transfer is pending, the state of the buffer region
+	is indeterminate. */
+	AsyncTransfer sub_data_async(std::size_t, std::size_t);
+
+private:
+	void check_sub_data(std::size_t, std::size_t, const char *);
+
+public:
 	std::size_t get_size() const { return size; }
+	using BufferBackend::get_multiplicity;
+	std::size_t get_total_size() const { return size*get_multiplicity(); }
+	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;
 };